JPH0531665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel pump control device for a fuel injection engine.

[Conventional technology]

In fuel injection engines, the amount of fuel supplied to the engine is controlled by controlling the opening time of the fuel injection valve. The pressure of the fuel that is force-fed from the fuel pump to the fuel injection valve is regulated by a pressure regulator. In other words,
The pressure regulator controls the pressure difference between the fuel pressure supplied to the fuel injection valve and the pressure of the atmosphere in which fuel injection is performed so that it is always maintained at a constant pressure.

Incidentally, the atmosphere in which fuel injection is performed, that is, the intake pipe pressure, becomes high when the engine is in a high load state, and becomes low when the engine is in a low load state.

Therefore, if the amount of fuel supplied to the fuel injection valve by the fuel pump is constant, the control action of the pressure regulator will cause excess fuel to be
The amount of fuel returned to the fuel tank will increase as the engine load decreases.

Therefore, by detecting the load state of the engine, the fuel pump is controlled so that the amount of fuel supplied to the fuel injection valve by the fuel pump is reduced in a predetermined low load range, and the excess fuel is It has been considered to reduce the amount of fuel returned from the pressure regulator to the fuel tank. Furthermore, instead of detecting the load state of the engine, it is also possible to directly or indirectly detect the fuel consumption of the engine and control the fuel pump in accordance with the detected fuel consumption.

Controlling the fuel pump in this way can eliminate unnecessary operation of the fuel pump, reduce the operating noise of the fuel pump in low load ranges such as during idling, and extend the life of the fuel pump. There are advantages such as being able to improve

However, if such fuel pump control is implemented, the drive speed of the fuel pump will be changed when the engine load changes significantly in a short period of time, for example, during a gear change operation in a vehicle with a manual transmission. The speed of the fuel pump is frequently changed every time the gear is changed. Further, even when the fuel pump is operated in a boundary region where speed switching occurs, the speed of the fuel pump is frequently switched.
The fuel pump is driven by a motor,
Switching the operation of the fuel pump is performed by switching the drive speed of the motor, so when the motor is switched from low speed to high speed, an inrush current flows to the motor, and if this is repeated, the fuel pump There is a problem in that it shortens the life of the motor.

One possible solution to this problem is to set a delay time for switching the drive speed. By setting the delay time, frequent speed switching of the fuel pump can be prevented.

[Problem to be solved by the invention]

By the way, when performing acceleration operation, the fuel injection amount gradually increases, but the fuel pump driving speed cannot be switched from low to high speed within the delay time set to prevent frequent speed switching of the fuel pump. During this period, there is a shortage of fuel supplied to the engine, causing problems such as the engine not being able to obtain sufficient output and causing knocking.

In view of the problems of the prior art, it is an object of the present invention to prevent frequent speed switching of the fuel pump during gear shifting or operation in an operating range where speed switching occurs. When fuel consumption increases, such as during accelerated driving, the drive speed of the fuel pump is quickly switched to a high speed side.

[Means to solve the problem]

In order to achieve this object, the present invention takes the measures shown in FIG. That is, it is a fuel pump control device for a fuel injection engine that adjusts the amount of fuel pumped to a fuel injection valve by controlling the driving speed of the fuel pump, and the control device adjusts the amount of fuel pumped to a fuel injection valve by controlling the driving speed of the fuel pump. A pump speed selection means that determines a driving speed and increases the driving speed of the fuel pump when fuel consumption is high and lowers it otherwise; and the driving speed of the fuel pump is selected by the pump speed selection means. When the driving speed of the fuel pump is set to the high speed side by the pump speed selection means, the pump speed switching means switches the pump speed to the high speed side. a first delay means for delaying the time; and a second delay means for delaying the switching of the pump speed to the low speed side by the pump speed switching means for a second time when the driving speed of the fuel pump is set to the low speed side by the pump speed selection means. a delay means; an acceleration detection means for detecting a predetermined acceleration operation state of the engine; and when a predetermined acceleration operation state is detected by the acceleration detection means, a delay by the first delay means is prohibited and the delay time is It is characterized by comprising a prohibition means for shortening the time to zero or a small amount.

[Effect]

According to the above means, the pump speed selection means selects a high driving speed of the fuel pump when the fuel consumption of the engine is large, and selects a low driving speed otherwise. Then, the pump speed switching means switches the driving speed of the fuel pump to the speed selected by the pump speed selection means.

At this time, the switching of the pump speed to the high speed side by the pump speed switching means is controlled by the first delay means.
The switching of the pump speed to the lower speed side by the pump speed switching means is delayed for a second time by the second delay means.

On the other hand, when the acceleration detecting means detects a predetermined accelerated operating state of the engine, the inhibiting means prohibits the first delaying means from delaying, and the delay time is reduced to zero or a small amount of time.

Therefore, normally, the switching of the driving speed of the fuel pump is delayed by the first or second period of time, but during predetermined acceleration operation, the delay of the first period of time is prohibited when switching from the low speed side to the high speed side. , delay time is reduced.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of an on-vehicle engine to which an embodiment is applied. This engine is equipped with an air flow meter 2 as an intake air amount sensor downstream of an air cleaner (not shown). , a competition plate 2A rotatably provided in a damping chamber, and a potentiometer 2B that detects the opening degree of the competition plate 2A. Therefore, the amount of intake air is detected as the voltage output from the potentiometer 2B. Further, an intake air temperature sensor 4 is provided near the air flow meter 2 to detect the temperature of intake air.

A throttle valve 6 is arranged downstream of the air flow meter 2, and the opening degree of the throttle valve 6 is detected by a throttle sensor 76. Further, a surge tank 8 is provided downstream of the throttle valve 6. An intake manifold 10 is connected to the surge tank 8, and a fuel injection valve 12 is disposed within the intake manifold 10 to inject fuel. The intake manifold 10 is connected to a fuel chamber 14 of an engine body 14.
A, and the fuel chamber 14A of the engine is connected via the exhaust manifold 16 to a catalytic converter (not shown) filled with a three-way catalyst. Note that 20 is a spark plug, and 24 is a coolant temperature sensor that detects the engine coolant temperature.

The spark plug 20 of the engine body 14 is connected to a distributor 26, and the distributor 26 is connected to an igniter 28. The distributor 26 is provided with a cylinder discrimination sensor 30 and an engine rotation speed sensor 32, which are comprised of a pickup and a signal rotor fixed to the distributor shaft. For example, the cylinder discrimination sensor 30 outputs a cylinder discrimination signal to the control circuit 34 at every 180 degrees of crank angle in the case of a 4-cylinder engine, and every 120 degrees in the case of a 6-cylinder engine. For example, a crank angle signal is output to the control circuit 34 every 30 degrees of crank angle.

The control circuit 34 includes the fuel injection valve 12 and the igniter 28, as well as the fuel pump controller 18.
For this purpose, detection signals are input from sensors placed in various parts of the engine.

Note that the throttle sensor 76 is constructed as shown in FIG. In other words, the throttle sensor 76
are movable contacts 76a, 76b, fixed contact 76c,
76d, etc., the movable contact 76a is rotated together with the throttle valve 6 and is grounded, and the movable contact 76b is connected to the throttle valve 6 with a predetermined play, so that the opening degree of the throttle valve 6 is adjusted. When the opening degree of the throttle valve 6 decreases, it is rotated away from the movable contact 76a as shown in FIG. In addition, fixed contacts 76c, 76
d, as shown in FIG.
It is connected to the power supply via g and 76h. Then, connect the terminal 76 from the opposite power supply side of the resistors 76g and 76h.
The detection signal is taken out by e and 76f.

By the way, if the engine is a six-cylinder engine, there are six fuel injection valves 12 in total, one for each cylinder, as shown in FIG.
12E is connected to the delivery pipe 68. Fuel from the fuel tank 58 is supplied to the delivery pipe 68 by a fuel pump 62 via a fuel filter 66, and the fuel pressure in the delivery pipe 68 is controlled by the intake manifold 10, which is the atmosphere in which fuel injection is performed. The pressure difference between the intake pressure and the intake pressure is controlled to always be a constant pressure. This control is performed by the pressure regulator 74, and excess fuel is returned to the fuel tank 58 as a result of fuel pressure control.

The fuel pump 62 is driven by a motor (not shown).
Battery 2 via fuel pump controller 18
Connected to 2. As shown in FIG. 4, the fuel pump controller 18 is composed of a resistor 80, a relay 82, and a transistor 88.
is inserted in the path connecting the battery 22 and the motor of the fuel pump 62, and is used to reduce the voltage supplied from the battery 22 to the motor of the fuel pump 62 by a predetermined voltage. . and a normally open switch 86 of the relay 82;
connected to bypass both ends of the resistor 80,
A coil 84 of the relay 82 is connected to the battery 22 via the collector and emitter of a transistor 88. Furthermore, the base of the transistor 88 is connected to receive a signal from the control circuit 34, and the base of the transistor 88 is connected to receive a signal from the control circuit 34.
Relay 82 is adapted to be controlled by a signal from control circuit 34. That is, when a signal is received from the control circuit 34 and the transistor 88 becomes conductive, the coil 84 of the relay 82 is energized.
The switch 86 is turned on, and the voltage of the battery 22 is directly supplied to the motor of the fuel pump 62 via the switch 86 without passing through the resistor 80. On the other hand, when the transistor 88 is non-conductive, the coil 84 of the relay 82 is not energized, so the switch 86 is turned off, and the voltage of the battery 22 is lowered and supplied to the motor of the fuel pump 62 via the resistor 80. Ru.

As shown in FIG. 3, the control circuit 34 includes a random access memory (RAM) 36, a read-only memory (ROM) 38, a central processing unit (CPU) 40, and a first input/output port. 42
, a second input/output port 44, a first output port 46, and a second output port 48.
6, the ROM 38, the CPU 40, the first input/output port 42, the second input/output port 44, the first output port 46, and the second output port 48 are connected to the bus 50.
connected by.

The first input/output port 42 includes a buffer 52.
A, 52B, 52C, air flow meter 2, cooling water temperature sensor 24 via multiplexer 54 and analog-to-digital (A/D) converter 56.
and an intake temperature sensor 4 are connected. The multiplexer 54 and the A/D converter 56 are controlled by a signal output from the first input/output port 42, and the air flow meter 2 and each sensor 2
The signals from 4 and 4 are sent to RAM 36 or CPU 4.
0 is input sequentially.

A fuel pump controller 18 is connected to the second input/output port 44 via a drive circuit 60.
A cylinder discrimination sensor 30 and an engine rotation speed sensor 32 are connected via a waveform shaping circuit 64 . Further, a throttle sensor 76 is connected via a buffer 90.

Furthermore, the first output port 46 is connected to the drive circuit 7
0 to the igniter 28 , and the second output port 48 is connected to the fuel injection valve 12 via a drive circuit 72 .

The RAM 38 of the control circuit 34 stores in advance a map of the basic ignition advance angle represented by the engine speed and intake air amount and the basic fuel injection time, and the CPU 40 stores the signal from the air flow meter 2 and the engine. The basic ignition advance angle and basic fuel injection time are read out based on the signal from the rotation speed sensor 32, and the basic ignition advance angle and basic fuel injection time are read out based on various signals including signals from the cooling water temperature sensor 24 and the intake air temperature sensor 4. Corrections are made to the time and the igniter 28 and fuel injector 12 are controlled.

Such control of the ignition advance angle and fuel injection time is achieved by executing a program stored in the ROM 38, and is controlled by the fuel pump controller 18.
The same applies to the control.

Here, a program for controlling the fuel pump controller 18 will be explained according to the flowcharts shown in FIGS. 6 to 9.

FIG. 6 shows an interrupt routine that is executed every 4 milliseconds, and each time, in step 210, a counter TAC is counted up.

FIG. 7 shows an interrupt routine that is executed every time a ground level detection signal is output from the terminals 76e and 76f of the throttle sensor 76.
That is, when the movable contact 76b contacts the fixed contacts 76c and 76d as the throttle valve 6 rotates in the direction of increasing the opening degree, the acceleration interrupt routine 230 is activated.

When the acceleration interrupt routine 230 is activated,
In step 241, it is determined whether or not an interrupt has occurred due to the output of a ground level detection signal from the terminal 76e. In the case of an interrupt caused by a detection signal from the terminal 76e, an affirmative decision is made in step 241, and the process proceeds to steps 242 and 243. In step 242, a flag f is set and an interrupt caused by a detection signal from the terminal 76e is performed. remember what happened,
In step 243, the counter TAC is cleared.
On the other hand, in the case of an interrupt caused by a detection signal from the terminal 76f, a negative determination is made in step 241, and the process proceeds to step 244, where it is determined whether the flag f is set. If the flag f has been set, the program proceeds to step 245 to reset the flag f, and then proceeds to step 246 to reset the counter.
It is determined whether TAC is less than or equal to a predetermined value, for example 25. If the counter TAC is below the predetermined value,
Proceed to step 247 and turn on the acceleration flag.
It remembers that it is in an accelerated driving state. step
When 244 and 246 are negative, the step
The process advances to step 250, returns to the original routine, and the processing of this accelerated interrupt routine 230 ends.

Therefore, in the acceleration interrupt routine 230, the time when the detection signals are output from the terminals 76e and 76f in order is measured by the counter TAC, and the time when the counter TAC becomes 25 or less, that is, 10 milliseconds (4 milliseconds) is determined. seconds x 25) or less, it is assumed that the vehicle is in an accelerated driving state, and processing is performed to turn on the acceleration flag.

FIG. 9 shows a fuel pump control routine which is a time interrupt routine every 50 milliseconds. When started by this fuel pump control routine, the step
At 110, it is determined whether Q/N representing the engine load is greater than a predetermined reference value of 0.7/rev. The intake air amount Q is detected by the air flow meter 2, and the engine speed N is calculated based on a signal detected by the engine speed sensor 32 every 30 degrees of crankshaft. and,
The reference value 0.7/rev is stored in the ROM 38.

If the engine is currently idling and Q/N is smaller than the reference value 0.7/rev, a negative determination is made in step 110, and the process proceeds to step 160, where the acceleration interrupt routine 230 described above is executed.
If the acceleration flag is on, turn it off. Next, proceed to step 141, where the counter
Increment C ₂ . And step 142
Then, it is determined whether the counter _C2 has reached a predetermined value of 10 or not. Until the counter _C2 reaches the predetermined value 10, a negative determination is made in step 142, and step 121 is reached.
However, it becomes idling and 0.5
As the second passes, this interrupt processing every 50 milliseconds is performed 10 times, so counter C ₂ becomes 10.
Step 142 is affirmatively determined, and step 143,
Proceed to 144.

In step 143, counter _C1 is cleared and
In step 144, counter _C2 is set to a predetermined value of 10. Then, in step 122 (see FIG. 4), resistor control is performed in which a resistor 80 is inserted into the circuit between the battery 22 and the motor of the fuel pump 62. That is, a signal is supplied from the input/output port 44 via the drive circuit 60 (see FIG. 3) to the transistor 88 of the fuel pump controller 18 to make it non-conductive. Therefore, the fuel pump 62 will operate at low speed.

After that, when the engine load increases and Q/N becomes larger than the standard value 0.7/rev, the step
If 110 is determined to be affirmative, the process proceeds to step 150, where it is determined whether or not the acceleration flag is turned on. If the acceleration flag is on, the step
If step 150 is determined in the affirmative, the process bypasses the processing after step 131 and proceeds directly to step 121. However, if the acceleration flag is not turned on, a negative determination is made in step 150 and the process proceeds to step 131 and subsequent steps. In step 131, the counter _C1 is incremented and
In step 132, it is determined whether the counter _C1 has reached a predetermined value of 10 or not. Until the counter _C1 reaches the predetermined value 10, a negative determination is made in step 132, so the process proceeds to step 122, where the register control is continued and the fuel pump 62 continues to operate at a low speed. After 0.5 seconds elapse after the engine load increases,
During this time, this fuel pump control routine, which is started every 50 milliseconds, will be repeated 10 times, so the counter C ₁ will be incremented 10 times in step 131, and the counter C ₁ will become 10.
If step 132 is affirmatively determined, step 133,
Proceed to 134. In step 133, counter _C1 is set to a predetermined value of 10, and in step 134, counter _C2 is cleared. Then, in step 121,
(See Figure 4) Turn on the switch 86 of the relay 82 connected in parallel to the resistor 80.
Register bypass control is performed to create a bypass path. That is, a signal is supplied from the input/output port 44 (see FIG. 3) to the transistor 88 of the fuel pump controller 18 via the drive circuit 60 to make it conductive. Therefore, the fuel pump 62
will operate at high speed.

While the engine is running at a relatively high load, for a very short period of time,
For example, if the load is in a relatively low load range for only about 0.3 seconds, the
Due to the 0.5 second delay, the fuel pump 62
There was no switching to low speed operation during the process. It remains in high speed operation. In other words, during high load operation, a positive decision is made in step 110 and register bypass control is performed in step 121. When the machine enters a low load region midway, a negative decision is made in step 110 and the process proceeds to steps 141 and 142. However, if the time in this low load range is about 0.3 seconds, the counter C‖ will only reach 6, so during that time, a negative judgment is made in step 142, and the process proceeds to step 121 without proceeding to the registered control in step 122. As a result, register bypass control will continue.

While the engine is running at a relatively low load, for a very short time,
Similarly, even in the high load range, due to the delayed operation, the fuel pump 62 continues to operate at low speed without being switched to high speed operation.

However, if the opening speed of the throttle valve 6 is fast and the acceleration interrupt routine 230 in FIG. , step 150 is answered in the affirmative, and the process proceeds to step 121 without executing the processes after step 131, where register bypass control is implemented without a 0.5 second time delay, and the fuel pump 62 is switched to high-speed operation. Therefore, it is possible to eliminate the problem of temporary fuel shortage due to a delay in switching the fuel pump 62 to high speed during acceleration operation.

FIG. 8 shows a modification of the acceleration interrupt routine 230 described with reference to FIG. 7, in which a step 248 is added compared to FIG. In step 248, it is determined whether the vehicle speed V detected by a vehicle speed sensor (not shown) is lower than a predetermined vehicle speed, for example, 2 km/h, and only when the vehicle speed V is equal to or higher than the predetermined vehicle speed, the process proceeds to step 247 to turn on the acceleration flag. I'm starting to do that.

Therefore, the acceleration interrupt routine 230 of FIG.
According to
Only when the speed exceeds Km/h, it is determined that the vehicle is in an accelerated driving state and the acceleration flag is turned on.

During racing operation (temporarily increasing the engine speed in a no-load state), the air flow meter 2 overshoots, apparently increasing the engine load. However, the actual fuel injection amount is not so large and there is no need to increase the driving speed of the fuel pump 62. At this time, as well as during acceleration operation, if the driving speed of the fuel pump 62 is immediately increased, it is possible to immediately increase the driving speed of the fuel pump 62. Since the driving speed of the fuel pump 62 must be lowered during the racing operation, the driving speed is repeatedly switched every time the racing operation is performed. In the acceleration interrupt routine 230 of FIG.
Even if the counter TAC is 25 or less, if the vehicle speed V is lower than 2 km/h, the driving speed of the fuel pump 62 is not immediately increased when racing driving because it is not determined to be an accelerating driving state. It is possible to eliminate the problem of frequent switching of the drive speed of the fuel pump 62 during operation.

In the flowcharts of FIGS. 6 to 9, the process in step 110 corresponds to the pump speed selection means of the present invention, and the process in steps 121 and 122 corresponds to the pump speed selection means of the present invention.
Corresponding to the pump speed switching means of the present invention, the step
The processing of steps 131 to 134 corresponds to the first delay means of the present invention, the processing of steps 141 to 144 corresponds to the second delay means of the present invention, and the processing of steps 210 to 250 corresponds to the first delay means of the present invention.
This corresponds to the acceleration detection means of the present invention, and the process of step 150 corresponds to the prohibition means of the present invention.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. , some of them are listed below.

(b) The delay time when the delay by the first delay means is prohibited by the prohibition means does not have to be zero, and if it is shortened to a small amount of time from the first time shown in steps 131 to 134, it is possible to During acceleration, the system switches to high-speed operation more quickly than during normal operation, so it is possible to eliminate a temporary fuel shortage when fuel consumption increases, as in the above embodiment. That is, when an affirmative determination is made in step 150, the predetermined value of the counter _C1 is changed to a value smaller than 10, and the same processing as in steps 131 to 134 is performed.
It can be changed into various forms using well-known techniques.

(b) The fuel consumption amount of the engine may be represented by a value such as the engine intake pressure or the amount of fuel injection per hour.

C. The drive speed of the fuel pump motor may be controlled by duty ratio control.

D. The first or second delay means for providing a time delay can also be configured by a hard circuit.

E) The acceleration detection means can also detect that the engine is in an accelerated operating state when the rate of increase in the engine load is equal to or higher than a predetermined value.

〔Effect of the invention〕

As described in detail above, according to the present invention, frequent switching of the fuel pump driving speed can be prevented during gear shifting or during operation in a boundary area where speed switching is performed, and moreover, The speed change from low speed to high speed is performed quickly, and it is possible to avoid fuel shortage when fuel consumption increases.

[Brief explanation of the drawing]

FIG. 1 is a complaint correspondence diagram, and FIG. 2 is a schematic diagram of an in-vehicle engine to which an embodiment of the present invention is applied.
3 is a block diagram showing an example of the control circuit of FIG. 2, and FIG. 4 is a diagram showing the electric circuit of the fuel pump controller and the fuel supply path of the fuel injection valve of FIGS. FIG. 5 is a diagram explaining the configuration of the throttle sensor, and FIGS. 6 to 9 are flowcharts showing the program contents of the computer in FIG. 3. 12, 12A to 12F...Fuel injection valve, 62...
...Fuel pump, 18...Fuel pump controller, 34...Control circuit, 76...Throttle sensor.

Claims (1)

[Scope of Claims] 1. A fuel pump control device for a fuel injection engine that adjusts the amount of fuel pumped to a fuel injection valve by controlling the driving speed of the fuel pump, which controls the amount of fuel consumed by the engine. a pump speed selection means that determines the driving speed of the fuel pump according to the fuel consumption, and increases the driving speed of the fuel pump when the fuel consumption is high and lowers the driving speed otherwise; a pump speed switching means for changing the driving speed of the fuel pump to a high speed side when the pump speed selection means sets the driving speed of the fuel pump to a high speed side; a first delay means for delaying the switching of the fuel pump by a first time period; a second delay means for delaying the time; an acceleration detection means for detecting a predetermined acceleration operation state of the engine; and when the predetermined acceleration operation state is detected by the acceleration detection means, a delay by the first delay means is prohibited. and inhibiting means for reducing the delay time to zero or a small amount of time.