KR20030074222A - Injection pump and a fuel supply system of a diesel engine including the same - Google Patents

Abstract

Provided is an injection pump that enables fine adjustment of the effective stroke length of the plunger without adjusting the position of the control rack by the governor.

In the vicinity of the outer circumferential surface of the plunger 26 facing the oil chamber 11, the sleeve 12 is provided in a state fitted to the plunger. The sleeve is provided with a sleeve port 121 for communicating the inner circumferential surface of the hole into which the plunger is inserted and the outer circumferential surface facing the oil chamber. The sleeve actuator 65 rotates the sleeve drive member 13 provided in each injection pump element 2 to move the sleeve up and down. The stroke position of the plunger 26, in which the cutout portion 263, which is blocked from the oil chamber by the inner circumferential surface of the sleeve 12 and the sleeve port, communicates with the fuel injection end position of the effective stroke at a position lower than the sleeve port.

Description

Injection pump and fuel supply device for diesel engines with the injection pump {INJECTION PUMP AND A FUEL SUPPLY SYSTEM OF A DIESEL ENGINE INCLUDING THE SAME}

The present invention relates to an injection pump of a fuel supply device of a diesel engine, and a fuel supply device of a diesel engine having the injection pump.

BACKGROUND Diesel engines known as internal combustion engines using diesel fuel are generally widely used in trucks, buses, passenger cars, and the like. In recent years, as a countermeasure against air pollution by diesel engines, attention has been paid to using DME (dimethyl ether) with clean exhaust gas instead of light oil. DME fuel is a liquefied gas fuel, unlike diesel fuel, which is a conventional fuel. That is, the boiling point temperature is lower than that of diesel, and while diesel is a liquid at room temperature under atmospheric pressure, DME has a property of becoming a gas at normal temperature.

BACKGROUND ART A fuel injection device of a general diesel engine includes an injection pump for supplying a desired amount of fuel to each fuel injection nozzle provided in each cylinder of the diesel engine. A fuel tank in which fuel is stored is connected to the injection pump, and during operation of the diesel engine, the fuel of the fuel tank is supplied to the oil chamber of the injection pump by a feed pump. do. The injection pump pumps the fuel in the oil chamber by the desired amount from each injection pump element connected to each fuel injection nozzle. The amount of fuel pumped from the injection pump element is determined in accordance with the effective stroke length of the plunger of the injection pump element. The effective stroke length of the plunger is changed by adjusting the position of the control rack and rotating the plunger from side to side, thereby adjusting the amount of fuel pumped from each injection pump element to each fuel injection nozzle.

The position of the control rack is controlled by a governor mounted on the injection pump. In general, the governor controls the rotation speed of the diesel engine by adjusting the position of the control rack, and structurally, the mechanical governor using centrifugal force of the weight and signals from various sensors are calculated by the control unit to determine the position of the control rack. It can be roughly divided into two types of electronic governors which are electronically controlled.

By the way, fuel, such as diesel, changes in density (kg / m <3>) and volume modulus (N / mm <2>) with temperature. For this reason, because the temperature of the fuel is different, the fuel injection amount fed from the injection pump to each fuel injection nozzle is changed even with the same effective stroke length. Therefore, there is a concern that the number of revolutions of the diesel engine may be greater or less than the desired number of revolutions depending on the temperature of the fuel. Therefore, it is necessary to adjust the position of the control rack according to the temperature of the fuel, that is, to correct the position of the control rack according to the temperature of the fuel. As described above, the electronic governor can electronically control the position of the control rack by calculating signals from various sensors in the control unit.

However, since the mechanical governor adjusts the position of the control rack by the automatic adjustment mechanism using the centrifugal force of the weight, it cannot be said that the position of the control rack is finely adjusted in accordance with the temperature of the fuel. In addition, since the ratio of the change according to the temperature of the density (kg / m 3) or the volume modulus (N / mm 2) is particularly large compared with the diesel fuel, the DME fuel may be particularly susceptible to the influence of the temperature change of the fuel. . Therefore, in the conventional diesel engine of diesel fuel, there exists a possibility that the change of rotation speed with the temperature change negligible to some extent will become so large that it cannot be negligible in the diesel engine of DME fuel. Therefore, in the injection pump equipped with a mechanical governor, a problem arises in that the fuel injection amount from each fuel injection nozzle cannot be adjusted in response to the temperature change of the fuel, and the mechanical governor is connected to the fuel injection device of the diesel engine of DME fuel. There is a problem that it can not be mounted.

This invention is made | formed in view of such a situation, The subject of this invention is providing the injection pump which can perform fine adjustment of the effective stroke length of a plunger, without adjusting the position of a control rack by a governor.

In order to achieve the above object, the invention described in claim 1 of the present invention is an oil chamber supplied with fuel in a fuel tank, a plunger which moves up and down in combination with a camshaft which is rotated by rotation of a drive shaft of a diesel engine, and the plunger And a plunger barrel having a hydraulic chamber that sucks and compresses the fuel from the oil chamber by rising, and a discharge valve installed in the hydraulic chamber and opened by the pressure of the fuel in the hydraulic chamber. An injection pump of a fuel supply device of a diesel engine having an injection pump element for discharging the fuel from the delivery valve to an injection pipe communicating with the fuel injection nozzle of the diesel engine by a predetermined amount at a predetermined timing. The injection pump element is placed up and down in the oil chamber with the plunger inserted. A sleeve having a substantially cylindrical shape, and a sleeve position adjusting means for moving the sleeve up and down, wherein the plunger has an upper end facing the hydraulic chamber and a plunger port for communicating the oil chamber. In the ascending stroke, the stroke position of the plunger, in which communication between the hydraulic chamber and the oil chamber by the plunger port is interrupted, becomes a start position of the effective stroke of the plunger, and the sleeve is a through hole into which the plunger is inserted. The plunger having a sleeve port for communicating between an inner circumferential surface of the circumferential surface and an outer circumferential surface facing the oil chamber, and in a rising stroke of the plunger, a cutout portion communicating with the hydraulic chamber formed on an outer circumferential surface of the plunger and the sleeve port. Stroke position of the effective plunger stroke An injection pump, characterized in that the injection end position.

Thus, the stroke position of the plunger which has the sleeve provided so that it can move up and down in the oil chamber in the state in which the plunger was inserted, the sleeve port formed in this sleeve, and the cutout part of the plunger which communicates with the hydraulic chamber are communicated. Since the injection end position of the effective stroke of the plunger is changed, the injection end position of the effective stroke of the plunger changes in accordance with the position of the sleeve. In addition, since the injection start position of the effective stroke of the plunger is the stroke position of the plunger in which communication between the hydraulic chamber and the oil chamber by the plunger port is interrupted, the injection start position of the effective stroke of the plunger does not change even if the sleeve position changes. Therefore, the injection end position of the effective stroke of the plunger can be adjusted by adjusting the position of the sleeve with the sleeve position adjusting means, whereby the effective stroke length of the plunger can be adjusted.

Therefore, according to the injection pump according to the invention of claim 1, since the injection end position of the effective stroke of the plunger can be adjusted by adjusting the position of the sleeve with the sleeve position adjusting means, fine adjustment of the effective stroke length of the plunger can be performed. The effect is that the governor can be executed without adjusting the position of the control rack.

In the invention described in claim 2, the sleeve position according to claim 1 is a fuel temperature sensor that detects a temperature of the fuel in the oil chamber and a position of the sleeve in accordance with a temperature of the fuel detected by the fuel temperature sensor. And an injection end position control means for adjusting the injection end position of the effective stroke of the plunger by adjusting by an adjustment means.

Therefore, according to the injection pump which concerns on this invention of Claim 2, according to the temperature of the fuel in the oil chamber detected by the fuel temperature sensor by the injection end position control means in addition to the effect by the invention of Claim 1 of this application, Since the injection end position of the effective stroke of the plunger can be adjusted, the effect of fine adjustment of the effective stroke length of the plunger can be obtained even in the injection pump equipped with the mechanical governor according to the temperature of the fuel.

In the invention according to claim 3, the sleeve position adjusting means according to claim 1, the sleeve driving unit for moving the sleeve to the desired position by energizing a drive signal corresponding to the position of the desired sleeve, and the sleeve An injection pump having a sleeve position detection sensor for detecting a position.

Since the position of the sleeve can be detected by the sleeve position detection sensor, it is possible to control the drive signal that is energized to the sleeve driver so that the sleeve moves to a desired position while checking the position of the sleeve. Therefore, the sleeve position can be adjusted more accurately.

Therefore, according to the injection pump according to the invention described in claim 3 of the present invention, since the adjustment of the sleeve position can be carried out more accurately in addition to the effect of the invention according to claim 1 of the present invention, more precise adjustment of the effective stroke length of the plunger. The effect of this becomes possible.

In the invention according to claim 4, in the second aspect, the sleeve position adjusting means includes a sleeve driving unit for moving the sleeve to a desired position by energizing a driving signal corresponding to the position of the desired sleeve; An injection pump having a sleeve position detection sensor for detecting a position.

Since the position of the sleeve can be detected by the sleeve position detection sensor, it is possible to control the drive signal that is energized to the sleeve driver so that the sleeve moves to a desired position while checking the position of the sleeve. Therefore, the sleeve position can be adjusted more accurately.

Therefore, according to the injection pump according to the invention described in claim 4, since the adjustment of the sleeve position can be carried out more accurately in addition to the effect of the invention according to claim 2, the adjustment of the effective stroke length of the plunger more accurately. The effect of this becomes possible.

The invention described in claim 5 is a fuel supply device for a diesel engine provided with the injection pump according to any one of claims 1 to 4.

According to the fuel supply device of the diesel engine according to the invention described in claim 5 of the present application, in the fuel supply device of the diesel engine, the effect of the invention according to any one of claims 1 to 4 described above can be obtained.

Invention of Claim 6 of this application is a fuel supply apparatus of the diesel engine of Claim 5 which uses DME (dimethyl ether) fuel as said fuel.

As described above, the DME fuel has a particularly large rate of change depending on the temperature of the density (kg / m 3) and the volume modulus (N / mm 2) as compared with the diesel fuel. Therefore, according to the fuel supply apparatus of the diesel engine which concerns on this invention of Claim 6, in the fuel supply apparatus of the diesel engine which used DME fuel as fuel by the effect of the invention of Claim 5 of this application, The effect of correcting the effective stroke length of the plunger according to the temperature can be appropriately performed without adjusting the position of the control rack by the governor.

1 is a system configuration diagram showing a schematic configuration of a DME fuel supply apparatus of a diesel engine according to the present invention;

2A is an essential part cross sectional view showing a state where the stroke position of the plunger of the injection pump element is at the fuel injection start position of the effective stroke;

2B is an enlarged view of a portion of FIG. 2A;

3A is an essential part cross sectional view showing a state where the stroke position of the plunger of the injection pump element is the fuel injection end position of the effective stroke;

3B is an enlarged view of a portion of FIG. 3A;

4A is an essential part cross sectional view showing a state where the sleeve in FIG. 2 is in another position;

4B is an enlarged view of a portion of FIG. 4A;

5A is an essential part cross sectional view showing a state where the sleeve in FIG. 3 is in another position;

5B is an enlarged view of a portion of FIG. 5A;

6a schematically shows the difference in the effective stroke length of the plunger due to the difference in the position of the sleeve, showing a state in which the sleeve is near the cutout;

Fig. 6B is a view schematically showing the difference in the effective stroke length of the plunger due to the difference in the position of the sleeve, and showing the state in which the sleeve is near the hydraulic chamber.

Explanation of symbols for the main parts of the drawings

1: injection pump 2: injection pump element

3: injection pipe 4: fuel tank

5: feed pump 6: oil separator

7: aspirator 8, 9: overflow fuel pipe

11: oil chamber 12: sleeve

13 sleeve drive member 14 fuel temperature sensor

21: outlet valve holder 22: outlet spring

23: delivery valve 24: delivery valve seat

25: plunger barrel 26: plunger

31 cylinder 32 fuel injection nozzle

41 cooler 51 filter

61: compressor 65: sleeve actuator

100: DME fuel supply device 121: sleeve port

200: diesel engine

Hereinafter, an embodiment of the present invention will be described based on the drawings.

First, a schematic configuration of a fuel supply device of a diesel engine will be described as an example of a DME fuel supply device of a diesel engine using DME fuel as an example.

1 is a system configuration diagram showing a schematic configuration of a DME fuel supply apparatus of a diesel engine according to the present invention.

The DME fuel supply apparatus 100 which supplies a DME fuel to the diesel engine 200 is equipped with the injection pump 1 which concerns on this invention. The injection pump 1 is provided with the same number of injection pump elements 2 as the number of cylinders 31 the diesel engine 200 has. The feed pump 5 pressurizes the DME fuel stored in the fuel tank 4 to a predetermined pressure and sends it to the feed pipe 52. The DME fuel outlet of the fuel tank 4 is provided below the liquid level of the DME fuel in the fuel tank 4, and the feed pump 5 is provided in the vicinity of the outlet of the DME fuel of the fuel tank 4. The DME fuel sent to the feed pipe 52 is filtered by the filter 51 and sent to the injection pump 1 via the three-way solenoid valve 71. The three-way solenoid valve 71 communicates in the direction of the arrow A in the on state in the injection state (at the time of operation of the diesel engine 200).

In this way, the DME fuel outlet of the fuel tank 4 is provided below the liquid level of the DME fuel in the fuel tank 4, and the feed pump 5 is provided near the outlet of the DME fuel of the fuel tank 4. In this configuration, since the DME fuel is delivered to the injection pump 1, the pressure drop in the fuel tank 4 can be reduced. As a result, the risk of vaporizing the DME fuel in the fuel tank 4 due to the decrease in the pressure in the fuel tank 4 can be reduced.

The cam chamber (not shown) in the injection pump 1 is a dedicated lubrication system separated from the lubrication system of the diesel engine 200, and the oil separator 6 leaks into the cam chamber in the injection pump 1. The lubricating oil in the cam chamber into which the mixed DME fuel is mixed is separated into the DME fuel and the lubricating oil, and the lubricating oil is returned to the cam chamber. The DME fuel separated by the oil separator 6 is sent to the compressor 61 driven by the cam in the cam chamber via a check valve 62 which prevents the pressure in the cam chamber from becoming below atmospheric pressure. After pressurization at 61, it is returned to fuel tank 4 via check valve 63 and cooler 41. The check valve 63 is provided to prevent the DME fuel from flowing back from the fuel tank 4 to the cam chamber when the diesel engine 200 is stopped.

Thus, since the cam chamber of the injection pump 1 is a dedicated lubrication system separated from the lubrication system of the diesel engine 200, the DME fuel leaked from the injection pump element 2 to the cam chamber is the diesel engine 200. There is no risk of breaking into the lubrication system. As a result, the DME fuel invading the lubrication system of the diesel engine 200 may be vaporized and the vaporized DME fuel may enter the crank chamber of the engine and be burned.

In addition, since the DME fuel is separated from the lubricating oil mixed with the DME fuel by the oil separator 6 provided in the cam chamber, and the separated DME fuel is sent to the fuel tank 4 by the compressor 61, The fall of the lubricating performance of the lubricating oil by mixing can be prevented. As a result, the performance deterioration of the injection pump 1 due to deterioration of the lubricating performance of the lubricating oil can be prevented.

In addition, since the compressor 61 is driven by a cam in the cam chamber, a drive source such as an electric motor is not necessary, thereby enabling the injection pump 1 which further saves power.

The DME fuel pressurized and discharged from the fuel tank 4 to the predetermined pressure by the feed pump 5 is discharged from the injection pump element 2 of the injection pump 1 via the injection pipe 3. At a timing, a predetermined amount is pumped to the fuel injection nozzle 32 provided in each cylinder 31 of the diesel engine 200. The DME fuel overflowed from the injection pump 1 passes via the overflow fuel pipe 8, via the check valve 91 and the cooler 41, which determine the pressure of the overflow fuel, the fuel tank 4. Return to). Further, the DME fuel overflowed from each fuel injection nozzle 32 passes through the overflow fuel pipe 9 and passes through the check valve 91 and the cooler 41 to determine the pressure of the overflow fuel. Return to 4).

In addition, the DME fuel supply device 100 is a DME fuel remaining in the oil chamber (not shown), the overflow fuel pipe 8 and the overflow fuel pipe 9 in the injection pump 1 when the diesel engine is stopped. Is an aspirator 7, a three-way solenoid valve 71, and a two-way solenoid valve 72 as a component of the 'residual fuel recovery means' for recovering the gas to the fuel tank 4.

The aspirator 7 has an inlet 7a, an outlet 7b, and a suction port 7c. The inlet 7a and the outlet 7b communicate in a straight line, and the inlet 7c branches in a substantially vertical direction from the communication path between the inlet 7a and the outlet 7b. The outlet side of the communication path (communication direction shown by arrow B), which communicates when the three-way solenoid valve 71 is off, is connected to the inlet 7a, and passes through the cooler 41 to the fuel tank. The outlet 7b is connected to the route to (4). In addition, the intake port 7c is connected to the two-way solenoid valve 72 which is in the off state in the injection state (at the operation of the diesel engine 200).

In the non-injection state (when the diesel engine 200 is stopped), the three-way solenoid valve 71 is turned off to form a communication path in the direction shown by the arrow B, and the two-way solenoid valve 72 is opened. On, the overflow fuel pipe 8 and the overflow fuel pipe 9 and the intake port 7c of the aspirator 7 communicate with each other (direction of the arrow C). Therefore, the DME fuel sent out from the feed pump 5 is not sent out to the injection pump 1 but is sent out to the aspirator 7, and exits from the inlet 7a to the outlet 7b to cool down the cooler 41. The fuel tank 4 is returned to the fuel tank 4 via the feed pump 5 and is again sent from the feed pump 5 to the aspirator 7. That is, the DME fuel liquid is brought to reflux via the aspirator 7. The DME fuel remaining in the oil chamber, the overflow fuel pipe 8 and the overflow fuel pipe 9 in the injection pump 1 flows through the inlet 7a and the outlet 7b. By this, the suction port 7c is sucked and recovered to the fuel tank 4.

In this way, the residual fuel recovery means sucks the DME fuel from the oil chamber, the overflow fuel pipe 8 and the overflow fuel pipe 9 by the aspirator 7 using the feed pump 5 as the driving source. Since it is set as the structure which collect | recovers by the fuel tank 4, it is not necessary to install a new pump etc. for residual fuel recovery.

Next, a schematic structure of the injection pump element 2 constituting the injection pump 1 according to the present invention will be described.

2A and 2B show the injection pump element 2 according to the invention, showing the state where the stroke position of the plunger is the fuel injection start position of the effective stroke. Fig. 2A is a sectional view of the main portion, and Fig. 2B is an enlarged view of a part thereof.

The delivery valve holder 21 has a shape having a delivery valve insertion hole 211, and is fixed to the base of the injection pump 1. The injection pipe 3 is connected to the fuel liquid delivery port 212 in communication with the delivery valve insertion hole 211. The delivery valve 23 is inserted and installed in the delivery valve insertion and installation hole 211 so as to reciprocate, and the delivery valve 23 is integrally provided with the delivery valve holder 21 by the delivery spring 22. It is pressurized by the delivery valve seat 24 which exists.

The plunger barrel 25 is provided in the single delivery unit with the delivery valve seat 24, and has the hydraulic chamber 25a which communicates with the delivery valve seat 24. As shown in FIG. The plunger 26 is inserted and provided in the hydraulic chamber 25a so that reciprocation is possible, and the upper end surface 26a faces the delivery valve 23. The plunger 26 is pushed up to the delivery valve 23 side by the cam (not shown) of the cam shaft which rotates by the driving force of the diesel engine 200, and raises, and when the cam is lowered, the plunger 26 ) Is lowered by the spring force of the spring (not shown) which pushes downward).

The plunger 26 is formed with the communication hole 262 which communicates with the upper end surface 26a about the center. The plunger 26 is also provided with a plunger port 261 which communicates the communication hole 262 with the outer circumferential surface of the plunger 26. That is, the hydraulic chamber 25a and the plunger port 261 communicate with each other via the communication hole 262. Moreover, the plunger 26 is provided with the notch 263 which cut | disconnected a part of outer peripheral surfaces of the plunger 26 at an angle. The notch 263 communicates with the communication hole 262. When the plunger 26 is lowered, the DME fuel of the oil chamber 11 is sucked into the hydraulic chamber 25a through the communication hole 262 from the plunger port 261 and the plunger 26 is lifted up. When the communication between the port 261 and the oil chamber 11 is interrupted by the plunger barrel 25, that is, when the pressure rises to the stroke position of the plunger 26 shown in FIGS. 2A and 2B, the hydraulic chamber 25a is closed. It becomes a sealed state. The stroke position of the plunger 26 becomes the fuel injection start position of the effective stroke of the plunger 26.

In the vicinity of the outer circumferential surface of the plunger 26 facing the oil chamber 11, the sleeve 12 is provided in a state of being fitted to the plunger 26. The sleeve 12 is formed with a sleeve port 121 for communicating the inner circumferential surface of the hole into which the plunger 26 is inserted and the outer circumferential surface facing the oil chamber 11. The sleeve 12 is provided to be movable up and down while the inner circumferential surface of the hole into which the plunger 26 is inserted is in sliding contact with the plunger 26. In the fuel injection start position of the effective stroke of the plunger 26, the notch 263 is interrupted | blocked with the oil chamber 11 by the inner peripheral surface of the sleeve 12 in the lower position than the sleeve port 121. As shown in FIG.

The injection pump 1 also has a sleeve actuator 65 (FIG. 1) as a 'sleeve position adjusting means' which moves the sleeve 12 up and down to adjust the position of the sleeve 12. The sleeve actuator 65 is electronically controlled by the control unit 15, and the sleeve driving portion for moving the sleeve 12 to a desired position by energizing a drive signal corresponding to the position of the desired sleeve 12. And a sleeve position detection sensor for detecting the position of the sleeve 12. The sleeve actuator 65 is a known electromagnetic coil actuator, and generates a magnetic field in the core by energizing an electromagnetic coil wound around the core, thereby rotating the rotor by the magnetic force of the magnetic field. And the sleeve 12 is moved up and down by rotating the sleeve drive member 13 provided in each injection pump element 2 by rotation of a rotor.

As described above, since the position of the sleeve 12 can be detected by the sleeve position detection sensor, the drive signal supplied to the sleeve driving unit is supplied to move the sleeve 12 to a desired position while checking the position of the sleeve 12. Can be controlled. Therefore, since the position of the sleeve 12 can be adjusted more accurately, the more effective adjustment of the effective stroke length of the plunger 26 becomes possible.

3A and 3B show the injection pump element 2 according to the invention, showing a state where the stroke position of the plunger 26 is the fuel injection end position of the effective stroke. 3A is a cross sectional view of a main part, and FIG. 3B is an enlarged view of a part thereof.

As the plunger 26 rises from the fuel injection start position of the effective stroke shown in FIGS. 2A and 2B, the liquid pressure of the DME fuel liquid in the hydraulic chamber 25a increases, whereby the delivery valve 23 causes the delivery valve seat to be discharged. It pushes up from 24 and the delivery valve 23 opens. The DME fuel in the hydraulic chamber 25a is pumped from the fuel liquid delivery port 212 to the fuel injection nozzle 32 via the injection pipe 3 via the delivery valve insertion hole 211.

When the plunger 26 is further raised at the fuel injection start position of the effective stroke of the plunger 26, the cutout portion cut off from the oil chamber 11 by the inner circumferential surface of the sleeve 12 at a position lower than the sleeve port 121 ( 263 is in communication with the sleeve port 121. Thereby, since the hydraulic chamber 25a communicates with the sleeve port 121 via the communication hole 262 and the notch 263, the DME fuel in the hydraulic chamber 25a is a sleeve as shown by the arrow (D). The oil flows into the oil chamber 11 through the port 121. Therefore, the hydraulic pressure of the DME fuel in the hydraulic chamber 25a decreases, and the stroke position of the plunger 26 becomes the fuel injection end position of the effective stroke of the plunger 26.

In addition, the notch 263 is formed obliquely with respect to the vertical movement direction of the plunger 26, in order to rotate the diesel engine 200 by desired rotation speed. The plunger 26 of each injection pump element 2 is engaged with the control rack which is not shown in figure, and is provided rotatably in the circumferential direction according to the rack position of a control rack. Then, by adjusting the position of the control rack by the mechanical governor 64 (FIG. 1), the plunger 26 rotates in the circumferential direction, and the plunger 16 in which the cutout portion 263 and the sleeve port 121 communicate with each other. Stroke position changes. Therefore, by adjusting the position of the control rack, the effective stroke length of the plunger 26 is changed, thereby allowing the DME fuel to be fed to the fuel injection nozzle 32 to rotate the diesel engine 200 at a desired rotational speed. You can adjust the amount.

4A and 4B show the injection pump element 2 according to the invention, showing a state where the stroke position of the plunger 26 is the fuel injection start position of the effective stroke. 4A is a cross-sectional view of the main portion, and FIG. 4B is an enlarged view of a part thereof. 5A and 5B show the injection pump element 2 according to the invention, which shows the state where the stroke position of the plunger 26 is the fuel injection end position of the effective stroke. Fig. 5A is a sectional view of the main portion, and Fig. 5B is an enlarged view of a part thereof.

The injection pump element 2 shown in FIGS. 4A, 4B and 5A, 5B has a sleeve 12 in comparison with the injection pump element 2 shown in FIGS. 2A, 2B and 3A, 3B. The position of is different, and the sleeve 12 is raised by the sleeve drive member 13 of the sleeve actuator 65 to the upper side. Therefore, the fuel injection start position of the effective stroke of the plunger 26 does not change as compared with the states shown in FIGS. 2A, 2B and 3A, 3B, but the fuel injection end position is shifted upward, that is, It is in the state away from the notch 263. FIG. Thus, the effective stroke length of the plunger 26 becomes long, thereby increasing the amount of DME fuel that is pumped through the injection pipe 3 to the fuel injection nozzle 32.

6A and 6B schematically show the difference in the effective stroke length of the plunger 26 due to the difference in the position of the sleeve 12. FIG. 6A shows a state where the sleeve 12 is located near the cutout 263 of the plunger 26, and FIG. 6B shows a state where the sleeve 12 is located near the hydraulic chamber 25a. .

The state shown in FIG. 6A is a state where the sleeve 12 is located near the cutout 263, that is, the sleeve 12 is in the position shown in FIGS. 2A, 2B and 3A, 3B. The fuel injection start position of the plunger 26 in which the plunger port 261 is blocked from the oil chamber 11 does not change depending on the position of the sleeve 12. And the stroke length E1 from the fuel injection start position of the plunger 26 where the sleeve 12 is located near the cutout 263 to communicate with the sleeve port 121 and the cutout 263 is communicated. Is short. Therefore, the effective stroke length S1 from the fuel injection start position of the plunger 26 to the fuel injection end position is shortened.

On the other hand, the state shown in FIG. 6B is a state where the sleeve 12 is located near the hydraulic chamber 25a, that is, the sleeve 12 is in the position shown in FIGS. 4A, 4B and 5A, 5B. . As described above, the fuel injection start position of the plunger 26 in which the plunger port 261 is blocked from the oil chamber 11 does not change depending on the position of the sleeve 12. And the stroke length E2 from which the sleeve 12 is located near the hydraulic chamber 25a, ie, from the fuel injection start position of the plunger 26, to the communication between the sleeve port 121 and the notch 263, is long. Therefore, the effective stroke length S2 from the fuel injection start position of the plunger 26 to the fuel injection end position becomes long.

In this way, since the injection end position of the effective stroke of the plunger 26 can be adjusted by adjusting the position of the sleeve 12 with the 'sleeve position adjusting means', fine adjustment of the effective stroke length of the plunger 26 is performed. The mechanical governor 64 can be executed without adjusting the position of the control rack.

In the oil chamber 11, a fuel temperature sensor 14 for detecting the temperature of the DME fuel in the oil chamber 11 is provided. As described above, the DME fuel is particularly susceptible to the influence of the temperature change of the fuel because the rate of change with temperature of density (kg / m 3) or volume modulus of elasticity (N / mm 2) is particularly large compared with diesel fuel. For this reason, in the conventional diesel fuel, the change of the rotation speed by the temperature change negligible in a certain range may become large so that it cannot be ignored in the diesel engine 200 of DME fuel.

Accordingly, the sleeve 12 is moved up and down by the sleeve actuator 65 in accordance with the temperature of the DME fuel detected by the fuel temperature sensor 14. Therefore, since the injection end position of the effective stroke of the plunger 26 can be adjusted according to the temperature of the DME fuel in the oil chamber 11 detected by the fuel temperature sensor 14, the injection pump equipped with the mechanical governor 64 is carried out. Also in (1), fine adjustment of the effective stroke length of the plunger 26 can be performed in accordance with the temperature of the DME fuel.

In addition, this invention is not limited to the said Example, A various deformation | transformation is possible within the scope of the invention as described in a claim, Needless to say that these also fall within the scope of this invention.

According to this invention, the injection pump which can perform fine adjustment of the effective stroke length of a plunger without adjusting the position of a control rack by a governor can be provided.

Claims (6)

An oil chamber supplied with fuel in a fuel tank, a plunger moving up and down in combination with a camshaft which is transmitted by rotation of a drive shaft of a diesel engine, and the fuel is discharged from the oil chamber by raising the plunger. And a plunger barrel having a hydraulic chamber for sucking and compressing the gas, and a discharge valve installed in the hydraulic chamber and opened by the pressure of the fuel in the hydraulic chamber, by a predetermined amount at a predetermined timing by vertical movement of the plunger. An injection pump of a fuel supply device for a diesel engine having an injection pump element for delivering the fuel from the delivery valve to an injection pipe communicating with a fuel injection nozzle of the diesel engine, The injection pump element includes a sleeve having a substantially cylindrical shape installed to be movable up and down in the oil chamber with the plunger inserted and the sleeve position adjusting means for moving the sleeve up and down, The plunger has a plunger port communicating with an upper end portion facing the hydraulic chamber and the oil chamber, and the stroke position of the plunger in which communication between the hydraulic chamber and the oil chamber by the plunger port is interrupted in an upstroke of the plunger port. Is the starting position of the injection of the effective stroke of the plunger, The sleeve has a sleeve port for communicating between the inner circumferential surface of the through hole into which the plunger is inserted and the outer circumferential surface facing the oil chamber, and in the ascending stroke of the plunger, communicating with the hydraulic chamber formed on the outer circumferential surface of the plunger. Characterized in that the stroke position of the plunger, in which the joint and the sleeve port communicate, is the injection end position of the effective stroke of the plunger. Injection pump. The method of claim 1, The fuel temperature sensor for detecting the temperature of the fuel in the oil chamber and the sleeve position adjusting means for adjusting the position of the sleeve in accordance with the temperature of the fuel detected by the fuel temperature sensor to terminate the injection of the effective stroke of the plunger. And injection end position control means for adjusting the position. Injection pump. The method of claim 1, The sleeve position adjusting means includes a sleeve driving portion for moving the sleeve to a desired position by energizing a drive signal corresponding to the desired position of the sleeve, and a sleeve position detecting sensor for detecting the position of the sleeve. By Injection pump. The method of claim 2, The sleeve position adjusting means includes a sleeve driving portion for moving the sleeve to a desired position by energizing a drive signal corresponding to the desired position of the sleeve, and a sleeve position detecting sensor for detecting the position of the sleeve. By Injection pump. With the injection pump as described in any one of Claims 1-4. Fuel supply of diesel engines. The method of claim 5, DME (dimethyl ether) fuel characterized in that the fuel Fuel supply of diesel engines.