JPH063167B2 - Method of controlling injection quantity of electronically controlled diesel engine - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for controlling an injection amount of an electronically controlled diesel engine, and particularly suitable for use in a diesel engine for a vehicle equipped with a fuel injection pump of a solenoid valve spill type,
The fuel injection amount is controlled by an electromagnetic spill valve that is controlled to open and close according to the angle count and time count of the engine rotation angle signal, with the engine rotation angle signal output for each constant crank angle as a reference. The present invention relates to an improvement in an injection amount control method for an electronically controlled diesel engine.

[Prior art]

2. Description of the Related Art In recent years, with the development of electronic control technology, particularly digital control technology, so-called electronically-controlled diesel engine that electronically controls a fuel injection pump of the diesel engine has been put into practical use. There are various methods of electronically controlling the fuel injection pump, and one of them is a so-called electromagnetic spill type fuel injection pump in which the spill of fuel in the fuel injection pump is controlled by a solenoid valve. In this electromagnetic spill type fuel injection pump, the fuel injection amount is controlled by opening the spill port by the electromagnetic spill valve at the spill timing when the fuel injection amount reaches the target value, and controlling the end of the pressure feed of the fuel. To do. The electromagnetic spill valve is usually installed in a rotation angle gear fixed to a drive shaft of a fuel injection pump for detecting an engine rotation angle and a rotation speed, and a roller ring for detecting the gear of the rotation angle gear. By the control device that takes in the detection signal from the engine rotation sensor consisting of the electromagnetic pickup and calculates and determines the fuel injection amount based on the rotation angle signal,
It is controlled to open and close. That is, the roller ring moves according to the position of the timer piston, the timing of the pressure feed of the plunger changes, and the injection timing changes. Also, since the relative positions of the roller ring and the plunger lift correspond on a one-to-one basis,
The engine rotation pulse and the plunger lift also have a one-to-one correspondence as shown in FIG. The electromagnetic spill valve is a normally open type,
It is energized based on the engine rotation pulse position,
Turned on at the 9th pulse before the start of plunger feeding (fuel injection)
The spill angle ANGspv at which the target injection amount is obtained is off (injection cut by spill). More specifically, the angle count C of the engine rotation angle signal
Time count minute θrem (° C
The electromagnetic spill valve is turned off when the time TSPon corresponding to (A) has elapsed. The time conversion of the time count amount θrem is obtained, for example, from the engine rotation time T180 _i−1 during the previous 180 ° CA.

[Problems to be Solved by the Invention]

However, the time count θrem varies with variations in the injection amount of the fuel injection nozzle and the injection pump, changes over time (the spill angle ANGspv changes to achieve the target rotation due to idle speed control), variations in the press fit of the rotation angle gear,
Automatic transmission, air conditioner, power steering device,
There are cases in which the reference angle count Cangl changes due to large variations due to factors such as changes in the injection amount due to electrical load, fuel temperature, changes in the injection amount due to normality, and the like. In order to prevent delay due to multiple interruptions such as engine rotation sensor, ignition interruption, 5ms interruption, and analog-digital conversion interruption when the angle count changes Cangl in this way, a set time, for example, 220μ from the rise of the engine rotation pulse.
If it is within s, as shown in FIG. 8 (A), the spill time TSpon corresponding to the time count amount θrem is obtained from the previous engine rotation pulse rising position. On the other hand, if it is 220 μs or more from the rising of the engine rotation pulse, As shown in FIG. 8 (B), it is possible to leave it as it is.
However, in such a method, when the rising edge of the reference engine rotation pulse is switched, 220 μ
s (0.9 ° CA, fuel injection amount at idle 3 mm ³ / st
Equivalent to) occurs. Therefore, the time count amount θrem (TSPo
Due to the variation factor of n), when the timing to turn off the electromagnetic spill valve comes just at the switching of the engine rotation pulse, the variation in the injection amount becomes large, especially near the idle including the low rotation range, and the engine vibration becomes extremely large. It had the problem of becoming large. Further, in FIGS. 7 and 8, the engine rotation pulses are shown at equal intervals, but when the engine is actually running, the interval near the zero pulse is wide (low speed), The interval near the pulse is narrow (high rotation speed).
Moreover, since the engine speed changes every second even within the interval of the engine rotation pulse, the correspondence between time and angle is not one-to-one. Therefore, the engine rotation time of 11.25 ° CA is 1/1 of the previous 180 ° CA engine rotation time.
6 (AVT45 / 4) is not the same, and at the switching point of the reference position of the engine rotation pulse, for example, the spill valve off-timing calculated from the 5th pulse and the spill-valve off timing calculated from the 6th pulse are considerably It will be different. As a result, the variation of the injection amount control due to the variation of the spill valve off timing increases at the switching point of the reference position of the engine rotation pulse. This tendency is greatest near the idle, and at high rpm,
It becomes negligible because the rotation fluctuation due to compression and explosion of the engine becomes small. As a method of improving the detection accuracy of the rotation angle, the number of teeth of the rotation angle gear may be increased, or one of the applicants has already applied for a patent application.
As proposed in 9-104949, it has been proposed to arrange a large number of magnetic poles having different polarities side by side on the circumference, but in any case, variations in injection amount due to variations in angle count Could not be effectively prevented.

[Object of the Invention]

The present invention has been made to solve the above-mentioned conventional problems, and can prevent the dispersion of the injection amount due to the dispersion of the angle count in the idle state, thus reducing the engine vibration and the rotational fluctuation. It is an object of the present invention to provide an injection amount control method for an electronically controlled diesel engine capable of achieving the above.

[Means for solving problems]

The present invention controls a fuel injection amount by an electromagnetic spill valve that is controlled to open and close according to an angle count amount and a time count amount of the engine rotation angle signal on the basis of an engine rotation angle signal output at every constant crank angle. In the injection amount control method for the electronically controlled diesel engine,
As shown in the outline of the figure, the procedure for detecting whether or not the engine is in the idle state, and during the idle time, the angle count of the engine rotation angle signal is kept constant, and the time count is always started from the same point and the electromagnetic spill is started. The procedure to control the opening and closing of the valve,
When not in the idle state, a procedure for obtaining an angle count that changes corresponding to the spill angle, starting time counting from the end point of the angle count, and controlling the opening and closing of the electromagnetic spill valve is included. It has been achieved. Further, according to the embodiment of the present invention, the idle state is set to an idle stable state so that the engine vibration and the rotational variation in the idle stable state, where engine vibration and rotational variation are serious problems, can be effectively reduced. In another embodiment of the present invention, the idle state is set near the idle region / low speed region so that engine vibration and rotation fluctuation can be reduced not only in the idle stable state but also in a wide range near the idle region. It was done. Further, according to another embodiment of the present invention, when the angle count changing corresponding to the spill angle is obtained, the margin time is corrected in consideration of the multiple interruptions, so that the accurate interruption can be performed regardless of the large number of interruptions. The injection amount control is performed appropriately.

[Action]

In the present invention, the fuel injection amount is controlled by the electromagnetic spill valve that is controlled to open and close according to the angle count and time count of the engine rotation angle signal with reference to the engine rotation angle signal output for each constant crank angle. At the time of control, during idling, the angle count of the engine rotation angle signal is kept constant, and time counting is always started from the same point to open / close the electromagnetic spill valve. Therefore, when idle, regardless of various variation factors,
As the reference angle count does not change,
The injection amount control does not fluctuate. Therefore, engine vibration and rotation fluctuation are reduced. On the other hand, when not in the idle state, the angle count that changes corresponding to the spill angle is obtained, and the time counting is started from the end point of the angle count to control the opening and closing of the electromagnetic spill valve as in the conventional case. There is. Therefore, the normal operation state is not adversely affected by the engine stall or the like due to the angle count being fixed at a constant value.

【Example】

Hereinafter, an embodiment of an electronically controlled diesel engine for a vehicle, in which an injection timing control method according to the present invention is adopted, will be described in detail with reference to the drawings. In this embodiment, as shown in FIG. 2, an intake air temperature sensor 12 for detecting the temperature of intake air is provided downstream of an air cleaner (not shown). Downstream of the intake air temperature sensor 12, a turbocharger 14 including a turbine 14A that is rotated by the heat energy of exhaust gas and a compressor 14B that is rotated in conjunction with the turbine 14A is provided. The upstream side of the turbine 14A and the downstream side of the compressor 14B of the turbocharger 14 are communicated with each other through a waste gate valve 15 for preventing the intake pressure from rising too much. On the bench lily 16 on the downstream side of the compressor 14B,
A main intake throttle valve 18 is provided which is linked to an accelerator pedal 17 provided in the driver's seat and is configured to rotate in a non-linear manner for limiting the flow rate of intake air during idling. An accelerator position sensor 20 detects an opening degree (hereinafter, referred to as an accelerator opening degree) Accp of the accelerator pedal 17. An auxiliary intake throttle valve 22 is provided in parallel with the main intake throttle valve 18, and the opening degree of the auxiliary intake throttle valve 22 is controlled by a diaphragm device 24. The negative pressure generated by the negative pressure pump 26 is supplied to the diaphragm device 24 via a negative pressure switching valve (hereinafter referred to as VSV) 28 or 30. An intake pressure sensor 32 for detecting the pressure of intake air is provided downstream of the intake throttle valves 18, 22. In the cylinder head 10A of the diesel engine 10,
An injection nozzle 34, a glow plug 36, and an ignition timing sensor 38 whose tip faces the engine combustion chamber 10B are provided. Further, the cylinder block 10C of the diesel engine 10 is provided with a water temperature sensor 40 for detecting the engine cooling water temperature. Fuel is pumped from the injection pump 42 to the injection nozzle 34. The injection pump 42 includes a drive shaft 42A that is rotated in conjunction with the rotation of the crankshaft of the diesel engine 10 and a feed pump 42B (90 in FIG. 2) fixed to the drive shaft 42A for pressurizing fuel. ° C), a fuel pressure adjusting valve 42C for adjusting the fuel supply pressure, and a gear 4 fixed to the drive shaft 42A.
From 2D rotational displacement to a reference position, eg top dead center (TDC)
A reference position sensor 44 made of, for example, an electromagnetic pick-up, and an electromagnetic pick-up made to detect the engine speed from the rotational displacement of a gear 42E (rotation angle gear) fixed to the drive shaft 42A. The engine rotation sensor 46, the roller ring 42H for reciprocating the face cam 42F and the plunger 42G, and changing the timing thereof, and the roller ring 4H.
Timer piston 42 for changing the rotational position of 2H
J (FIG. 2 shows a 90 ° expanded state), a timing control valve (hereinafter referred to as TCV) 48 for controlling the injection timing by controlling the position of the timer piston 42J, and a spill. An electromagnetic spill valve 50 for controlling the fuel injection amount by changing the fuel escape timing from the plunger 42G via the port 42K, a fuel cut valve 52 for cutting the fuel at the time of an abnormality, and a fuel cut valve 52. Delivery valve 42L to prevent backflow and backward drip
And are provided. The gear 42E has a plane shape as shown in FIG. 3, for example. A glow current is supplied to the glow plug 36 via a glow relay 37. The intake temperature sensor 12, the accelerator position sensor 20, the intake pressure sensor 32, the ignition timing sensor 38, the water temperature sensor 40,
An electronic control unit (hereinafter referred to as ECU) includes a reference position sensor 44, an engine rotation sensor 46, a glow current sensor 54 for detecting a glow current flowing through the glow plug 36, an air conditioner switch, a neutral safety switch output, and a vehicle speed signal. ) 56 is input and processed,
According to the output of the ECU 56, the VSV 28, 30,
The glow relay 37, the TCV 48, the electromagnetic spill valve 50, the fuel cut valve 52, etc. are controlled. As shown in detail in FIG. 4, the ECU 56 includes a central processing unit (hereinafter, referred to as CPU) 56A for performing various arithmetic processes, an output of the water temperature sensor 40 input via a buffer 56B, and a buffer 56C. The intake air temperature sensor 12 output that is input via the buffer 56D, the intake pressure sensor 32 output that is input via the buffer 56D, and the buffer 56
A multiplexer for sequentially taking in the output of the accelerator position sensor 20 input via E, the phase correction voltage signal input via the buffer 56F, the τ correction voltage signal input via the buffer 56G, etc. MPH) 56H, an analog-digital converter (hereinafter referred to as A / D converter) 56J for converting an analog signal of the MPX 56H output into a digital signal and taking it into the CPU 56A, and the engine rotation sensor 46. Waveform shaping circuit 56 for taking the output into the waveform shaping circuit CPU 56A
K and the reference position sensor 44 output are waveform-shaped and CP
A waveform shaping circuit 56L for taking in the U56A, a waveform shaping circuit 56M for shaping the output of the ignition timing sensor 38 into the CPU 56A, and a CP for the starter signal.
A buffer 56N for taking in the U56A, a buffer 56P for taking in an air conditioner signal into the UPU 56A, and a buffer 56 for taking in a torque converter signal into the CPU 56A.
Q, a drive circuit 56R for driving the fuel cut valve 52 according to the calculation result of the CPU 56A, and the C
A drive circuit 56S for driving the TCV 48 according to the calculation result of the PU 56A, a drive circuit 56T for driving the electromagnetic spill valve 50 according to the calculation result of the CPU 56A, and a current flowing through the electromagnetic spill valve 50. Current detection circuit 56U for detecting the voltage and feeding back to the drive circuit 56T, a low voltage detection circuit 56V for detecting a low voltage and inputting it to the drive circuit 56T, and a self-detection circuit according to the calculation result of the CPU 56A. Drive circuit 56W for outputting a diagnostic signal (hereinafter referred to as a diagnostic signal)
And a drive circuit 56X for driving the warning light according to the calculation result of the CPU 56A. Here, the phase correction voltage signal is a signal for correcting the phase difference between the normal position and the actual mounting position, which occurs when the reference position sensor 44 is attached to the injection pump 42. Also, the τ correction voltage signal is the injection pump 42
It is a signal for correcting the shift of the responsiveness due to the individual difference of each component in. The control of the injection amount in this embodiment is executed according to the flow chart as shown in FIG. That is, first, step 110
The engine speed Ne calculated from the output of the engine speed sensor 46, the accelerator opening Accp calculated from the output of the accelerator position sensor 20, the water temperature sensor 40
The spill angle ANGspv is calculated from the engine cooling water temperature obtained from the output, the intake air temperature obtained from the output of the intake air temperature sensor 12, and the like. Then proceed to step 112,
For example, that the accelerator pedal 17 is not fully closed at the time of starting or for a while after starting, and it has been a while since the accelerator pedal 17 was fully closed.
It is determined whether the vehicle is in the idle stable state because all the conditions such as the neutral range or the vehicle speed of zero in the drive range and the fact that the dump pot is not effective are satisfied. When the judgment result is positive,
In step 113, it is determined whether the engine rotation pulse is the fifth pulse or less. When the determination result of the preceding step 112 is negative and it is determined that it is in a normal operation state, or when the determination result of step 113 is positive and it is determined that the fourth pulse should be counted. Then, in step 114, the reference position Cangl of the engine rotation pulse corresponding to the conventional spill angle ANGspv is calculated, and the time count TSOon based on the Cangl is calculated. Specifically, as shown in the following equation, the spill angle ANGsp
v is the angle per tooth of the engine rotation sensor 46,
For example, the angle count Cangl is calculated by dividing by 11.25 ° CA. ANGspv / 11.25 → Cangl + remainder (1) Next, the remainder of this calculation result is the average 45 ° CA engine rotation time AVT45 (= T180 / 4) calculated from the time T180 from the previous reference position, that is, the tooth-missing position. ) Is used to convert the time count of the spill angle into TSPon. Remainder × AVT45 / 4 → TSPon (2) In this step 114, considering the multiple interruption, a margin time of 220 μs is provided to correct the angle count Cangl and the time count TSPon. . After the end of step 114, this routine is exited. On the other hand, if the determination result of the above step 113 is negative,
That is, when it is determined that the engine is in the idle stable state and the engine rotation pulse is not equal to or less than the fifth pulse, the routine proceeds to step 116, where the angle count amount Cangl is fixed to a constant value, for example, 5, and the five angle values are constantly maintained. End point of count,
That is, the time count TSPon is calculated from the rising edge of the fifth pulse, and the routine exits. On the other hand, from the engine rotation sensor 46 to the waveform shaping circuit 5
The process corresponding to the engine rotation sensor output pulse input via 6K is performed by the input interrupt (IC
AP) routine. That is, every time a pulse is input from the engine speed sensor 46, the process goes to step 210 to increment the engine speed interruption counter Cnirq. Next, in step 212, the count value of the counter Cnirq is changed to the previous step 114 or 1
It is determined whether or not it is equal to the angle count Cangl of the spill angle obtained in 16. In short, the determination in step 212 is to determine whether or not there is a spill time before the next engine rotation interruption. When the determination result of step 212 is positive and it is determined that there is a spill time, the process proceeds to step 214, and as shown in the following equation, at the current interrupt time Tint, the previous step 1
Time count TS of spill angle obtained in 14 or 116
Pon is added to the output comparison register OCR to prepare for spill. After the end of step 214 or when the result of the determination in the previous step 212 is negative, the process proceeds to step 216, and the count value of the counter Cnirq is set so that the electromagnetic spill valve 50 is closed in preparation for the next opening control. It is determined whether the value is 9, for example. When the determination result is positive, that is, when it is determined that it is time to close the electromagnetic spill valve 50, the process proceeds to step 218, and as shown in the following equation, until the interrupt calculation is finished at the current interrupt time Tint. The output comparison register OCR is inserted with the margin time α added to prepare for closing the electromagnetic spill valve 50. Tint + α → OCR (3) After completion of the above step 218, or if the determination result of step 216 is negative, the process proceeds to step 220, and it is determined whether or not the missing tooth position corresponds to the reference position. . When the judgment result is positive and it is judged that it is the reference position,
In step 222, the counter Cnirq is cleared, and in step 224, the time T1 from the previous missing tooth position is set.
The engine speed Ne is calculated using 80. After the end of step 224, or when the result of the determination in the preceding step 220 is negative, this input interrupt routine is ended. Although not shown, the electromagnetic spill valve 50 is opened and closed at the time set in the output comparison register OCR. In the present embodiment, since the idle state is the idle stable state only, the control according to the present invention is performed effectively and to the minimum necessary, and there is no adverse effect such as engine stall on other areas. The idle state to which the present invention is applied is not limited to the idle stable state, and may be a normal idle state, or, for example, the accelerator opening Accp is less than 4%, the engine speed Ne is less than 1000 rpm, and the spill angle ANGspv is the engine rotation pulse. Of 4
When it is between No. 6 and No. 6, it is also possible to fix it to No. 4 and control by TSPon for the time count from there, or to execute in the vicinity of the idle area. In this case,
It is possible to reduce engine vibration and rotation fluctuation over a wider range.

【The invention's effect】

As described above, according to the present invention, it is possible to accurately control the injection amount control in the idle state regardless of various variation factors, and it is possible to reduce engine vibration and rotation fluctuation. Have an effect.

[Brief description of drawings]

FIG. 1 is a flow chart showing the gist of a method for controlling an injection amount of an electronically controlled diesel engine according to the present invention, and FIG. 2 shows an overall configuration of an embodiment of an electronically controlled diesel engine for an automobile to which the present invention is adopted. A sectional view including a partial block diagram, FIG. 3 is a plan view showing a rotary angular gear used in the above-mentioned embodiment, and FIG. 4 is a block diagram showing the configuration of an electronic control unit. 5 is a flow chart showing a routine for calculating the spill angle, and FIG. 6 is a flow chart showing an engine rotation pulse input interrupt routine for processing the output of the engine rotation sensor.
FIG. 8 is a diagram showing an example of the relationship between the engine speed, the engine rotation pulse, the on / off state of the electromagnetic spill valve, and the plunger lift in the conventional example, and FIGS. The time count is 220μ
FIG. 6 is a diagram showing an example of a relationship between an engine rotation pulse and an on / off state of an electromagnetic spill valve when the time is less than s and 220 μs or more. 10 ... Diesel engine, 42 ... Injection pump, 42E ... Gear (rotating angular gear), 46 ... Engine rotation sensor, 50 ... Electronic spill valve, 56 ... Electronic control unit, ANDspv ... Spill angle, Cangl ... Angle count, θrem, TSPon ... Time count minutes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noritaka Ibuki 1-1, Showa-cho, Kariya City, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor Takashi Hasegawa 1-1-chome, Showa-cho, Kariya City, Aichi Prefecture Sozo Co., Ltd.

Claims (4)

[Claims] 1. A fuel injection amount is controlled by an electromagnetic spill valve whose opening and closing is controlled according to an angle count and a time count of the engine rotation angle signal with reference to an engine rotation angle signal output at every constant crank angle. In the injection amount control method of the electronically controlled diesel engine that is controlled, a procedure for detecting whether or not the engine is in an idle state, and at the time of idle, the angle count of the engine rotation angle signal is set to be constant, and always from the same point. The procedure to start the time counting and control the opening and closing of the electromagnetic spill valve, and when not in the idle state, obtain the angle count that changes corresponding to the spill angle and start the time counting from the end point of the angle count An injection amount control method for an electronically controlled diesel engine, comprising: a procedure for controlling opening / closing of a spill valve; 2. The injection amount control method for an electronically controlled diesel engine according to claim 1, wherein the idle state is set to an idle stable state. 3. The injection amount control method for an electronically controlled diesel engine according to claim 1, wherein the idle state is in the vicinity of an idle region / low speed region. 4. The electronically controlled diesel engine according to claim 1, wherein when calculating the angle count that changes corresponding to the spill angle, correction is made for a margin time in consideration of a large number of interrupts. Injection amount control method.