JPH0734993A - Fuel pump control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To increase a fuel pressure to a sufficiently high value and to relax the uncomfortable feeling of a passenger owing to the working noise of a fuel pump by controlling the fuel pump so that it is not driven until start ON is detected during a time in which a fuel pressure during Key-ON exceeds a given value. CONSTITUTION:After fuel is fed with a pressure from a fuel tank 9 to a fuel pressure regulating valve 10 with the aid of a fuel pump 4, the fuel is injected through a fuel injection valve 2 to an internal combustion engine 1. Based on detecting signals from sensors 5-7, the fuel injection valve 2 is controlled by a control unit 3. In this case, the ON-state of each of the ignition switch 8a and the start switch 8b of a key switch 8 is detected. Meanwhile, a fuel pressure during ON of the ignition switch 8a is detected. As a result, control is made so that the fuel pump 4 is not run until ON of the start switch 8b is detected during a time in which a fuel pressure available during ON of the ignition switch 8a exceeds a given value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump control system for an internal combustion engine, and more particularly to keeping the fuel pressure at a predetermined level or higher after key-on until fuel injection is started, at least when the starter is on. The present invention relates to a fuel pump control device for an internal combustion engine that drives a fuel pump.

[0002]

2. Description of the Related Art Conventionally, as a fuel pump control device for an internal combustion engine in which the fuel pressure is kept at a predetermined pressure or higher after the key-on until the fuel injection is started, for example, Japanese Patent Publication No. Sho 60.
No. 8340 (Japanese Patent Laid-Open No. 56-27064) is known. This technique has been to raise the fuel pressure sufficiently before the fuel injection is started by operating the fuel pump immediately after detecting the key switch on.

[0003]

However, in this conventional device, since the fuel pump is operated immediately after the key is turned on, the fuel pump is operated in a quiet state before the internal combustion engine is actually started. There is a problem in that the pump is activated, and the operating noise gives an occupant an unpleasant feeling.

Therefore, according to the present invention, the fuel pump control apparatus for an internal combustion engine is capable of sufficiently increasing the fuel pressure by the time the fuel injection is started after the key-on, and can alleviate the discomfort to the occupant. The purpose is to provide.

[0005]

In order to achieve the above object, the fuel pump control apparatus for an internal combustion engine according to the present invention, as described in claim 1, changes the fuel pressure after key-on until fuel injection is started. In order to keep the pressure equal to or higher than a predetermined pressure, in a fuel pump control device for an internal combustion engine that drives a fuel pump at least when the starter is turned on, a key-on detecting means for detecting that the key is turned on and a starter on for detecting that the starter is turned on. If the fuel pressure at the time of key-on is detected as a predetermined value or more from the detection result of the detection means, the fuel pressure information detection means for detecting the information about the fuel pressure at the time of key-on, and the detection result of the fuel pressure information detection means, until the starter on is detected. And a control means for controlling the fuel pump so as not to be driven.

Further, as described in claim 2, in the fuel pump control device for an internal combustion engine according to claim 1, when the control means determines that the fuel pressure at key-on is less than the predetermined value. The internal combustion engine is characterized in that, based on the detection result of the fuel pressure information detecting means, a period that is continuously or stepwise different is set as a fuel pump drive period before the starter is turned on so that the higher the fuel pressure at key-on becomes, the shorter the fuel pressure becomes. The fuel pump control device of the

Further, as described in claim 3, in the fuel pump control device for the internal combustion engine according to claim 2,
When the fuel pressure at the time of key-on is recognized to be less than the predetermined value, the control means is based on the detection result of the fuel pressure information detection means, so that the higher the fuel pressure at the time of key-on, the later the timing becomes. The gist of a fuel pump control device for an internal combustion engine is also characterized in that a timing that is delayed gradually or stepwise is set as a fuel pump drive start timing before the starter is turned on.

On the other hand, as described in claim 4, the fuel of the internal combustion engine for driving the fuel pump at least when the starter is turned on in order to keep the fuel pressure higher than a predetermined pressure after the key is turned on and before the fuel injection is started. In the pump control device, a switching means for switching the fuel pump between a high output driving state and a low output driving state, a key-on detecting means for detecting that the key is turned on, and a starter-on detecting means for detecting that the starter is turned on. And a control means for setting a low output drive state as a fuel pump drive condition after the key is turned on and before the starter is turned on, and a high output drive state as a fuel pump drive condition after the starter is turned on. A fuel pump control device for an internal combustion engine is also included.

According to a fifth aspect of the present invention, in the fuel pump control device for an internal combustion engine according to the fourth aspect, fuel pressure information detecting means for detecting information regarding the magnitude of the fuel pressure at the time of key-on is further provided. When the fuel pressure at the time of key-on is recognized to be less than the predetermined value, the control means continuously operates so that the higher the fuel pressure at the time of key-on, the later the time, based on the detection result of the fuel pressure information detection means. Alternatively, the fuel pump control device for the internal combustion engine is characterized in that the fuel pump drive start time before the starter is turned on is a time that is gradually delayed.

Further, as described in claim 6, in the fuel pump control device for the internal combustion engine according to claim 5, the control means further recognizes that the fuel pressure at the time of key-on is less than the predetermined value. At this time, based on the detection result of the fuel pressure information detection means, the internal combustion engine is characterized in that the fuel pump drive period before starter on is set to a continuously or stepwise different period so that the fuel pressure at the time of key-on becomes shorter as it becomes higher. The fuel pump control device of the engine is also the subject.

[0011]

According to the fuel pump control device of the first aspect,
In a situation where the vehicle interior from the key-on to the starter-on is quiet, if the fuel pressure at the key-on is equal to or higher than a predetermined value, the fuel pump is not driven, but the starter-on is driven. Therefore, in the situation where the fuel pressure is already sufficiently high from the time of key-on and the fuel pressure can be raised to the predetermined fuel pressure by the start of fuel injection by driving the fuel pump after the starter is turned on, the pump is operated while the vehicle interior is quiet. No sound is produced. Therefore, the occupant does not feel uncomfortable even though it is not necessary. It should be noted that after the starter is turned on, the interior of the vehicle is no longer quiet due to engine operating noise and the like, so even if an operating noise of the fuel pump is generated, no particular discomfort is given.

According to the fuel pump control device of the second aspect, before the starter is turned on, the fuel pump is driven for a shorter period as the fuel pressure at the time of key-on is higher. The fact that it is driven only for a short period shortens the period in which discomfort is incurred due to the operating noise, and alleviates discomfort as a whole. Also, the original purpose of increasing the fuel pressure before the start of fuel injection is not impaired.

Further, according to the fuel pump control apparatus of the third aspect, in order to achieve the above-mentioned operation in the apparatus of the second aspect, the fuel pump is controlled to be started and stopped before the starter is turned on. , When the fuel pressure is high from the beginning, it is started late, so if the starter turns on quickly after that, it will continue to operate without stopping and restarting. As a result, the fuel pump and relays as its peripherals will not be switched on and off more than necessary, and their durability will not be unnecessarily impaired.

On the other hand, according to the fuel pump control device of the fourth aspect, after the key is turned on, the output is low before the starter is turned on, so that a large operating noise is not generated.
On the other hand, after the starter is turned on, high output drive is performed, but since the interior of the vehicle is no longer quiet, there is no concern about the fuel pump operating noise, but rather the fuel pressure can be raised quickly. With the advantage that it has the same effect as the device according to the first and second aspects. It should be noted that, after the fuel pressure becomes equal to or higher than a predetermined value, the high output drive state and the low output drive state may be appropriately selected and controlled according to the operating state of the internal combustion engine.

Further, according to the fuel pump control device of the present invention, when the fuel pressure at the time of key-on is high, the driving start timing of the fuel pump is delayed, so that the period of generation of the operating noise can be kept to a necessary minimum. Therefore, the pump operating noise can be reduced to a low level for a short period while the vehicle interior is quiet. Further, according to the fuel pump control device of the sixth aspect, the operating noise can be suppressed more finely.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments will be described below with reference to the drawings in order to further clarify the content of the present invention. First, the first embodiment will be described. In FIG. 1, 1 is an internal combustion engine (engine), 2 is a fuel injection valve attached to an intake pipe, 3 is a control unit for producing signals for driving the fuel injection valve 2 and the fuel pump (F / P) 4, and is a microcomputer. It is composed of Reference numeral 5 is an intake air amount sensor that detects the intake air amount, 6 is a rotation sensor that detects the rotation of the crank of the engine 1, 7 is a cooling water temperature sensor that detects the temperature of the cooling water of the engine 1, and 8 is a control unit 3
Etc., a key switch having an ignition switch 8a for turning on / off a power source and a start switch 8b for turning on / off a starting device of the engine 1, 9 is a fuel tank, and 10 is a fuel pressure adjusting valve for keeping a fuel pressure constant. is there.

The fuel is sent from the fuel tank 9 to the fuel pressure adjusting valve 10 after being increased in pressure by the F / P 4. The fuel pressure adjusting valve 10 keeps the fuel pressure constant and sends the fuel to the fuel injection valve 2. The fuel injection valve 2 is made of an electromagnetic valve, and is opened only while the signal from the control unit 3 is on, and the fuel is injected into the intake pipe of the engine 1. The control unit 3 has a built-in microcomputer and calculates a fuel injection signal corresponding to the intake air amount signal from the intake air amount sensor 5, the rotation signal from the rotation sensor 6, and the water temperature signal from the cooling water temperature sensor 7 to calculate the crank It outputs to the fuel injection valve 2 every fixed rotation. This fuel injection signal continues until the rotation sensor 6 detects that the crank has stopped rotating.

Further, the control unit 3 receives the signal from the rotation sensor 6 while the crank is rotating and the F / P 4
Operate. Next, the drive control of the fuel pump 4, which is executed by the control unit 3 at predetermined time intervals,
It will be described based on the flowchart of FIG.

This process is started by turning on the key switch. First, in S1, it is determined whether the starter is turned on. In the normal key operation of the driver, since it takes about 400 ms from the key switch on to the starter on, it is determined to be NO at the beginning, and the process jumps to S2.

In S2, it is determined whether the flag X is 0 or not. This flag X is a flag for determining whether or not the starter has been turned on once or whether the starter has not been turned on yet. Once the starter is turned on, X = 1 is set. (S9). The flag X is set to 0 in the initialization routine of the CPU when the key switch is turned on. Therefore, since X = 0 at first, the process jumps to S3.

At S3, the engine cooling water temperature THW is read. The reason for reading THW is that the fuel pressure in the fuel pipe is estimated by substituting the time after the engine is stopped. The relationship between THW and fuel pressure is as shown in FIG. In other words, the cooling water temperature THW and the fuel pressure have a relationship that they drop in substantially the same manner as time passes after the engine is stopped.
Is the same as detecting the fuel pressure at key-on.

In the subsequent S4, it is determined whether THW is lower than 60 ° C. (that is, whether fuel pressure is estimated to be less than 100 aKPa). If YES, jump to S5. In S5, the F / P is operated for 200 ms and the routine is exited. On the other hand, if NO in S4, the process jumps to S6.

In S6, it is further determined whether or not THW is 80 ° C. or higher (that is, whether or not the fuel pressure is estimated to be 250 KPa). If YES, the fuel pressure has risen sufficiently, so the routine exits as it is. That is, the F / P is not operated and no unpleasant operating sound is generated. On the other hand, if NO in S6, the process jumps to S7. In this case, the fuel pressure has risen to some extent and is estimated to be in the range of 100 to 250 KPa.
After putting a delay of s, the F / P is activated for 100 ms. During the first 100 ms, the F / P does not operate and no unpleasant sound is produced. Also, the period during which the operating noise is generated is 1
It stays at 00ms.

On the other hand, if it is determined in S1 that the starter is turned on, the process jumps to S8. In S8, F /
Operate P to raise the fuel pressure sufficiently. Since the starter is rotating at this point, the operating noise of the F / P is not an issue. Next, in S9, the flag X = 1 is set. Therefore, thereafter, the process of leaving this routine through S1 and S2 is repeated until the engine is stopped and the key is turned off, and the F / P continues to be in steady operation.

Time charts relating to the processing of the flow chart of FIG. 2 are shown in FIGS. As shown in FIG. 3, when THW <60 ° C. at the time of key-on, the F / P operates for 200 ms immediately after the key-on, and quickly raises the fuel pressure to 250 KPa or more. The F / P is stopped until the starter is turned on. Also, the F / P operates again together with the starter on. Therefore, F
The generation of the unpleasant sound due to / P is limited to 200 ms, and the unpleasant feeling is reduced as compared with the conventional device. Nevertheless, the fuel pressure can be sufficiently increased by the start of the first fuel injection.

On the other hand, as shown in FIG.
When W ≧ 80 ° C, F / until the starter turns on
P does not work. Under this condition, it is estimated that the fuel pressure at the time of key-on is at least 200 KPa, so that the fuel pressure is sufficiently 25 during the time from the start-on to the first fuel injection timing (usually about 50 ms or more).
A fuel pressure of 0 KPa or higher can be secured. In this case, no unpleasant operating noise is generated while the vehicle interior is quiet.

Further, as shown in FIG. 5, when the key is turned on, 60
When ℃ ≤ THW <80 ℃, 10 immediately after key-on
After a delay of 0 ms, the F / P is activated and 100
Stop after ms. In this case, since the fuel pressure at the time of key-on is at least 100 KPa, it is possible to sufficiently raise the fuel pressure to 250 KPa or more by such F / P operation. As a result, the unpleasant noise is generated only for the minimum necessary period. Note that normally, FIG.
However, depending on the habit of the driver, the starter on may be very quick (about 200 ms).
In such a case, the time chart is as shown in FIG. In this case as well, the effect of suppressing the generation of unpleasant sound is the same, but further, the F / P continues to operate without stopping. This reduces ON / OFF operations of the relay and the pump itself, and suppresses contact damage. Therefore, as compared with the case where the F / P is first operated for 100 ms as shown in FIG.
Increases durability. Moreover, the fuel pressure can be sufficiently increased. From this point of view, when setting the delay time, considering the relationship with the normal key operation time of 400 ms, the drive condition setting of S5 is 200 ms.
When the drive condition is set to 300 ms in the drive condition setting in S7, the durability is further improved.

Next, a second embodiment will be described. In the second embodiment, originally, the flow rate of F / P is set to the economy mode (Lo).
And the power mode (Hi) can be switched in two stages, and F /
This is an example applied to a vehicle that is conserving P drive power. Except for this point, it is the same as the first embodiment, and therefore the flow chart of the immediate processing will be described.

Also in this embodiment, the process shown in the flowchart of FIG. 7 is started by turning on the key switch. First, in S10, it is determined whether or not the starter is turned on, and NO
Then jump to S11. In S11, it is determined whether or not the flag X = 0. If YES, the process jumps to S12 to drive the F / P Lo. The flag X has the same operation as that of the above-described embodiment. If S11 is YES, it means that the keyer is in the state before the starter is turned on. Therefore, since the F / P sound is annoying when the Hi drive is performed, the Lo drive is performed in S12. In addition, Lo
In the case of driving, the fuel pressure rises slowly compared to Hi driving.
However, when the starter turned on after that, YE was performed at S10.
When it is determined to be S, the process jumps to S13, and the F / P is switched to Hi drive. Therefore, after this, the fuel pressure rises quickly. S
After switching the F / P to Hi drive in 13, the process proceeds to S14 and X = 1 is set. Therefore, once the engine is started, both S10 and S11 are determined to be NO, and F /
The drive of P continues. After this, set F / P to H
Due to the original purpose of i / Lo switching, an operation mode suitable for power saving etc. will be executed.

A time chart relating to this embodiment is shown in FIG.
Shown in. The illustrated example shows the case where the key-on is performed in a state where the pressure in the fuel pipe has dropped to almost 0 after a considerably long time has elapsed after the engine was stopped. As shown in the figure, when the key switch is turned on, Lo driving of the F / P is immediately started, so that the fuel pressure gradually starts to rise. Then, when the starter is turned on, the drive is switched to Hi drive, so that the fuel pressure rises quickly. As a result, in a situation where the passenger compartment is quiet before the starter is turned on, only a small operating noise is generated by the Lo drive, which alleviates discomfort to the occupant. After the starter is turned on, such F / P operating noise is erased by other operating noise, so that no discomfort is caused even when driven by Hi, and good startability is obtained by rapid increase in fuel pressure. The fuel pressure can be quickly increased.

A third embodiment will be described as still another embodiment. This is a combination of the two previous embodiments. As shown in the flowchart of FIG. 9, S2
1, S22, S24, S26, and S23, S
The process of 29 is S1, S2, S4, S6 of the first embodiment.
This is a step for achieving the same purpose and function as the determination and processing in S3 and S9. Further, the processing of S28 is the same in content as the processing of S13 of the second embodiment. The steps peculiar to the third embodiment are S25 and S27.

In S25, that is, after key-on and before starter-on, when THW <60 ° C. at key-on, F / P is immediately driven to Lo. In S27, that is,
After key-on and before starter-on, 6 at key-on
When 0 ° C. ≦ THW <80 ° C., the F / P is driven Lo after a delay of 100 ms. In this example,
When THW ≧ 80 ° C., the F / P is not driven until the starter is turned on, so that no operating noise is generated wastefully.

The timing chart for this embodiment is shown in FIG.
0 to 12 are shown. According to the third embodiment, the operating noise of the F / P when the passenger compartment is quiet can be reduced, and the operating noise is generated only for a short period as long as possible, while sufficiently increasing the fuel pressure. You can In particular,
When compared with the second embodiment, 60 ° C. ≦ THW <80 ° C.
Under the condition (1), Lo driving is performed after a delay of 100 ms, which is more advantageous in that the operation sound generation period is short. Another difference from the first embodiment is that the intensity of the generated sound is low and the effect of reducing discomfort in that sense is high. In order to capture the good points of the first embodiment, the processing content of S25 is set to "300 m.
The driving period in Lo driving is also changed according to the fuel pressure at the time of key-on, such as "F / P-Lo driving for s" and "F / P-Lo driving for 150 ms after 100 ms delay" in S27. And is even more effective.

Although some embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modes can be adopted without departing from the scope of the present invention. For example,
In the first and third examples, THW <60 ° C., 60 ° C.
≦ THW <80 ° C, THW ≧ 80 ° C
The pump driving conditions before the starter was turned on were 3 levels.
The drive period and the delay period may be continuously set for the HW.

Alternatively, in the second embodiment, the case where the pump output is switched between two stages has been described, but the present invention can be applied to a configuration in which a multistage pump output control of three stages or more is performed by a fuel pump control, for example. . In other words, when the key switch is turned on, operate the F / P in a low pump output drive state of one or two steps so that the F / P operation sound is not bothered, and the engine operates after the starter switch is turned on. Therefore, since the F / P operation sound is not a concern, the pump output state may be set to a high output state of two or more stages or three or more stages and switched to an operation state according to the engine operating state.

Further, the means for knowing the fuel pressure at the time of key-on is not limited to the detection of THW, but the elapsed time after the key-off may be used as a parameter, or the fuel pressure itself may be directly detected. It should be noted that THW may use the output of the water temperature sensor originally provided in the engine and has good responsiveness, and is therefore excellent in terms of simplicity and responsiveness.

[0037]

As described above, according to the fuel pump control system for an internal combustion engine of the present invention, the fuel pressure can be sufficiently increased before the fuel injection is started after the key-on, and the passengers can be prevented. It is possible to alleviate the discomfort caused.

In particular, the apparatus according to claims 1 to 3 achieves the above effect from the viewpoint of shortening the generation period of the unpleasant actuating sound as much as possible. In particular, the apparatus according to claim 3 is further activated / stopped. -There is also an effect that the operation such as restart is reduced as much as possible, and the durability of the fuel pump and relays as its peripheral devices is not unnecessarily impaired.

On the other hand, the apparatus according to claims 4 to 6 achieves the above effect from the viewpoint of reducing the intensity of unpleasant operating noise, and in particular, the apparatus according to claim 5 requires a period for generating the operating noise. By minimizing it, the above effect is enhanced,
The device according to the sixth aspect enables more fine control.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a system according to an embodiment.

FIG. 2 is a flowchart of control processing in the first embodiment.

FIG. 3 is a time chart as an example of a control process of the first embodiment.

FIG. 4 is a time chart as an example of a control process of the first embodiment.

FIG. 5 is a time chart as a control processing example of the first embodiment.

FIG. 6 is a time chart for explaining the effect of the first embodiment.

FIG. 7 is a flowchart of control processing in the second embodiment.

FIG. 8 is a time chart as a control processing example of the second embodiment.

FIG. 9 is a flowchart of control processing in the third embodiment.

FIG. 10 is a time chart as a control processing example of the third embodiment.

FIG. 11 is a time chart as a control processing example of the third embodiment.

FIG. 12 is a time chart as a control processing example of the third embodiment.

FIG. 13 is a graph showing the relationship between the cooling water temperature and the fuel pressure with the elapsed time after key-on.

[Explanation of symbols]

1 ... Engine, 2 ... Fuel injection valve, 3 ... Control unit, 4 ... Fuel pump, 5 ... Intake amount sensor, 6 ... Rotation sensor, 7 ... Cooling water temperature sensor , 8 ... Key switch, 8a ... Ignition switch, 8b ... Start switch, 9 ... Fuel tank, 10 ... Fuel pressure adjusting valve.

Claims (6)

[Claims] 1. A fuel pump control device for an internal combustion engine, which drives a fuel pump at least when a starter is turned on, so that the fuel pressure is kept at a predetermined pressure or higher before the fuel injection is started after the key is turned on. The key-on detection means that detects that the starter is turned on, the starter-on detection means that detects that the starter is turned on, the fuel pressure information detection means that detects information related to the fuel pressure at key-on, and the detection result of the fuel pressure information detection means when the key-on And a control means for controlling the fuel pump so as not to be driven until the starter ON is detected when the fuel pressure is above a predetermined value. 2. The fuel pump control device for an internal combustion engine according to claim 1, wherein the control means is based on a detection result of the fuel pressure information detection means when it is recognized that the fuel pressure at the time of key-on is less than the predetermined value. A fuel pump control device for an internal combustion engine, wherein continuously or stepwise different periods are set as fuel pump drive periods before starter on so that the higher the fuel pressure at key-on becomes, the shorter the fuel pressure becomes. 3. The fuel pump control apparatus for an internal combustion engine according to claim 2, wherein the control means further detects a detection result of the fuel pressure information detection means when the fuel pressure at key-on is found to be less than the predetermined value. Based on the above, the fuel pump control of the internal combustion engine is characterized in that the fuel pump drive start time before the starter on is set to a time which is continuously or stepwise delayed such that the fuel pressure at the time of key-on becomes slower as the fuel pressure becomes higher. apparatus. 4. A fuel pump control device for an internal combustion engine, which drives a fuel pump at least when a starter is turned on, so that the fuel pressure is kept at a predetermined pressure or higher before fuel injection is started after key-on. Switching means for switching between an output drive state and a low output drive state, a key-on detection means for detecting that the key is turned on, a starter-on detection means for detecting that the starter is turned on, and the starter is turned on after the key is turned on. A fuel pump control device for an internal combustion engine, comprising: a control unit that sets a low output drive state as a fuel pump drive condition before and a high output drive state as a fuel pump drive condition after a starter is turned on. 5. The fuel pump control device for an internal combustion engine according to claim 4, further comprising fuel pressure information detection means for detecting information regarding the magnitude of the fuel pressure at the time of key-on, said control means being the fuel at the time of key-on. When it is recognized that the pressure does not reach the predetermined value, based on the detection result of the fuel pressure information detection means, the starter is turned on continuously or stepwise so that the higher the fuel pressure at the time of key-on, the later. A fuel pump control device for an internal combustion engine, characterized in that a previous fuel pump drive start time is set. 6. The fuel pump control device for an internal combustion engine according to claim 5, wherein the control means further detects a detection result of the fuel pressure information detection means when the fuel pressure at the time of key-on is found to be less than the predetermined value. Based on the above, a fuel pump control device for an internal combustion engine, wherein continuously or stepwise different periods are set as the fuel pump drive period before starter on so that the fuel pressure becomes shorter as the key-on becomes higher.