JPH0459458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection control device for a diesel engine.

Recently, in diesel engines, fuel injection timing, fuel injection amount, etc. are controlled by microcomputers. Power is supplied to this microcomputer system when the key switch is turned on, and after the key switch is turned off, it is maintained for a certain period of time, for example, two seconds, so that even if the key switch is turned off, the diesel engine cannot be controlled for only two seconds. It becomes possible. In other words, two types of power supply means are provided. For example, during this time, engine noise and vibration are reduced by throttling the intake air after the engine is stopped and controlling the fuel injection amount for a certain period of time, for example, 0.3 seconds.

However, in the conventional type described above, even if fuel injection amount control is stopped, fuel injection timing control is performed while power is being supplied to the microcomputer system, and as a result, fuel injection There was a problem in that the operating sound of the timing control actuator continued and was unpleasant.

In view of the problems with the conventional type described above, an object of the present invention is to reduce the unpleasant operating noise of the actuator by stopping fuel injection timing control as well as stopping fuel injection amount control.

FIG. 1 is an overall block diagram for clearly showing the configuration of the present invention. In Figure 1, battery 3
1 is connected to a first power supply means via a key switch 32, and is also connected to a second power supply means via a main switch 33. The main switch 33 is turned on by the first power supply means and also by the second power supply means. The fuel injection timing control means and the fuel injection amount control means of the diesel engine are operated by either the first or second power supply means. The first and second timer means are set and driven by an off signal from the first power supply means, that is, when the key switch 32 is turned off. 1st and 2nd at this time
The drive signal for the timer means is supplied by the second power supply means. The first timer means stops both the fuel injection timing control means and the fuel injection amount control means of the diesel engine after measuring a predetermined time _tA , and the second timer means stops both the fuel injection timing control means and the fuel injection amount control means after measuring a predetermined time _tA. The main switch 33 is turned off after measuring a long predetermined time _tB .

Embodiments of the present invention will be described in detail with reference to FIG. 2 and the following drawings.

FIG. 2 is an overall schematic diagram showing an embodiment of a fuel injection control device for a diesel engine according to the present invention.
In FIG. 2, 10 is an engine main body, 20 is a fuel injection pump, and 30 is a control circuit (ECU) using a microcomputer.

An intake air temperature sensor (such as a thermistor) 102 and an intake pressure sensor 104 are provided in the intake passage of the engine body 10. Further, an intake throttle control device is provided in the intake passage of the engine body 10. The intake throttle control device reduces engine noise and vibration by restricting intake air when the engine is idling or when the engine is stopped.
8. Diaphragm 1 that controls the sub-throttle valve 108
10, and VSVs 112 and 114 that control chambers A and B of the diaphragm 110. The main throttle valve 106 is driven by the accelerator pedal 116, and the main throttle valve 106 is driven by the accelerator pedal 116.
An accelerator opening sensor 118 that generates a signal indicating the opening of the main throttle valve 106 is provided on the shaft. 120 is a vacuum pump, and therefore, VSVs 112 and 114 switch each chamber of the diaphragm 110 between negative pressure and atmospheric pressure by means of the control circuit 30. Note that the sub-throttle valve 108 is controlled to open and close in three stages (fully open, half open, and fully closed).
That is, if both VSV112 and 114 are off, it is fully open, if VSV112 is off and VSV114 is on, it is half open, and if both VSV112 and 114 are on, it is fully closed. Further, the cylinder block of the engine body 10 is provided with a water temperature sensor 122 for detecting the temperature of cooling water. moreover,
A fuel injection valve 124 is provided in the intake passage of the engine body 10 for each cylinder to supply pressurized fuel from the fuel supply system to the intake port.

The fuel injection pump 20 is connected to a drive shaft 202, which is driven by an engine.
Gear 204 and roller 2 provided at the end of 2
06, a cam plate 208 loosely coupled to the roller 206, and a pump plunger 210 coupled to the plate 208 for delivering fuel to the fuel injection valve nozzle 124 of the engine. The fuel injection pump 20 also includes a fuel pump 214 (90° developed view) that sends fuel to the fuel injection nozzle 124 and a timer piston chamber 212 (90° developed view), a timer control valve 216 that determines advance angle adjustment, and a gear 204. A rotation angle sensor 218 for detecting engine rotation speed that outputs a pulse signal according to the rotation speed, and a linear solenoid 2
Spill ring 2 for adjusting injection amount driven by 20 to adjust the amount of fuel released from the spill boat
22, a plunger 224 that drives the spill ring 222, a spill position sensor 226 that detects the amount of movement of the plunger 224, and a pump plunger 210
a fuel cut valve 228 that controls on/off the amount of fuel supplied to the pump plunger 15; and a delivery valve 2 that prevents backflow or lag of fuel from the pump plunger 15.
30, timer position sensor 232 that detects the amount of movement of the timer control valve 216, timer piston 2
It consists of 34 mag.

Cam plate 208 is pump plunger 210
It also rotates and reciprocates. This reciprocating motion is caused by the movement of the cam plate 208 to the roller 206, which is rotatable but fixed in the axial direction of the shaft 202.
This occurs when the vehicle rides over the vehicle. The fuel is distributed by rotating the pump plunger 210. Regarding the adjustment of the injection amount, the maximum injection amount is determined by the effective stroke of the pump plunger 210.

In addition, in Fig. 2, 31 is a battery, 32
33 is a key switch, and 33 is a main relay circuit. That is, when the key switch 32 is turned on (IG position), the voltage of the battery 31 is supplied as a power source to the control circuit 30, and the control circuit 30 is reset (activated). As a result, the control circuit 30 turns on the main relay circuit 33, so that the voltage of the battery 31 is supplied to the control circuit 30 even if it bypasses the key switch 31. In other words,
Even if the key switch 32 is turned off, power can be supplied to the control circuit 30 for a predetermined period of time.

FIG. 3 is a detailed block circuit diagram of control circuit 10 of FIG. 2. In FIG. 2, each analog signal of the accelerator opening sensor 118, water temperature sensor 122, intake pressure sensor 104, intake temperature sensor 102, spill position sensor 226, and timer position sensor 232 is connected to an A/D converter with a built-in analog multiplexer.
The analog signals are supplied to a converter 302, and each analog signal is sequentially A/D converted. The digital output signal of the rotation angle sensor 218 is converted into a rotation speed signal by the waveform shaping circuit 304 and then sent to the input/output port 3.
06 is supplied to a predetermined position.

A/D converter 302 and input/output port 306
is the CPU 310 and RAM 3 via the common bus 308.
12, ROM 314, and input/output port 316. Two power supply circuits 318 and 320 are connected to the CPU 310. The power supply circuit 318 connects the battery 3 via the key switch 32.
1, and the power supply circuit 320 is connected to the battery 31 via the main relay circuit 33. In this case, the CPU 310 is operated by at least one power supply circuit. Each power supply circuit 318, 320 is composed of a constant voltage source, an integrating circuit, and a Schmitt trigger circuit.
The ROM 314 stores in advance programs such as an initial routine, a main routine, a fuel injection timing calculation routine, and a fuel injection amount calculation routine, as well as various fixed data, constants, etc. necessary for these processes. In addition, the I/O port 316 has
Fuel cut valve 228, linear solenoid 22
0, timer control valve 216, VSV112, 11
4. Main relay circuit 33 is connected.

The operation of the control circuit shown in FIG. 3 will be explained with reference to the flowcharts shown in FIGS. 4 to 7.

Figure 4 shows the initial routine, in which the key switch 31 is turned on (IG position) and the battery 31 is turned on.
The initial routine starts at step 401 by an initial reset signal generated when the voltage of 0 is applied to the power supply circuit 318. In step 402, flag F is set, i.e.
Let F=1. Note that F=1 indicates execution of fuel injection timing and injection amount control, and F=0 means stop of fuel injection timing and injection amount control. Next, in step 403, the timer counter value C is cleared,
In step 404, the main relay circuit 33 is turned on. As a result, power is supplied to the CPU 310 from the two power supply circuits 318 and 320.

FIG. 5 shows a time interrupt routine in which, for example, an interrupt step 501 starts every 8 msec. In step 502, the CPU 310 determines whether the key switch 32 is off, that is, whether the output of the power supply circuit 318 is at a low level or a high level. If the key switch 32 is on, the process proceeds to step 508; on the other hand, if the key switch 32 is off, the process proceeds to step 503. In step 503,
Determine whether C≧ _tA . For example, _tA is 0.3sec. Therefore, step 503 is the key switch 32.
This monitors whether 0.3 seconds have passed since the switch was turned off. If C<t _A , proceed to step 507;
Count up the counter value C for 8 msec
The counter value C is incremented by a corresponding amount. If C≧ _tA , the program proceeds to step 504, clears the flag F (F=0), and stops fuel injection timing and injection amount control. Next, in step 505, it is determined whether C≧ _tB . For example, _tA is 2 seconds. Therefore, step 505 is performed after the key switch 32 is turned off.
It monitors whether 2 seconds have passed. C
If <t _B , the process proceeds to step 507, where the counter value C is counted up and incremented by an amount corresponding to a time of 8 msec. If C≧ _tB , the process proceeds to step 506, the main relay 33 is turned off, and the process proceeds to step 508. In this case, the control circuit 30
The power supply to the device will be completely stopped.

6 and 7 are interrupt routines that are started every predetermined rotation of the engine, and show a fuel injection timing calculation routine and a fuel injection amount calculation routine, respectively.

In FIG. 6, after starting at interrupt step 601, it is determined at step 602 whether flag F=0. If F=0, the process advances to step 603 and fuel injection timing control is stopped. In other words,
Energization duty ratio t _ON of timer control valve 216 =
Set it to 0% (or 100%). On the other hand, if F=1, the process proceeds to step 604 and normal fuel injection timing calculation is performed. This fuel injection timing calculation is performed by calculating the basic injection timing based on the final fuel injection amount and engine rotational speed, and correcting this based on the outputs of sensors such as the water temperature sensor and the intake air temperature sensor. The routine then ends in step 605.

Similarly, in FIG. 7, after starting at interrupt step 701, at step 702 flag F=
Determine whether it is 0 or not. If F=0, step
The process advances to 703, and fuel injection amount control is stopped. In other words, the energization duty ratio of the linear solenoid 220 is
Set t' _ON = 0%. On the other hand, if F=1, the process proceeds to step 704 and normal fuel injection amount calculation is performed. This fuel injection timing calculation is performed by calculating the basic injection amount based on the accelerator opening degree and engine rotational speed, and correcting this based on the output of each sensor such as the water temperature sensor, intake pressure sensor, and intake temperature sensor. be exposed. The routine then ends in step 705.

The energization duty ratio t _ON of the timer control valve 216 and the energization duty ratio t _ON ′ of the linear solenoid 220 determined in FIGS. 6 and 7 are
It is stored in a predetermined area of the RAM 312, and fuel injection timing control and fuel injection amount control are performed by a routine not shown. In this case, fuel injection timing control is performed more precisely by detecting the position of the timer piston 234 by the timer position sensor 232 and providing feedback, and fuel injection amount control is performed by the spill position sensor 226.
By detecting the position of the spill ring 222 and providing feedback, more precise control is achieved. Furthermore, when F=0, the CPU 310 turns off the fuel cut valve 228 to stop the fuel supply in a routine not shown.

8A to 8F are timing diagrams for explaining the operation of the control circuit of FIG. 3. FIG. That is, the eighth
As shown in Figure A, when the key switch 32 is turned off at time t _O , as shown in Figures 8B and 8C,
Both VSVs 112 and 114 are turned on, and as a result, the sub-throttle valve 108 is fully closed. However, as shown in FIG. 8F, the on state of main relay 33 is maintained, and as shown in FIGS. 8D and 8E, energization control of linear solenoid 220 and timer control valve 216 is also maintained. Time _tA ,
That is, after the key switch 32 is turned off, for example
After 0.3 seconds have elapsed, the energization control of the linear solenoid 220 and the timer control valve 216 are both turned off, and therefore both the fuel injection amount control and the fuel injection timing control are stopped. At time _tB , for example, 2 seconds after the key switch 32 is turned off, the main relay circuit 33 is turned off, and the power supply is completely stopped, the VSVs 112 and 114 are turned off, and the sub-throttle valve 108 is fully open. will be restored. Note that the dotted line waveform shown in FIG. 8E shows the conventional case.

As explained above, according to the present invention, fuel injection timing control is stopped together with fuel injection amount control, so that the unpleasant operating noise of the injection timing control actuator, that is, the timer control valve 216 can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram for clearly showing the configuration of the present invention, FIG. 2 is an overall schematic diagram showing an embodiment of the fuel injection control device for a diesel engine according to the present invention, and FIG. 3 is the same as that shown in FIG. A detailed block circuit diagram of the control circuit, FIGS. 4 to 7 are flowcharts showing the operation of the control circuit in FIG. 3, and FIGS. 8A to F are timing diagrams explaining the operation of the control circuit in FIG. 3. It is. 10... Engine body, 20... Fuel injection pump,
30...Control circuit, 31...Battery (power supply),
32... Key switch, 33... Main relay circuit, 108... Sub throttle valve, 110... Main throttle valve, 112, 114... Vacuum switching valve (VSV), 216... Timer control valve,
220... Linear solenoid, 222... Spill ring, 226... Spill position sensor, 232...
…Timer position sensor.

Claims (1)

[Scope of Claims] 1. A battery, a first power supply means connected to the battery when a key switch is turned on;
a main switch that is turned on by the power supply means; a second power supply means that is connected to the battery by the main switch and turns on the main switch; and a second power supply means that is turned on by the first or second power supply means. a fuel injection timing control means and a fuel injection amount control means of the diesel engine, which are operated by the diesel engine; and first and second timer means, which are set when the key switch is turned off and are driven by the second power supply means. , wherein the first timer means stops both the fuel injection timing control means and the fuel injection amount control means after measuring a first predetermined time; A fuel injection control device for a diesel engine, wherein the main switch is turned off and the second power supply means is turned off after measuring a second predetermined time that is longer than the first predetermined time. 2. The fuel injection control device according to claim 1, wherein the fuel injection timing control means is stopped by setting an energization duty ratio of a timer control valve of the fuel pump to 100%. 3. The fuel injection control device according to claim 1, wherein the fuel injection timing control means is stopped by setting an energization duty ratio of a timer control valve of the fuel pump to 0%.