NO129394B - - Google Patents

Description

Procedure and device for load regulation • ;

of vessel engines.

The present invention relates to a method for .... load regulation of ship engines, the speed of which is regulated to a constant value by means of means that influence the fuel supply

len to engines, "and where the fuel pump position ayfolps etc. compar-

nes with pre-set limit values, so that. a., exceeding these limit values triggers a corrective signal which., converted into a pulse train, is supplied to a servo system for adjustment of a speed pys propeller with adjustable blades in such a way that; the load on the mp- > tor returns to the set value. The invention also relates to a further device. execution of the procedure..

Normally, the fuel pump stroke is used as a parameter for the engine's load and as an input value in load regulators of known types. The fuel pump stroke, i.e. the filling, can be regarded as directly proportional to the delivered engine torque. Other parameters for engine load such as exhaust gas temperature, rpm for turbo chargers, etc. can also be used as a measure of the motor load.

A load regulator of a known type receives its input value from the fuel pump's control rod, which controls a so-called signal generator, which can be hydraulic, pneumatic or electric... The signal from the signal generator is then used to correct the propeller pitch so that the desired engine load is achieved._ .......

Certain types of 'regulators' are equipped with a built-in hydraulic load regulating valve, The valve controls a servomotor which in turn in a suitable !manner..corrects the propeller pitch and thus extracted...engine torque.. Over a cam. be allowed" reias ion. between rpm and fuel pump stroke. The cam represents the desired value for the number of revolutions, and the motor can therefore be overloaded if an external load pushes the number of revolutions below the desired value. are complicated in ".mechanical' terms.*;".' The load level can be adjusted with screws. There are no simple constructions for continuous remote control of the load level. With certain regulators, you can get two load levels that are controlled remotely, but the construction then becomes complicated.

The adjustment of the sensitivity of the load regulator is not possible in any other way than by changing the regulator valve.

There are difficulties in making the load regulator stable, partly because several servo systems are included in the construction. The signal from the load controller corrects the servo motor's setting, which in turn corrects the servo motor in the propeller hub. In order to avoid the aforementioned difficulties and clear the shortcomings of the road, the present invention has been given the characteristics stated in the patent claims, and stability is thus also achieved during the pitch correction. Short-term load changes need not affect the propeller pitch, as the time required for a load change to affect the pitch can be made uncontrollable. Furthermore, the motor's load level can be continuously adjusted so that there e.g. there is the possibility of slowly increasing the engine load during the engine's warm-up phase. Overloading the engine due to a mismatch between the engine speed and the fuel pump setting is excluded by the fact that the measured value for the engine speed is the reference value for the engine load.

In the following, the invention will be illustrated by means of two embodiments which are shown schematically in the drawing. Fig. 1 schematically shows a first embodiment of the invention.

Fig. 2 shows a control system for the pitch control.

Fig. 3 schematically shows another embodiment of the invention. Fig. 4 is a diagram showing an example of a load curve with curves for limit loads plotted.

Working principle.

The fuel pump position (load) has been chosen as the measure of the load and this is therefore sensed with a position sensor (one for each engine in multi-engine systems). Signals from the encoder are compared with a reference value that corresponds to the maximum permissible load for the motor in question at the relevant rpm. In case of overload, a down-regulating pulse is obtained for the rise and in case of under-load an up-regulating one. The pulse does not directly affect the main servo motor, but only the feedback circuit, thereby ensuring safety. To ensure stability, both pulse time and pulse frequency can be set, as can the time to the first pulse. It can be expressed in such a way that the equipment senses the effect of a pulse by the time a further pulse is emitted.

In the case of multi-motor systems, the pulse indicating overload is automatically selected, and if there is overload and underload at the same time, the overload signal takes priority.

As a result of setting the appropriate time until the first pulse, the proposed system will not affect the pitch in case of short-term disturbances, but increases the average load (e.g. in headwind) where a downregulation of the pitch occurs, and vice versa.

As the slope correction can only intervene to a limited extent, catastrophic over-regulation cannot occur under any circumstances.

With a switch between "manual" and "automatic", the automatic can be switched on or off, and in the "manual" position, the pitch can be fine-tuned from the bridge with thick knobs.

Design:

In order to obtain a reliable system, which can easily be adapted to standard equipment, an electro-hydraulic system with semi- !Lederk'omponent:er3'fr-aA signalgi-y.ernevMl^fsty-r.eorganene-j-fore-detghy.dr.au-lisketsysterrrrr. and, 31 to the tie rod ?5 and locking screws respectively. 21. Impact-, on-, rspeed. QViS operations manager is placed ne 11 about Ptc-i.inel.2t t<r>~, and

n.; a tv» r- 39 s ►Note-correct: "the setting ave equipment em wild fuel piumpens

.-position v(;load.one.)risåledesi all t-id-r. is laid to run with -.a set area f' pro f ulli. lastj unnt.agen-jd ider •korfte^itidsr.um:' daoiautomatikkenvlkke} when to cvxirjc-e,t'vfiiéks*,-ived?.,etj.al^^ farfcj rforo.yeri,i or •vedi. powerful! rapts jo .o,y.edjClan^ will" autpmatik-rkenl. on the other hand? Set? the climbs sl-iki that the engines gojh fully-tloaded {.ejitejiL mo t st ande n, t6k erc ell e r* minke r, t (d . <yr. iS!,.lj,ma nj fjår .erv ,op timal utilization Low-resources .pgi hjoyest possible?, fartf without-itva-rig tpyerjb.elast-ji-ingv Itv foresee s<cin |den- rf ortbindelse/tat (axelgeneratprjeruer,? inn-[kpbletjt) aitso^ that jnotprene.s,tpmd-reiningsta-1.,;er- -constant^ i\ sun and^.-l „J jne r enj eventvUsll disconnection -of.,-the automatic .b.lir,^ulighe-Æene.:cfor?.to in4uster,ejtstigi^ng,; manual.tCtf ra3 brpen^met, gp.de.rorVed. ff.,ex.t éu.hold^{the pushbutton- for.orj ^mskeJV, pulled down for a fprLsk j,ellig,long {time gets, man_(et0.stp\rrei el^lerQmindr^, t-rinn,jitcstyr^ngskoj]rejcsponen. In fig. , 1, is the invention,;me_s]taanyjendty .fatter, two-,.ho.wood engine,er.?, 1 and. 2.p , .Dlsse.,,drlveri overn a..exchange. 3- pro-;Pelle n?£jS;hy.isajblads t igningj can be rearranged withj.etppmstilling^organ 5 iSo m- .Bianovreres. with..a,, ser.yosystem. _ Manov.er0.f,or..adjustment., of. the propeller..for speed,, forward ..or, aft,- comes.,,,,,on, it. directly, lin i e rf W- $ ri??$ U. ?n?) ^ M^^^^^ m^ T Ptftemthggr &acet this way pWgåTr-en.signalomf ormer. SJepo^pmdannertcsignals2rfrom?:ten. fsignalyelger,lQ.r.to, pulsesThis.sse..pulses„ledes, to; (see the system, 6 etc. is, with the help of the relay and solenoid valve, transformed into manipvrement pulses for the servo system. The manipvration pulses correspond directly to the pulses that go out from the signal converter. The signal selector 10 receives its signals from a device 11: at each engine, a device which registers and detects the position of the fuel pump and thus the respective engine's load. .. In principle, the body can consist of two limit switches. which is affected „by irr^ane i. u -i P< / -> a >/ noi, .'j;aJe P^tmpe L<ire«x , something ' kra. t.en ;-om cppr: ta r -a certain setting of the fuel pump Alternatively, the body can consist ira ■-'••/K.ec -om vi Pk or p-: ae c.f oismae ovo^iwre-3 ti i piac«Pn ^r and of a position converter which constantly emits a signal whose character be-u" t.o f (i \ v. '-.Por :c:-. pi/ir?;-, yj :-r °frr Punaoc p^P. i\ra (*;an ocn re-.ji - tuned by the position of the fuel pump. ,This signal stays in the organ. 11 tere .• i r-j rv/KC?t ^o"; vir::er pi "iPrac^M without: Pr t rtr.' nKsoi-pSi^t i i sorted so that from this only further signals of a certain o /e r t i- t - l stcr-ps^ot -fj og ur tro ve 1 v tripp vi r ;;o° srenpv ie t is character, e.g. those that correspond to exceeding a certain position; ^ rt •.; '■■ <-t' roa . of the fuel pump setting. „ / ... -■ ;'t v: i , vou .Hi. -.t :•-?-<•...vv-:' r r r. which is shown : :'ig...

At a certain position of the fuel pump setting, e.g. a position that means significant overload with the desire for a rapid downregulation of the propeller pitch, the signal triggered in the organ 11 is led directly to the servo system 6 via the signal selector 10 as indicated by line 12. There is then no step-by-step adjustment of the propeller pitch, but such a only when the major congestion has been eliminated.

In the event that the body 11 consists of two limit position switches which limit the setting range for the fuel pump where no adjustment of the propeller takes place, the intended effect is achieved by arranging at least one further limit position switch outside the said setting range. Signals triggered by this switch are passed through the line 12 past the signal converter 9 and to the servo system 6, which adjusts the pitch.

In the event that the device 11 includes a position converter, this performs a distinction so that only signals of a certain nature are allowed through, e.g. signals corresponding to a high setting on the fuel pump. This signal passes the signal converter 9 through the line 12.

In fig. 2 shows how the servo system is arranged. The regulating device 9 - 11 is connected to the normal control system for the pitch regulation. A desired value for the rise is always set and transferred in the form of an e.g. pneumatic signal to an auxiliary servomotor 21. The auxiliary servomotor influences via a changeover crank 22 and a valve rod 23 the hub servomotor 24. This turns the propeller blades to a position directly corresponding to the position of the auxiliary servomotor's piston.

The auxiliary servo motor 21 is provided with a feedback loop consisting of a servo motor 25, mechanical feedback links 26 and 27 and a valve 28. The servo motor 25 is controlled by the regulator via a solenoid valve 29 - With the servo motor 25, the regulator can vary the auxiliary motor's feedback and thus vary the propeller pitch around the set desired value.

As can be seen from fig. 2, the maximum possible change of position depends on the position of the adjustment crank. Thus, e.g. the position is not changed at all by the servo motor 25 if the crank is in a rest position corresponding to pitch zero.

Another embodiment of the regulation device is shown in fig. 3. The electronics in this are as far as possible built up with integrated circuits. The logic circuits are of the high-level type with disturbance sensitivity ^>3 'V, while the counters used are of the low-level type.

Input signals come in the form of an alternating voltage from

a tachometer dynamo 31" Another input signal comes in the form of a direct voltage from the fuel pump's position sensor (0 - 10 V) and is routed separately via potentiometers 32, 33 to a signal selector 34.

The output signals are made up of control signals (220 V alternating voltage) to the inputs of two solenoid valves 35.

The signals are processed as follows:

The load curve is produced in a function generator 36, and the highest fuel pump position (BPL) is sensed in the signal selector 34.

Comparison between the desired value of BPL and the highest measured value is carried out in a totalizer 37* The difference obtained in the totalizer is compared with the limits for overload and underload.

Exceeding the limits starts after a certain delay a pulse train produced by a pulse generator.or 38.

A possible pulse train from the pulse generator to one or the other of the solenoid valves 35 adjusts the rise so that the load again comes within the permitted limits, provided that these are within the regulation range.

In more detail, the signal processing takes place as follows: The speed voltage from the speed counter dynamo 31 is rectified in the rectifier 39 and then serves to control the function generator 36. The function generator, whose active elements are made up of tc operational amplifiers, produces a function which, with four straight lines, approximately represents the relevant load curve. The function is determined by the setting of a number of potentiometers. The generator's output voltage (0 - +10 V) is therefore at any given moment a measure for the highest permissible fuel pump position.

With a potentiometer 40 connected after the function generator, the load curve can be shifted downwards to the desired value for the fuel pump position:

Uut<=>BPLbor * K«

The fuel pumps' position sensor is connected to the signal selector 34, which releases the largest (most negative) input signal again. The selector's output voltage indicates the largest measured value for BPL, but with a negative sign:

U ^ <=> BPL ,. max • K.

. out paint value max

The selector 34 consists of m silicon diodes where m = number of motors.

The output voltages from the signal selector and from the potentiometer 40 connected after the function generator 36 are added in a sign-changing summer 37 - The active element is an operational amplifier.

The output voltage from the adder is then a measure of the difference:

BPL o 1 a • — BPL, , .

paint value max bpr

The adder is connected to two comparators 4la and 42a.

If the difference BPL o- rQ ... mQV<-> BPL, , is greater than the design value max should

a certain adjustable value, one comparator's output voltage changes from 0 V to +10 V and thus indicates overload. If the difference is negative and greater than a certain value, the other comparator's output voltage changes to +10 V and thus indicates underload.

The comparators 4la and 42a are connected to a logic with the following function: The signals from the comparators are stopped if the current number of revolutions is lower than a predetermined value (number of revolutions at idle). This is realized by means of AND circuits 43a, 44a and a third comparator 45, which senses the number of revolutions.

If the number of revolutions is higher than the idle value and an overload or underload signal is output from the comparators 4la or 42a, a signal goes to the pulse generator 38 via a delay circuit in this and an OR circuit 46. After an adjustable delay, the pulse generator begins to emit a pulse train with adjustable pulse length and pulse frequency. The pulse train lasts as long as the load is outside the permitted range.

The delay circuit and the pulse generator mainly consist of three pre-settable counters.

If a "hand-auto" switch 47 is in the "auto" position, the pulse train is released further from either the increase or decrease channel 48 or 49 via AND circuits 50a, 51a, and when via an OR circuit 50b, 51b an amplifier 52 resp. 53. In case of large over- or underload and rpm higher than the idle rpm, affect a continuous signal from the comparators 4lb resp. 42b OR circuits 50b resp. 51b via the 0G circuits 43b resp. 44b. To each of the OR circuits 50 and 51, a signal line 54 or 55 from a maneuvering device 56 for manual control of the propeller pitch.

The amplifiers 52, 53, which are built around thyristors, each close a relay in time with the incoming pulse frequency. The relays 35 connect 220 V alternating voltage to the relevant input on the solenoid valve (not shown), with which a rise change proportional to the total pulse time is obtained.

For maneuvering the regulator there is a maneuvering

box on the bridge and a control panel in the control room. The switch 47 is located on the maneuvering ring box for "hand-auto" control of the propeller pitch. There are also two push buttons for the manual control

Eng. In the push buttons, there are built-in lamps that function automatically

tion indicates the correction pulses on oke- or decrease channel, while with manual function they indicate under- or overload.

There are four lamps on the control panel in the control room

57» 58, of which two 57 are connected in parallel with the lamps in the maneuvering

the case, while the other two 5^ .always indicate the correction pulses.

There are also six switches for setting the pulse generator's delay, pulse length and pulse frequency. For setting different reference values for underload, overload and idling speed and for lowering the load curve to the appropriate Snske value level there are four potentiometer knobs.

Claims (13)

1. Procedure for load regulation of ship engines whose rpm is regulated at a constant value by means of organs that affect the fuel supply to the engine, and where the fuel pump position is sensed and compared with pre-set limit values, so that an exceedance of the diss<p> limit values triggers a corrective signal which, converted into a pulse train, is fed to a servo system for repositioning a vessel propeller with adjustable blades in such a way that the load on the engine returns to the set value, characterized by ai - the pulses when the limit values are exceeded up to a certain point are directed to the servo system so that the adjustment of the pitch of the propeller blades takes place step by step with one step for each of the pulses in the pulse train, while the corrective signal when the mentioned limit values are exceeded beyond this point is first exceeded directly to the servo system so that a continuous pitch correction takes place, after which the corrective signal when passing a pump position closer to a ay the mentioned limit values is transformed into a pulse train for stepwise pitch correction. 2. Method as stated in claim 1, characterized in that each pulse in the pulse train is transformed into a pneumatic or hydraulic signal for the servo system. 3. Method as stated in claim 1, characterized in that the length of the pulses is adjustable. 4. Method as stated in claim 1, characterized in that the time between the pulses is adjustable. 5. Method as specified in claim 1, characterized in that the corrective signal is judged with regard to its duration and only after a certain adjustable duration is transformed into a pulse train. 6. Procedure as specified in claim 1, characterized in that the positions of the limit values are adjustable. 7. Method as stated in claim 6, characterized in that the setting of the limit values is carried out in a certain period of time depending on the permitted increase in the motor load. 8. Device for load regulation of marine engines whose rpm is regulated to a constant value by means of organs that affect the fuel supply to the engine, and where the fuel pump position is sensed and compared with pre-set limit values, so that a. exceeding these limit values triggers a corrective signal" which, converted into a pulse train, is applied to a servo system for repositioning a ship propeller with adjustable blades in such a way that the load on the engine returns to the set value in accordance with claim 1, an input signal in the form of an alternating voltage from a tachometer dynamo in a function generator produces a function that approximately represents a certain load curve, and this function generator's output voltage provides a measure for the permitted fuel pump position, as well as where the fuel pump position is indicated by means of a signal selector by a voltage that is added to the output voltage from the generator, and the signed sum resulting from the addition is judged by two comparators connected to the adder, characterized by the fact that the comparators are connected to a pulse generator which transforms one or the other of the signals from the comparators into pulse trains each of which reach via separate wires a relay that orors the comparator in question and ends in time with the incoming pulse frequency, and which connects a maneuvering voltage for maneuvering a servo motor for changing the position of the propeller blades, and that two comparators in case of large over-resp. underload continuously connects a control overvoltage for control of the same servo motor. 9. Device as stated in claim 8, characterized in that the pulse generator contains an adjustable delay circuit. 10. Device as specified in claim 8, characterized in that the pulse generator can be adjusted with regard to pulse length and frequency. 11. Device as stated in claim 8, characterized in that each line from the comparators to the pulse generator contains an AND circuit connected to the third comparator, which detects the number of revolutions. 12. Device as specified in claim 8, characterized by a potentiometer connected after the function generator for displacement of the load curve. 13. Device as specified in claim 8, characterized in that the function generator is made up of two operational amplifiers, and that the output function by four straight lines approximately represents the load curve.