CA2020317A1 - Fuel supply and control system for compression ignition engines - Google Patents
Fuel supply and control system for compression ignition enginesInfo
- Publication number
- CA2020317A1 CA2020317A1 CA 2020317 CA2020317A CA2020317A1 CA 2020317 A1 CA2020317 A1 CA 2020317A1 CA 2020317 CA2020317 CA 2020317 CA 2020317 A CA2020317 A CA 2020317A CA 2020317 A1 CA2020317 A1 CA 2020317A1
- Authority
- CA
- Canada
- Prior art keywords
- fuel
- engine
- principal
- pilot
- ether
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 328
- 230000006835 compression Effects 0.000 title claims abstract description 40
- 238000007906 compression Methods 0.000 title claims abstract description 40
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims abstract description 154
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 104
- 239000007788 liquid Substances 0.000 claims abstract description 63
- 238000002485 combustion reaction Methods 0.000 claims abstract description 58
- 238000002347 injection Methods 0.000 claims abstract description 44
- 239000007924 injection Substances 0.000 claims abstract description 44
- 238000009833 condensation Methods 0.000 claims abstract description 21
- 230000005494 condensation Effects 0.000 claims abstract description 21
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 230000003197 catalytic effect Effects 0.000 claims abstract description 6
- 238000006243 chemical reaction Methods 0.000 claims description 47
- 238000000034 method Methods 0.000 claims description 19
- 238000000605 extraction Methods 0.000 claims description 10
- 239000003054 catalyst Substances 0.000 claims description 9
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000000926 separation method Methods 0.000 claims description 7
- 238000003860 storage Methods 0.000 claims description 7
- 230000001133 acceleration Effects 0.000 claims description 6
- 230000000977 initiatory effect Effects 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 5
- 239000003921 oil Substances 0.000 claims description 4
- 230000033228 biological regulation Effects 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 2
- 239000010687 lubricating oil Substances 0.000 claims description 2
- 238000005374 membrane filtration Methods 0.000 claims description 2
- 238000004508 fractional distillation Methods 0.000 claims 1
- 238000003809 water extraction Methods 0.000 claims 1
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 abstract description 197
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 62
- 235000019441 ethanol Nutrition 0.000 description 61
- 239000002283 diesel fuel Substances 0.000 description 16
- 230000004048 modification Effects 0.000 description 11
- 238000012986 modification Methods 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- 239000007789 gas Substances 0.000 description 10
- 238000011161 development Methods 0.000 description 5
- 230000018109 developmental process Effects 0.000 description 5
- 230000008901 benefit Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000007792 addition Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005461 lubrication Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 125000004177 diethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 229960004756 ethanol Drugs 0.000 description 1
- 125000001033 ether group Chemical group 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- -1 methanol Chemical compound 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Classifications
-
- Y02T10/125—
Landscapes
- Output Control And Ontrol Of Special Type Engine (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Abstract
ABSTRACT OF DISCLOSURE
A fuel supply system for a single or multi-cylind-er internal combustion engine (1) of the compression ignition kind (eg a diesel engine) and including a liquid fuel injection means (2) for injecting liquid fuel into the combustion chamber(s) of the engine (1); the system employing a main supply source of liquid alcohol fuel (4) such as methanol as the principal fuel for the engine and an ether pilot fuel having a wider flammability range and lower ignition temperature than the principal alcohol fuel. Prescribed quantities of the ether pilot fuel are arranged to be delivered to the engine (1) during operation for mixing with the principal fuel (4) and ignition of the delivered pilot fuel to raise the temper-ature of the fuel mixture in the combustion chamber(s) sufficiently to enable full ignition under compression of the principal fuel. The system preferably including means for producing the ether pilot fuel from a bye-pass supply (7,8,9) of the principal liquid alcohol fuel (4) by way of a heat exchanger/catalytic convertor device 10; and including a condensation means (16,18) for removal of at least a part of any any readily condensible content of the pilot fuel before delivery to the engine (1) to permit ignition under compression of the delivered pilot fuel.
A fuel supply system for a single or multi-cylind-er internal combustion engine (1) of the compression ignition kind (eg a diesel engine) and including a liquid fuel injection means (2) for injecting liquid fuel into the combustion chamber(s) of the engine (1); the system employing a main supply source of liquid alcohol fuel (4) such as methanol as the principal fuel for the engine and an ether pilot fuel having a wider flammability range and lower ignition temperature than the principal alcohol fuel. Prescribed quantities of the ether pilot fuel are arranged to be delivered to the engine (1) during operation for mixing with the principal fuel (4) and ignition of the delivered pilot fuel to raise the temper-ature of the fuel mixture in the combustion chamber(s) sufficiently to enable full ignition under compression of the principal fuel. The system preferably including means for producing the ether pilot fuel from a bye-pass supply (7,8,9) of the principal liquid alcohol fuel (4) by way of a heat exchanger/catalytic convertor device 10; and including a condensation means (16,18) for removal of at least a part of any any readily condensible content of the pilot fuel before delivery to the engine (1) to permit ignition under compression of the delivered pilot fuel.
Description
1 ~ ~ 2 ~ 3 ~
FUEL SUPPLY AND CONTROL S~'STEM FOR COMPRESSION IGNITION ENGINES
sack~round:
This invention relates to compression ignition engines or what are commonly known as diesel en~ines,which are conven-tionally designed to operate by thecompression ignition ~
an appropriate diesel oil fuel; and to the design orconversion of such engines so as to be operable with an alternative ~uel either in full substitution of the diesel oil fuel oth-erwise employed~or at least in the substitution of a major part of such diesel oil fuel~during normal operating condit-ions of the engine.
These proposals have been made for the employment of gases and liquid alcohol fuels as alternatives for spark ignition internal combustion engines and compression ignition or 'diesel' engines; and whilst considerable success has been achieved ~ith the employment of gaseous and liquid alco-hol fuels as alternative fuels for spaxk ignition engines, and success to a lesser degree has been achieved with the gas conversion of diesel engines, proposals for operating diesel engines on a liquid alcohol fuel have not achieved the same degree of success. The ability to convert diesel engines to successEully and efficiently operate on an alcohol Euel such as a methanol is affected by the fact that such alcohol fuels do not spontaneously ignite in the combustion chamber of a t~pical diesel engine. This problem may be overcome by modification of a diesel engine to provide for spark ignition of fuel in a supplementary small combustion chamber connected to a main combustion chamber of a diesel " , ~
.
2a203~7 engine; but problems have arisen in development of this system and the system does involve substantial modifications to the basic engine and associated component design, and the adoption o~ such a system as a whole is not considered at present to be a viable commercial proposition.
Prior Art An alternative recently developed system Eor diesel en-gines has involved the proposal to employ a pilot fuel such as an ether having a wider inflammability ran~e and lower ignitior.
temperature than the principal alternative alcohol fuel, and this system forms the basis of the present invention.
Re~erence is made to United States Patent Ser.~o 4,422,42 (Norton - assignor to A.E.C.I.Limited)which relates to a device for converting an alcohol to an ether when fitted to a com-pression ignition engine,.the device comprising a heat exch-anger having an inlet to receive the alcohol and an outletin communication with thè inlet end o~ a catalytic conversion chamber which contains a catalyst for conversion o~ an alcohol to an ether. The conversion chamber has an outlet pipe to lead the ether to a cylinder of a compression ignition engine.
~lcohol is fed ~rom a storage tank along lines and direct to the cylinder and also along a line to a heat exchanger.
Surnmar~ o~ Invention Whilst the theoretical aspects disclosed in the speci-fication o~ this European patent application are basically sound, it is considered that the speci~ication and device disclosed does not go ~ar enough in providing a practical solution to e~fective and e~icient operation of a diesel engine on alcohol fuel, and it is an object of the present invention to provide further developments which are believed ,, . : .
- ' ' . , ~
.
. . . ' .
-3-t ~2~3~
to render the operation of a diesel engine on a alcohol fuel such as methanol a practical and commercially viable proposi-t-ion. Other and more particular objects and advantages of the present invention will become apparent ~rom the ensuing 5 description.
According to this invention therefore, there is provid-ed a ~uel supply system for an internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into each combustion chamber of the engine, said system comprising a supply source of liquid alcohol fuel as the principal fuel, a main fuel supply line from said supply source coupled to the fuel injection means for supply of the principal fuel to the engine, a source of supply of an ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel, and delivery means for delivering pres-cribed quantities of said pilot fuel to the engine via a condensation extraction means which removes at least part of any readily condensible content of the pilot fuel prior to delivery to the engine and mixing with inlet air in the com-bustion chamber of the engine, said pilot fuel reacting with air in the combustion chamber to ignite under compression to raise the temperature oE the fuel mixture therein and enable initiation and acceleration oE ignition under compression of said principal fuel on injection.
Preferably, the system provides that the engine is adapted or designed to operate on up to 100% alcohol fuel, and whilst a separate source of the pilot fuel can be provi-ded it is prefera~le that the pilot fuel be manufactured -4- C~2 by a conversion of a proportion of the principal alcohol fuel. Thus, the system may additionally include a secondary fuel supply line from the main or a further supply source of the principal alcohol fuel coupled to the pilot fuel delivery means for directing a proportion of said principal fuel to a reactor conversion device for at least partial conversion to an ether pilot fuel.
In another aspect of the invention there is provided a method of operating a single or multi-cylinder internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into the or each combustion chamber of the engine, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel in-jection means for injection into the engine.
b. bye-passing a quantity of the liquid alcohol fuel to a reactor conversion device for the production o an ether pilot ~uel having a wider flammability range and higher cetane number than the principal ~uel c. subjecting the ether pilot Euel to a condensation process for the removal o:E at least a part o~ any readil~ condensible content Erom the ether pilot fuel, ancl delivering prescribed quantities o~ said at least partly separated ether fuel to the engine combustion chamber(s) for ignition under pressure on the com-pression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiat-ion and acceleration of combustion of said principal , .
.
FUEL SUPPLY AND CONTROL S~'STEM FOR COMPRESSION IGNITION ENGINES
sack~round:
This invention relates to compression ignition engines or what are commonly known as diesel en~ines,which are conven-tionally designed to operate by thecompression ignition ~
an appropriate diesel oil fuel; and to the design orconversion of such engines so as to be operable with an alternative ~uel either in full substitution of the diesel oil fuel oth-erwise employed~or at least in the substitution of a major part of such diesel oil fuel~during normal operating condit-ions of the engine.
These proposals have been made for the employment of gases and liquid alcohol fuels as alternatives for spark ignition internal combustion engines and compression ignition or 'diesel' engines; and whilst considerable success has been achieved ~ith the employment of gaseous and liquid alco-hol fuels as alternative fuels for spaxk ignition engines, and success to a lesser degree has been achieved with the gas conversion of diesel engines, proposals for operating diesel engines on a liquid alcohol fuel have not achieved the same degree of success. The ability to convert diesel engines to successEully and efficiently operate on an alcohol Euel such as a methanol is affected by the fact that such alcohol fuels do not spontaneously ignite in the combustion chamber of a t~pical diesel engine. This problem may be overcome by modification of a diesel engine to provide for spark ignition of fuel in a supplementary small combustion chamber connected to a main combustion chamber of a diesel " , ~
.
2a203~7 engine; but problems have arisen in development of this system and the system does involve substantial modifications to the basic engine and associated component design, and the adoption o~ such a system as a whole is not considered at present to be a viable commercial proposition.
Prior Art An alternative recently developed system Eor diesel en-gines has involved the proposal to employ a pilot fuel such as an ether having a wider inflammability ran~e and lower ignitior.
temperature than the principal alternative alcohol fuel, and this system forms the basis of the present invention.
Re~erence is made to United States Patent Ser.~o 4,422,42 (Norton - assignor to A.E.C.I.Limited)which relates to a device for converting an alcohol to an ether when fitted to a com-pression ignition engine,.the device comprising a heat exch-anger having an inlet to receive the alcohol and an outletin communication with thè inlet end o~ a catalytic conversion chamber which contains a catalyst for conversion o~ an alcohol to an ether. The conversion chamber has an outlet pipe to lead the ether to a cylinder of a compression ignition engine.
~lcohol is fed ~rom a storage tank along lines and direct to the cylinder and also along a line to a heat exchanger.
Surnmar~ o~ Invention Whilst the theoretical aspects disclosed in the speci-fication o~ this European patent application are basically sound, it is considered that the speci~ication and device disclosed does not go ~ar enough in providing a practical solution to e~fective and e~icient operation of a diesel engine on alcohol fuel, and it is an object of the present invention to provide further developments which are believed ,, . : .
- ' ' . , ~
.
. . . ' .
-3-t ~2~3~
to render the operation of a diesel engine on a alcohol fuel such as methanol a practical and commercially viable proposi-t-ion. Other and more particular objects and advantages of the present invention will become apparent ~rom the ensuing 5 description.
According to this invention therefore, there is provid-ed a ~uel supply system for an internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into each combustion chamber of the engine, said system comprising a supply source of liquid alcohol fuel as the principal fuel, a main fuel supply line from said supply source coupled to the fuel injection means for supply of the principal fuel to the engine, a source of supply of an ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel, and delivery means for delivering pres-cribed quantities of said pilot fuel to the engine via a condensation extraction means which removes at least part of any readily condensible content of the pilot fuel prior to delivery to the engine and mixing with inlet air in the com-bustion chamber of the engine, said pilot fuel reacting with air in the combustion chamber to ignite under compression to raise the temperature oE the fuel mixture therein and enable initiation and acceleration oE ignition under compression of said principal fuel on injection.
Preferably, the system provides that the engine is adapted or designed to operate on up to 100% alcohol fuel, and whilst a separate source of the pilot fuel can be provi-ded it is prefera~le that the pilot fuel be manufactured -4- C~2 by a conversion of a proportion of the principal alcohol fuel. Thus, the system may additionally include a secondary fuel supply line from the main or a further supply source of the principal alcohol fuel coupled to the pilot fuel delivery means for directing a proportion of said principal fuel to a reactor conversion device for at least partial conversion to an ether pilot fuel.
In another aspect of the invention there is provided a method of operating a single or multi-cylinder internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into the or each combustion chamber of the engine, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel in-jection means for injection into the engine.
b. bye-passing a quantity of the liquid alcohol fuel to a reactor conversion device for the production o an ether pilot ~uel having a wider flammability range and higher cetane number than the principal ~uel c. subjecting the ether pilot Euel to a condensation process for the removal o:E at least a part o~ any readil~ condensible content Erom the ether pilot fuel, ancl delivering prescribed quantities o~ said at least partly separated ether fuel to the engine combustion chamber(s) for ignition under pressure on the com-pression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiat-ion and acceleration of combustion of said principal , .
.
2 ~
fuel during at least initial starting and/or low load operating phases of the engine.
In a further aspect there is provided a method operating a single or multi.-cylinder internal combustion engine of the compression ignition kind and having a liquid fuel injection means for injecting fuel into the or each combustion chamber, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to vapourising and reactor conversion means for the production of alcohol fuel vapourand ether pilot fuel, said ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel and alcohol fuel vapour to a condensation process for the removal of at least a part of any readily condensible content from the ekher pilot fuel and alcohol fuel vapour,and delivering prescribed quantities of the ethe~ pilot fuel and alcohol fuel vapour to the engine combustion chamber~s)for igni.tion under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol, principal fuel, to enable initiation and acceleration o~
combustion of said principal fuel during at least initial starting and/or low load operating phases'of the engine and to provide additional energy to the engine in addition to the said principal fuel under other load operating phases.
.,.
,., ' . ' ~ " .
-6- 2~2~3~
Drawings Some preferred aspects of the invention will now be described by way o~ example and with reference to the accom-panying drawings, in which:
FIGURE 1 is a schematic diagragm illustrating one first fuel supply system in accordance with the invention FIGURE 2 is a similar s~ematic diagrammatic view ill~
ustrating a modification of the invention, FIGURE 3 is a further similarsche.matic diagrammatic view illustrating a further modification or variation of the invention, and FIGURE 4 is a further schematic diagrammatic view illustrating a modification of the pilot fuel supply means.
Description of Invention Referring firstly to figure 1 of the drawings, the invention is particularly applicable to a typical compression engine or diesel engine 1 of the single or multi-cylinder kind with a reciprocating piston for each cylinder; with an injector pump 2 driven directly or indireatly by the engine 1 for the delivery of prescribed quantities o~ operat-ing fuel to the respective combustion chamber(s) defined by the cylinder(s) and piston(s). In a kypical diesel engine, the normally provided injector pump 2 is directly connected via a variable speed fuel delivery pump 3 to the diesel fuel oll supply tank and is readily capable of handling the fuel flow requirement, whereas with the employment of an alcohol such as methanol ~of lower calorific value and lower cetane number than diesel fuel) as the principal fuel, .~ . .
~. . .
... .
~ ~a2~3l7 a considerably greater injection pump capacity must be pro-vided to cope with such requirement. Having regard to the nature of an alcohol such as methanol, it is also pre~er-ably desirable to provide supplementary lubrication for the injector pump (lubrication in the normal course o~ events being provided by the diesel fuel); and thus lubricating oil may be injected into the system by means of a suitable metering pump 5 (electrically or engine driven)pumping pres-cribed quantities of oil from an oil supply source or tank 6 to the input side o~ the methanol delivery pump 3 for mixing with the methanol delivered to the injector pump 2 from the supply tank 4.
As previously indicated, whilst a separate source of pilot ether fuel can be provided for supply to the engine 1, pre~erably the main source o~ the methanol or other prin-cipal alcohol fuel is provided with a secondary or by-pass fuel line 7 which passes a ~uantity of the methanol to a controllable pilot fuel pump 8 (which can be electrically driven or driven directly or indirectly mechanically by the engine 1 e.g. by any direct or indirect couplin~ means) such that the rate of operation of the pilot fuel pump 8, and thus the ~uantity of fuel pumped thereby,is controlled and made to vary with the rate o~ delivery of the injected fuel and/or with the engine speed. The outlet line 9 from the pilot fuel pump 8 is directed to a reactor or converter device 10 in the form of a heated or heat exchanger device having a catalytic conversion chamber containing a catalyst for conversion of methanol fed thereto by way of the outlet line 9 ~o an ether fuel having a greater or wider in~lamm~
ability range than the incomin~ methanol ~uel. Preferably, the methanol fuel ls converted to a dimethylether (DME) which may be readily mixed with the inle-t air ~or the engine l to ignite under compression and initiate combustion o~ the methanol injected in the diesel engine l.
Methanol can be readily converted to DME at moderate temper-atures over a suitable dehydration catalyst, and the convers-ion device disclosed in the aforementioned United States Patent Ser.No. 4,422,412 or any other suitable reactor, conversion device or ether generator,can be employed. It is pre-ferable that the heat exchanger catalytic converter 10need not require excessively high temperatures to operate, as one pre~erred means o~ providing the heat for the heat exchanger is by way o~ utilisation of the exhaust outlet system or line 11 for the engine, the reactor or ether generator (heat exchanger catalytic converter) 10 being arranged to be direc-tly coupled to the exhaust line 11; and a study has found that an inexpensive alumina catalyst can achieve good con-version rates of methanol to DME at temperatures as low a 250C to~OOC. Heat and mass transfer calculations indicatethat only a small part o~ the heat energy available in the diesel engines exhaust system 11 is re~uired to power a continuous DME reactor.
The reactor or ether generator 10can alternatively be separate from the exhaustand beelectrically heated, but the : existing exhaust system 11 ofthe engine1provides a convenient source of otherwise wasted heat and obviates the continuing electric power draw-off of a reactor or generator converter heated and operated solely by electricity.
;~'.
2~3~ 7 It will be appreciated of course tha-t there will be no available exhaust heat for operation of the reactor or con verter ~Owhencoupled to the exhaust system11when the engine1is started from cold; and there are optional cold starting systems involving,for example:
(a) Maintaining a supply of diesel fuel ~or the engine1and using such supply for start up in the usual manner passing, the diesel oil fuel to the engine1 by way of the injector pump2;
followed by a switching over to methanol operationand operation 10 of the reactor converter 10 for supplementary supply of ether or DME pilot fuel to the engine1 when the exhaustsystem 11 has reached the desired temperature for effective operation of the reactor converter'10.
(b) A separate supply of pre-formed ether or DME can be ' 15 provided for initial mixing with the engine inlet air, followed by a switching over to the methanol supply line 7 to the pilot fuel pump 8 and reactor ~,converter 10 again once the exhaust system 11 has reached the desired temperature sufficient to operate the reactor converter 10.
(c) The reactor converter,10 canbe provided with a supplementary electrical heating element for initial warm-up and operation for conversion of the methanol to ether or DME, with the exhaust system~11t~king over the heating and conversion operation again on reaching the desired temperature. This system is however not favoured (except perhaps in the case of a stationary engine and the ability to employ mains electric power), as in~the case of a motor vehicle there would be an undesirable electric power draw-of~ ~rom the battery prior to starting; and also a time delay in starting of the engine 1.
-- ` 2~2~3~7 (d) Alterna-tively and as illustrated in -figures 1 to 3, a methanol burner device 12 can be employed, fed by a suitable methanol by-pass line 13 from the main feed line 4a from the methanol supply source and by way of a cold start solenoid valve 14. The burner 12 being coupled to or associated with the exhaust system 11 at or adjacent the reactor converter 10 so as to provide initial high temperatures to the exhaust 11, and thus reactor converter 10, for operation as required in providing the e-ther or DME in operation of the engine 1. The burner device 12 may burn other fuels.
In the process of supply of the bye-passed quantity of methanol or liquid alcohol fuel to the reactor converter device 10, and the conversion of some of that bye-passed fuel to the ether or DME pilot fuel, the heat exchanger will create water and methanol vapour (or other liquid alcohol fuel vapour) con-taining the ether or DME pilot fuel; and figure 1 illustrates a direct line 15 for passage of vapourized methanol and diethyl or dimethyl ether ~rom the reactor converter 10 to the inlet air system or manifold of the engine 1. ~Iowever,for moree~ective and eficient operation it i5 preferred that at least a part of any condensate or readily condensible content of the vapour is re-moved from the pilot fuel prior to passing into the engine 1, to enable rapi~ reaction during compression with the air in the respective combustion chamber, and raising the temperature of the injected methanol sufficiently to ignite under compression.
Accordingly, and with reference now to figure 2 of the drawings, in one arrangement a liquid separator unit 16 is interposed in .
2~2~3~
the output line 15 from the reactor converter 10 to separate out at least a part o~ the suspended liquid and readily con-densible content from the DME vapour supplied to the engine 1.
The separator 16 can be of various kinds and may simply provide for membrane filtration, or alternatively provide for ~ractional distillation, dessication or centrifugal separation. The liquid and condensate separated out thereby can be discharged by way of a by-pass line 17 into the engine exhaust system 11 at the outlet or downstream side of the reactor converter 10, and thus provide an added advantage in assisting cooling of the exhaust system 11 at the outlet side without affecting the heat required for operation of the heat exchanger forming part of the reactor converter 10. Alternatively, the extracted water and condensate (which may contain some methanol or alcohol fuel content) can be directed to a separate storage tank for possible further treat-ment;
In operation of the~reactor converter 10, not all of the methanol directed thereto by way of the pilot fuel pump 8 will at all times be converted to the preferred dimethyl ether pilot fuel or a readily combustible (under compression) DME, methanol and water, vapour mix; and as a preferred alternative to the separator 16 arrangement mentioned with reference to figure 2 of the drawings, as shown in Eigure 3 o~ the drawings a condenser 18 is employed in place of the water separator 16 and arranged to be operab.le so as to provide direct or partly direct DME gas or vapour mix to the engine 1 by way o:E a first line 19, and any excess unconverted liquid methanol and extracted condensate can be directed via a eecond line 20 to the injector pump 2 for mixiny , .
-12-- 2~3~
with the principal methanol alcohol fuel to be injected thereby to the engine cylinder combustion chamber(s).
Nonnally, the employment of an alternative fuel supply system and apparatus for operation of diesel engines on a liquid alcohol fuel such as methanol will in many instances involve the requirement to make some modification to or adjustment of the fuel injector pump, or to provide an alternative specially designed injector pump, so as to be capable of accommodating the larger volume (when com-pared with the volume of diesel oil fuel providing the same power output - methanol having in the region of about half the calorific value of diesel oil fuel) of methanol or other liquid alcohol fuel to be employed as the pr:Lncipal fuel. llhe degree of charge will of course be dependent upon the nature and required operations of the engine conc erned, and minimal change to the fuel injection pump may be in order where optimum performance of the engine is of no real concern. For example, in a stationary engine set-up with the engine arranged to normally operate at a substantially constant speed or within a substantially constant or limited speed range, a simple increase in the standard injector pump 2 maximum rack opening position is likely to be sufficient compen-sation for the reduced calorific value of mathanol when compared ; with diesel oil; but for higher speeds a more complete retuning of the injection system may be required.
However, in most cases optimum engine performance is desirable (sometimes even essential), and another object of the present invention is to enable the Euel supply system and apparatus described and illustrated to be adapted and employed in a manner enabling optimum, or near optimum, performance of an engine under all (or at least a wide range of) operational phases without the .....
-13- 2~2~3~7 requirement for costly fuel injection pump modiEication or construction. The following involve further preferred appli-cations of the invention.
As previously mentioned the excess or liquid ~lethanol and/or condensate extracted by the condenser 18 can be introduced to the liquid methanol principal fuel line for direct injection therewith to the engine 1. The latter method of disposing of and usefully using the methanol or alcohol vapour has been found to be advantageous to engine efficient. As a development of this aspect it has been found that, if, instead of passing all of the methanol or alcohol fuel vapour (after condensation) to the engine 1 by way of the liquid fuel injectors 2, a controlled proportion of the methanol or alcohol fuel vapour be directed with the appropriate proportion of dlmethyl ether into the inlet air for the engine 1, it can be more advantageously employed to supplement the energy input of the principal liquid fuel. In this case the dimethyl ether vapour combined with the methanol or alcohol vapour initiate and accelerate the combustion of the principal liquid fuel through their prior ignition and combustion in addition to supplementing the energy input.
Whilst it is envisaged that the ether pilot fuel and desired additional fuel vapour can be separately produced and delivered to khe inlet air line for the engine, as the ether pilot fuel is derived by conversion from the vapourised ~uel it is more convenient and economical to utilise the same reactor converter device 10 (which will operate at between 250 to 400 degrees centi-grade - usually at about 300 degrees centigrade) and control the proportion of ether pilo-t fuel formed relative to the re-maining vapour; so that ether pilot fuel and methanol (or other alcohol) vapour mix can be delivered as one by way of the ether/D~E
' , -14- ~2~3~
pilot fuel line 15) for mixiny and combusti~n with the inlet air in assisting rapid and efficient combustion of the injected liquid methanol or alcohol princlpal fuel, and reducing the actual quantity o~ principal fuel required to be injected for optimum engine performance. This method and reduction in quantity of principal fuel to be injected enables efficient engine operation without the need for expensive change or modification of existing diesel fuel injection pumps, or the provision of a custom designed methanol or alcohol liquid fuel injection pump.
A convenient method of removing water from the pilot ether or DME fuel produced by the reactor converter device 10 without removing or causing unnecessary condensation of the methanol or . alcohol vapour, is by employment of the condenser 18 as described with reference to figure 3 of the drawings, and controlling the condenser temperature and pressure within appropriate prescribed limits - as methanol (or other alcahol) and water have different condensation characteristics, the desired water separation from the ether/DME pilot fuel and the provision of controlled quantities of methanol or alcohol vapour is readily achievable by appropriate temperature/pressure control. Other methods of achieving the same separation of water from the ether/DME pilot fuel and methanol/
alcohol vapour can be employed eg as described wi.th re~erence to figure 2 of the drawings, the separator 16 can employ absorbtion filtration techni.ques.
The optimum proportion of methanol/alcohol fuel vapour relative to the ether/DME pilot fuel in the pilot stream~ or line ; 15, and as delivered to the inlet air side of the engine 1, can be simply controlled by setting the mass of catalyst in the reactor converter device 10, as required together with adjustment .. . .
' , -15- 2~2~3~7 to condensation conditions in condenser 18 - as the mass of the reactor catalyst is reduced for any given flow rate of incoming liquid methanol/alcohol fuel delivered by way of the bye-pass line 7 and delivery pump 8, so the proportion of un-reacted methanol/alcohol to ether/DME pilot fuel in the outlet stream or line 15,19 is increased. In a typical arrangement, an input of one kilogram of methanol to the reactor converter device 10 operating at about 300 degrees centigrade will produce a pilot fuel vapour in the approximate proportions 0.3 kilogram Methanol, 0.2 kilogram water and 0.5 kilogram DME - this vapour can be cooled by the condenser 18 to about 20-60 degrees centigrade for extraction of the readily condensible water and methanol content of the vapour.
The methods of operation of a compression ignition engine in accordance with the present invention, and employment of the system and apparatus described, are particularly ; applicable for smooth and efficient operation under such as low load and/or speed phases (and/or during warm up stages), as well as for generally obtaining optimum performance from the engine; but it will be appreciated that with a hot engine and high speed operations, the principal liquid methanol or other alcohol fuel may be readily combustible and at least reasonably efficiently employed without the need ~or initiated and accelerated combustion by prior introduction of the ether/DME
pilot fuel, by itsel or in combination with the unconverted methanol/alcohol vapour. Smooth and efficient operation of a compression ignition engine throughout all stages or phases of operation is, however, not readily attainable utilising only liquid methanol or other alcohol fuel as the principal fuel; and .
--16- 2~2~3~
the present invention overcomes this problem and additionally avoids the need for special high capacity fuel injection pump provision or changes.
In providing a self contained system providing for 'cold starting' of an engine, it is preferred to employ the previously referred to system or method (b) of providing a separate supply of preformed ether or DME pilot fuel for initial mixing with the inlet air prior to switching over to the system providing for production of the pilot fuel from the bye-passed methanol or other alcohol fuel for ongoing operation. Another development of the invention comprises the addition to the previously disclosed apparatus of a pilot fuel storage vessel and a pressure control valve in the pilot fuel delivery lines 15 and 19 from the reactor converter 10 to the water separator 16 or condenser 18; to enab'le collection and storage of a quantity of the ether/DME pilot fuel produced during operation of the engine and alternative fuel conversion system, for'use in subsequent starting or re-starting operations (particularly when no exhaust heat is available for the reactor converter 10).
The accompanying drawing in figure 4 diagrammatically illustrates one form of this further pilot fuel supply develop-ment. The pilot fuel bye-pass pump 8 delivers liquid rnethanol or other alcohol fuel to the reactor converter 10, which is heated as before by any suitable means (eg by a burner 12 or by exhaust heat) to the desir~d temperatur,e range of between 250 and 400 degrees centigrade for the production of methanol/
alcohol fuel vapour, and at least partial conversion to ether or DME, ~or delivery on to a cooler or condenser 18; which is set to operate at the desired pressure and/or temperature required to allow condensation and separation out of at least part of the :
-17- 2~3~7 condensible portion of the ~uel vapour (within which the ether~DME pilot fuel is embodied). The extracted condensate may be variable according to requirements and operating corldit-ions and/or the kind of en~ine involved, and could involve a small part or a major part o~ the condensate content of the vapour passed to the condenser 18.
The separated or partly separated vapour fuel is then passed by way of delivery line 19 to a substantially sealed pressure vessel 24 through upper inlet and outlet connections 25, 26, and on through a pressure control valve 27 to the engine for mixin~ with the inlet air for combustion during operation as previously described. The pressure control valve isset above the vapour pressure of the cooled ether or DME
pilot fuel and methanol (or other alcohol) and at a level allow-ing pilot fuel and vapour delivery to the engine as required.
The vessel 24 is thus pressurised so that ether/DME pilot fuel and vapour delivered thereto from the cooler/condenser 18 will condense to liquid 28 within the vessel 24, and at least some can be stored for subsequent use in starting or re-starting the engine after stopping. The ether/DM~ pilot fuel can be hled off through the outlet connection 26 as required by the engine by lowering the set-point of the pressure control valve 27 to below the vapour pressure of the stored liquid pilot fuel 28, and allowing such liquid pilot Euel 28 (retained in the liquid state under pressure) to flash off back to a vapour.
Mixing of the pilot fuel in the inlet air system of the engine 1 can be simply by way of a spud type gas mixer coupled to the engines inlet duct.
, ' : .
.
a203~7 For further efficiency in operation, over wide ranges of engine speeds and loads, it may be desirable to provide for regulation and boosting of the engine combustion chamber temperatures to specific ranges above those normally maintained for operation of the engine l using diesel fuel as the principal fuel, to further assist and stabilise the ignition and combust-ion of the methanol with a minimum supplement of the ether pilot fuel. This will be particularly applicable follo~ing initial starting up and when operating under light load conditions and/or low engine speeds, when the temperatures within the combustion chamber(s) may not reach the desired range necessary to enable effective or efficieint burning of the methanol fuel.
Accordingly, boosting of gas temperatures inside the combustion chamber(s) can be effectively obtained by providing an inlet air throttling valve 21 in the inlet air line or duct 22 to regulate the volume of air (and thus its cooling effect) fed to the engine; and/or an exhaust gas throttle valve can be provided in the engine gas exhaust sytem (provided in addition or as an alternative to the inlet air throttling valve 21) to enable raising and regulation of exhaust gas temperatures suffficiently high to maintain operation of the pilot fuel generator or converter lO. The inlet throttling valve 21 is preferably arranged to be automatically regulated eg by electric servo, bimetal control or other temperature sensitive means controllable directly or indirectly by way of a temperature sensor device ~3 coupled to the enyines exhaust system 11 in cl~ose proximity to the engines exhaust valves and manifold assembly.
~ny similar or other suitable means can be provided for control -19- 2~3:~
of an exhaust throttle valve when fitted.
Further modifications for most effective operation under a wide range of engine speeds and loads, as may be required in particular in vehicle operation, can include the installation of further cylinder head and oil temperature control devices, and a methanol or other alcohol ~uel recirculation system to prevent vapour lock in the injection pump 2. In more sophisticated engine systems electronics can be employed for the close control of principal alcohol fuel and/or pilot fuel, whereby such supply is subject to control according to engine loading and/or speed; but generally speaking the provision of the basic equipment comprising the controlled pilot fuel pump 8 for determining substantially precise pilot fuel requirements fed to the reactor converter 10 and engine 1, the catalyst or ether generator 10 and the provision of a condensate separator 16 or condenser 18 and means controlling the supply of drier or dry DME and fuel vapour to the engine 1 in prescribed quantities with the inlet air, will.enable employment of the normally provided engine and associated components without major modifications and with sufficient efficiency to enable employment of up to 100% methanol as the main operation fuel and without the need to provide a separate main supply for diesel fuel. The provision for inlet air and/or exhaust gas throttling involves no major change to existing inlet and exhaust systems and is thus a desirably incorporated feature facilitating effective operation under light loads by maintaining gas exhaust temperature~s above 250 degrees centigrade.
-20- 202~3~
In the basic forms of the invention and under cold start and initial warm up conditions, up to 60% (in ener~y value) pilot ether fuel may be necessary for operation of the engine;
but during normal optimum operating conditions, and with the preferred aspects of the invention the proportion (in energy value) of the pilot fuel required may be as low as 1%.
It will thus be seen that the present invention can be readily appli.ed to existing vehicles or machinery (station-ary or moving) employing compression ignition engines normally designed to operate on diesel fuel, with standard "kit-set"
componentry; and/or new vehicles and machinery employing com-pression engines for operation on methanol as described can be provided at relatively little.additional costs, and with ~iable monetary savings and gains in operating costs with the generally lower costs of methanol and other alcohol fuels - without loss in efficiency in operation and with the further added advantages of methanol or other alcohol fuel employment involving clean burning . with less air polution, and also longer engine life under most operating additions, when compared with conventional diesel oil use.
The aforegoing description has been primarily directed to the employment of methanol as the principal liquid alcohol fuel, and it will be appreciated that any of the components o~ the described system referred to as involving or using methanol will be similarly arranged (with or without modification as may be appropriate) to involve or use any other similar and suitable alcohol fuel alternatively employed as the principal alcohol fuel.
.
~2~3~7 Some preferred aspects of the invention have been described by way of example and with reference to the accompanying drawings, but other variations of and modifications to the invention can take place without departing from the scope of the appended claims.
; 15 ~.
~ 20
fuel during at least initial starting and/or low load operating phases of the engine.
In a further aspect there is provided a method operating a single or multi.-cylinder internal combustion engine of the compression ignition kind and having a liquid fuel injection means for injecting fuel into the or each combustion chamber, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to vapourising and reactor conversion means for the production of alcohol fuel vapourand ether pilot fuel, said ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel and alcohol fuel vapour to a condensation process for the removal of at least a part of any readily condensible content from the ekher pilot fuel and alcohol fuel vapour,and delivering prescribed quantities of the ethe~ pilot fuel and alcohol fuel vapour to the engine combustion chamber~s)for igni.tion under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol, principal fuel, to enable initiation and acceleration o~
combustion of said principal fuel during at least initial starting and/or low load operating phases'of the engine and to provide additional energy to the engine in addition to the said principal fuel under other load operating phases.
.,.
,., ' . ' ~ " .
-6- 2~2~3~
Drawings Some preferred aspects of the invention will now be described by way o~ example and with reference to the accom-panying drawings, in which:
FIGURE 1 is a schematic diagragm illustrating one first fuel supply system in accordance with the invention FIGURE 2 is a similar s~ematic diagrammatic view ill~
ustrating a modification of the invention, FIGURE 3 is a further similarsche.matic diagrammatic view illustrating a further modification or variation of the invention, and FIGURE 4 is a further schematic diagrammatic view illustrating a modification of the pilot fuel supply means.
Description of Invention Referring firstly to figure 1 of the drawings, the invention is particularly applicable to a typical compression engine or diesel engine 1 of the single or multi-cylinder kind with a reciprocating piston for each cylinder; with an injector pump 2 driven directly or indireatly by the engine 1 for the delivery of prescribed quantities o~ operat-ing fuel to the respective combustion chamber(s) defined by the cylinder(s) and piston(s). In a kypical diesel engine, the normally provided injector pump 2 is directly connected via a variable speed fuel delivery pump 3 to the diesel fuel oll supply tank and is readily capable of handling the fuel flow requirement, whereas with the employment of an alcohol such as methanol ~of lower calorific value and lower cetane number than diesel fuel) as the principal fuel, .~ . .
~. . .
... .
~ ~a2~3l7 a considerably greater injection pump capacity must be pro-vided to cope with such requirement. Having regard to the nature of an alcohol such as methanol, it is also pre~er-ably desirable to provide supplementary lubrication for the injector pump (lubrication in the normal course o~ events being provided by the diesel fuel); and thus lubricating oil may be injected into the system by means of a suitable metering pump 5 (electrically or engine driven)pumping pres-cribed quantities of oil from an oil supply source or tank 6 to the input side o~ the methanol delivery pump 3 for mixing with the methanol delivered to the injector pump 2 from the supply tank 4.
As previously indicated, whilst a separate source of pilot ether fuel can be provided for supply to the engine 1, pre~erably the main source o~ the methanol or other prin-cipal alcohol fuel is provided with a secondary or by-pass fuel line 7 which passes a ~uantity of the methanol to a controllable pilot fuel pump 8 (which can be electrically driven or driven directly or indirectly mechanically by the engine 1 e.g. by any direct or indirect couplin~ means) such that the rate of operation of the pilot fuel pump 8, and thus the ~uantity of fuel pumped thereby,is controlled and made to vary with the rate o~ delivery of the injected fuel and/or with the engine speed. The outlet line 9 from the pilot fuel pump 8 is directed to a reactor or converter device 10 in the form of a heated or heat exchanger device having a catalytic conversion chamber containing a catalyst for conversion of methanol fed thereto by way of the outlet line 9 ~o an ether fuel having a greater or wider in~lamm~
ability range than the incomin~ methanol ~uel. Preferably, the methanol fuel ls converted to a dimethylether (DME) which may be readily mixed with the inle-t air ~or the engine l to ignite under compression and initiate combustion o~ the methanol injected in the diesel engine l.
Methanol can be readily converted to DME at moderate temper-atures over a suitable dehydration catalyst, and the convers-ion device disclosed in the aforementioned United States Patent Ser.No. 4,422,412 or any other suitable reactor, conversion device or ether generator,can be employed. It is pre-ferable that the heat exchanger catalytic converter 10need not require excessively high temperatures to operate, as one pre~erred means o~ providing the heat for the heat exchanger is by way o~ utilisation of the exhaust outlet system or line 11 for the engine, the reactor or ether generator (heat exchanger catalytic converter) 10 being arranged to be direc-tly coupled to the exhaust line 11; and a study has found that an inexpensive alumina catalyst can achieve good con-version rates of methanol to DME at temperatures as low a 250C to~OOC. Heat and mass transfer calculations indicatethat only a small part o~ the heat energy available in the diesel engines exhaust system 11 is re~uired to power a continuous DME reactor.
The reactor or ether generator 10can alternatively be separate from the exhaustand beelectrically heated, but the : existing exhaust system 11 ofthe engine1provides a convenient source of otherwise wasted heat and obviates the continuing electric power draw-off of a reactor or generator converter heated and operated solely by electricity.
;~'.
2~3~ 7 It will be appreciated of course tha-t there will be no available exhaust heat for operation of the reactor or con verter ~Owhencoupled to the exhaust system11when the engine1is started from cold; and there are optional cold starting systems involving,for example:
(a) Maintaining a supply of diesel fuel ~or the engine1and using such supply for start up in the usual manner passing, the diesel oil fuel to the engine1 by way of the injector pump2;
followed by a switching over to methanol operationand operation 10 of the reactor converter 10 for supplementary supply of ether or DME pilot fuel to the engine1 when the exhaustsystem 11 has reached the desired temperature for effective operation of the reactor converter'10.
(b) A separate supply of pre-formed ether or DME can be ' 15 provided for initial mixing with the engine inlet air, followed by a switching over to the methanol supply line 7 to the pilot fuel pump 8 and reactor ~,converter 10 again once the exhaust system 11 has reached the desired temperature sufficient to operate the reactor converter 10.
(c) The reactor converter,10 canbe provided with a supplementary electrical heating element for initial warm-up and operation for conversion of the methanol to ether or DME, with the exhaust system~11t~king over the heating and conversion operation again on reaching the desired temperature. This system is however not favoured (except perhaps in the case of a stationary engine and the ability to employ mains electric power), as in~the case of a motor vehicle there would be an undesirable electric power draw-of~ ~rom the battery prior to starting; and also a time delay in starting of the engine 1.
-- ` 2~2~3~7 (d) Alterna-tively and as illustrated in -figures 1 to 3, a methanol burner device 12 can be employed, fed by a suitable methanol by-pass line 13 from the main feed line 4a from the methanol supply source and by way of a cold start solenoid valve 14. The burner 12 being coupled to or associated with the exhaust system 11 at or adjacent the reactor converter 10 so as to provide initial high temperatures to the exhaust 11, and thus reactor converter 10, for operation as required in providing the e-ther or DME in operation of the engine 1. The burner device 12 may burn other fuels.
In the process of supply of the bye-passed quantity of methanol or liquid alcohol fuel to the reactor converter device 10, and the conversion of some of that bye-passed fuel to the ether or DME pilot fuel, the heat exchanger will create water and methanol vapour (or other liquid alcohol fuel vapour) con-taining the ether or DME pilot fuel; and figure 1 illustrates a direct line 15 for passage of vapourized methanol and diethyl or dimethyl ether ~rom the reactor converter 10 to the inlet air system or manifold of the engine 1. ~Iowever,for moree~ective and eficient operation it i5 preferred that at least a part of any condensate or readily condensible content of the vapour is re-moved from the pilot fuel prior to passing into the engine 1, to enable rapi~ reaction during compression with the air in the respective combustion chamber, and raising the temperature of the injected methanol sufficiently to ignite under compression.
Accordingly, and with reference now to figure 2 of the drawings, in one arrangement a liquid separator unit 16 is interposed in .
2~2~3~
the output line 15 from the reactor converter 10 to separate out at least a part o~ the suspended liquid and readily con-densible content from the DME vapour supplied to the engine 1.
The separator 16 can be of various kinds and may simply provide for membrane filtration, or alternatively provide for ~ractional distillation, dessication or centrifugal separation. The liquid and condensate separated out thereby can be discharged by way of a by-pass line 17 into the engine exhaust system 11 at the outlet or downstream side of the reactor converter 10, and thus provide an added advantage in assisting cooling of the exhaust system 11 at the outlet side without affecting the heat required for operation of the heat exchanger forming part of the reactor converter 10. Alternatively, the extracted water and condensate (which may contain some methanol or alcohol fuel content) can be directed to a separate storage tank for possible further treat-ment;
In operation of the~reactor converter 10, not all of the methanol directed thereto by way of the pilot fuel pump 8 will at all times be converted to the preferred dimethyl ether pilot fuel or a readily combustible (under compression) DME, methanol and water, vapour mix; and as a preferred alternative to the separator 16 arrangement mentioned with reference to figure 2 of the drawings, as shown in Eigure 3 o~ the drawings a condenser 18 is employed in place of the water separator 16 and arranged to be operab.le so as to provide direct or partly direct DME gas or vapour mix to the engine 1 by way o:E a first line 19, and any excess unconverted liquid methanol and extracted condensate can be directed via a eecond line 20 to the injector pump 2 for mixiny , .
-12-- 2~3~
with the principal methanol alcohol fuel to be injected thereby to the engine cylinder combustion chamber(s).
Nonnally, the employment of an alternative fuel supply system and apparatus for operation of diesel engines on a liquid alcohol fuel such as methanol will in many instances involve the requirement to make some modification to or adjustment of the fuel injector pump, or to provide an alternative specially designed injector pump, so as to be capable of accommodating the larger volume (when com-pared with the volume of diesel oil fuel providing the same power output - methanol having in the region of about half the calorific value of diesel oil fuel) of methanol or other liquid alcohol fuel to be employed as the pr:Lncipal fuel. llhe degree of charge will of course be dependent upon the nature and required operations of the engine conc erned, and minimal change to the fuel injection pump may be in order where optimum performance of the engine is of no real concern. For example, in a stationary engine set-up with the engine arranged to normally operate at a substantially constant speed or within a substantially constant or limited speed range, a simple increase in the standard injector pump 2 maximum rack opening position is likely to be sufficient compen-sation for the reduced calorific value of mathanol when compared ; with diesel oil; but for higher speeds a more complete retuning of the injection system may be required.
However, in most cases optimum engine performance is desirable (sometimes even essential), and another object of the present invention is to enable the Euel supply system and apparatus described and illustrated to be adapted and employed in a manner enabling optimum, or near optimum, performance of an engine under all (or at least a wide range of) operational phases without the .....
-13- 2~2~3~7 requirement for costly fuel injection pump modiEication or construction. The following involve further preferred appli-cations of the invention.
As previously mentioned the excess or liquid ~lethanol and/or condensate extracted by the condenser 18 can be introduced to the liquid methanol principal fuel line for direct injection therewith to the engine 1. The latter method of disposing of and usefully using the methanol or alcohol vapour has been found to be advantageous to engine efficient. As a development of this aspect it has been found that, if, instead of passing all of the methanol or alcohol fuel vapour (after condensation) to the engine 1 by way of the liquid fuel injectors 2, a controlled proportion of the methanol or alcohol fuel vapour be directed with the appropriate proportion of dlmethyl ether into the inlet air for the engine 1, it can be more advantageously employed to supplement the energy input of the principal liquid fuel. In this case the dimethyl ether vapour combined with the methanol or alcohol vapour initiate and accelerate the combustion of the principal liquid fuel through their prior ignition and combustion in addition to supplementing the energy input.
Whilst it is envisaged that the ether pilot fuel and desired additional fuel vapour can be separately produced and delivered to khe inlet air line for the engine, as the ether pilot fuel is derived by conversion from the vapourised ~uel it is more convenient and economical to utilise the same reactor converter device 10 (which will operate at between 250 to 400 degrees centi-grade - usually at about 300 degrees centigrade) and control the proportion of ether pilo-t fuel formed relative to the re-maining vapour; so that ether pilot fuel and methanol (or other alcohol) vapour mix can be delivered as one by way of the ether/D~E
' , -14- ~2~3~
pilot fuel line 15) for mixiny and combusti~n with the inlet air in assisting rapid and efficient combustion of the injected liquid methanol or alcohol princlpal fuel, and reducing the actual quantity o~ principal fuel required to be injected for optimum engine performance. This method and reduction in quantity of principal fuel to be injected enables efficient engine operation without the need for expensive change or modification of existing diesel fuel injection pumps, or the provision of a custom designed methanol or alcohol liquid fuel injection pump.
A convenient method of removing water from the pilot ether or DME fuel produced by the reactor converter device 10 without removing or causing unnecessary condensation of the methanol or . alcohol vapour, is by employment of the condenser 18 as described with reference to figure 3 of the drawings, and controlling the condenser temperature and pressure within appropriate prescribed limits - as methanol (or other alcahol) and water have different condensation characteristics, the desired water separation from the ether/DME pilot fuel and the provision of controlled quantities of methanol or alcohol vapour is readily achievable by appropriate temperature/pressure control. Other methods of achieving the same separation of water from the ether/DME pilot fuel and methanol/
alcohol vapour can be employed eg as described wi.th re~erence to figure 2 of the drawings, the separator 16 can employ absorbtion filtration techni.ques.
The optimum proportion of methanol/alcohol fuel vapour relative to the ether/DME pilot fuel in the pilot stream~ or line ; 15, and as delivered to the inlet air side of the engine 1, can be simply controlled by setting the mass of catalyst in the reactor converter device 10, as required together with adjustment .. . .
' , -15- 2~2~3~7 to condensation conditions in condenser 18 - as the mass of the reactor catalyst is reduced for any given flow rate of incoming liquid methanol/alcohol fuel delivered by way of the bye-pass line 7 and delivery pump 8, so the proportion of un-reacted methanol/alcohol to ether/DME pilot fuel in the outlet stream or line 15,19 is increased. In a typical arrangement, an input of one kilogram of methanol to the reactor converter device 10 operating at about 300 degrees centigrade will produce a pilot fuel vapour in the approximate proportions 0.3 kilogram Methanol, 0.2 kilogram water and 0.5 kilogram DME - this vapour can be cooled by the condenser 18 to about 20-60 degrees centigrade for extraction of the readily condensible water and methanol content of the vapour.
The methods of operation of a compression ignition engine in accordance with the present invention, and employment of the system and apparatus described, are particularly ; applicable for smooth and efficient operation under such as low load and/or speed phases (and/or during warm up stages), as well as for generally obtaining optimum performance from the engine; but it will be appreciated that with a hot engine and high speed operations, the principal liquid methanol or other alcohol fuel may be readily combustible and at least reasonably efficiently employed without the need ~or initiated and accelerated combustion by prior introduction of the ether/DME
pilot fuel, by itsel or in combination with the unconverted methanol/alcohol vapour. Smooth and efficient operation of a compression ignition engine throughout all stages or phases of operation is, however, not readily attainable utilising only liquid methanol or other alcohol fuel as the principal fuel; and .
--16- 2~2~3~
the present invention overcomes this problem and additionally avoids the need for special high capacity fuel injection pump provision or changes.
In providing a self contained system providing for 'cold starting' of an engine, it is preferred to employ the previously referred to system or method (b) of providing a separate supply of preformed ether or DME pilot fuel for initial mixing with the inlet air prior to switching over to the system providing for production of the pilot fuel from the bye-passed methanol or other alcohol fuel for ongoing operation. Another development of the invention comprises the addition to the previously disclosed apparatus of a pilot fuel storage vessel and a pressure control valve in the pilot fuel delivery lines 15 and 19 from the reactor converter 10 to the water separator 16 or condenser 18; to enab'le collection and storage of a quantity of the ether/DME pilot fuel produced during operation of the engine and alternative fuel conversion system, for'use in subsequent starting or re-starting operations (particularly when no exhaust heat is available for the reactor converter 10).
The accompanying drawing in figure 4 diagrammatically illustrates one form of this further pilot fuel supply develop-ment. The pilot fuel bye-pass pump 8 delivers liquid rnethanol or other alcohol fuel to the reactor converter 10, which is heated as before by any suitable means (eg by a burner 12 or by exhaust heat) to the desir~d temperatur,e range of between 250 and 400 degrees centigrade for the production of methanol/
alcohol fuel vapour, and at least partial conversion to ether or DME, ~or delivery on to a cooler or condenser 18; which is set to operate at the desired pressure and/or temperature required to allow condensation and separation out of at least part of the :
-17- 2~3~7 condensible portion of the ~uel vapour (within which the ether~DME pilot fuel is embodied). The extracted condensate may be variable according to requirements and operating corldit-ions and/or the kind of en~ine involved, and could involve a small part or a major part o~ the condensate content of the vapour passed to the condenser 18.
The separated or partly separated vapour fuel is then passed by way of delivery line 19 to a substantially sealed pressure vessel 24 through upper inlet and outlet connections 25, 26, and on through a pressure control valve 27 to the engine for mixin~ with the inlet air for combustion during operation as previously described. The pressure control valve isset above the vapour pressure of the cooled ether or DME
pilot fuel and methanol (or other alcohol) and at a level allow-ing pilot fuel and vapour delivery to the engine as required.
The vessel 24 is thus pressurised so that ether/DME pilot fuel and vapour delivered thereto from the cooler/condenser 18 will condense to liquid 28 within the vessel 24, and at least some can be stored for subsequent use in starting or re-starting the engine after stopping. The ether/DM~ pilot fuel can be hled off through the outlet connection 26 as required by the engine by lowering the set-point of the pressure control valve 27 to below the vapour pressure of the stored liquid pilot fuel 28, and allowing such liquid pilot Euel 28 (retained in the liquid state under pressure) to flash off back to a vapour.
Mixing of the pilot fuel in the inlet air system of the engine 1 can be simply by way of a spud type gas mixer coupled to the engines inlet duct.
, ' : .
.
a203~7 For further efficiency in operation, over wide ranges of engine speeds and loads, it may be desirable to provide for regulation and boosting of the engine combustion chamber temperatures to specific ranges above those normally maintained for operation of the engine l using diesel fuel as the principal fuel, to further assist and stabilise the ignition and combust-ion of the methanol with a minimum supplement of the ether pilot fuel. This will be particularly applicable follo~ing initial starting up and when operating under light load conditions and/or low engine speeds, when the temperatures within the combustion chamber(s) may not reach the desired range necessary to enable effective or efficieint burning of the methanol fuel.
Accordingly, boosting of gas temperatures inside the combustion chamber(s) can be effectively obtained by providing an inlet air throttling valve 21 in the inlet air line or duct 22 to regulate the volume of air (and thus its cooling effect) fed to the engine; and/or an exhaust gas throttle valve can be provided in the engine gas exhaust sytem (provided in addition or as an alternative to the inlet air throttling valve 21) to enable raising and regulation of exhaust gas temperatures suffficiently high to maintain operation of the pilot fuel generator or converter lO. The inlet throttling valve 21 is preferably arranged to be automatically regulated eg by electric servo, bimetal control or other temperature sensitive means controllable directly or indirectly by way of a temperature sensor device ~3 coupled to the enyines exhaust system 11 in cl~ose proximity to the engines exhaust valves and manifold assembly.
~ny similar or other suitable means can be provided for control -19- 2~3:~
of an exhaust throttle valve when fitted.
Further modifications for most effective operation under a wide range of engine speeds and loads, as may be required in particular in vehicle operation, can include the installation of further cylinder head and oil temperature control devices, and a methanol or other alcohol ~uel recirculation system to prevent vapour lock in the injection pump 2. In more sophisticated engine systems electronics can be employed for the close control of principal alcohol fuel and/or pilot fuel, whereby such supply is subject to control according to engine loading and/or speed; but generally speaking the provision of the basic equipment comprising the controlled pilot fuel pump 8 for determining substantially precise pilot fuel requirements fed to the reactor converter 10 and engine 1, the catalyst or ether generator 10 and the provision of a condensate separator 16 or condenser 18 and means controlling the supply of drier or dry DME and fuel vapour to the engine 1 in prescribed quantities with the inlet air, will.enable employment of the normally provided engine and associated components without major modifications and with sufficient efficiency to enable employment of up to 100% methanol as the main operation fuel and without the need to provide a separate main supply for diesel fuel. The provision for inlet air and/or exhaust gas throttling involves no major change to existing inlet and exhaust systems and is thus a desirably incorporated feature facilitating effective operation under light loads by maintaining gas exhaust temperature~s above 250 degrees centigrade.
-20- 202~3~
In the basic forms of the invention and under cold start and initial warm up conditions, up to 60% (in ener~y value) pilot ether fuel may be necessary for operation of the engine;
but during normal optimum operating conditions, and with the preferred aspects of the invention the proportion (in energy value) of the pilot fuel required may be as low as 1%.
It will thus be seen that the present invention can be readily appli.ed to existing vehicles or machinery (station-ary or moving) employing compression ignition engines normally designed to operate on diesel fuel, with standard "kit-set"
componentry; and/or new vehicles and machinery employing com-pression engines for operation on methanol as described can be provided at relatively little.additional costs, and with ~iable monetary savings and gains in operating costs with the generally lower costs of methanol and other alcohol fuels - without loss in efficiency in operation and with the further added advantages of methanol or other alcohol fuel employment involving clean burning . with less air polution, and also longer engine life under most operating additions, when compared with conventional diesel oil use.
The aforegoing description has been primarily directed to the employment of methanol as the principal liquid alcohol fuel, and it will be appreciated that any of the components o~ the described system referred to as involving or using methanol will be similarly arranged (with or without modification as may be appropriate) to involve or use any other similar and suitable alcohol fuel alternatively employed as the principal alcohol fuel.
.
~2~3~7 Some preferred aspects of the invention have been described by way of example and with reference to the accompanying drawings, but other variations of and modifications to the invention can take place without departing from the scope of the appended claims.
; 15 ~.
~ 20
Claims (26)
1. A fuel supply system for an internal combust-ion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into each combustion chamber of the engine, said system comprising a supply source of liquid alcohol fuel as the principal fuel, a main fuel supply line from said supply source coupled to the fuel injection means for supply of the principal fuel to the engine, a source of supply of an ether pilot fuel having a wider flamma-bility range and higher cetane number than the principal fuel,and delivery means for delivering prescribed quanti-ties of said pilot fuel to the engine via a condensation extraction means which removes at least part of any readily condensible content of the pilot fuel prior to delivery to the engine and mixing with inlet air in the combustion chamber of the engine, said pilot fuel reacting with air in the combustion chamber to ignite under compression to raise the temperature of the fuel mixture therein and enable initiation and acceleration of ignition under compression of said principal fuel on injection.
2. Apparatus for the operation of a single or multi-cylinder internal combustion engine of the com-pression ignition kind utilising a liquid alcohol fuel as the principal fuel for the engine, comprising a first delivery means arranged to be coupled to a supply source of liquid alcohol fuel and to deliver prescribed quantities thereof to fuel injection means for the engine, a reactor conversion means capable of converting liquid alcohol fuel to an ether coupled to a second delivery means which is arranged to receive some of the principal liquid alcohol fuel and deliver metered prescribed quantities of the principal fuel to said reactor conver-sion means for conversion to a pilot ether fuel,condens-ation extraction means coupled to and arranged to receive ether pilot fuel from said reactor conversion means and to remove at least a major part of the condensable content from said ether pilot fuel prior to delivery by said second delivery means of prescribed quantities of the pilot fuel to the engine combustion chamber(s) simul-taneously with the admission of air to said combustion chamber(s) and prior to injection by said fuel injection means of prescribed quantities of the principal alcohol fuel.
3. Apparatus as claimed in claim 2 , wherein said pilot fuel delivery means comprises an elect-rically driven fuel pump the rate of operation of which is controlled and made to vary with the rate of delivery and injection of the principal alcohol fuel and/or with the engine speed.
4. Apparatus as claimed in claim 2 , wherein said pilot fuel delivery means comprises a fuel pump which is arranged to be driven directly or indirectly by the engine and such that the rate of operation of the pilot fuel pump is controlled and made to vary with the rate of delivery and injection of the principal alcohol fuel and/or with the engine speed.
5. Apparatus as claimed in claim 2 or claim 26, wherein said reactor conversion device is coupled to and arranged to be heated by an exhaust outlet system of the engine, and wherein an alcohol fuel burner device is coupled to or positioned relative to the engine exhaust outlet system at or adjacent said reactor con-version device and arranged on operation to provide initial high temperatures to the exhaust system and reactor conversion device for cold starting of the engine and production of the pilot fuel.
6 . Apparatus as claimed in claim 2 , wherein the liquid fuel injection means comprises an injector pump and said first delivery means comprises a delivery pump for delivering the principal alcohol to said injector pump, and a supplementary oil metering pump is provided for delivering prescribed quantities of lubricating oil to the input side of said injector pump.
7. Apparatus as claimed in claim 2, wherein said condensation extraction means is a separator unit interposed in an output line from the reactor conversion device.
8. Apparatus as claimed in claim 7, wherein said separator unit incorporates membrane filtrat-ion means for the separation of at least a major part of any condensation in the pilot fuel delivered to the engine.
9. Apparatus as claimed in claim 7 , wherein said separator unit incorporates fractional dis-tillation means for the separation of at least a major part of any condensation in the pilot fuel delivered to the engine.
10. Apparatus as claimed in claim 7 , wherein said separator unit provides for centrifugal separation of at least a major part of any condensation content in the pilot fuel delivered to the engine.
11. Apparatus as claimed in claim 7 , wherein condensate separated out from the pilot fuel by the said separator unit is arranged to be discharged by way .
of a by-pass line into an exhaust system of the engine.
of a by-pass line into an exhaust system of the engine.
12. Apparatus as claimed in claim 2 , wherein condensate separated out from the pilot fuel by the separator unit is arranged to be discharged into the engine exhaust system at the outlet or downstream side of the reactor conversion device.
13. Apparatus as claimed in claim 2 , wherein said condensation extraction means comprises a condenser which is arranged and operable to receive partially converted fuel from the reactor conversion device and provide dry ether pilot fuel to the engine by way of a first feed line, excess unconverted fuel from the reactor conversion device and condensate extracted from the ether pilot fuel being arranged to be directed by way of a second line to the principal alcohol fuel injection means for mixing with the principal alcohol fuel to be injected thereby into the engine combustion chamber(s).
14. Apparatus as claimed in claim 2 , wherein an inlet air throttling valve is provided for an inlet air line or duct of the engine to regulate the volume of air fed to the engine and enable control of the cooling effect of the inlet air for control and adjust-ment of gas temperatures within the combustion chamber(s) of the engine, operation of said inlet air throttling valve being effected by temperature sensitive actuating means controllable directly or indirectly by a temperature sensor device coupled to an exhaust gas outlet part of the engine.
15. Apparatus as claimed in claim 2 , wherein an exhaust gas throttle valve is provided for an exhaust outlet system of the engine to enable raising and regu-lation of the exhaust gas temperature for effective operation of said pilot fuel reactor conversion means;
operation of said exhaust gas throttle valve being effected by temperature sensitive actuating means con-trollable directly or indirectly by a temperature sensor device coupled to said exhaust system.
operation of said exhaust gas throttle valve being effected by temperature sensitive actuating means con-trollable directly or indirectly by a temperature sensor device coupled to said exhaust system.
16 A method of operating a single or multi-cylinder internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into the or each combustion chamber of the engine, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to a reactor conversion device for the production of an ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel to a condens-ation process for the removal of at least a part of any readily condensible content from the ether pilot fuel,and delivering prescribed quantities of said at least partly separated ether fuel to the engine combustion chamber(s) for ignition under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiation and acceleration of combustion of said principal fuel during at least initial starting and/or low load operating phases of the engine.
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to a reactor conversion device for the production of an ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel to a condens-ation process for the removal of at least a part of any readily condensible content from the ether pilot fuel,and delivering prescribed quantities of said at least partly separated ether fuel to the engine combustion chamber(s) for ignition under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiation and acceleration of combustion of said principal fuel during at least initial starting and/or low load operating phases of the engine.
17. A method operating a single or multi-cylinder internal combustion engine of the compression ignition kind and having a liquid fuel injection means for inject-ing fuel into the or each combustion chamber, comprising the steps of:
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to vapourising and reactor conversion means for the production of alcohol fuel vapour and ether pilot fuel, said ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel and alcohol fuel vapour to a condensation process for the removal of at least a part of any readily condensible content from the ether pilot fuel and alcohol fuel vapour and delivering prescribed quantities of the ether pilot fuel and alcohol fuel vapour to the engine combustion chambers for ignition under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiation and acceleration of combustion of said principal fuel during at least initial starting and/or low load operating phases of the engine and to provide additional energy to the engine in addition to the said principal fuel under other load operating phases.
a. providing a supply source of a liquid alcohol fuel as the principal fuel for the engine and feeding said principal fuel via a main supply line to said fuel injection means for injection into the engine b. bye-passing a quantity of the liquid alcohol fuel to vapourising and reactor conversion means for the production of alcohol fuel vapour and ether pilot fuel, said ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel c. subjecting the ether pilot fuel and alcohol fuel vapour to a condensation process for the removal of at least a part of any readily condensible content from the ether pilot fuel and alcohol fuel vapour and delivering prescribed quantities of the ether pilot fuel and alcohol fuel vapour to the engine combustion chambers for ignition under pressure on the compression stroke of the engine and prior to injection of the liquid alcohol principal fuel, to enable initiation and acceleration of combustion of said principal fuel during at least initial starting and/or low load operating phases of the engine and to provide additional energy to the engine in addition to the said principal fuel under other load operating phases.
18. A method as claimed in claim 17 wherein the vapour-ising and reactor conversion means is a reactor conversion device arranged to produce a common mix supply of the pilot ether fuel and alcohol fuel vapour.
19. A method as claimed in claim 16 or claim 17, wherein the reactor conversion device is a heat exchanger device having a catalytic conversion chamber containing a catalyst for the conversion of some of the by-passed liquid alcohol fuel to an ether fuel; the mass of catalyst within the reactor conversion device, and operating temperature thereof, being set and controlled to determine the prescribed proportions of ether fuel and alcohol fuel vapour required to be delivered to the engine.
20. A method as claimed in claim 17, wherein the alcohol fuel vapour is delivered with the ether pilot fuel to a condensation and extraction means which is controlled as to the operating temperature and pressure such that the extraction process is effective for removal of at least a part of any readily condensible content of the ether pilot fuel and alcohol fuel vapour, and wherein the condensate is injected into the principal alcohol fuel supply line.
21. A method of operating a single or multi-cylinder internal combustion engine of the compression ignition kind, as claimed in claim 16 or claim 17 and including the step of producing an excess in the engine requirements for the ether pilot fuel and storing at least some of said excess pilot fuel in a pressure vessel for release and supply to the engine on demand during operation and/or for use in starting or re-starting after stopping of the engine.
22. A fuel supply system for an internal combustion engine of the compression ignition kind and having liquid fuel injection means for injecting fuel into each combustion chamber of the engine, said system comprising a supply source of liquid alcohol fuel as the principal fuel,a main supply line from said supply source coupled to the fuel injection means for supply of the principal fuel to the engine, a secondary or by-pass fuel supply line from said supply source (or a further supply source of the principal alcohol fuel) coupled to a pilot fuel delivery means and a reactor conver-sion device which is arranged to at least partially convert some of said principal alcohol fuel to an ether pilot fuel having a wider flammability range and higher cetane number than the principal fuel, said delivery means being arranged to deliver prescribed quantities of said pilot fuel to the engine with inlet air and via said reactor conversion device and a condensation extraction device which removes at least a part of any readily condensible content of the pilot fuel prior to delivery to the engine and mixing with the inlet air in the combustion chamber(s) of the engine, said pilot fuel reacting with air under compression to ignite and raise the temperature of the fuel mixture therein and initiate and accelerate ignition under compression of said principal fuel on injection.
23. A fuel supply system as claimed in claim 22, wherein said reactor converter device is arranged to produce an ether pilot fuel and alcohol vapourmix for delivery with the inlet air to the engine combustion chamber(s) and ignition under compression prior to ignition of the injected principal fuel.
24. Apparatus for the operation of a single or multi-cylinder internal combustion engine of the compression ignition kind utilising a liquid alcohol fuel as the prin-cipal fuel for the engine, comprising a first delivery means arranged to be coupled to a supply source of liquid alcohol fuel and to deliver prescribed quantities thereof to fuel injection means for the engine, a reactor conversion means capable of converting liquid alcohol fuel to an ether coupled to a second delivery means which is arranged to receive some of the principal liquid alcohol fuel and deliver metered prescribed quantities of the principal fuel to said reactor conversion means for conversion to a pilot ether fuel, condensation extraction means coupled to and arranged to receive ether pilot fuel from said reactor conversion means and to remove at least a part of the readily condensible con-tent from said ether pilot fuel prior to delivery by said delivery means of prescribed quantities of the pilot fuel to the engine combustion chamber(s) with the admission of air and prior to injection by said fuel injection means of pres-cribed quantities of the principal alcohol fuel to said combustion chamber(s).
25. Apparatus as claimed in claim 24 , wherein said reactor converter device is arranged to produce an ether pilot fuel and alcohol vapour mix for delivery with the inlet air to the engine combustion chamber(s) and ignition under compression prior to ignition of the injected principal fuel.
26. Apparatus as claimed in claim 24 or claim 25, wherein a pressure storage vessel and pressure control valve are located in the pilot fuel delivery line between said water extraction device and the engine for the produced pilot fuel to be passed therethrough, the pressure control valve being actuable to control delivery pressure of said pilot fuel or pilot fuel and alcohol vapour mix to the engine and/or cause liquification of said pilot fuel or pilot fuel and alcohol vapour mix for storage under pressure within said storage vessel and release in vapour form as required.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NZ22980289A NZ229802A (en) | 1988-02-18 | 1989-07-04 | Liquid alcohol fuel system for compression ignition engine; ether pilot fuel freed of condensate prior to induction in airstream |
| NZ229802 | 1989-07-04 | ||
| JP1215866A JPH0388957A (en) | 1989-08-22 | 1989-08-22 | Compression ignition engine fuel supply system and its control system |
| JP1-215866 | 1989-08-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2020317A1 true CA2020317A1 (en) | 1991-01-05 |
Family
ID=26521094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2020317 Abandoned CA2020317A1 (en) | 1989-07-04 | 1990-07-03 | Fuel supply and control system for compression ignition engines |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2020317A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9109498B2 (en) | 2009-04-16 | 2015-08-18 | Ethanol Boosting Systems, Llc | Dimethyl ether (DME) enhanced gasoline engine |
-
1990
- 1990-07-03 CA CA 2020317 patent/CA2020317A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9109498B2 (en) | 2009-04-16 | 2015-08-18 | Ethanol Boosting Systems, Llc | Dimethyl ether (DME) enhanced gasoline engine |
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