JP2505408B2 - Fuel injection timing control device for fuel injection pump - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection timing control device for a fuel injection pump that supplies fuel to a diesel engine, and more particularly to a pulse drive in which the fuel injection timing is controlled with a duty ratio. The present invention relates to a fuel injection timing control device for a fuel injection pump, which is controlled via a hydraulic control valve opened and closed by a signal.

[Prior Art] Conventionally, in order to adjust the fuel injection timing of the fuel injection pump, as shown in FIG. 9, a roller ring 74 of the fuel injection pump is inserted through a timer piston 72 positioned by the hydraulic pressure of the high pressure chamber 70. Timer device for controlling the rotation angle position 76
And a hydraulic control valve 78 that is opened and closed by a pulse drive signal with a varying duty ratio to control the hydraulic pressure of the high-pressure chamber 70 that determines the position of the timer piston.

[Problems to be Solved by the Invention] However, in the above-described conventional fuel injection timing control device, for example, as described in Japanese Utility Model Laid-Open No. 56-136141, a hydraulic control valve 78 for controlling the timer piston position is provided at a predetermined cycle. It is configured to open and close with a pulse drive signal whose duty ratio is controlled, but lacking a configuration for keeping the on / off state of the pulse drive signal constant throughout the fuel injection period. Drive signal output from the fuel injection pump to the hydraulic pressure adjustment valve during the fuel injection period is constant (ON or
(OFF state), it changes to ON state or OFF state as shown in Fig. 10 (B) or (C), and within the fuel injection period as shown by the one-dot chain line or broken line in Fig. 10 (A). There is a problem that the fuel injection rate of the fuel injection pump changes and the fuel injection amount of the fuel injection pump fluctuates.

That is, as shown in FIG. 10B, when the pulse drive signal is in the ON state, the hydraulic pressure adjusting valve 78 is opened, the hydraulic pressure in the hydraulic cylinder high pressure chamber 70 is lowered, and the timer piston
The roller ring 74 is moved to the retard side via 72,
As shown in FIG. 10C, when the pulse drive signal is OFF, the hydraulic pressure adjusting valve 78 is closed and the hydraulic pressure in the hydraulic cylinder high pressure chamber 70 rises, and the roller ring is passed through the timer piston 72. Since 74 is moved to the advance side,
The fuel injection rate, which is represented by the inclination of the lift amount of the cam roller abutting on the roller ring 74 in FIG. 9A, changes depending on the ON-OFF state of the pulse drive signal, and the fuel injection amount changes. Of.

Therefore, the present invention, during the fuel injection period of the fuel injection pump,
The pulse drive signal is always in a constant state, and the fuel injection amount control device of the fuel injection pump is configured so that the fuel injection amount does not change due to the change of the pulse drive signal. It took such a structure.

[Means for Solving Problems] That is, in the structure of the present invention as means for solving the above problems, as shown in FIG. 1, the roller ring position of the fuel injection pump M1 is hydraulically positioned. A fuel injection timing adjusting member M2 that controls the fuel injection timing by controlling it through a timer piston, and a fuel injection timing adjusting member that is opened and closed by a pulse drive signal that controls the ratio of ON period and OFF period per pulse. A hydraulic control valve M3 for controlling the hydraulic pressure applied to M2 and an operating state detecting means M5 for detecting the operating state of the diesel engine M4 which is fueled via the fuel injection pump M1.
And a target fuel injection timing calculation means M6 for calculating a target fuel injection timing of the fuel injection pump M1 based on the detection result of the operating state detection means M5, and a fuel injection timing adjusted by the fuel injection timing adjusting member M2. Is controlled to match the target fuel injection timing calculated by the target fuel injection timing calculation means M6 with the ratio of the ON period and the OFF period per pulse of the pulse drive signal output to the hydraulic control valve M3. A fuel injection timing control device for a fuel injection pump, comprising signal control means M7 and drive signal output means M8 for outputting the controlled pulse drive signal to the hydraulic control valve M3. Timing detection means M9 for detecting a predetermined timing before injection is provided, and the drive signal output means M8 is used to turn on or off the pulse drive signal at the detected predetermined timing. As an at least the fuel injection pump M1 the output state
A fuel injection timing control device for a fuel injection pump is characterized in that the fuel injection timing control device is configured to continue until the end of one fuel injection period and does not switch the on / off state during the fuel injection period.

Here, the fuel injection timing adjusting member M2 is a fuel injection pump.
The above-mentioned timer device for adjusting the roller ring device of M1. The timer piston position is controlled by the hydraulic pressure controlled by the hydraulic control valve M3, and thereby the roller ring position is adjusted.

Further, the drive signal output means M8 outputs a pulse drive signal to the hydraulic control valve M3 in which the ratio of ON period and OFF period per pulse is controlled by the drive signal control means M7. The timing detection means M9 is provided, and the drive signal output means M8 sets the pulse drive signal to the on state or the off state at a predetermined timing detected by the timing detection means M9, and this output state is at least one fuel of the fuel injection pump M1. It is configured to continue until the end of the injection period, and the on / off state is not switched during the fuel injection period. This is because the period of the pulse drive signal is synchronized with the fuel injection period of the fuel injection pump M1 and the pulse drive signal is turned on or off during the fuel injection of the fuel injection pump M1.

[Operation] In the fuel injection timing control device of the present invention configured as described above, the drive signal output means M8 includes the fuel injection pump M1.
At a predetermined timing before fuel injection, the output state of the pulse drive signal for opening and closing the hydraulic control valve M3 is set to the ON state or the OFF state and this output state is continued at least until the end of one fuel injection period of the fuel injection pump M1. , Do not switch the ON / OFF state during the fuel injection period. Therefore, the pulse drive signal cycle in which the ratio of the ON period and the OFF period per time is controlled by the drive signal control means M7 matches the fuel injection period of the fuel injection pump M1, and during the fuel injection period of the fuel injection pump M1. Indicates that the pulse drive signal is in an ON or OFF constant state.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic configuration diagram of a fuel injection pump and a diesel engine equipped with the fuel injection timing control device of this embodiment.

In the drawing, reference numeral 1 denotes a distribution type fuel injection pump, which is driven by rotation of a drive pulley 3 connected to a crankshaft of a diesel engine 2 via a belt or the like, and pressure-feeds fuel to a fuel injection nozzle 4 of the diesel engine. A protrusion 5 is provided on the drive pulley 3 so that a predetermined crank angle of the diesel engine 2 can be detected by using a crank angle sensor 7 provided in a pump housing 6 of the fuel injection pump 1. Further, a vane pump 9 which is a fuel feed pump and a pulsar 10 having a plurality of protrusions on the outer peripheral surface are attached to a drive shaft 8 of the fuel injection pump 1 connected to the drive pulley 3, and the tip portion thereof is not shown. It is connected to the cam plate 11 via a coupling.

The cam plate 11 is integrally joined to the plunger 12,
It is rotated according to the rotation of the drive shaft 8. Further, the cam plate 11 is connected to a roller ring 14 positioned by a timer device 13, and is reciprocated in the left-right direction in the drawing by a cam roller 15 attached to the roller ring 14. Therefore, the cam plate 11 and the plunger 12 are rotated and reciprocated by the rotation of the drive shaft 8.

Next, the plunger 12 is connected to a fuel cut valve (FC
V) is inserted into a pump cylinder 17 in communication with a fuel chamber 16 in a pump housing 6 through an intake port opened and closed, and the reciprocating motion pressurizes the fuel, and a diesel engine 2 through a delivery valve 18. Fuel is pressure-fed to each cylinder. That is, a fuel passage 12a corresponding to the number of cylinders is formed at the tip of the plunger 12, and when moving leftward in the figure, the fuel in the fuel chamber 16 is sucked into the pressurizing chamber 17a and rightward in the figure. When moving, the fuel in the pressurization chamber 17a is pressurized to distribute port 1
It is configured to pump fuel from 7b.

On the other hand, a spill port 17c is formed in the pump cylinder 17 so as to communicate with the pressurizing chamber 17a, and the fuel chamber 1 is connected via the solenoid valve 20.
Communicated with 6. The solenoid valve 20 is operated by opening and closing the needle valve 21, and when the plunger 12 moves to the right in the drawing, that is, when the fuel is pressurized and pressure-fed, the pressurizing chamber 17a and the fuel chamber 16 are communicated with each other. Overflow the fuel to stop the fuel supply to the diesel engine.

Next, the timer device 13 is composed of a timer housing 13a, a timer piston 13b fitted in the timer housing 13a and connected to the roller ring 14, and a spring 13c for biasing the timer piston 13b in the right direction in the drawing. By positioning the timer piston 13b by the fuel pressure in the high pressure chamber 13d into which the high pressure fuel in the fuel chamber 16 is introduced,
The position of the roller ring 14 is determined and the fuel injection timing is adjusted. The fuel pressure in the high pressure chamber 13d is the same as that in the high pressure chamber 13d and the low pressure chamber 13e.
The pressure is regulated by a hydraulic control valve 23 which is provided in a communication passage 22 for communicating with and is opened and closed by a pulse drive signal whose duty ratio is controlled.

The roller ring 14 positioned by the timer device 13 and the solenoid valve 23 has a position facing the pulsar 10,
A rotation angle sensor 25 that generates a detection signal each time a protrusion formed on the outer peripheral surface of the pulsar 10 crosses is provided, and the rotation speed of the fuel injection pump 1, that is, the engine rotation speed of the diesel engine 2,
The fuel injection cycle of the fuel injection pump 1 can be detected respectively. That is, as shown in FIG. 3, on the outer peripheral surface of the pulsar 10, 56 protrusions 37 having cutting teeth at four positions that divide the outer peripheral surface into four equal parts are formed. A detection signal as shown in FIG. 4 (a) is output, and by performing waveform shaping of this detection signal, as shown in FIG. 4 (b), the reference signal A synchronized with the fuel injection cycle and the rotation indicating the number of revolutions. The angle signal B is obtained. Further, this rotation angle sensor 25 has a roller ring 14
Since the cam roller 15 is fixed on the cam roller 15 and moves along with the rotation, the lift time of the cam roller 15, that is, the fuel injection timing can be detected from the reference signal A and the rotation angle signal B. In this embodiment, the rotation angle sensor 25 is fixed so that fuel injection is started when the fourth rotation angle signal is output after the reference signal A is output.

Next, in the diesel engine 2, a cooling water temperature sensor 26 for detecting the cooling water temperature, and an intake air temperature sensor 27 for detecting the intake air temperature.
Also, an intake pressure sensor 28 for detecting the intake pressure is provided so that the operating state of the diesel engine 2 can be detected. Reference numeral 29 is an accelerator sensor that detects the amount of depression of the accelerator pedal 29a, which also allows the operating state of the diesel engine 2 to be detected.

The detection signals from the cooling water temperature sensor 26, the intake air temperature sensor 27, the intake pressure sensor 28, the accelerator pedal 29, and the detection signals from the crank angle sensor 7 and the rotation angle sensor 25 are input to the electronic control circuit 30, respectively. The solenoid valve 20 and the hydraulic control valve 23 are drive-controlled. That is, electronic control circuit
At 30, the fuel injection amount and the fuel injection timing to the diesel engine 2 are controlled by drivingly controlling the electromagnetic valve 20 and the hydraulic control valve 23 according to the operating state of the diesel engine 2 detected by the various sensors. It is configured as follows. As shown in FIG. 5, the electronic control circuit 30 has an A / D converter 31 for converting an analog signal output from each sensor into a digital signal, and a pulse signal output from each sensor for waveform shaping. Waveform shaping circuit 32, A / D
A CPU 33 that executes fuel injection control of the fuel injection pump 1 based on detection signals from the above-described sensors that are input via the converter 31 or the waveform shaping circuit 32, a control program necessary for executing control processing by the CPU 33, ROM 34 in which various data are stored in advance, RAM 35 in which data necessary for executing control processing by the CPU 33 is temporarily read and written, and the solenoid valve 2
0 or a drive circuit 36 that outputs a drive signal to the hydraulic control valve 23,
Composed of 37.

Hereinafter, the fuel injection timing control, which is the main control processing executed by the electronic control circuit 30 according to the present invention, will be described in detail with reference to the flowcharts shown in FIGS. 6 to 8.

FIG. 6 is repeatedly executed in the electronic control circuit 30, and the duty ratio of the pulse drive signal applied to the hydraulic control valve 23 is set so that the fuel injection timing becomes the target fuel injection timing set according to the operating state of the diesel engine. The pulse drive signal control processing for feedback control is shown.

When this process starts, first execute step 101,
The engine speed Ne is calculated based on the detection signal from the rotation angle sensor 25, and the process proceeds to the next step 102. In step 102, various detection signals representing the operating state of the diesel engine 2 output from the cooling water temperature sensor 26, the intake air temperature sensor 27, the intake pressure sensor 28, and the accelerator sensor 29 are read, and the process proceeds to step 103.

In step 103, the target fuel injection timing is calculated based on the engine speed Ne calculated in step 101 and the detection signal representing the engine state read in step 102. That is, the basic target fuel injection timing is calculated using the engine speed Ne and the depression amount of the accelerator pedal detected by the accelerator sensor 29 as parameters, and the obtained values are then used as the cooling water temperature THW, the intake temperature Ta, and the intake pressure. The target fuel injection timing is calculated by a conventional method in which the target fuel injection timing is determined by making corrections such as Pa. Further, the ratio of the ON period and the OFF period per pulse of the pulse drive signal is determined based on the target injection timing by the conventional method.

Next, at step 104, the crank angle sensor 7
And the actual fuel injection timing is calculated based on the detection signal from the rotation angle sensor 25, and the routine proceeds to step 105. In this process, since the fuel injection start timing can be detected based on the detection signal from the rotation angle sensor 25 as described above, the detection signal output from the rotation angle sensor 25 and the detection output from the crank angle sensor 7 are detected. The signal is used to calculate the fuel injection timing with respect to the crank angle of the diesel engine 2.

Next, at step 105, an error Terr between the target fuel injection timing obtained at step 103 and the actual fuel injection timing obtained at step 104 is calculated, and the routine proceeds to step 106. Then, in step 106, it is judged whether or not the error Terr is positive, and if Terr> 0, that is, if the actual fuel injection timing is on the advance side with respect to the target injection timing,
In step 107, the ON time of the pulse drive signal is extended by a predetermined time in order to retard the fuel injection timing, and the processing of this routine is once ended.

On the other hand, when it is determined in step 106 that Terr ≦ 0, the process proceeds to step 108 and it is determined whether or not the error Terr is negative this time. When it is determined that Terr <0, that is, when the actual fuel injection timing is on the retard side with respect to the target injection timing, the routine proceeds to step 109, where the fuel injection timing is advanced. In order to correct the above, the ON time of the pulse drive signal is shortened by a predetermined time, and the processing of this routine is once ended.

Next, FIG. 7 shows a rotation angle signal interrupt process executed every time a rotation angle signal is output from the rotation angle sensor 25.
A pulse drive signal is output at each predetermined rotation angle of the fuel injection pump 1 in synchronization with the fuel injection cycle.

When the processing is started, first, step 201 is executed to judge whether or not the flag F is in the set state. The flag F is a flag that is set when the reference signal of the rotation angle signal is input in the processing described later and is reset when a predetermined number (three in this embodiment) of rotation angle signals are input thereafter. Is reset, the process proceeds to step 202. In step 202, the time from the last execution of this interrupt processing to the current execution, that is, the pulse interval Tp of the rotation angle signal is calculated, and the routine proceeds to step 203.

In step 203, the obtained pulse interval T
p and the pulse interval Tp (n- found in the previous processing
The value obtained by multiplying 1) by a constant K is compared in magnitude to determine whether or not the rotation angle signal input this time is a reference signal. This is because when the reference signal is input, the pulse interval Tp during that time is about 2.5 times the normal value, so the value of the constant K is set to 2.28, and the pulse interval Tp is K times the previous pulse interval Tp (n-1). If it is above, it can be detected that the current rotation angle signal is the reference signal. When it is determined in step 203 that the rotation angle signal is not the reference signal, the processing of this routine is ended as it is.

On the other hand, if it is determined in step 203 that the rotation angle signal is the reference signal, step 204 is executed and flag F is set.
Is set, and the process proceeds to step 205. In step 205, the value of the counter C used for detecting the pulse drive signal output timing in the processing described later is cleared, and the processing of this routine ends.

Next, when it is determined in step 201 that the flag F is in the set state, the process proceeds to step 206 and the value of the counter C is incremented. And next step 207
Then, it is determined whether the value of the counter C is 3 or more, that is, whether the third rotation angle signal is input after the reference signal is detected. The process of this step 207 is performed by the hydraulic control valve 23.
In the process for detecting the timing of outputting the pulse drive signal, when C <3, it is determined that it is not the output timing of the pulse drive signal, and the process of this routine is finished as it is.

On the other hand, when it is determined in step 207 that C ≧ 3, that is, when the output timing of the pulse drive signal is detected, the process proceeds to step 208, the flag F is reset, and the process proceeds to next step 209. Then, in step 209, the control signal is output so that the pulse drive signal output from the drive circuit 37 is turned on and the time until the pulse drive signal is inverted to the off state, that is, step 107
Alternatively, the ON time of the pulse drive signal set in step 109 is set, and the processing of this routine ends.

In the fuel injection timing control device of the present embodiment configured as described above and the fuel injection timing is controlled, as shown in FIG.
The pulse drive signal of the hydraulic control valve 23 is output at every predetermined rotation angle before fuel injection in synchronism with the fuel injection cycle, and is always controlled to be in the ON state during fuel injection. Therefore, during the fuel injection, the roller ring 14 always moves to the retard side, and the fuel injection can be always executed at a constant fuel injection rate, and the fuel injection amount can be controlled well.

Here, in the above-described embodiment, the pulse drive signal is controlled to always be in the ON state during fuel injection, but the pulse drive signal is controlled to be in the OFF state at a predetermined rotation angle before fuel injection, and the pulse drive signal during fuel injection is controlled. The fuel injection rate can be controlled to be constant at all times even if is always turned off.

In the above embodiment, the fuel injection pump using the solenoid valve for controlling the fuel injection amount, that is, for controlling the fuel overflow timing in the pressurizing chamber 17a of the fuel injection pump 1 has been described as an example. The present invention can be applied to any fuel injection pump configured to adjust the fuel injection timing using the device and the hydraulic control valve.

[Advantages of the Invention] As described in detail above, according to the fuel injection timing control device of the fuel injection pump of the present invention, the pulse drive signal output to the hydraulic control valve during the fuel injection period of the fuel injection pump is ON or OFF.
The OFF state becomes a constant state, and the roller ring moves in either one of the advance side and the retard side. Therefore, the fuel injection rate is always stable and the fuel injection rate can be controlled well.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 9 show one embodiment of the present invention, and FIG. 2 is a schematic configuration showing the fuel injection pump and its peripheral devices of the present embodiment. 3 and 4 are explanatory views showing the shapes of the outer peripheral surfaces of the rotation angle sensor 25 and the pulsar 10, and FIG. 4 is a diagram showing the detection signal output from the rotation angle sensor 25 and the rotation angle signal after waveform shaping. 5, FIG. 5 is a block diagram showing the configuration of the electronic control circuit 30, FIG. 6 is a flowchart showing the pulse drive signal control processing executed in the electronic control circuit 30, and FIG. 7 is the rotation angle signal interrupt processing. Flowchart representing the eighth
FIG. 9 is a time chart for explaining the operation of the present embodiment, FIG. 9 is an explanatory view for explaining the configuration of a timer device conventionally used, and FIG. 10 is for explaining that the fuel injection amount is changed by this operation. It is a time chart. M1,1 ...... Fuel injection pump M2 ...... Fuel injection timing adjusting member M3,23 ...... Hydraulic control valve M4,2 ...... Diesel engine M5 ...... Operating state detection means M6 ...... Target fuel injection timing calculation means M7 ...... Drive signal control means M8 …… Drive signal output means M9 …… Timing detection means 7 …… Crank angle sensor, 13 …… Timer device 25 …… Rotation angle sensor, 26 …… Cooling water temperature sensor 27 …… Intake air temperature sensor, 28 ...... Intake pressure sensor 29 …… Accelerator sensor, 30 …… Electronic control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Masuda, 1-1, Showa-cho, Kariya city, Nihon Denso Co., Ltd. (72) Inventor, Hidetsugu Takemoto, 1-1, Showa-cho, Kariya city, Nihon Denso Co., Ltd. ( 72) Inventor Takashi Hasegawa 1-1-1, Showa-cho, Kariya City, Nippon Electric Co., Ltd. (56) Reference JP-A-60-212632 (JP, A) JP-A-59-120725 (JP, A) 58-158132 (JP, U) Actually opened 59-100937 (JP, U)

Claims (1)

(57) [Claims] 1. A fuel injection timing adjusting member for controlling a roller ring position of a fuel injection pump via a timer piston positioned by hydraulic pressure to adjust a fuel injection timing, and an on period and an off period per pulse. A hydraulic control valve that is opened and closed by a pulse control signal with a controlled ratio to control the hydraulic pressure applied to the fuel injection timing adjusting member, and an operating state that detects the operating state of a diesel engine fueled via the fuel injection pump. Detecting means, target fuel injection timing calculating means for calculating the target fuel injection timing of the fuel injection pump based on the detection result of the operating state detecting means, and fuel injection timing adjusted by the fuel injection timing adjusting member, One part of the pulse drive signal output to the hydraulic control valve is matched so as to match the target fuel injection timing calculated by the target fuel injection timing calculation means. Fuel injection timing of a fuel injection pump including drive signal control means for controlling a ratio of ON period and OFF period per loss, and drive signal output means for outputting the controlled pulse drive signal to the hydraulic control valve. In the control device, timing detection means for detecting a predetermined timing before fuel injection of the fuel injection pump is provided, and the drive signal output means sets the pulse drive signal to an on state or an off state at the detected predetermined timing. A fuel injection timing of the fuel injection pump, characterized in that the output state is continued at least until the end of one fuel injection period of the fuel injection pump, and the on / off state is not switched during the fuel injection period. Control device.