JPS61294141A - Distributor type fuel injection device - Google Patents

Abstract

PURPOSE:To easily perform a proper control for a fuel injection rate in accordance with an engine condition, by giving rotating and reciprocating motions to a plunger through a cam disc and forming its cam surface to ununiform speed cam shape changing a displacement speed of the plunger. CONSTITUTION:A cam disc (ununiform speed cam) 11, which non-linearly sets a time change of a cam lift distance, is provided in the end part of a driving shaft 3, and a fuel injection device, giving rotating and reciprocating motions of ununiform speed to a plunger 12 by rotating the cam disc 11 and attracting fuel to be pressurized in a pressurizing chamber 17, enables the fuel to be supplied to an injection nozzle through passages 18, 19 and a feed valve 21. While the pressurizing chamber 17 can be connected with a low pressure side through a solenoid operated valve 24 and a passage 28. And the device controls the solenoid operated valve 24 to be opened and closed by an injection start timing signal and an injection end timing signal in accordance with an engine condition output from a control unit 31. While the device, controlling a solenoid operated valve 44 similarly by an injection rate signal from the control unit 31, enables a cam use start position to be adjusted by an injection rate adjusting unit 40.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a distribution type fuel injection pump, and more specifically, to a distribution type fuel injection pump that allows control of fuel injection rate.

(Prior Art) Conventional distributed fuel injection device, for example, Japanese Patent Application Laid-Open No. 48-592
In the device described in Publication No. 20, fuel pressurized by a vane pump or the like is fed into a pump housing that houses a roller holder, a cam disk, etc., and is then pumped according to the rotational lift operation of a plunger. It was configured to deliver the required amount of fuel to the injection nozzle of each cylinder at the required timing, and the fuel injection rate was determined by a cam profile that matched the engine's requirements and was constant. Therefore, the fuel injection rate has been set at a value that allows the required output to be obtained without deteriorating the exhaust gas.

(Problem to be solved by the invention) In this way, in conventional devices, the fuel injection rate characteristics are fixed to the required characteristics by the cam profile, so if the operating conditions (for example, load condition) change, Of course, it is not possible to inject a commensurate 1-rejection rate,
It has been difficult to further improve the exhaust gas purification rate and to obtain sufficient output with the improved purification rate.

An object of the present invention is to provide an optimum fuel injection rate to an engine in all rotation ranges and load ranges by adjusting the fuel injection rate in a distributed fuel injection ponder, and to improve the direction of exhaust gas purification rate and The object of the present invention is to provide a distribution type fuel injection pump that can achieve the contradictory effects of maintaining a high output (I7).

(Means for Solving the Problems) To achieve the above object, the present invention provides a distribution system that pressurizes fuel in a high-pressure social chamber and injects it according to the rotation and reciprocating motion of a syringe executed in response to the rotation of a cam. In the type fuel injection system, there is a solenoid valve that forcibly lowers the pressure in the oil pump, and an F9T valve that forcibly reduces the pressure of the fuel injection valve depending on the engine condition.
These first and second timing signals are used to activate fuel injection in accordance with a first timing signal indicating a desired fuel injection start timing and a second timing signal indicating a required fuel injection start timing according to the state of the engine. means for controlling the opening and closing of the electromagnetic valve, means for outputting a certain fuel injection rate signal according to the state of the engine, means for adjusting the starting position of the cam, and adjusting means for adjusting the starting position of the cam. It is equipped with an electromagnetic valve that adjusts the position of the light means according to the injection rate signal, and the cam is constructed from an inconstant velocity cam.

(Function) With the above configuration, the use start position of the inconstant velocity cam can be set to the desired position by controlling the solenoid valve.
The pumping speed of the plunger can be adjusted freely, making it possible to control the fuel injection rate. Furthermore, since the injection amount and injection timing are controlled by a solenoid valve, the injection amount can naturally be controlled.
-1 The injection timing can also be controlled arbitrarily according to the engine's firing demand. . The fuel injection device 1 is used in combination with an internal combustion engine (not shown), and supplies fuel to each cylinder of the internal combustion engine. The injection bong 7'2 includes a vane pump 4 connected to a drive shaft 3 that is rotationally driven at a rotation speed related to the rotation speed of the internal combustion engine, and a roller holder 5.

The vane pump 4 pressurizes fuel supplied through a passage 6 from a fuel tank (not shown) and sends it to a passage 8 in the nozzle 7. One end of the drive shaft 3 extends into the nodding chamber 9, and is connected to a cam disk 11 via a driving disk 10. A plunger 12 is pressed against one side of the cam disk 11 by a plunger spring 13. There is. The cam disk 11 is formed as an inconstant velocity cam which imparts an inconstant velocity motion to the plunger 12, and the temporal change of the cam rift 1 is set as shown in FIG. The syringer 12t4 is fitted into a cylinder portion 14 formed in the housing 7, and as the drive shaft 30 rotates, the syringer 12 rotates and reciprocates at the same time. The fitting end of the plunger 12 has intake slits 15 (the number of which corresponds to the number of cylinders of the engine).
Only one of the four intake slits is shown in the drawing. ) is formed, and when the intake port 16 formed at the end of the passage 8 and the intake slit overlap during the downward stroke of the plunger 12, the pressurized fuel being fed through the passage 8 is sucked into the high pressure chamber 17.

This sucked pressurized fuel begins to be compressed when the intake date 16 is closed by the rotational lift operation of the sylanger 12 and the cam lift begins. Plunger 12
The inner passage 18 communicates with a distributor slit 19, and when the plunger 12 continues to rotate and lift further, the IJ pipeta slit 19 overlaps with the outlet valve and the cellarage 20, the compressed high-pressure fuel passes through the delivery valve 21. It is opened and delivered to a quantity eve 22 which is connected to an injection nozzle (not shown).

This fuel injection device 1 includes a solenoid valve 24 connected to a pressure chamber 17 through a passage 23 in order to start and end fuel injection at a desired timing regardless of the position of the plunger 12. . Solenoid valve 24 ik
It is composed of a piston 26 in which a passage 25 is formed, and a cylinder chamber 27 formed in the housing 7 to accommodate the piston 26. One end of the cylinder chamber 27 is It is connected to a fuel tank (not shown) and is open to the atmosphere. Piston 2
6 is spring-biased by a resilient spring 29 so as to be constantly pushed upward. When the excitation coil 30 is deenergized, as shown in FIG.
The piston 26 is positioned so that the width of the piston 5 is in communication with the piston 26, the solenoid valve 24 is opened, and the pressure chamber 17 communicates with the passage 28.

On the other hand, when the excitation coil 30 is energized, the piston 26 is attracted against the spring force of the spring 29 and moves downward, so that the open end of the passage 23 on the cylinder chamber side
It is closed by the side walls of 6 and becomes a closed shape. This %M valve 24 is controlled to open and close by the control device [31] so that it is closed at the new fuel injection start timing and reopened at the required injection end timing.

Referenced 40 is an injection rate adjustment device, in which the mechanism of a conventional timer device is used. The injection rate adjusting device 40 includes a piston 42 elastically biased by a spring 41 , and the pressure within the passage 8 is applied to one end surface of the piston 42 via a throttle 43 . A pressure regulating valve 44 is provided for the purpose of adjusting 17 the pressure applied to the piston 42 and positioning the piston 42 at a desired position. By adjusting the opening degree of this pressure regulating valve 44, the cylinder The pressure in chamber 45 can be set to a desired value. The piston 42 is articulated to the other end of a rod 46 whose one end is connected to the roller holder 5, and according to the position of the piston 42 the roller holder 5
By changing the angular position of the fuel injection rate, the fuel injection rate can be adjusted. Note that this injection rate adjusting device 40 is shown unfolded at 90° in FIG.

A block diagram of the control device 31 is shown in FIG. The control device 31 includes a known rotation speed detection sensor 50 that generates a rotation pulse S1 at a frequency corresponding to the rotation speed of the engine.
The co-rotating pulse S1 has a phase-locked loop circuit 5.
1, the frequency is multiplied, and the frequency is increased by the required multiple. The rotor 52m, which rotates in synchronization with the gear 50a constituting the rotational speed detection sensor 50, is combined with the pickup coil 52b, and (b) the protrusion 52c of the trochanter 52& approaches and moves away from the pickup coil 52b, thereby increasing the speed of the engine. The sensor 52 outputs the top dead center No. 16 S indicating the top dead center timing. Phase-locked loop circuit (PLL) 51 Multiplyed rotation pulse S from 51 and top dead center signal S are crank angle calculation circuit 5
3, and a crank angle signal S4 indicating the crank angle of the engine is output. Reference numeral 54 indicates a sensor that detects the position of an accelerator pedal (not shown), and the signal S from the sensor 54 is an accelerator signal that generates an accelerator signal S at a level corresponding to the position of the accelerator pedal. The generator 55 is manually powered. The multiplied rotation i4 pulse S is input to the rotation signal generator 56, which outputs a rotation signal +3''? at a level corresponding to the rotation speed.

The rotation signal S and the accelerator signal S are input to the effective injection angle calculation circuit 57 together with the water temperature signal S indicating the water temperature and the load signal S indicating the magnitude of the load, and the optimum injection angle is calculated according to the information contained in these signals. The injection angle is calculated. The calculation data D1 from the effective injection angle calculation circuit 57 is input as a code signal for determining the digit of the counter 58 to a programmable counter 58 to which the multiplied rotation pulse S is input as a count pulse.

Reference numeral 59 indicates a target advance angle signal S indicating the crank angle corresponding to the target injection start timing. This is a target advance angle calculation [circuit] that generates a target advance angle signal 818.
It is made based on No. S. The target advance angle signal S1° is the comparator 6.
0 is compared with the crank angle signal S4, and when both signals match, that is, when the current crank angle matches the crank angle corresponding to the target injection start timing, the injection start timing pulse P is The output from the comparator 60 is 10). This injection start timing pulse P1 is sent to the programmable counter 58 as a count start timing signal.
and is applied to the set terminal S of the R-S flip-flop 61. The number of count pulses input to the programmable counter 58 each time the engine crankshaft rotates by a required angle is known in advance, and the calculated data D1
is binary data containing the base pulse number corresponding to the required angle calculated based on the count pulse number for the required rotation angle known in advance. Therefore, at the timing when the injection start timing Noculus P occurs, the counter 58
starts counting the number of rotations of the multiplier rotation noculus S, and when the count reaches the number determined by the calculation data D1, the end timing pulse P is sent to the counter 58.
The signal is output from the R-s flip processor 7-61 and applied to the reset input terminal R of the R-s flip processor 7-61. The Q output of the R-S clip flop 61 is applied to the excitation coil 30 of the solenoid valve 24 shown in FIG. Therefore, the solenoid valve 24 is closed at the timing when the injection start timing pulse P1 is generated.
It is controlled to be opened at the timing when the end timing pulse P is generated. That is, at the required injection start timing calculated by the control device 31, the high-solescia chamber 17 is disconnected from the passage 28, fuel injection is started, and at the end timing determined by the effective injection angle calculation circuit 57, the high-solescia chamber 17 is disconnected from the passage 28. The Lushad chamber 17 communicates with the passage 28 and fuel injection ends. In this way, the start and end of fuel injection can be electrically controlled extremely accurately by controlling the solenoid valve 24.

Next, the operation of the injection rate dS moderating device 40 will be explained.

For injection rate control, the output of the effective injection angle calculation circuit 57 shown in FIG. This is done by adjusting the position of the piston 42. 3 is a diagram illustrating the relationship between the rotational agent degree θ of the drive + kb 3 and the lift amount L of the cam disk 11, that is, the displacement amount of the sylanger 12. It is assumed that the cam lift amount changes along the curve ah with respect to the drive shaft rotation angle θ. Then, the electromagnetic valve 24 is energized at the rotation angle θ to start fuel injection, and deenergized at the rotation angle θt to end the fuel injection.
It is assumed that fuel is injected over a period t from the point in time to the point in time at the rotation angle θt. When the cam lift amount changes along this curve A, the cam lift amount from the start of injection to the end of injection is represented by LA in the figure, and a fuel injection amount proportional to this lift amount LA is injected and supplied into the cylinders of the engine. That will happen.

Next, due to the upper row of fuel oil pressure in the cylinder chamber 45, the piston 42 moves to the left in FIG. 1 against the spring force of the spring 41, and the roller holder 5 is rotated to set the cam lift timing. Assume that the cam rift (cam rift) t changes along the curve B by advancing the rotation angle θ with respect to the curve A in FIG. In this case, if there is no change in the fuel injection start timing and end timing by the solenoid valve 24, the fuel injection amount will be ref)iiiLB
The value is proportional to ′. As described above, this lift iLB is formed so that the cam disc 11 moves the syringe 12 back and forth at an inconstant speed, so that the lift amount LA
It's really big. More specifically, the shape of the cam surface of the cam disk 11 is determined by the drive shaft rotation angle range between the injection start timing and the injection end timing set in the realizable operating range of the engine (for example, 28 in curve A in the figure). point to point 23), the slope of the curve A representing the change in cam lift amount changes as the rotation angle θ increases, that is, the displacement speed of the plunger 12 is adjusted within the rotation angle range.
The rotation angle is formed so that it increases as the rotation angle θ increases, or the first half of the rotation angle decreases in the second half of the increase. Therefore, in the example shown in FIG. 3, when the cam lift amount changes along curve B, which is advanced by the rotation angle θ with respect to curve A, the rift iLB becomes a value larger than the lift amount LA. . In other words, by advancing the cam lift timing, the fuel injection rate increases, and the number of fuel injection lids increases for the same fuel injection period t.

Conversely, the fuel oil pressure in the cylinder 45 decreases and the piston 4
2 retards the υ cam lift timing by the rotation angle θ2 by the spring force of the spring 41, so that the fuel injection amount for the same injection timing t becomes a value proportional to the rif) amount LC which is smaller than the ref) mLA. At this time, contrary to the above operation, the fuel injection rate decreases.

(Effects) As detailed above, according to the distribution type fuel injection pump of the present invention, the cam surface of the cam disk is formed in a shape that changes the displacement speed of the plunger within the required stroke range in the compression stroke of the sylanger. , an electromagnetic valve for controlling the start timing and end timing of the fuel injection by closing and opening the oil path is disposed in the middle of the oil path that communicates the high pressure chamber and the low pressure side (tank side), and the roller A passage connected to the holder and releasing the fuel pressure acting on the injection rate adjusting device that rotates the roller holder in response to the differential pressure between the pressure source and the spring pressure to control the injection rate of the fuel to the low pressure side. Since a solenoid valve that controls the fuel pressure acting on the injection rate adjustment device is installed in the engine, it is possible to control the fuel injection rate in accordance with the engine requirements, and the injection timing also changes depending on the engine operating conditions. It can be adjusted accordingly, and has an excellent effect of making exhaust gas countermeasures more efficient and ensuring sufficient output.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a block diagram of the control device shown in FIG. 1, and FIG. 3 is a characteristic diagram for explaining the operation of the fuel injection rate adjusting device. 1...Fuel injection device, 2...Fuel injection pump, 11
...Cam disc, 12...Plunger, 14...
・Cylinder part, 17... High sole pressure chamber, 2
4... Solenoid valve, 31... Control device, 50... Rotation speed detection sensor, 51... Phase lock loop circuit,
53... Crank angle calculation circuit, 54... Sensor, 5
5... Accelerator signal generator, 56... Rotation signal generator, 57... Effective injection angle calculation circuit, 58... Programmable counter, 59... Target advance angle calculation circuit, 60
...Comparator, 61...R-8 flip flop,
Dl...Calculation data, Pl...Injection start timing pulse, P,...End timing pulse, So...
Rotation □ Lus, S 2... Top dead center signal, S3... Multiply rotation/9 Lus, S4... Crank angle signal, S...
・Accelerator signal, S...Rotation signal, Sl. ...Target advance angle signal.

Claims (1)

[Claims] 1. In a distribution type fuel injection device that pressurizes and injects fuel in a high-pressure chamber according to the rotation and reciprocating motion of a plunger executed in response to the rotation of a cam, in order to forcibly reduce the pressure in the high-pressure chamber. to perform fuel injection in accordance with the solenoid valve, a first timing signal indicating a required fuel injection start timing according to the engine condition, and a second timing signal indicating the required fuel injection end timing according to the engine condition. Said first and second
means for controlling the opening and closing of the electromagnetic valve based on a timing signal; means for outputting a required fuel injection rate signal according to the operating state of the engine; means for adjusting the start position of the cam; and a position of the start position adjusting means. a solenoid valve that adjusts the injection rate according to the injection rate signal, and the cam is an inconstant velocity cam.