JPH045728Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an engine control device, and more particularly to an improved start/stop control circuit for an electric motor-driven fuel pump that pumps fuel to a fuel injection nozzle.

(Prior Art) Conventionally, in ignition type engines in which an electric motor drives a fuel pump that pumps fuel to the engine's fuel injection nozzles, the fuel injection nozzles are controlled by an electronic engine control device. When the ignition switch is turned on and the engine control system starts operating, the fuel pump also starts operating.

By the way, if one of the fuel injection nozzles malfunctions or one of the fuel injection nozzles becomes inoperable due to a malfunction of the electronic engine control device,
Or, if multiple injection nozzles become unsealed, fuel will continue to leak from the injection nozzles and be continuously supplied into the corresponding cylinder. It will no longer be emitted from the engine, causing problems with engine operation.

Therefore, a relay switch is installed in the drive circuit of the electric motor, and a switch is installed in the relay coil of this relay switch that opens when the opening of the vane-type intake air amount sensor installed in the intake passage becomes less than a predetermined value. It is common to do so.

On the other hand, Japanese Patent Application Laid-open No. 45-34162 discloses that a switch device is installed in the drive circuit of the electric motor for driving the fuel pump, which opens when the engine speed drops below the settable minimum speed (for example, 30 rpm). A fuel injection device is described in which a starting switch is provided so that power can be supplied to the electric motor at the time of starting (cranking) the engine.

(Problem to be solved by the invention) In the vane type intake air amount sensor mentioned above, since the vane has inertia, the opening degree of the vane changes for a short period of time due to overshoot of the vane in the direction of closing the vane during deceleration. In many cases, the fuel pressure decreases below a predetermined value, and in that case, there is a problem in that the switch connected to the vane opens, the relay switch opens, and the fuel pump stops.

On the other hand, in the fuel injection device described in the above publication, the engine speed detected by the engine speed sensor is the minimum settable speed (for example,
A switch device is installed that opens when the engine speed drops below 30 rpm, but the low-speed resolution of mass-produced engine speed sensors used in actual vehicles is extremely low, so it is only possible to precisely detect engine speeds of at least 200 rpm or higher. Therefore, the fuel injection device described in the above-mentioned publication has a problem in that it is difficult to reliably control the stoppage of the fuel pump.

(Means for Solving the Problems) An engine control device according to the present invention is an engine having an electric fuel pump that pumps fuel to a fuel injection nozzle of the engine. A first determining means is provided for determining whether the engine speed has fallen below a predetermined value, and a second determining means is provided for detecting that the engine speed has fallen below a predetermined value. and stop means for stopping the operation of the pump when the opening degree of the pump is below a predetermined value and the engine speed is below a predetermined value.

(Function) In the engine control device according to the present invention,
Due to the actions of the first and second determining means and the stopping means,
The fuel pump is stopped only when the opening degree of the intake air amount sensor becomes less than a predetermined value and the engine speed becomes less than a predetermined value.

Note that the predetermined value of the engine rotation speed is set to a predetermined rotation speed (for example, 300 rpm) that can be reliably detected by the engine rotation speed sensor.

Therefore, even if the vane of the intake air amount sensor overshoots in the closing direction during deceleration, the fuel pump continues to operate as long as the engine speed is higher than a predetermined value.

When the engine starts, the throttle valve opens and intake air flows, and the vane of the intake air amount sensor does not overshoot in the closing direction, so the opening degree of the intake air amount sensor becomes larger than a predetermined value and the fuel pump will definitely work.

(Effects of the invention) According to the engine control device according to the invention, as explained above, due to the very simple configuration consisting of the first discrimination means, the second discrimination means, and the stop means,
It is possible to eliminate the drawbacks caused by malfunctions of the intake air amount sensor vane due to overshoot, and to perform fuel pump stop control with high precision.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

This embodiment is an example in which the present invention is applied to a 4-stroke, 4-cylinder, vertical fuel injection engine for automobiles.

As shown in FIG. 1, a combustion chamber 4 is formed by a cylinder block 1, a cylinder head 2, and a piston 3, and an intake valve 6 opens and closes the downstream end of an intake port 5.
and an exhaust valve 8 that opens and closes the downstream end of the exhaust port 7, an air cleaner 10 is provided at the upstream end of an intake passage 9 connected to the intake port 5, and a measuring plate is provided in the intake passage 9 in order from the upstream side. type intake air amount sensor 11 and turbo charger 1
A compressor 12b, an intercooler 13, a throttle valve 14, and a surge tank 15 are installed at the lower end of each branched intake pipe of the intake manifold portion of the intake pipe forming the intake passage 9. Injector 16 that injects fuel
is installed.

On the other hand, a turbine 12a of the turbocharger 12 is interposed in the middle of the exhaust passage 17.

Furthermore, various sensors other than the intake air amount sensor 11 include a water temperature sensor 18 that detects the temperature of cooling water in the water jacket of the cylinder block 1.
is attached to cylinder block 1, and crankshaft 1
For example, an electromagnetic pickup-type rotation speed detection sensor 20 that outputs a rotation speed signal (crank angle signal) every time the crankshaft 9 rotates 180 degrees is provided in conjunction with the crankshaft 19, and the intake passage 9 near the air cleaner 10
A first intake temperature sensor 21 is installed in the surge tank 15 to detect the intake air temperature, and a second intake air temperature sensor 21 is installed in the surge tank 15 to detect the intake air temperature after supercharging and after being cooled by the intercooler 13.
An intake temperature sensor 22 is interposed, and the throttle valve 14
For example, a potentiometer-type throttle opening sensor 23 for detecting the opening of the throttle valve 14 is provided in conjunction with the valve shaft of the throttle valve 14.

Further, the throttle valve 14 is provided with an idle switch (not shown) which is turned on until the throttle valve 14 opens by a set amount when the accelerator pedal is slightly depressed, and turned off when the throttle valve 14 is opened by more than the set amount.

And each of the above-mentioned sensors 11, 18, 20 to 23
Distributor 2 receives the detection signal from etc.
4, an injector 16, and a control unit 26 for controlling a warning lamp 25.
The control unit 26 also receives signals from an inhibitor switch 27, a gear switch 28 mounted on the transmission for detecting the gear connection state, and a voltage signal from the battery.

Here, the engine control device according to the present invention includes:
This system is characterized by stop control of the fuel pump that pumps fuel to the injector 16, and will be explained in detail with reference to FIG.

Electric motor 31 that drives the fuel pump 30
A relay switch 34 is interposed in a drive circuit 33 that supplies power to the motor 31 from a power source 32, and a relay coil 34 of the relay switch 34
As shown in the figure, a first switch 35 and a second switch 36 are connected in parallel.

The first switch 35 is provided in conjunction with the vane 11a of the vane-type intake air amount sensor 11, and when the amount of intake air to the engine becomes almost zero, the opening degree of the vane 11a becomes extremely large. When the opening degree of the vane 11a is less than a small predetermined value, the first switch 35 is opened, and when the opening degree of the vane 11a is larger than the predetermined value, the first switch 35 is closed.

The second switch 36 is made of an NPN transistor, and even when the ignition switch 37 is closed, the second switch 36 is activated when the engine speed is below a very small predetermined value (for example, 300 rpm).
The comparator 38 and the switch 36 are opened.
An AND gate 39 is provided as shown in the figure, a rotational speed voltage signal corresponding to the engine rotational speed is input to the + input terminal of the comparator 38, and the above-mentioned predetermined value (for example, 300rpm)
The output terminal of the comparator 38 is connected to one input terminal of an AND gate 39, and the other input terminal of the AND gate 39 receives the reference voltage ( +Vc) line, and the output terminal of the AND gate 39 is connected to the base of the transistor 36.

Note that the rotation speed voltage signal is a rotation speed signal from the rotation speed detection sensor 20, which is input to the control unit 2.
This is obtained by performing D/A conversion at the output interface of No. 6.

In the above configuration, when starting the engine, the ignition switch 37 is closed, and when the engine speed during cranking is less than 300 rpm, the rotation speed voltage signal is a lower voltage than the reference voltage, so the output of the comparator 38 is AND gate 3 with “L”
The output of transistor 9 becomes "L", and transistor 36 is not conductive and is OFF.

However, when cranking, the throttle valve 14
is slightly opened and intake air is taken in, so the vane 11a of the intake air amount sensor 11 is opened to a greater extent than the predetermined value, the first switch 35 is closed, current flows through the relay coil 34a, and the relay contact 34b is closed. When it is closed, power is supplied to the motor 31 and the fuel pump 30 is operated.

When the engine is operating at a rotation speed higher than 300 rpm, the output of the comparator 38 is "H" and the ignition switch 37 is closed.
Since the output of the AND gate 39 becomes "H", the transistor 36 becomes conductive and the second switch 36 remains closed.

Therefore, when the car decelerates, the intake air amount sensor 1
Even if the first vane 11a overshoots in the closing direction and the first switch 35 opens, the second switch 36 closes, so the fuel pump 30 does not stop.

When the engine is stopped, both the first switch 35 and the second switch 36 are opened, and the fuel pump 30 is stopped.

Note that since the operation of the engine control device is based on the premise that the ignition switch 37 is closed, the AND gate 39 is omitted and the comparator 38 is used.
The output line of the transistor 36 may be directly connected to the base of the transistor 36. Further, the second switch 36 does not necessarily need to be composed of a transistor, but may be composed of a relay switch or the like.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall configuration diagram of an engine control device, and FIG. 2 is an electrical circuit diagram for a fuel pump. 16... Injector, 20... Rotation speed detection sensor, 26... Control unit, 30...
Fuel pump, 31... Electric motor, 33... Drive circuit, 34... Relay switch, 34a... Relay coil, 34b... Relay contact, 35... First
Switch, 36...Second switch, 38...Comparator, 39...AND gate.

Claims (1)

[Claim for Utility Model Registration] In an engine equipped with an electric fuel pump that pumps fuel to the fuel injection nozzle of the engine, a first determination is made to determine whether the opening degree of the vane-type intake air amount sensor has fallen below a predetermined value. means, a second determining means for detecting that the engine speed has become below a predetermined value, and a second determining means for detecting that the opening degree of the intake air amount sensor is below the predetermined value and the engine speed is at the predetermined value. 1. A control device for an engine, comprising: a stop means for stopping the operation of the pump when the temperature is below a certain value.