JPH09119335A - Fuel supplying controller of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormalities of pressure of fuel without using any feedback control signal by annunciating the abnormalities through a process of energizing an alarm when fuel pressure detected by a fuel pressure sensor is not less than the upper limit value set according to the engine speed of an engine or not more than the lower limit value. SOLUTION: When a driver turns a key switch 13 to an ignition terminal ing, control of a controller 11 is started, and reading of output signals of a crank angle sensor 14, a fuel pressure sensor 9 and a car speed sensor 15 is performed. Whether the engine speed Ne exceeds the set engine speed Ns, for example, 300arpm is judged. In Ne>Ns, whether fuel pressure Pf from the fuel pressure sensor 9 exceeds the fuel pressure upper limit value Ph or the fuel pressure lower limit value Pi stored as a memory map according to the engine speed Vc or not is judged. In Pf>Ph or Pf<Pi, it is judged that a high-pressure fuel supplying system is in the abnormal state, and an alarm lamp 16 is energized.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for an engine, and more particularly to a fuel supply for an engine equipped with a high-pressure fuel supply system for pumping fuel injected by an injector to a direct injection (DI) gasoline engine. The present invention relates to a control device.

[0001]

2. Description of the Related Art Conventionally, an electronically controlled fuel injection device used in a gasoline engine or the like is shown in FIG. 6, in which fuel (gasoline) in a fuel tank 1 is sucked up by an electric low pressure pump 2. To a certain pressure,
It is sent to the electric or mechanical high-pressure pump 4 through the pipe 3a.

This high-pressure pump 4 is for pressurizing fuel to a pressure optimum for supplying it from an injector 6 to an intake system of an engine through a pipe 3b and a fuel rail 5.

The fuel pressurized by the high-pressure pump 4 and given to the fuel rail 5 is given to the electric or mechanical high-pressure regulator 7 through the pipe 3c, and further the pipe 3d.
Pipe 3e given to mechanical low pressure regulator 8
It is returned to the fuel tank 1 more.

That is, the fuel in the fuel tank 1 circulates through the fuel supply system of the low pressure pump 2 → high pressure pump 4 → fuel rail 5 → high pressure regulator 7 → low pressure regulator 8.

While the fuel circulates in the fuel supply system as described above, the high-pressure regulator 7 constituting the high-pressure fuel supply system together with the high-pressure pump 4 and the fuel rail 5 constantly adjusts the pressure of the circulated fuel to a predetermined value. The high pressure fuel, which is being pressurized, is converted to atmospheric pressure by the low pressure regulator 8 and returned to the fuel tank 1.

A pipe 3f is connected from the high-pressure pump 4 to the low-pressure regulator 8, which is the high-pressure pump 4.
Can leak a part of the fuel to the pipe 3b to the side of the pipe 3f to make the fuel pressure (fuel pressure) variable, and the leaked fuel pressure can be returned to the atmospheric pressure by the low pressure regulator 8. There is.

When the fuel is directly returned from the high pressure regulator 7 into the tank 1, evaporation in the tank 1 is rapidly performed and the cavitation and vapor generation of the low pressure pump 2 are increased. It has to be put back and for this purpose the low pressure regulator 8 is used. The low pressure pump 2 reduces the load and maintains a stable fuel pressure by setting the inlet of the high pressure pump 4 to a certain constant value.

An electromagnetic valve (not shown) is built in the injector 6, and an energization time (that is, an injection amount) of the electromagnetic valve is controlled by an engine control module (not shown) (hereinafter, simply referred to as a controller).
The injector 6 is opened and closed by controlling the.

In this case, the controller is basically based on the theoretical A / F (air-fuel ratio) based on the engine speed from a speed sensor (not shown) and the intake air amount from an air flow sensor (not shown). It is determined based on the engine temperature from a cooling water temperature sensor (not shown) and the exhaust oxygen concentration from the O ₂ sensor.

[0010]

In the conventional example as described above, in the high-pressure fuel supply system from the high-pressure pump 4 to the low-pressure regulator 8 via the fuel rail 5 and the high-pressure regulator 7, especially the pressure of the high-pressure pump is abnormal. It cannot detect a dangerous state of rising or decreasing and cannot issue a warning.

Therefore, in Japanese Utility Model Laid-Open No. 5-69374, as an abnormality warning device for a cylinder injection type gasoline engine, a target fuel pressure when performing feedback control to the high pressure regulator so that the actual fuel pressure matches the target fuel pressure is used. The feedback control correction signal corresponding to the pressure difference from the actual fuel pressure is compared with the allowable range based on the upper and lower limit values, and when it deviates from the allowable range, it is determined to be abnormal and a warning is issued.

However, in the prior art according to this publication, since the feedback control current to the high-pressure regulator is used as a parameter for determining the abnormality, it cannot be applied to an engine that does not perform feedback control of fuel pressure, and the feedback control is not possible. When the current deviates from the permissible range, it is simply determined that the fuel pump is abnormal and a warning is issued.
It also occurs when a fuel leak occurs in the pipe between the injectors, but in this case if the driver ignores the warning and continues to run, it will cause a serious accident such as a vehicle fire. There was a problem.

Therefore, according to the present invention, in a fuel supply control apparatus for an engine having a high-pressure fuel supply system for pressure-feeding fuel injected by an injector to a direct injection gasoline engine, the fuel pressure is controlled without using a feedback control signal. The purpose is to detect abnormalities and implement appropriate measures.

[0014]

[Means for Solving the Problems]

[1] To achieve the above object, a high-pressure fuel supply system for pumping fuel injected by an injector to a direct injection gasoline engine according to the present invention, an engine speed sensor, an alarm device, and A fuel pressure sensor provided in the high-pressure fuel supply system for detecting fuel pressure, and for activating the alarm device when the fuel pressure is equal to or higher than an upper limit value or lower than a lower limit value set corresponding to the engine speed. And a controller.

That is, in the present invention, the alarm device is driven when the fuel pressure detected by the fuel pressure sensor provided in the high pressure fuel supply system is equal to or higher than the upper limit value or equal to or lower than the lower limit value.

In this case, the upper limit value and the lower limit value of the fuel pressure are set to increase as the engine speed increases.

As a result, even in an engine that does not perform fuel pressure feedback control, it is possible to detect a fuel pressure abnormality and issue a warning to the driver or the like.

[2] In the present invention, a solenoid valve may be further provided in the high pressure fuel supply system, and the controller may control the solenoid valve to close when the fuel pressure is equal to or lower than the lower limit value. it can.

As a result, when a fuel leak occurs in the pipe between the fuel pump and the injector, the fuel pressure drops. Therefore, the controller detects this and closes the solenoid valve to prevent a vehicle fire due to fuel leak or the like. Can be prevented.

[3] Further, in the present invention, a vehicle speed sensor is provided, and the controller controls the solenoid valve to be closed after a delay time corresponding to the vehicle speed when the fuel pressure is equal to or lower than the lower limit value. It is also possible.

As a result, the engine is stopped after a predetermined time corresponding to the vehicle speed has elapsed, so that it is possible to prevent a rear-end collision accident or the like due to the sudden stop of the vehicle during traveling.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of an engine fuel supply control apparatus according to the present invention. This embodiment and the embodiment shown in FIG. 6 include a fuel rail 5 to a high pressure regulator 7. The fuel pressure sensor 9 is provided in the pipe 3c leading to and the high pressure solenoid valve 10 is provided in the pipe leading from the high pressure pump 4 to the fuel rail 5.

The fuel pressure sensor 9 is not limited to the pipe 3c, but the low pressure pump 2 → high pressure pump 4 → fuel rail 5 →
It may be installed anywhere in the high-pressure fuel supply system (high-pressure pump 4 → fuel rail 5 → high-pressure regulator 7) in the fuel supply system composed of the high-pressure regulator 7 → the low-pressure regulator 8.

The solenoid valve 10 is also most preferably on the discharge side of the high-pressure pump 4, but is not limited to this, and may be attached anywhere in the high-pressure fuel supply system.

FIG. 2 schematically shows an electrical system diagram of the engine fuel supply control apparatus according to the present invention. The injector 6 controls the energization time by an engine control module (ECM) 11 as a controller. It is supposed to be done.

The controller 11 is adapted to be supplied with a DC voltage from a vehicle battery 12, and the battery 12 is connected to a key switch 13. By turning on the key switch 13,
First, the ignition signal (battery voltage) is applied to the controller 11 from the ignition terminal ing, and then the starter signal (battery voltage) is applied from the starter terminal st.

The controller 11 also receives a crank angle signal from the crank angle sensor 14, that is, an engine speed signal, and a fuel pressure signal from the fuel pressure sensor 9,
A vehicle speed signal is input from the vehicle speed sensor 15, and a control signal is given to the alarm lamp 16 and the high pressure solenoid valve 10.

FIG. 3 is a flow chart of a control program stored and executed in the controller 11 shown in the electrical system diagram of FIG. 2, and FIGS. 4 and 5 are flow charts shown in FIG. FIG. 3 shows various memory maps used in FIG.
The operation of the embodiment of the engine fuel supply control apparatus according to the present invention shown in FIGS. 1 and 2 will be described below with reference to FIG.

First, when the driver turns the key switch 13 to the ignition terminal ing when the driver starts the engine, the ignition switch is turned on, and the control program shown in FIG. 3 is started (step S1). .

[0030] Then, the controller 11 immediately when the ignition switch is turned ON, the engine speed signal N _e from the crank angle sensor 14, the fuel pressure P _f from the fuel pressure sensor 9, vehicle speed signal V from the vehicle speed sensor 15 _c and
Is read (step S2).

The controller 11 further determines whether or not the key switch 13 is located at the starter switch terminal st (step S3), and the starter switch terminal st.
When it is found that the starter switch is turned on, the process proceeds to step S8 described later.

In step S3, when the starter switch terminal st is not set, it is judged whether or not the engine speed exceeds the set speed N _{s of,} for example, 300 rpm (step S4), and N _e ≤N _s. When it is found that the engine has just started to rotate, the process proceeds to step S8, but when it is found that N _e > N _s , the process proceeds to step S5.

In step S5, the fuel pressure P _f from the fuel pressure sensor 9 is the engine speed V _{c as} shown in FIG.
It is determined whether or not the fuel pressure upper limit value P _h stored in the controller 11 as a memory map in advance by experiments or the like is exceeded, and when it is found that P _f > P _h The alarm lamp 16 is activated because the supply system is in an abnormally high pressure state (step S6). Then, the process returns to step S2.

On the other hand, when it was found to be P _f ≦ P _h in step S5, when further compared with the P _f and the fuel pressure lower limit value P _l in step S7, it was found that a P _f ≧ P _l is Proceed to step S8, and alarm lamp 1
6 is turned off so that the solenoid valve 10 is opened, that is, in a normal state without special control, step S2
Return to

On the other hand, when it is found in step S7 that P _f <P _l , the controller 11 indicates that the high-pressure fuel supply system is in an abnormally low pressure state, and there is a possibility that fuel leakage has occurred. Energize (step S9).

Further, the controller 11 executes step S1.
If it is determined that the timer count is not started at 0, and it is found that the timer count is not yet started, the vehicle speed-timer shown in FIG. keep reading the timer time T _L corresponding from the memory map in the vehicle speed V _c (step S11), and starts the timer count (step S12).

Then, in step S13, the magnitude relationship between the current count value T _N after the timer count is started and the timer set value T _L is judged, and when it is found that T _N ≤T _L , the process returns to step S2, When it is found that T _N ≧ T _L , the solenoid valve 10 is controlled to be closed.

[0038]

As described above, according to the engine fuel supply control device of the present invention, the fuel pressure detected by the fuel pressure sensor provided in the high pressure fuel supply system is the upper limit value corresponding to the engine speed. Since it is configured to issue an alarm when it is above or below the lower limit, fuel pressure is directly monitored as a parameter for abnormality determination, so it can also be applied to engines that do not have a feedback control system to the high pressure regulator. Becomes

Further, if a solenoid valve is further provided in the high pressure fuel supply system and the solenoid valve is controlled to be closed when the fuel pressure is equal to or lower than the lower limit value, fuel leakage will occur even when there is an abnormality, especially when the fuel pressure is low. In this case, the engine can be forcibly stopped by issuing a warning and stopping the fuel injection in this case, thereby preventing a serious accident such as a fire.

Further, in the present invention, when the fuel pressure is equal to or lower than the lower limit value, the solenoid valve can be controlled to be closed after the delay time corresponding to the vehicle speed, whereby the engine can be operated after a predetermined time corresponding to the vehicle speed has elapsed. Since the vehicle is stopped, it is possible to prevent a rear-end collision accident or the like due to the vehicle suddenly stopping during traveling. Since the engine can be stopped after a lapse of a predetermined time even when the vehicle speed is 0 km / h, it is possible to prevent erroneous operation due to pulsation of fuel pressure and instantaneous abnormality determination (erroneous diagnosis) during transient operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a fuel supply system in a fuel supply control device for an engine according to the present invention.

FIG. 2 is a block diagram showing an electric system system in a fuel supply control device for an engine according to the present invention.

FIG. 3 is a flowchart showing a control program stored and executed in the controller shown in FIG.

4 is stored in the controller shown in FIG. 2 and FIG.
Engine speed used in the flowchart shown in −
It is a graph figure of a memory map showing the relationship with fuel pressure.

5 is stored in the controller shown in FIG. 2 and FIG.
FIG. 9 is a graph of a memory map showing the relationship between vehicle speed and timer time used in the flowchart shown in FIG.

FIG. 6 is a block diagram showing a fuel supply system in a conventional engine fuel supply control device.

[Explanation of symbols]

1 Fuel Tank 2 Low Pressure Pump 3a to 3f Piping 4 High Pressure Pump 5 Fuel Rail 6 Injector 7 High Pressure Regulator 8 Low Pressure Regulator 9 Fuel Pressure Sensor 10 High Pressure Electromagnetic Valve 11 Controller (Engine Control Module) 13 Key Switch 14 Crank Angle Sensor 15 Vehicle Speed Sensor 16 Alarm In the lamp diagrams, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Yamada No. 8 Tsutana, Fujisawa City, Kanagawa Prefecture Isuzu Motors Limited Fujisawa Factory

Claims (3)

[Claims] 1. A high-pressure fuel supply system for pressure-feeding fuel injected by an injector to a direct injection gasoline engine, an engine speed sensor, an alarm device, and a fuel provided in the high-pressure fuel supply system. A fuel pressure sensor for detecting a pressure; and a controller for activating the alarm device when the fuel pressure is equal to or higher than an upper limit value or lower than a lower limit value set corresponding to the engine speed. Fuel supply control device for engine. 2. The electromagnetic valve according to claim 1, further comprising an electromagnetic valve in the high pressure fuel supply system, wherein the controller controls the electromagnetic valve to be closed when the fuel pressure is equal to or lower than the lower limit value. Fuel supply control device for the engine. 3. A vehicle speed sensor according to claim 2, wherein the controller controls the solenoid valve to be closed after a delay time proportional to the vehicle speed when the fuel pressure is equal to or lower than the lower limit value. Fuel supply control device for the engine.