JP2782708B2 - Fuel injection timing control device for fuel injection pump - Google Patents

Description

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. [Prior art] Conventionally, as a fuel injection timing control device for a fuel injection pump, a reference position sensor that detects TDC (top dead center) of a diesel engine by rotation of a pump drive pulley and a roller ring of the fuel injection pump are linked. The actual fuel injection timing (hereinafter simply referred to as the actual fuel injection timing) is detected from a rotation angle sensor that detects the rotation angle of the drive shaft of the fuel injection pump, and the actual fuel injection timing is determined as the target fuel injection timing ( In some cases, feedback control is performed so that the target fuel injection timing is simply referred to as the target fuel injection timing.
153939). The means for adjusting the fuel injection timing in the feedback control adjusts the fuel injection timing by moving the rotation angle position of the roller ring of the fuel injection pump, and has a configuration as shown in FIG. As shown in the drawing, a hydraulic control valve 70 opened and closed by a pulse drive signal having a controlled duty ratio causes a high-pressure chamber 74 of a timer device 72 to operate.
Is controlled, and the rotational angular position of the roller ring 78 is moved via the timer piston 76 positioned by the hydraulic pressure of the high-pressure chamber 74. Thus, the fuel injection timing is adjusted. [Problems to be Solved by the Invention] However, in the conventional fuel injection timing control device for a fuel injection pump, the actual fuel injection timing is detected once per cycle in synchronization with the input from the reference position sensor. On the other hand, since the calculation of the target fuel injection timing is performed several times in one cycle in synchronization with the time interruption period of the CPU, the target fuel injection timing is calculated when the rotational speed of the diesel engine is in a transient state. The actual fuel injection timing at the correct time does not correspond to the timing, and a desired roller ring position cannot be obtained. As a result, hunting or excessive delay of the fuel injection timing occurs, which has a problem that drivability and emission are adversely affected. The present invention has been made in view of the above-described problems, and has been developed to provide a fuel injection pump that prevents hunting and excessive delay of a fuel injection timing even in a transient state of the rotational speed of a diesel engine, and improves drivability and emission. It is an object to provide a fuel injection timing control device. Configuration of the Invention [Means for Solving the Problems] In order to achieve the object, the present invention has the following configuration as means for solving the problems. That is, according to the present invention, as exemplified in FIG. 1, a fuel injection timing adjusting means M2 for controlling a position of a roller ring of a fuel injection pump and adjusting a fuel injection timing, and a roller ring of the fuel injection pump M1. In conjunction therewith, a rotation angle detection means M3 for detecting a rotation angle of a drive shaft of the fuel injection pump, and a reference position detection means M5 for detecting a reference position of a cycle of a diesel engine M4 supplied with fuel via the fuel injection pump. From the rotation angle detected by the rotation angle detection means M3 and the reference position detected by the reference position detection means M5, the actual fuel injection timing of the fuel injection pump is synchronized with the rotation angle of the diesel engine. Actual fuel injection timing detection means M6
Operating state detecting means M7 for detecting an operating state of the diesel engine, an operating state detected by the operating state detecting means M7, and a rotation angle detected from data detected by the rotation angle detecting means M3, A target fuel injection timing calculating means M8 for calculating a target fuel injection timing of the fuel injection pump in synchronization with time; an actual fuel injection timing detected by the actual fuel injection timing detecting means M6; and the target injection timing calculating means M8. An error from the target injection timing calculated in the above is obtained, and a control amount of the fuel injection timing adjusting means M2 is calculated in synchronization with time according to the error, and the fuel injection timing adjusting means M2 is controlled according to the control amount. The fuel injection timing control device for a fuel injection pump, comprising: a control unit M9, wherein the amount of change in the rotational speed of the diesel engine per predetermined time is greater than a predetermined value. A transient state detecting means M10 for detecting as a transient state; and when the transient state detecting means M10 detects a transient state, the fuel injection timing adjusting means M2 calculated according to the error in the control means M9. Correction means M11 for correcting the control amount according to the amount of change in the rotational speed per the predetermined time.The control means M9 controls the fuel injection in accordance with the control amount corrected by the correction means M11. A fuel injection timing control device for a fuel injection pump characterized by controlling the timing adjusting means M2. [Operation] With the above configuration, the actual fuel injection timing detecting means M6 determines the actual fuel injection timing of the fuel injection pump from the diesel engine based on the rotation angle detected by the rotation angle detecting means M3 and the reference position detected by the reference position detecting means M5. While detecting in synchronization with the rotation angle of
The target fuel injection timing calculating means M8 calculates the target fuel injection timing in synchronization with time from the operating state detected by the operating state detecting means M7 and the rotation angle detected by the rotation angle detecting means M3. Also, the control means M9 calculates the control amount of the fuel injection timing adjustment means M2 in synchronization with time, and the control amount of the fuel injection timing adjustment means M2 when it is determined that the transient state is detected by the transient state detection means. Is also corrected in time synchronization according to the transient state. Therefore, even in a large transient state in which the actual fuel injection timing at the exact time does not correspond to the target fuel injection timing, the fuel injection timing correction amount calculated according to the amount of change per unit time of the rotation speed is calculated as Eventually, it becomes possible to directly affect the control amount of the fuel injection timing calculated in time synchronization, and compared to a system in which the magnitude of the transient state of the engine is reflected in the calculation of the target injection timing, Regardless of the rotational speed, the injection timing control amount finally calculated in time synchronization can be directly corrected at the common correction interval of time synchronization according to the transient state, so that the injection timing responsiveness in the transient state is improved. It can be stably improved. 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 provided with the fuel injection timing control device of the first embodiment of the present invention and a diesel engine. In FIG. 1, reference numeral 1 denotes a distribution type fuel injection pump, which is driven by rotation of a drive pulley 3 connected to a crank shaft of a diesel engine 2 via a belt or the like, and feeds fuel to a fuel injection nozzle 4 of the diesel engine. The drive pulley 3 is provided with a projection 5. The reference cam angle sensor 7 provided on the pump housing 6 of the fuel injection pump 1 is used to determine a predetermined crank angle of the diesel engine 2 (in this embodiment, TDC (top dead center). Point)) can be detected. A drive shaft 8 of the fuel injection pump 1 connected to the drive pulley 3 is provided with a vane pump 9 as a fuel feed pump and a pulsar 10 having a plurality of projections on its outer peripheral surface. It is connected to the cam plate 11 via a coupling. The cam plate 11 is integrally joined with 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 figure 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) (not shown).
U) is inserted into a pump cylinder 17 which is communicated with a fuel chamber 16 in the pump housing 6 via an intake port opened and closed by the U), pressurizes the fuel by the reciprocating motion, and delivers the diesel engine 2 through a delivery valve 18. Pumps fuel 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 in the left direction in the drawing, the fuel in the fuel chamber 16 is sucked into the pressurizing chamber 17a, and the fuel passage 12a moves rightward in the drawing. When moving, the fuel in the pressurizing chamber 17a is pressurized and the distribution 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 is communicated with the fuel chamber 16 via the pilot injection valve 20. The pilot injection 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, at the time of fuel pressurized pressure feed, the pressurized chamber 17a and the fuel chamber 16 communicate with each other. The fuel overflows and the fuel supply to the diesel engine is stopped. Next, the timer device 13 includes a timer housing 13a, a timer piston 13b fitted into the timer housing 13a, and connected to the roller ring 14, and a spring 13c for urging the timer piston 13b rightward in the drawing. By positioning the timer piston 13b by the fuel pressure of 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 equal to 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 with which the opening and closing are controlled by a pulse drive signal having a controlled duty ratio. The roller ring 14 positioned by the timer device 13 and the hydraulic control valve 23 has a real cam angle at which a detection signal is generated every time a protrusion formed on the outer peripheral surface of the pulsar 10 crosses the position facing the pulsar 10. A sensor 25 is provided to detect the rotational speed of the fuel injection pump, that is, the engine rotational speed of the diesel engine 2 and the fuel injection cycle of the fuel injection pump. That is, as shown in FIG. 3, the outer peripheral surface of the pulsar 10 is formed with 56 projections 37 each having four cutting edges that divide the outer peripheral surface into four equal parts. A detection signal as shown in FIG. 4 (A) is output, and the detection signal is shaped into a waveform, as shown in FIG. 4 (B), to indicate the reference signal A and the rotation speed synchronized with the fuel injection cycle. The reference cam angle signal B is obtained. Further, since the actual cam angle sensor 25 is fixed to the roller ring 14 and moves with its rotation, the cam roller
It is possible to detect the time of the 15th lift, that is, the fuel injection start timing.
In this embodiment, the actual cam angle sensor 25 is fixed so that fuel injection is started when the fourth actual cam angle signal is output after the output of the reference signal A. A detection signal as shown in FIG. 4 (C) is output from the reference cam angle sensor 7 described above, and the detection signal is shaped into a waveform to produce the diesel engine 2 as shown in FIG. 4 (D). The TDC signal C is obtained. The actual cam angle sensor 25
The phase difference d from when the fourth real cam angle signal is output after the output of the reference signal A of the detection signal to when the TDC signal C is obtained indicates the fuel injection timing. And the actual cam angle sensor 25, the actual fuel injection timing can be detected. Next, the diesel engine 2 has a cooling water temperature sensor 26 for detecting its cooling water temperature and an intake air temperature sensor 27 for detecting the intake air temperature.
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. An accelerator sensor 29 detects an amount of depression of an accelerator pedal 29a. The accelerator sensor 29 can detect the operating state of the diesel engine 2 also by this. The detection signals from the cooling water temperature sensor 26, the intake air temperature sensor 27, the intake pressure sensor 28, and the accelerator sensor 29, and the detection signals from the reference cam angle sensor 7 and the actual cam angle sensor 25 are respectively sent to the electronic control circuit 30. The pilot injection valve 20 and the hydraulic control valve 23 are driven and controlled. That is, in the electronic control circuit 30, the pilot injection valve is controlled in accordance with the operation state of the diesel engine 2 detected by the various sensors.
By controlling the drive of the hydraulic control valve 20 and the hydraulic control valve 23, the fuel injection amount and the fuel injection timing to the diesel engine 2 are controlled. And this electronic control circuit
30 is an A / D converter 31 for converting an analog signal output from each sensor into a digital signal, as shown in FIG.
A waveform shaping circuit 32 for shaping a pulse signal output from each of the above sensors, an A / D converter 31 or a waveform shaping circuit 32
CPUs 33 and C that execute fuel injection control of the fuel injection pump 1 based on detection signals from the sensors input through
A control program and various data necessary for executing control processing in the PU 33 are stored in the ROM 34 in advance, and data necessary for executing control processing in the CPU 33 are temporarily read and written in the RA.
M35 and drive circuits 36 and 37 for outputting drive signals to the pilot injection valve 20 and the hydraulic control valve 23, respectively. Hereinafter, fuel injection timing control, which is a main control process according to the present invention, which is executed by the electronic control circuit 30, will be described in detail with reference to FIGS. FIG. 6 is a flowchart showing a first interrupt process for calculating a target fuel injection timing θT, and FIG. 7 is an actual fuel injection timing θ.
FIG. 8 is a flowchart showing a second interrupt process for detecting R, and FIG. 8 shows a main process for calculating and applying a drive signal to the hydraulic control valve 23 based on an error Δθ between the target fuel injection timing θT and the actual fuel injection timing θR. It is a flowchart shown. The first interrupt processing shown in FIG. 6 is a routine which is executed in synchronization with the time interruption cycle of the CPU. In step 110, it is determined whether or not the actual cam angle sensor 25 has detected the incisor position of the pulsar 10. If "YES", that is, the incisor position is detected, the process proceeds to step 120, where the incisor position is determined. Thereafter, a counter i for counting the number of the pulse position is cleared to zero. On the other hand, if "NO" is determined in the step 110, the process proceeds to a step 130, where the counter i is incremented by 1, and in a subsequent step 140, it is determined whether or not the counter i is a. It is determined whether or not the pulse position after the incisor is the a-th pulse position. In this embodiment, a is 4 because fuel injection is started fourth after the cutting teeth as described above. In step 140, select "YE
If "S", that is, if the value of the counter i is 4, the process proceeds to the subsequent step 150, where the timer for counting the phase difference d in FIG. 4 is set. After the processing of step 120 or step 150 is completed, or when “NO” is determined in step 140, the processing proceeds to subsequent step 160. In step 160, the input time Ti of the pulse signal of the actual cam angle sensor 25 is calculated. In the following step 170, the current time is calculated from the difference between the calculated input time Ti and the input time Ti-1 calculated in the previous processing of this routine. The engine rotation speed Nei is calculated. In the following step 180,
From the detection data from the accelerator sensor 29, the accelerator opening α
In the next step 190, the target fuel injection timing θT is calculated in accordance with the engine speed Nei calculated in step 170 and the accelerator opening α calculated in step 180. When the processing in step 190 is completed, the processing exits to “RETURN” and ends once. Subsequently, the second interruption process shown in FIG. 7 is a routine executed in synchronization with the input of the reference cam angle sensor 7,
When the process is started, the process is executed from step 210 first.
In step 210, the phase difference d indicated by the timer started counting in step 150 in FIG. 4 is temporarily stored in the real-time memory MTj of the RAM 35. In the following step 220, the timer started counting in step 150 of FIG. 6 is reset. In subsequent step 230, the actual fuel injection timing θR is calculated by multiplying the time value of the real time memory MTj stored in step 210 by the angle conversion coefficient. When the process of step 230 is completed, the process exits to “RETURN” and ends once. Subsequently, the main processing shown in FIG. 8 is a routine that is repeatedly executed at predetermined time intervals. In step 310, the actual fuel injection timing θR calculated in the second interrupt
Error Δ from target fuel injection timing θT calculated by interrupt processing
is calculated, and in step 320, the integral amount DIi of the timer control duty corresponding to the error Δθ is calculated from a map as shown in FIG. In the following step 330, the integral amount DIi is incremented by the integral amount total DI added up to the previous time to calculate the integral amount DI. Following step 340
Then, the engine rotation speed Nei calculated in step 170 of the first interrupt processing is read, and an engine rotation speed difference ΔN between the engine rotation speed Nei and the engine rotation speed Nei-1 at the time of the previous processing of this routine is calculated. In the following step 350, it is determined whether or not the engine rotational speed is in a transient state by determining whether or not the absolute value of the engine rotational speed difference ΔN is equal to or greater than a predetermined value b. If “YES” in the step 350, that is, if it is determined that the state is the transient state, the process proceeds to a step 360, and the correction amount ΔD of the timer control duty according to the engine speed ΔN is set to the tenth.
It is calculated from the map shown in the figure. On the other hand, "NO" in step 350
Is determined, the process proceeds to step 370, where the duty correction amount ΔD is set to zero. When the processing of step 360 or step 370 is completed, the processing moves to step 380. In step 380, the proportional amount DPi of the timer control duty according to the error Δθ calculated in step 310 is
It is calculated according to a map as shown in FIG. In the following step 390, the calculated integral amount DI, proportional amount DPi and correction amount Δ
D is added to each other to calculate a total duty ratio ΔD. In the following step 395, the drive circuit 37 outputs a pulse drive signal having the total duty ratio ΔD from the drive circuit 37.
Control. When the processing in step 395 is completed, the processing exits to “RETURN” and ends once. Next, the main processing will be described in more detail with reference to the timing chart of FIG. When the engine rotation speed Nei increases as time elapses as shown in FIG. 12A (acceleration state), the engine rotation speed difference becomes larger than a predetermined value and it is determined that the engine is in a transient state (FIG. 12B). In the transient state, the duty correction amount ΔD is set as shown in FIG.
Further, the integral amount DI is set as shown in FIG. 10D, and the proportional amount DPi is set as shown in FIG. In this example, it is assumed that DPi takes a value of zero. Then, the correction amount Δ, the integral amount DI, and the proportional amount DPi are added to calculate the total duty ratio ΣD as shown in FIG.
The duty ratio ΔD is output to 23. As a result, the fuel injection timing is determined as shown by the solid line in FIG. In FIG. 9G, the dashed line indicates the target fuel injection timing, and the dashed line indicates the fuel injection timing of the related art in which duty correction is not performed during a transient state of the engine rotation speed. Therefore, the present embodiment configured as described above can prevent hunting of the fuel injection timing and delay of the transient even in the case of the transient state of the engine rotational speed, and as a result, the drivability and the emission can be improved. Things. In the present embodiment, since the correction amount ΔD is set using the engine speed difference ΔN as a parameter, control can be performed according to the degree of the transient state, and fuel can be supplied at a more appropriate fuel injection timing. it can. Next, a fuel injection timing control device for a fuel injection pump according to a second embodiment of the present invention will be described with reference to FIGS. This embodiment differs from the first embodiment in that the electronic control circuit 30
The main control executed by the electronic control circuit 30 is the same as that of the first embodiment. FIG. 13 is a flowchart showing the main processing of the present embodiment corresponding to FIG. 8 of the first embodiment. Steps 410, 420, 430, 440, 450, and 495 in FIG.
The processing is the same as that of steps 310, 320, 330, 340, 350, and 395 in the figure, and a description thereof will be omitted. If "YES" in the step 450, that is, if it is determined that the engine rotational speed is in a transient state, the step
The process proceeds to 460, where a correction coefficient K corresponding to the engine speed difference ΔN is calculated. On the other hand, if “NO” is determined in the step 450, the process proceeds to a step 470, where the correction coefficient K
To the value 1.0. Step 460 or Step 47
After finishing the process of step 0, the process proceeds to step 480.
At 480, the proportional amount DPi of the timer control duty according to the error Δθ calculated at step 410 is calculated according to a map as shown in FIG. In the following step 490, the total duty ratio ΔD is calculated by multiplying the calculated proportional amount DPi by the correction coefficient K and further adding the integral amount DI calculated in step 430. Subsequently, the process proceeds to step 495, and outputs the total duty ratio ΔD. Then, the process exits to “RETURN” and ends once. Although the configuration of the second embodiment of the present invention has been described in detail above, the present embodiment adds the correction amount DPi · K corresponding to the engine rotation speed difference ΔN to the first embodiment to obtain the engine rotation speed difference ΔN.
Thus, finer correction of the fuel injection timing can be performed, and hunting and excessive delay of the fuel injection timing can be more accurately prevented. Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments at all, and it goes without saying that various embodiments can be made without departing from the gist of the present invention. Effects of the Invention As described above, according to the present invention, in the injection timing control device in which the calculation of the actual injection timing is performed in synchronization with the rotation angle of the engine and the calculation of the target injection timing is performed in time synchronization, In a large transient state where the actual fuel injection timing at the exact time does not correspond to the timing, the fuel injection timing correction amount calculated according to the amount of change in the rotation speed per time is finally synchronized with the time. Can be directly applied to the control amount of the fuel injection timing calculated by Therefore, in comparison with a system in which the magnitude of the transient state of the engine is reflected in the calculation of the target injection timing, for example, in the present invention, the transient state is corrected for the final control amount according to the change in the rotational speed per time. Therefore, since the final fuel injection timing control amount can be corrected, the responsiveness of transient correction is significantly improved, and the correction amount is calculated in the same way as the control amount calculation in time synchronization instead of rotation speed synchronization. Therefore, there is an excellent effect that the correction according to the transient state can be stably performed irrespective of the difference in the rotation speed change per unit time or the difference in the rotation speed at that time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the structure of the present invention, FIGS. 2 to 12 show a first embodiment of the present invention, and FIG. 2 shows a fuel injection pump of the present embodiment. FIG. 3 is a schematic diagram showing the configuration of a real cam angle sensor 25 and a pulsar.
FIG. 4 is an explanatory view showing the shape of the outer peripheral surface of FIG. 10. FIG. 4 is a detection signal output from the actual cam angle sensor 25, an actual cam angle signal after waveform shaping, a detection signal output from the reference cam angle sensor 7, and FIG. FIG. 5 is a diagram showing a reference cam angle signal after waveform shaping; FIG. 5 is a block diagram showing a configuration of an electronic control circuit;
9 is a flowchart showing a first interrupt process executed in the electronic control circuit, FIG. 7 is a flowchart showing a second interrupt process, FIG. 8 is a flowchart showing a main process, and FIGS. Map used in main processing, FIG. 12 is a time chart for explaining the operation of this embodiment, FIGS. 13 and 14 show a second embodiment of the present invention, and FIG. FIG. 14 is a flowchart showing a main process to be executed, FIG. 14 is a map used in the main process, and FIG. 15 is an explanatory diagram for explaining a configuration of a timer device conventionally used. 7 Reference cam angle sensor 13 Timer device 23 Hydraulic control valve 25 Actual cam angle sensor 29 Accel sensor 30 Electronic control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-60238 (JP, A) JP-A-60-17252 (JP, A) JP-A-56-146025 (JP, A) JP-A-59-60 153939 (JP, A) Fully open sho 59-116541 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 41/00-41/40

Claims (1)

(57) [Claims] A fuel injection timing adjusting means for controlling a position of a roller ring of the fuel injection pump to adjust a fuel injection timing; and a rotation detecting a rotation angle of a drive shaft of the fuel injection pump in conjunction with the roller ring of the fuel injection pump. Angle detection means, reference position detection means for detecting a reference position of a cycle of a diesel engine supplied with fuel via the fuel injection pump, rotation angle detected by the rotation angle detection means, and reference position detection means An actual fuel injection timing detecting means for detecting an actual fuel injection timing of the fuel injection pump in synchronization with a rotation angle of the diesel engine from the reference position detected in the above, and an operating state for detecting an operating state of the diesel engine. Detecting means, an operating state detected by the operating state detecting means, and a rotational speed detected from data detected by the rotational angle detecting means, Target fuel injection timing calculating means for calculating a target fuel injection timing of the fuel injection pump in synchronization with time; actual fuel injection timing detected by the actual fuel injection timing detecting means and calculated by the target injection timing calculating means. A control means for calculating an error from the target injection timing, calculating a control amount of the fuel injection timing adjusting means in synchronization with time in accordance with the error, and controlling the fuel injection timing adjusting means according to the control amount. In the fuel injection timing control device for a fuel injection pump, transient state detection means for detecting a state in which the amount of change in the rotational speed of the diesel engine per predetermined time is larger than a predetermined value as a transient state of the diesel engine; When the transient state of the rotational speed is detected by the means, the control of the fuel injection timing adjusting means calculated according to the error by the control means. Correction means for correcting the amount in accordance with the change amount of the rotation speed per the predetermined time, wherein the control means controls the fuel injection timing adjustment means according to the control amount corrected by the correction means. A fuel injection timing control device for a fuel injection pump.