CN102536568A - In-line diaphragm-type pressurizing pump for dimethyl-ether engine - Google Patents

Abstract

The invention relates to an in-line diaphragm pressure pump for a dimethyl ether engine. Its technical scheme is: be provided with 2～4 cams on the camshaft (15); Tappet body parts are housed in the tappet holes identical with the number of cams that the lower pump body (10) is provided with, on the camshaft (15) The cam is in active contact with the corresponding roller (14), and the upper end of the tappet (13) is equipped with an adjustment block (11); the plunger (8) in the plunger sleeve (6) installed on the upper pump body (5) The lower end is in movable contact with the corresponding adjustment block (11); the pump head upper cover (1) installed on the plunger sleeve hole and the pump head lower cover (3) are provided with a diaphragm (2); the pump head upper cover (1) The oil passages of the oil inlet valve (23) and the oil outlet valve (22) on the pump head communicate with the 2~5 oil holes of the pump head upper cover (1), and the hole-shaped hydraulic oil chamber of the pump head lower cover (3) communicates with the pump head The 2~5 oil holes of the lower cover (3) communicate with each other; the oil cavity formed by the pump head lower cover (3) and the diaphragm (2) communicates with the oil cup part (26) through the oil pipe (25). The invention has the characteristics of small volume, high pressure and small pressure pulsation, etc., and can effectively solve the problem of wear of the plunger pair.

Description

A kind of in-line diaphragm booster pump for dimethyl ether engine

technical field

The present invention belongs to the technical field of dimethyl ether engine. In particular, it relates to an in-line diaphragm pressurizing pump for a dimethyl ether engine.

Background technique

With the rapid development of my country's national economy and the rapid growth of the number of motor vehicles, the demand for energy continues to increase. At the same time, the impact of motor vehicle emissions on the environment is becoming more and more serious, and the contradiction between the two is becoming more and more acute. . Energy shortage and environmental pollution have become important problems to be solved urgently in our country. Therefore, it is imminent to find suitable alternative clean fuels.

Dimethyl Ether (DME for short), the molecular structure is CH ₃ -O-CH ₃ . Dimethyl ether is gaseous at room temperature, has almost no toxicity, low boiling point, and low natural temperature; its cetane number exceeds 55 (higher than diesel), and it has a wide range of sources and low cost. It has received widespread attention as an alternative fuel for diesel engines. Compared with diesel and other alternative fuels, DME has the advantages of high efficiency, low emission, low noise and smokeless combustion. Studies have shown that DME fuel can increase the power of traditional direct-injection diesel engines by 16%, increase thermal efficiency by 2% to 3%, reduce NOx emissions by about 40%, and reduce the pressure increase rate from the original 0.6MPa/°CA to 0.28~0.47MPa/°CA, achieve smokeless combustion, and the noise is significantly reduced; it can even meet the strict European Stage IV emission limit standards and the California Ultra Low Emission Vehicle (ULEV) standard.

Due to the obvious difference in the physical and chemical properties of dimethyl ether compared with diesel oil, dimethyl ether is not suitable for direct use in diesel engines. The low viscosity of dimethyl ether (viscosity is about 1/10~1/20 of diesel) is easy to As a result, the plunger couple of the fuel injection pump in the high-pressure fuel supply system is easily worn, resulting in insufficient fuel supply and low pump oil pressure. In order to make DME convenient to use in diesel engines, the fuel supply system of diesel engines needs to be improved accordingly.

In the existing research, there are mainly two solutions to solve the problem of wear and leakage of the plunger coupling parts of the fuel injection pump: one is to use a high proportion of dimethyl ether and diesel oil (Li Benzheng, Guo Zengjie, Hu Zhen, etc. Gao Experimental research on the wear of high-pressure oil pump plunger couples with proportional dimethyl ether and diesel fuel mixture [J]. Diesel Engine, 2006, 28 (3): 21-23); the other is to add lubrication improvement to dimethyl ether fuel (Huang Zhuoyong, Hu Tiegang, Zhou Longbao, etc. Research on improving the lubricating performance of dimethyl ether fuel [J]. Journal of Xi'an Jiaotong University, 2005, 39 (3): 233-237). Studies have shown that, compared with pure dimethyl ether, high-proportion DME-diesel blended fuel can effectively improve the early wear and leakage of high-pressure plunger parts, but in the long run, it does not fundamentally solve the problem of fuel injection pump plunger parts. In addition, adding a lubricity improver to dimethyl ether fuel can reduce the wear of the paired parts to a certain extent, but it will have a negative impact on the combustion and emission performance. When the amount added exceeds a certain percentage, it will Significantly produces particulate (PM) emissions.

In the existing research, based on the theory of easy atomization of dimethyl ether and homogeneous compression ignition (HCCI), a controllable premixed combustion (CPC) system is designed, and the fuel supply system can adopt a low-pressure common rail injection scheme (Tao Jun, Wang Weihua, You Caixia, et al. Design and test of low pressure common rail fuel injection system for dimethyl ether engine [J]. Journal of Wuhan University (Engineering Science Edition), 2010, (06): 770-773+783). Preliminary studies have shown that the common rail injection pressure is 6.0MPa, or even lower can achieve better injection and combustion, and the common rail pressure can be stabilized at about 10MPa to enable the engine to obtain relatively satisfactory power, fuel consumption and emission indicators. Therefore, the pressure boosting requirements of the booster pump for delivering dimethyl ether fuel to the common rail pipe are not high.

The hydraulic diaphragm pump relies on the back and forth agitation of the flexible diaphragm to inhale and discharge the liquid medium. There is no problem of medium leakage from the gap between the plunger couples; the interface between the plunger couples relies on an independent lubrication system to achieve lubrication and sealing during movement. Preliminary experiments show that although the hydraulic diaphragm pump can solve the wear and sealing problems of dimethyl ether fuel, the existing hydraulic diaphragm pumps are generally driven by motors, which have the disadvantages of large volume, relatively low output pressure, few reciprocating times during movement, and pressure Due to the shortcomings of large pulsation, it does not have the conditions for direct use in vehicle engines, and the existing hydraulic diaphragm pump structure must be improved and optimized.

Contents of the invention

In order to achieve the above object, the present invention aims to overcome the defects of the prior art, and the purpose is to provide a simple structure, small volume, high pressure, small pressure pulsation, convenient operation, safe use, and can effectively solve the problem caused by the low viscosity of dimethyl ether. The wear problem of plunger coupling parts and the in-line diaphragm booster pump for dimethyl ether engines that meet the requirements of vehicles.

In order to achieve the above object, the technical solution adopted by the present invention is: the pump body is composed of an upper pump body and a lower pump body connected by studs. The camshaft is horizontally installed at the lower part of the lower pump body, and there are 2~4 cams on the camshaft; the lower pump body is provided with tappet holes equal to the number of cams, and each tappet hole is located directly above the corresponding cam. Each tappet hole is equipped with a tappet body part. The tappet body part is composed of a tappet, a roller and a roller pin. The roller is installed in the tappet through the roller pin. Each cam on the camshaft moves with its corresponding roller. For contact, the upper end of the tappet is equipped with an adjusting spacer.

The upper pump body is provided with plunger sleeve holes equal to the number of cams, each plunger sleeve hole is equipped with a plunger sleeve, and the lower end of the plunger in each plunger sleeve is in movable contact with the corresponding adjustment pad; The upper end of the plunger spring is supported on the lower plane of the upper pump body, and the lower end of the plunger spring is supported on the spring seat at the lower part of the plunger.

The convex part of each pump head lower cover (3) is embedded in the upper part of the corresponding plunger sleeve hole, the pump head upper cover and the pump head lower cover are fixed on the upper pump body by studs, the pump head upper cover and the pump head lower There is a diaphragm at the center between the covers; the upper cover of the pump head is equipped with an oil inlet valve and an oil outlet valve. The 2~5 oil holes provided at the center of the lower plane communicate with each other; the lower part of the lower cover of the pump head is provided with a hole-like hydraulic oil chamber, and the top of the hole-like hydraulic oil chamber is set at the center of the upper plane of the lower cover of the pump head. Some 2~5 oil holes are connected, and the bottom of the hole-shaped hydraulic oil chamber is concentrically connected with the plunger hole of the plunger sleeve; the oil chamber formed by the space between the lower cover of each pump head and the corresponding diaphragm passes through the corresponding The oil pipe communicates with the oil cup part.

A high-pressure sealing ring is installed between the lower cover of the pump head and the plunger sleeve.

The camshaft is installed in two left and right tapered roller bearings, and the input end of the camshaft is provided with a coupling.

The upper side of the lower pump body has a window, and the window is equipped with a window cover; the middle side of the lower pump body is equipped with an oil dipstick, and the bottom of the lower pump body is equipped with an oil drain screw.

The cylindrical surface of the tappet is provided with a straight groove along the vertical direction, and the positioning screw is inserted into the straight groove.

The plunger and the plunger sleeve form a plunger pair, the number of the plunger pair is equal to the number of cams on the camshaft and the number of oil cup parts, and the middle part of the cylindrical surface of the plunger is provided with an annular pressure-relief groove; The material is high-quality alloy steel, and the gap between the plunger 8 and the plunger sleeve 6 is 0.0012~0.0025mm.

The oil cup part is composed of an oil cup cover, a pressure relief valve, an air release valve, an oil replenishment valve and a valve seat. The pressure relief valve, the air release valve and the oil replenishment valve are evenly arranged on the valve seat, and an oil passage is arranged in the valve seat, and the pressure relief valve, the air release valve and the oil replenishment valve communicate with the oil pipe through the oil passage.

Due to the adoption of the above scheme, the cam on the camshaft of the present invention is in active contact with the roller, and the eccentric rotation of the cam drives the plunger to reciprocate up and down in the plunger sleeve; the reciprocating movement of the plunger makes the hydraulic oil squeeze the diaphragm back and forth, and the diaphragm repeatedly Agitation, so as to achieve the purpose of absorbing and discharging dimethyl ether fuel; the power of the camshaft comes directly from the engine, which is enough to provide an output pressure above 10MPa; there are 2~4 cams on the camshaft, and the interval angles between the cams are equal. When the camshaft rotates, the cams work alternately, increasing the oil supply frequency, reducing the stroke of the plunger and the amount of oil supplied per stroke, thereby reducing the deflection of the diaphragm. While ensuring the flow of DME fuel, Can increase the life of the diaphragm. Therefore, the device has the advantages of simple structure, high pressure, small pressure pulsation and long working life.

The plunger couple used in the present invention is generally made of high-quality alloy steel. After fine processing and paired grinding, the matching gap between the plunger and the plunger sleeve is between 0.0012 and 0.0025mm, which ensures the tightness between the plunger couple. Sealing, compared with the traditional packing sealing method, the volume of the device is further reduced; the plunger couple is self-lubricated by hydraulic oil, and the hydraulic oil can be diesel or hydraulic oil with a viscosity similar to diesel; the cylinder of the plunger There is an annular decompression groove on the surface to form a decompression zone, which reduces the leakage of hydraulic oil and further improves the sealing performance; the dimethyl ether fuel and the hydraulic oil are separated by a diaphragm, and the dimethyl ether fuel is not connected to the plunger couple. touch. Therefore, the device effectively solves the problem of wear of the plunger pair due to the low viscosity of dimethyl ether.                     

The oil cup part used in the present invention is a hydraulic oil supply control system. The space communicated between the diaphragm and the upper end surface of the plunger forms a hydraulic chamber, and the hydraulic oil enters the hydraulic chamber from the oil cup part through the oil pipe. When filling hydraulic oil into the hydraulic chamber, open the vent valve to discharge the gas in the hydraulic chamber; when the pressure in the hydraulic chamber rises abnormally, the pressure relief valve takes off to protect the diaphragm and pump head. The take-off pressure of the pump is set to about 1.1 times of the discharge pressure of dimethyl ether fuel; when the hydraulic oil in the hydraulic chamber reaches a certain amount of leakage, the oil replenishment valve opens to realize automatic oil replenishment. The oil cup part is connected with the lower cover of the pump head through the oil pipe, so that the hydraulic oil supply control system is separated from the pump body, which increases the convenience of installation and operation. Therefore, the device is convenient to operate and safe to use.

Therefore, the present invention has the characteristics of simple structure, small volume, high pressure, small pressure pulsation, convenient operation and safe use. requirements.

Description of drawings

Fig. 1 is a kind of structural representation of the present invention;

Fig. 2 is the A-A direction sectional view of Fig. 1;

Fig. 3 is the structural representation of oil cup part 26 among Fig. 2;

FIG. 4 is a schematic diagram of the right view of FIG. 3 .

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, the present invention is further described, not limitation to its protection scope:

Example 1

An in-line diaphragm booster pump for a dimethyl ether engine, as shown in Figures 1 and 2, the pump body is composed of an upper pump body 5 and a lower pump body 10 connected by studs. The camshaft 15 is horizontally installed on the bottom of the lower pump body 10, and the camshaft 15 is provided with 2 cams; the lower pump body 10 is provided with 2 tappet holes, and each tappet hole is located directly above the corresponding cam, and each tappet hole Tappet body parts are all housed in the post hole, and tappet body parts are made up of tappet 13, roller 14 and roller pin 12, and roller 14 is installed in the tappet 13 by roller pin 12, each cam on the camshaft 15 and The respective corresponding rollers 14 are in movable contact, and the upper end of the tappet 13 is equipped with an adjusting block 11 .

There are two plunger sleeve holes in the upper pump body 5, each plunger sleeve hole is equipped with a plunger sleeve 6, and the lower end of the plunger 8 in each plunger sleeve 6 is in movable contact with the corresponding adjustment pad 11 ; The upper end of the plunger spring 7 is supported on the lower plane of the upper pump body 5, and the lower end of the plunger spring 7 is supported on the spring seat 9 at the bottom of the plunger 8.

The raised part of each pump head lower cover (3) is embedded in the upper part of the corresponding plunger sleeve hole, the pump head upper cover 1 and the pump head lower cover 3 are fixed on the upper pump body 5 by studs, and the pump head upper cover 1 A diaphragm 2 is provided at the center between the pump head lower cover 3; the pump head upper cover 1 is equipped with an oil inlet valve 23 and an oil outlet valve 22, and the outlet of the oil inlet valve 23 passes through the oil passage and the oil outlet valve 22 The inlet is connected, and the oil passage is connected with the 2~5 oil holes provided at the center of the lower plane of the pump head upper cover 1; the lower part of the pump head lower cover 3 is provided with a hole-shaped hydraulic oil chamber, and the hole-shaped hydraulic oil chamber The top of the pump head lower cover 3 communicates with the 2~5 oil holes provided at the center of the upper plane of the pump head lower cover 3, and the bottom of the hole-shaped hydraulic oil chamber communicates with the plunger hole of the plunger sleeve 6 concentrically; each pump head The oil cavity formed by the space between the lower cover 3 and the corresponding diaphragm 2 communicates with the oil cup part 26 through respective oil pipes 25 .

A high-pressure sealing ring 4 is installed between the lower cover 3 of the pump head and the plunger sleeve 6 .

Described camshaft 15 is installed in two left and right tapered roller bearings 18, and the input end of camshaft 15 is provided with coupling 19.

One side of the lower pump body 10 is provided with a window, and the window is provided with a window cover 21;

The cylindrical surface of the tappet 13 is provided with a straight groove along the vertical direction, and the set screw 24 is inserted into the straight groove.

The plunger 8 and the plunger sleeve 6 form a plunger pair, the number of the plunger pair is 2 with the number of cams on the camshaft 15, and the number of oil cup parts 26, and the middle part of the cylindrical surface of the plunger 8 is provided with a ring-shaped reducing The pressure groove 20; the material of the plunger pair is high-quality alloy steel, and the gap between the plunger 8 and the plunger sleeve 6 is 0.0012-0.0025mm.

As shown in FIGS. 3 and 4 , the oil cup part 26 is composed of an oil cup cover 27 , a pressure relief valve 30 , an air release valve 31 , an oil replenishment valve 28 and a valve seat 29 . The pressure relief valve 30, the air release valve 31 and the oil replenishment valve 28 are evenly arranged on the valve seat 29, and an oil passage is arranged in the valve seat 29, and the pressure relief valve 30, the air release valve 31 and the oil replenishment valve 28 pass through the oil The road communicates with the oil pipe 25.

Example 2

The utility model relates to an in-line diaphragm pressurizing pump for a dimethyl ether engine. Except that there are 3 to 4 cams, plunger couples, oil cup parts 26, tappet parts, pump head upper cover 1, pump head lower cover 3 and diaphragm 2 provided on the camshaft 15, the rest are implemented in the same way. example 1.

The cam on the camshaft 15 of this specific embodiment is in active contact with the roller 14, and the eccentric rotation of the cam drives the plunger 8 to reciprocate up and down in the plunger sleeve 6; the reciprocating movement of the plunger 8 makes the hydraulic oil squeeze the diaphragm 2 back and forth , the diaphragm 2 is agitated repeatedly, so as to achieve the purpose of sucking and discharging dimethyl ether fuel; the power of the camshaft 15 comes directly from the engine, which is enough to provide an output pressure above 10MPa; the camshaft 15 is provided with 2~4 cams, When the camshaft 15 rotates, the cams work alternately, which increases the frequency of oil supply, reduces the stroke of the plunger 8 and the amount of oil supplied per stroke, thereby reducing the deflection of the diaphragm 2. While ensuring the dimethyl ether fuel flow rate, the life span of the diaphragm 2 can be increased. Therefore, the device has the advantages of simple structure, high pressure, small pressure pulsation and long working life.

The plunger couple used in this specific embodiment is made of high-quality alloy steel. After fine processing and matching grinding, the matching gap between the plunger 8 and the plunger sleeve 6 is between 0.0012 ~ 0.0025mm, ensuring that the plunger couple Compared with the traditional packing sealing method, the volume of the device is further reduced; the plunger pair is self-lubricated by hydraulic oil, and the hydraulic oil is diesel oil or hydraulic oil with a viscosity similar to diesel oil; the plunger There is an annular decompression groove 20 on the cylindrical surface of 8, which forms a decompression zone, reduces the leakage of hydraulic oil, and further improves the sealing performance; the dimethyl ether fuel and the hydraulic oil are separated by the diaphragm 2, and the dimethyl ether fuel does not Contact with the plunger couple. Therefore, the device effectively solves the problem of wear of the plunger pair due to the low viscosity of dimethyl ether. the

The oil cup part 26 used in this specific embodiment is a hydraulic oil supply control system. The space communicated between the diaphragm 2 and the upper end surface of the plunger 8 forms a hydraulic chamber, and the hydraulic oil enters the hydraulic chamber from the oil cup part 26 through the oil pipe 25 . When pouring hydraulic oil into the hydraulic chamber, open the vent valve 31 to discharge the gas in the hydraulic chamber; when the pressure in the hydraulic chamber rises abnormally, the pressure relief valve 30 takes off to protect the diaphragm 2 and the pump head. The take-off pressure of the pressure relief valve 30 is set to about 1.1 times of the discharge pressure of the dimethyl ether fuel; when the hydraulic oil in the hydraulic chamber reaches a certain amount of leakage, the oil replenishment valve 28 is opened to realize automatic oil replenishment. The oil cup part 26 is connected with the pump head lower cover 3 through the oil pipe 25, so that the hydraulic oil supply control system is separated from the pump body, which increases the convenience of installation and operation. Therefore, the device is convenient to operate and safe to use.

Therefore, this specific embodiment has the characteristics of simple structure, small volume, high pressure, small pressure pulsation, convenient operation, safe use, etc., can effectively solve the problem of plunger couple wear caused by low viscosity of dimethyl ether, and can meet Automotive requirements.

Claims (6)

1. a dimethyl ether engine is characterized in that with diaphragm type compression pump in upright arrangement: the pump housing is connected to form through double-screw bolt by upper pump casing (5) and lower pump body (10); Camshaft (15) flatly is installed in the bottom of lower pump body (10), and camshaft (15) is provided with 2 ~ 4 cams; Lower pump body (10) is provided with the tappet hole that equates with the cam number; Each tappet hole be positioned at corresponding cam directly over; In each tappet hole the tappet body component is housed all, the tappet body component is made up of tappet (13), roller (14) and roller pin (12), and roller (14) is installed in the tappet (13) through roller pin (12); Each cam on the camshaft (15) contacts with each self-corresponding roller (14) is movable, and adjustment cushion block (11) is equipped with in the upper end of tappet (13);

In upper pump casing (5), be provided with the plunger trepanning that equates with the cam number, each plunger trepanning all is equipped with plunger bushing (6), plunger (8) lower end in each plunger bushing (6) and the movable contact of corresponding adjustment cushion block (11); The upper end of piston spring (7) is bearing in the lower plane of upper pump casing (5), and the lower end of piston spring (7) is bearing on the spring seat (9) of plunger (8) bottom;

The convex portion of each pump head lower cover (3) embeds the top of corresponding plunger trepanning, and pump head loam cake (1) is fixed on the upper pump casing (5) through double-screw bolt with pump head lower cover (3), and the center position between pump head loam cake (1) and the pump head lower cover (3) is provided with barrier film (2); Pump head loam cake (1) is equipped with oiling valve (23) and outlet valve (22), and the outlet of oiling valve (23) communicates through the import of oil duct and outlet valve (22), and said oil duct communicates with 2 ~ 5 oilholes that the center position of pump head loam cake (1) lower plane is provided with; Pump head lower cover (3) bottom is provided with poroid hydraulic fluid chamber, and the top of said poroid hydraulic fluid chamber and pump head lower cover (3) are gone up 2 ~ 5 oilholes that the center position on plane is provided with and communicated, concentricity the communicating of plunger hole of the bottom of said poroid hydraulic fluid chamber and plunger bushing (6); The oil pocket that each pump head lower cover (3) and space between corresponding barrier film (2) constitute communicates with lubricating cup parts (26) through oil pipe (25) separately;

Between pump head lower cover (3) and the plunger bushing (6) high-pressure seal ring (4) is installed.

2. dimethyl ether engine according to claim 1 is characterized in that with diaphragm type compression pump in upright arrangement said camshaft (15) is installed in left and right two tapered roller bearings (18), and the input end of camshaft (15) is provided with coupling (19).

3. dimethyl ether engine according to claim 1 is characterized in that with diaphragm type compression pump in upright arrangement said lower pump body (10) top one side has window, and window is equipped with scuttle (21); Lower pump body (10) middle part one side is equipped with oil scale (17), and the screw of draining the oil (16) is equipped with in the bottom of lower pump body (10).

4. dimethyl ether engine according to claim 1 is characterized in that with diaphragm type compression pump in upright arrangement the cylndrical surface of said tappet (13) vertically has straight trough, and positioning screwn (24) is inserted in the straight trough.

5. dimethyl ether engine according to claim 1 is with diaphragm type compression pump in upright arrangement; It is characterized in that said plunger (8) and plunger bushing (6) constitute plunger coupled parts; The plunger coupled parts number is counted with cam number, lubricating cup parts (26) on the camshaft (15) and is equated that the middle part, cylndrical surface of plunger (8) has ring decompression groove (20); The material of plunger coupled parts is a superior alloy steel, and the gap of plunger 8 and plunger bushing 6 is 0.0012 ~ 0.0025mm.

6. dimethyl ether engine according to claim 1 is with diaphragm type compression pump in upright arrangement; It is characterized in that said lubricating cup parts (26) are made up of lubricating cup cover (27), pressure-relief valve (30), bleed valve (31), Fill valve (28) and valve seat (29); Pressure-relief valve (30), bleed valve (31), Fill valve (28) are arranged on the valve seat (29) equably; Valve seat is provided with oil duct in (29), and pressure-relief valve (30), bleed valve (31) and Fill valve (28) communicate with oil pipe (25) through said oil duct.

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