JP4979738B2 - Engine control system - Google Patents

Description

  The present invention relates to an engine control system, and more particularly to a fuel pump control technique in an engine control system.

In a conventional engine control system, a fuel pump that supplies fuel pumped up from a fuel tank to a fuel injection valve that injects the fuel into the engine, and a pressure of fuel discharged from the fuel pump (hereinafter referred to as fuel pressure) is set to a predetermined pressure. A system is known that includes a pressure regulator that regulates pressure and an engine control unit that controls various actuators such as a fuel pump in accordance with the operating state of the engine.
In this type of engine control system, the fuel pump is always driven to discharge the fuel from the fuel pump, and the excess fuel is returned to the fuel tank by the pressure regulator, so that fuel with a constant fuel pressure is always supplied to the fuel injection valve. Can be supplied.

The fuel pump motor for driving the fuel pump is generally controlled by switching ON / OFF of energization of the electromagnetic relay. In the case of such fuel pump control, the fuel discharge amount of the fuel pump is a constant amount. When the fuel pump discharges a certain amount of fuel, for example, when the fuel amount required by the engine is low and the fuel injection amount from the fuel injection valve is small, the fuel is excessively supplied to the fuel injection valve. In this case, the excess fuel is returned to the fuel tank through the pressure regulator, but there is a problem that fuel vapor is likely to be generated when the fuel that has reached a high temperature returns to the fuel tank.
In order to solve this problem, a method is known in which the discharge amount of the fuel pump is controlled by correcting the basic injection amount from the fuel injection valve, a change in battery voltage, and the like. (For example, see Patent Document 1)

Japanese Patent Laid-Open No. 9-1226029

However, the conventional techniques have the following problems.
That is, in the case of steady operation where the fuel amount required by the engine is constant or moderate acceleration / deceleration operation, the fuel injection amount (vehicle required fuel) injected from the fuel injection valve and the fuel amount discharged from the fuel pump are The flow rate of fuel through the pressure regulator is constant, but in transient operating situations such as sudden acceleration and deceleration of the engine, if the fuel pump is not responsive, the fuel pump will not deliver enough fuel Occurs, and the fuel flow rate through the pressure regulator becomes unstable. In the case of a low-performance pressure regulator, the fuel pressure regulation limit will be exceeded, leading to a decrease in fuel pressure or an increase in fuel pressure, possibly leading to unstable injection amount, irregular engine speed, and unstable vehicle behavior. come.
In such a case, in order to keep the fuel pressure constant, it is necessary to improve the performance of the pressure regulator, but this hinders the cost reduction of the vehicle.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an engine control system that realizes stabilization of fuel pressure and fuel injection amount with an inexpensive system configuration.

An engine control system according to the present invention includes a fuel injection amount calculating means for calculating a fuel injection amount of a fuel injection valve based on an output of a sensor for detecting an operating state of the engine, and a fuel obtained from the fuel injection amount calculating means. Fuel discharge amount calculation means for calculating the fuel discharge amount of the fuel pump from the injection amount and the engine rotation speed, and a target fuel pump motor rotation speed of the fuel pump motor based on the fuel discharge amount obtained by the fuel discharge amount calculation means In an engine control system having a target fuel pump motor rotation speed calculating means for calculating the fuel consumption, and a deceleration fuel cut means for performing fuel cut when the throttle opening is suddenly closed, the fuel discharge amount calculating means is provided with a throttle opening of the throttle valve. The amount of change in the throttle opening of the throttle valve is detected from the output of the detected throttle position sensor, and the throttle If time variation is equal to or less than the predetermined value and equal to or larger than the predetermined value, the fuel pump motor speed correction means for correcting the target fuel pump motor speed of the fuel pump motor, the deceleration fuel cut period by the reduction fuel cut means During, the fuel pump motor rotation speed is gradually reduced according to a predetermined time and change amount, and finally the tailing process is carried out until the fuel discharge amount allows the engine to idle, and the deceleration fuel cut continuation period The fuel pump discharge amount correction control means at the time of deceleration fuel cut to make the fuel pump discharge amount according to the above.

  According to the engine control system of the present invention, it is possible to obtain an engine control system that realizes stabilization of the fuel pressure and the fuel injection amount with an inexpensive configuration.

  The above-described and other objects, features, and effects of the present invention will become more apparent from the detailed description and the drawings in the following embodiments.

1 is a schematic overall configuration diagram of an engine control system according to Embodiment 1 of the present invention. It is a control block diagram in Embodiment 1 of this invention. It is a flowchart of the arithmetic processing performed with the engine control unit in Embodiment 1 of this invention. FIG. 4 is a relationship diagram between a normal fuel injection amount and a fuel pump discharge amount in the first embodiment of the present invention. It is a fuel injection amount at the time of acceleration fuel pump discharge amount correction control in Embodiment 1 of this invention and a fuel pump discharge amount relationship diagram. FIG. 3 is a relationship diagram of throttle opening, fuel injection amount, and fuel pump discharge amount during acceleration fuel pump discharge amount correction control according to Embodiment 1 of the present invention. It is a fuel injection amount at the time of deceleration fuel pump discharge amount correction control in Embodiment 1 of this invention and a fuel pump discharge amount relationship diagram. FIG. 5 is a relationship diagram of a throttle opening, a fuel injection amount, and a fuel pump discharge amount at the time of deceleration fuel pump discharge amount correction control according to Embodiment 1 of the present invention. It is a fuel injection quantity at the time of engine protection cut time fuel pump discharge amount correction control in Embodiment 1 of this invention, and a fuel pump discharge amount relationship figure. FIG. 4 is a relationship diagram between a fuel pump discharge amount and a motor rotational speed of the fuel pump according to Embodiment 1 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic overall configuration diagram of an engine control system according to Embodiment 1 of the present invention. In FIG. 1, a control unit 1 stores a program and a map for controlling the operation of the entire engine, a throttle position sensor 3 that measures the opening of a throttle valve 2, and an engine temperature that measures the wall temperature of the engine. From the sensor information such as the sensor 4, the crank angle sensor 5 used for measuring the crank position and calculating the engine rotational speed, and the intake air temperature sensor 10 (see FIG. 2) for measuring the temperature of the intake air, an appropriate fuel injection timing, The fuel injection amount is calculated, and a drive signal is output to the fuel injection valve 9 which is a fuel injection device. Similarly, an ignition signal is output to an ignition coil (not shown) at an appropriate timing based on information from various sensors, a spark is generated by an ignition plug (not shown), and the mixture of fuel and intake air in the engine cylinder is burned, The crankshaft rotates as the piston is pushed out.
A fuel pump motor 7 of the fuel pump is driven by a drive signal from the control unit 1, and the fuel pump sucks and discharges fuel from the fuel tank 6 through a filter.
The discharged fuel is adjusted to a predetermined pressure by the pressure regulator 8, passes through the high-pressure fuel pipe, and is supplied to the fuel injection valve 9.
In FIG. 1, the fuel pump motor 7 of the fuel pump is disposed outside the fuel tank 6, but even if it is disposed within the fuel tank 6, it does not affect the present invention.

FIG. 2 shows a control block diagram of the control unit 1 in the engine control system according to the first embodiment of the present invention.
In FIG. 2, the control unit 1 detects engine operating conditions such as engine speed and engine load (throttle opening etc.) from the sensors 3 to 5, and based on the outputs of these sensors 3 to 5, The fuel injection amount calculation means 100 determines the fuel injection amount Qinj required by the engine.
The determined fuel injection amount Qinj and information from the throttle position sensor 3 are processed in the fuel discharge amount calculating means 200 to calculate the fuel pump discharge amount Qpump_fix. Details of the control of the control unit 1 including the fuel discharge amount calculating means 200 will be described later with reference to FIG.

From the fuel pump discharge amount Qpump_fix calculated by the fuel discharge amount calculation means 200 and the engine rotation speed from the crank angle sensor 5, the target fuel pump motor rotation speed calculation means 300 calculates the target rotation speed Npump_trgt of the fuel pump motor 7. .
Regarding the control method of the fuel pump motor 7, it is conceivable to use feedback control using the actual rotational speed Npump_real obtained from the fuel pump motor 7 in view of aging deterioration and individual differences of the fuel pump. Even if not, the present invention can be used.
When feedback control of the fuel pump motor 7 is performed, the fuel pump motor rotational speed FB control means 400 is calculated from the actual rotational speed Npump_real from the fuel pump motor 7 and the target rotational speed Npump_trgt from the target fuel pump motor rotational speed calculation means 300. Thus, the optimum feedback rotation speed Npump_fb for commanding the fuel pump motor 7 is calculated.
The feedback rotation speed Npump_fb (target rotation speed Npump_trgt when the fuel pump is driven by open loop control without using feedback control) is actually calculated by the fuel pump motor command value conversion means 500 as a drive command value for the fuel pump. A certain PWM duty value DUTYpump is converted, the converted command value PWM duty value DUTYpump is transmitted to the fuel pump motor 7, and the fuel pump motor is controlled to reach the target rotational speed.

FIG. 3 is a flowchart for one cycle of the arithmetic processing performed in the engine control unit 1 according to Embodiment 1 of the present invention. Details of the control in the engine control unit 1 of FIG. 2 will be described in detail with reference to FIG.
In FIG. 3, in step S <b> 1, output signals from various sensors 3 to 5 and 10 connected to the control unit 1 are read.
In step S2, the driving state of the vehicle is detected from the various sensors 3 to 5, and 10, and the fuel injection amount Qinj required by the vehicle is calculated by the fuel injection amount calculation means 100. The fuel injection amount injected from the fuel injection valve 9 is the fuel injection amount Qinj calculated in step S2. The fuel injection amount Qinj indicates the amount of fuel for one injection injected from the fuel injection valve 9.
Actually, in order to drive the fuel injection valve, the fuel injection amount Qinj is converted into the fuel injection valve drive time Tinj, and the fuel injection valve is driven in accordance with the fuel injection timing corresponding to the state of the vehicle from various sensor information. Drive for time Tinj and inject fuel.

The fuel discharge amount calculation means 200 changes the fuel pump discharge amount Qpump according to the fuel injection amount Qinj, thereby preventing the occurrence of fuel pressure instability due to excessive supply or insufficient supply of the fuel pump discharge amount Qpump. The relationship between the fuel discharge amount Qpump_nml and the fuel injection amount Qinj of the fuel pump in the normal state where the vehicle state is the acceleration state, the deceleration state, and the fuel cut state is as shown by the broken line a in FIG.
In FIG. 4, the horizontal axis represents the fuel injection amount Qinj, and the vertical axis represents the normal fuel pump discharge amount Qpump_nml.

Fuel pump discharge amount Qpump_nml ← Fuel injection amount Qinj

In step S3, it is determined from the information in the engine control unit whether fuel cut control is currently being performed. Fuel cut control shall be classified into engine protection cut for the purpose of engine protection performed at high engine speed, and deceleration fuel cut for the purpose of deceleration of vehicle speed performed by a quick closing operation of the throttle opening. I can do it.
In step S3, if the fuel is not being cut, the process proceeds to step S4. If the fuel is being cut, the process proceeds to step S11.

In step S4, the fuel injection amount Qinj calculated in step S2 is stored as the previous fuel injection amount Qinj_old. Since the fuel injection amount Qinj is updated for each cycle, the processing is performed in consideration of the case where the previous fuel injection amount Qinj is referred to.

Previous fuel injection amount Qinj_old ← Current fuel injection amount Qinj

The stored previous fuel injection amount Qinj_old is used in a fuel cut process described later.

In step S5, it is determined according to the output from the throttle position sensor 3 whether the fuel pump discharge amount Qpump of the fuel pump needs to be corrected while the vehicle is accelerating.
If the throttle opening change amount ΔTH is equal to or greater than the predetermined value 1, it is determined that the vehicle is in an acceleration state, and the process proceeds to step S6. If the condition is not satisfied in step S5, the process proceeds to step S8.

In step S6, it is determined whether or not the fuel pump discharge amount is permitted to be corrected by the acceleration fuel pump discharge amount correction control means in step S7 described later.
As a determination condition, if the fuel pump discharge amount is not yet corrected by the acceleration fuel pump discharge amount correction control means described later, the process proceeds to step S7. If it has already been corrected, the process proceeds to step S15 without doing anything.

In step S7, the fuel injection amount Qinj calculated in step S2 is converted into a corrected fuel pump discharge amount Qpump_chng for acceleration by the acceleration fuel pump discharge amount correction control means.
FIG. 5 shows the relationship between the fuel injection amount Qinj during normal operation and the corrected fuel pump discharge amount Qpump_chng at the time of acceleration fuel pump discharge amount correction control means.
In FIG. 5, the horizontal axis represents the fuel injection amount Qinj, and the vertical axis represents the corrected fuel pump discharge amount Qpump_chng. The broken line a in FIG. 5 shows the relationship between the fuel discharge amount Qpump_nml and the fuel injection amount Qinj of the fuel pump in the normal state. The solid line b in FIG. 5 shows the relationship between the fuel injection amount Qinj and the corrected fuel pump discharge amount Qpump_chng in the acceleration state, and the corrected fuel pump discharge amount Qpump_chng is compared with the normal fuel injection amount Qinj. The feature is that the amount is increased.

  When the fuel pump motor response is low and the fuel pressure adjustment capacity of the pressure regulator is low, the fuel pump motor's fuel discharge rate at the moment of acceleration is determined if the rotational speed of the fuel pump motor is determined according to the fuel injection amount Qinj. There is a possibility that the fuel pressure will decrease. In order to prevent this state, the relationship between the fuel injection amount Qinj and the corrected fuel pump discharge amount Qpump_chng as shown by the solid line b in FIG. 5 is stored in the engine control unit in advance. 6A, 6B, 6C, and 6D show the relationship between the series of slot opening and fuel injection amount in this case, the fuel pump discharge amount without correction, and the fuel pump discharge amount with correction. Show.

  As shown in FIG. 6, the throttle opening is suddenly opened, the fuel injection amount Qinj is increased, and the discharge amount Qpump of the fuel pump is changed accordingly. However, if the fuel pump is controlled by a normal method, the fuel pump When the responsiveness of the motor is poor, it takes time to reach the required fuel pump discharge amount, and the actual fuel pump discharge amount Qpump_real is insufficient with respect to the fuel injection amount Qinj, which may lead to a decrease in fuel pressure. Therefore, the fuel pump discharge amount correction control means increases the rotational speed of the fuel pump motor so as to obtain the corrected fuel pump discharge amount Qpump_chng, thereby securing the actual fuel pump discharge amount Qpump_real. (See Fig. 6 (d))

In step S8, it is determined whether the vehicle is decelerating according to the output of the throttle position sensor 3. If the throttle opening change amount ΔTH is less than or equal to the predetermined value 2, it is determined that the vehicle is in a decelerating state and the process proceeds to step S9.
If the condition is not satisfied in step S8, the process proceeds to step S15.

  In step S9, it is determined whether the fuel pump discharge amount is permitted to be corrected by the deceleration fuel pump discharge amount correction control means in step S10 described later. As a determination condition, when the fuel pump discharge amount correction control means described later has not yet corrected the fuel pump discharge amount, the process proceeds to step S10. If it has already been corrected, the process proceeds to step S15 without doing anything.

  In step S10, the fuel pump discharge amount correction control means at the time of deceleration converts the fuel injection amount Qinj calculated in step S2 into a corrected fuel pump discharge amount Qpump_chng for deceleration. FIG. 7 shows the relationship between the fuel injection amount Qinj during normal operation and the corrected fuel pump discharge amount Qpump_chng during deceleration fuel pump discharge amount correction control means. In FIG. 7, the horizontal axis represents the fuel injection amount Qinj, and the vertical axis represents the corrected fuel pump discharge amount Qpump_chng. The broken line a in FIG. 7 shows the relationship between the fuel discharge amount Qpump_nml and the fuel injection amount Qinj of the fuel pump in the normal state. The solid line c in FIG. 7 shows the relationship between the fuel injection amount Qinj and the corrected fuel pump discharge amount Qpump_chng in the deceleration state, and the corrected fuel pump discharge amount Qpump_chng is compared to the normal time with respect to the fuel injection amount Qinj. The feature is that it is reduced in weight.

When the fuel pump motor response is low and the fuel pressure regulation capability of the pressure regulator is low, the fuel pump motor discharge rate at the moment of deceleration is determined if the rotational speed of the fuel pump motor is determined according to the fuel injection amount Qinj. May become excessive and fuel pressure may increase. In order to prevent this state, the relationship between the fuel injection amount Qinj and the corrected fuel pump discharge amount Qpump_chng as shown by the solid line c in FIG. 7 is stored in the engine control unit in advance.
8A, 8B, 8C, and 8D show the relationship between the series of slot opening and fuel injection amount in this case, the fuel pump discharge amount without correction, and the fuel pump discharge amount with correction. Show.

  As shown in FIG. 8, the throttle opening is suddenly closed, the fuel injection amount Qinj is also decreased, and the discharge amount Qpump of the fuel pump is changed accordingly. However, if the fuel pump is controlled by a normal method, the fuel pump When the responsiveness of the motor is poor, it takes time to reach the required fuel pump discharge amount, and the actual fuel pump discharge amount Qpump_real becomes excessive with respect to the fuel injection amount Qinj, which may increase the fuel pressure. Therefore, the fuel pump discharge amount correction control means at the time of deceleration reduces the rotational speed of the fuel pump motor so as to obtain the corrected fuel pump discharge amount Qpump_chng, thereby improving the follow-up accuracy of the actual fuel pump discharge amount Qpump_real. (See Fig. 8 (d))

In step S11, it is determined from the information in the engine control unit 1 whether the currently executed fuel cut control is an engine protection cut. If the engine protection cut is in progress, the process proceeds to step S12. If the engine protection cut is not in progress, the process proceeds to step S14.
In step S12, it is determined whether or not correction of the fuel pump discharge amount is permitted by the engine protection cut time fuel pump discharge amount correction control unit in step S13 described later. As a determination condition, if the fuel pump discharge amount has not been corrected by the engine protection cut fuel pump discharge amount correction control unit, which will be described later, the process proceeds to step S13. If it has already been corrected, the process proceeds to step S15 without doing anything.

In step S13, since the fuel injection amount Qinj is basically 0 during the fuel cut, the previous fuel injection amount Qinj_old immediately before the fuel cut stored in step S4 is changed to the corrected fuel pump discharge during the engine protection cut. Convert to quantity Qpump_chng.
FIG. 9 shows the relationship between the fuel injection amount Qinj during normal operation and the corrected fuel pump discharge amount Qpump_chng during engine protection cut fuel pump discharge amount correction control means.
In FIG. 9, the horizontal axis represents the previous fuel injection amount Qinj_old, and the vertical axis represents the corrected fuel pump discharge amount Qpump_chng. The broken line a in FIG. 9 shows the relationship between the fuel discharge amount Qpump_nml and the fuel injection amount Qinj of the fuel pump in the normal state. The solid line d in FIG. 9 shows the relationship between the fuel injection amount Qinj_old immediately before the engine protection cut and the corrected fuel pump discharge amount Qpump_chng, and the corrected fuel pump discharge amount Qpump_chng is slightly reduced compared to the normal time. It is a feature.

  The engine protection cut is performed when the engine rotational speed is high, and aims to prevent the engine from rotating beyond a predetermined rotational speed. Therefore, when the engine protection cut is canceled and fuel injection is performed again, the same large amount of fuel injection as that immediately before the engine protection cut is performed is required. Therefore, the fuel pump is driven so as to inject the fuel injection amount immediately before the engine protection cut even during the engine protection cut. Since fuel injection is not performed during the engine protection cut, the fuel pump discharge amount becomes excessive and the fuel pressure rises, but there is no problem because the engine protection cut is in progress.

In step S14, the fuel pump discharge amount during deceleration fuel cut is corrected by the fuel pump discharge amount correction control means during deceleration fuel cut. In the case of the deceleration fuel cut, the rotational speed of the engine decreases in a state where the deceleration fuel cut is established and a state where the deceleration fuel cut returns. Therefore, it is necessary to reduce the fuel pump discharge amount at the time of deceleration fuel cut return. As the duration of the deceleration fuel cut is longer, the state in which fuel is not supplied to the engine continues, and the engine speed tends to decrease. Therefore, the corrected fuel pump discharge amount Qpump_chng during deceleration fuel cut is decreased by a predetermined value for each cycle as described below.
However, the corrected fuel pump discharge amount Qpump_chng is not reduced below the predetermined fuel discharge amount Qpump_idle at the engine idle speed.

Qpump_chng (1) = Qinj_old
Qpump_chng (n) = Qpump_chng (n-1)-predetermined value

When returning from the deceleration fuel cut, the fuel pump is driven so that the fuel discharge amount is based on the corrected fuel pump discharge amount Qpump_chng. It prevents the fuel discharge amount from becoming excessive.

In step S15, acceleration fuel pump discharge amount correction control means, deceleration fuel pump discharge amount correction control means, engine protection cut fuel pump discharge amount correction control means, and deceleration fuel cut fuel pump discharge amount correction control means are implemented. It is determined whether or not the fuel pump discharge amount return condition is satisfied, and if either is satisfied, the process proceeds to step S16.
If neither is established, the process proceeds to step S17.

In the case of the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means, the corrected fuel pump discharge amount Qpump_chng and the fuel injection amount Qinj calculated in step S2 are as follows. If they match, it is determined that the correction return of the fuel pump is established.
In addition, even when the predetermined time has elapsed, if the corrected fuel pump discharge amount Qpump_chng and the fuel injection amount Qinj calculated in step S2 do not coincide, it is determined that the fuel pump correction return is established, and the corrected fuel pump discharge amount Qpump_chng for each cycle Is tailored to decrease or increase the unit amount so that it becomes the same amount as Qinj.
In the case of the engine protection cut fuel pump discharge amount correction control means and the deceleration fuel cut fuel pump discharge amount correction control means, when the engine protection cut or deceleration fuel cut returns, it is determined that the fuel pump correction return is established.

In step S16, the final fuel pump discharge amount Qpump_fix is determined, and the normal fuel pump discharge amount Qpump_nml calculated in step S2 becomes the final fuel pump discharge amount Qpump_fix.
In step S15, if the correction does not coincide even after a predetermined time has elapsed between the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means, the corrected fuel pump discharge amount Qpump_chng subjected to tailing processing is finally set. Let the fuel pump discharge amount be Qpump_fix.
In step S17, the corrected fuel pump discharge amount Qpump_chng is set to the final fuel pump discharge amount.
Qpump_fix.
In step S18, the target fuel pump motor rotational speed calculation means 300 determines the motor rotational speed of the fuel pump from the final fuel pump discharge amount Qpump_fix. The relationship between the final fuel pump discharge amount Qpump_fix and the motor rotational speed Npump_trgt of the fuel pump is shown in FIG.

  There is a possibility that the target fuel pump motor rotation speed Npump_trgt and the command value DUTYpump to the fuel pump motor in step S20 described later may not match due to the aging of the fuel pump and the individual differences between the fuel pumps. In view of such a case, in step S19, the actual rotational speed of the fuel pump motor 7 is taken into the engine control unit 1 as a fuel pump driving method, and the target fuel pump motor is controlled by the fuel pump motor rotational speed FB control means 400. Feedback control to rotation speed. The target fuel pump motor rotation speed is the fuel pump motor rotation speed Npump_trgt calculated in step S18, and the fuel pump motor actual rotation speed Npump_real is measured by, for example, measuring the period of the induced voltage of the fuel pump motor. Calculate the speed. A feedback rotation speed Npump_fb that is optimal for commanding the fuel pump is calculated from the actual rotation speed Npump_real and the target rotation speed Npump_trgt. The feedback control method is a known control that has been used in the past, and is therefore omitted here. When it is impossible to measure the actual rotational speed of the fuel pump motor, the process may proceed from step S18 to step S20.

  In step S20, when the fuel pump motor command value conversion means 500 performs feedback control of the rotation speed of the fuel pump motor, the feedback rotation speed Npump_fb is used, and when the fuel pump motor is driven by open loop control without using feedback control. The target rotational speed Npump_trgt is actually converted into a PWM duty value DUTYpump, which is a drive command value for the fuel pump motor. The converted PWM duty value DUTYpump is transmitted to the fuel pump motor 7 to drive the fuel pump motor 7.

  As described above, according to the engine control system of Embodiment 1 of the present invention, it is possible to obtain an engine control system that realizes stabilization of fuel pressure and fuel injection amount with an inexpensive configuration.

That is, according to the engine control system of Embodiment 1 of the present invention,
(1) A fuel injection amount calculating means for calculating a fuel injection amount of the fuel injection valve based on an output of a sensor for detecting an operating state of the engine, a fuel injection amount obtained from the fuel injection amount calculating means, and an engine rotation A fuel discharge amount calculating means for calculating the fuel discharge amount of the fuel pump from the speed, and a target for calculating a target fuel pump motor rotational speed of the fuel pump motor in order to obtain the fuel discharge amount obtained from the fuel discharge amount calculating means In the engine control system having the fuel pump motor rotation speed calculation means, the fuel pump motor rotation speed correction means detects the throttle opening change amount of the throttle valve from the output of the throttle position sensor that detects the throttle opening of the throttle valve, When the amount of change in throttle opening is greater than or equal to a predetermined value and less than or equal to the predetermined value, the target fuel position of the fuel pump motor is reduced. Therefore, the target fuel pump of the fuel pump motor can be corrected even when the fuel pump motor response is low when the throttle opening changes when the fuel supply amount required by the engine changes rapidly. By changing the motor rotation speed, it is possible to prevent fluctuations in the fuel pressure due to excessive or insufficient fuel pump discharge.

  (2) Further, the fuel pump motor rotational speed correction means preliminarily sets the target fuel pump motor rotational speed of the fuel pump motor as a corrected target fuel pump motor rotational speed when the amount of change in throttle opening is equal to or greater than a predetermined value. Acceleration fuel pump discharge amount correction for increasing the fuel discharge amount of the fuel pump by controlling the fuel pump motor in accordance with the corrected target fuel pump motor rotational speed for a predetermined time by a predetermined amount. Since the control means is provided, even when the responsiveness of the fuel pump motor is low and the pressure regulation performance of the pressure regulator is also low, it is possible to prevent a decrease in fuel pressure due to insufficient discharge amount by increasing the discharge amount of the fuel pump in advance It becomes. In addition, not only normal fuel injection but also asynchronous fuel injection may be performed during acceleration, and the amount of asynchronous fuel injection can be compensated for by increasing the fuel pump discharge amount.

  (3) Further, the fuel pump motor rotational speed correcting means sets the target fuel pump motor rotational speed of the fuel pump motor as a corrected target fuel pump motor rotational speed when the amount of change in throttle opening is less than a predetermined value. Decreasing fuel pump discharge amount during deceleration by decreasing the fuel discharge amount of the fuel pump by reducing the fuel pump motor by controlling the fuel pump motor according to the corrected target fuel pump motor rotational speed for a predetermined time by a predetermined amount. Since the correction control means is provided, even if the responsiveness of the fuel pump motor is low and the pressure regulator performance is also low, the fuel pump discharge amount is reduced in advance to prevent an increase in fuel pressure due to excessive discharge amount. It becomes possible.

  (4) Further, the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means correct the target fuel pump motor rotational speed of the fuel pump motor and fix the correction for a predetermined time. When the fuel pump motor is controlled in accordance with the post-target fuel pump motor rotational speed, the target fuel pump motor rotational speed calculated from the fuel injection amount of the fuel injection valve within a predetermined time for executing the correction is the post-correction Since the fuel pump motor is controlled in accordance with the target fuel pump motor rotational speed calculated from the fuel injection amount of the fuel injection valve when it coincides with the target fuel pump motor rotational speed, the engine requirements When the amount of fuel injected and the amount of fuel discharged from the fuel pump match, the normal fuel pump motor control is immediately started. Prevents increase or decrease the discharge amount of the fuel pump to the main or more, it is possible to minimize the fluctuation of the fuel pressure.

  (5) Further, the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means correct the target fuel pump motor rotational speed of the fuel pump motor and fix the correction for a predetermined time. When the fuel pump motor is controlled in accordance with the post-target fuel pump motor rotational speed, the post-correction target fuel pump motor rotational speed is calculated from the fuel injection amount of the fuel injection valve after a predetermined time for executing the correction. Since tailing processing is performed to increase or decrease according to a predetermined time and change amount so as to coincide with the target fuel pump motor rotation speed, the discharge amount of the fuel pump is increased or decreased more than necessary. It is possible to prevent fuel pressure fluctuations to be minimized.

  (6) In the engine protection cut that protects the engine by suppressing the increase in the engine rotation speed when the engine rotation speed is high and there is a risk of damaging the engine, when returning from the engine protection cut However, since the engine speed is high, a large amount of fuel is required. Therefore, since the rotation speed of the fuel pump motor is maintained at the same rotation speed as before the engine protection cut, it is possible to prevent a decrease in fuel pressure due to a shortage of the fuel pump discharge amount when the engine protection cut is restored.

(7) Further, in the deceleration fuel cut in which the fuel cut is performed when the throttle opening is suddenly closed for the purpose of vehicle deceleration, fuel efficiency improvement, etc., the engine rotational speed decreases at the time of return from the deceleration fuel cut, and the required fuel injection Since the amount also decreases, the fuel pump motor rotation speed is gradually reduced according to a predetermined time and amount of change during the deceleration fuel cut period, and finally the engine can idle. By performing tailing processing to the fuel discharge amount and setting the fuel pump discharge amount according to the deceleration fuel cut continuation period, it is possible to prevent an increase in fuel pressure due to excessive fuel pump discharge amount when returning from the deceleration fuel cut Become. The engine rotation speed when returning from the deceleration fuel cut is indefinite, but the fuel pump discharge amount can be controlled according to the deceleration fuel cut duration by the fuel pump discharge amount tailing process during the deceleration fuel cut. .
The tailing process is performed up to the rotational speed of the fuel pump motor that can secure the fuel discharge amount required during the idling operation, which is the minimum rotational speed of the engine.

(8) When the fuel cut is restored, the rotational speed of the fuel pump motor is immediately returned to the state before correction, so that the fuel pump discharge amount is not corrected more than necessary.
With the control described above, an engine control system that can stabilize the fuel pressure and the fuel injection amount can be obtained even with a fuel pump motor with low responsiveness, an inexpensive low-performance pressure regulator, or the like.

1 control unit, 2 throttle valve, 3 throttle position sensor,
4 Engine temperature sensor, 5 Crank angle sensor, 6 Fuel tank, 7 Fuel supply device, 8 Pressure regulator, 9 Fuel supply valve,
100 fuel injection amount calculation means, 200 fuel discharge amount calculation means,
300 target fuel pump motor rotation speed calculation means,
400 fuel pump motor rotational speed FB control means,
500 Fuel pump motor command value conversion means

Claims (7)

Fuel injection amount calculation means for calculating the fuel injection amount of the fuel injection valve based on the output of the sensor that detects the operating state of the engine, the fuel injection amount obtained from the fuel injection amount calculation means, and the engine rotational speed Fuel discharge amount calculating means for calculating the fuel discharge amount of the pump, and target fuel pump motor rotation speed for calculating the target fuel pump motor rotation speed of the fuel pump motor based on the fuel discharge amount obtained by the fuel discharge amount calculation means In an engine control system having calculation means and deceleration fuel cut means for performing fuel cut when the throttle opening is suddenly closed ,
The fuel discharge amount calculating means detects a throttle opening change amount of the throttle valve from an output of a throttle position sensor for detecting a throttle opening of the throttle valve, and when the throttle opening change amount is a predetermined value or more In the following cases, the fuel pump motor rotation speed correction means for correcting the target fuel pump motor rotation speed of the fuel pump motor and the deceleration fuel cut period by the deceleration fuel cut means are set to a predetermined time and change amount. In response, the fuel pump motor speed is gradually reduced, and tailing processing is finally performed until the fuel discharge amount allows the engine to idle, and the fuel is reduced to a fuel pump discharge amount corresponding to the deceleration fuel cut duration. An engine control system comprising an hour fuel pump discharge amount correction control means .   The fuel pump motor rotational speed correction means is configured to set a target fuel pump motor rotational speed of the fuel pump motor as a corrected target fuel pump motor rotational speed in a predetermined amount when the amount of change in throttle opening is equal to or greater than a predetermined value. A fuel pump discharge amount correction control means for accelerating that increases the fuel discharge amount of the fuel pump by controlling the fuel pump motor according to the corrected target fuel pump motor rotational speed for a predetermined time. The engine control system according to claim 1.   The fuel pump motor rotational speed correction means is configured to set a target fuel pump motor rotational speed of the fuel pump motor as a corrected target fuel pump motor rotational speed in a predetermined amount when the amount of change in throttle opening is equal to or less than a predetermined value. The fuel pump discharge amount correction control means at the time of deceleration for decreasing the fuel discharge amount of the fuel pump by controlling the fuel pump motor according to the corrected target fuel pump motor rotation speed for a predetermined time. The engine control system according to claim 1.   The post-correction target fuel pump motor that is fixed for a predetermined time by correcting the target fuel pump motor rotational speed of the fuel pump motor by the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means. When the fuel pump motor is controlled according to the rotational speed, the target fuel pump motor rotational speed calculated from the fuel injection amount of the fuel injection valve within a predetermined time for executing the correction is the corrected target fuel pump motor rotational speed. 4. The fuel pump motor is controlled according to the target fuel pump motor rotational speed calculated from the fuel injection amount of the fuel injection valve thereafter when the speed matches the speed. Engine control system. The post-correction target fuel pump motor that is fixed for a predetermined time by correcting the target fuel pump motor rotational speed of the fuel pump motor by the acceleration fuel pump discharge amount correction control means and the deceleration fuel pump discharge amount correction control means. In the case where the fuel pump motor is controlled in accordance with the rotational speed, the target fuel pump motor obtained by calculating the corrected target fuel pump motor rotational speed from the fuel injection amount of the fuel injection valve after a lapse of a predetermined time for executing the correction. 4. The engine control system according to claim 2, wherein tailing processing is performed to increase or decrease in accordance with a predetermined time and change amount so as to coincide with the rotation speed.   When the engine speed is high and there is a risk of damaging the engine, the fuel cut is carried out, and an engine protection cut means for protecting the engine by suppressing an increase in the engine rotation speed is provided. During the fuel cut period by the engine protection cut means The engine control system according to claim 1, further comprising engine protection cut time fuel pump discharge amount correction control means for maintaining the rotation speed of the fuel pump motor at a rotation speed equivalent to that immediately before engine protection cut. The engine control system according to claim 1 or 6 , wherein when the fuel cut is restored, the rotational speed of the fuel pump motor is immediately returned to the state before correction .

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