JPS603460A - Electronically controlled fuel injection device - Google Patents

Abstract

PURPOSE:To prevent a catalyzer from overheating or getting an accidental fire, by installing a device to detect a continuous injection state of each fuel injection valve and another device to control a fuel injection system coming into a state of continuous injection or movement of the whole system. CONSTITUTION:A central processing unit 1 generates an injection control pulse, while each of injection valve driving circuits 21-2n feeds an injection valve with a driving signal. When anything trouble happens in the injection valve driving circuit 21 and thereby an electric current continues to flow in from a coil 31, the output of a contibuous rating detection circuit 51 keeps the state of a signal 1. The CPU 1 detecting this signal state releases a switch 41. As a result, the troubled injection driving circuit 21 is separated from a first injection system, and a first injection valve is thus stopped. With this constitution, overheating or an accidental fire in a catalyzer is effectively preventable from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an electronically controlled A11 fuel injection system.

Prior Art and Problems An electronically controlled fuel injection system of an independent injection type has been used in which fuel injection is performed for each cylinder (one valve is injected) and each fuel injection valve is independently controlled to fall.

In this independent injection system, unlike the simultaneous injection system in which each fuel injector is operated simultaneously, if the injection valves in that system enter a continuous injection state due to a failure in a part of the injection valve management circuit, the engine function will be disabled. However, the driver can continue driving without noticing this.

However, under such conditions, there is a risk that gasoline or very concentrated raw gas will flow into the exhaust pipe in an unburned state, overheating the catalyst and even causing a fire. Of course, it is possible to detect the occurrence of these field lightning situations using temperature sensors, oxygen concentration sensors, etc., and notify the driver of this, but detection errors may occur due to sensor malfunctions, or incorrect detection may occur. 1 Even if the driver is notified, the driver may overlook the
Alternatively, even if the driver recognizes the situation correctly, an inexperienced driver may not be able to take appropriate measures.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide an electronically controlled fuel injection device that can effectively prevent catalyst overheating and fire.

Structure of the Invention The present invention achieves the above object by providing a means for detecting whether each fuel injection valve is in a continuous injection state, and an operation of the fuel injection system or the entire system when the continuous injection state is achieved in response to the detection result. The device is configured to include means for suppressing

The details of the present invention will be explained below with reference to two examples.

Examples of the invention The figure is a configuration block diagram of an embodiment of the present invention.

The case of an engine consisting of cylinders [n117I] is exemplified. 1 generates injection control pulses in response to engine conditions such as engine speed, crankshaft position signals, etc. Z:rC
PU, 21.22...2n is an injection valve drive circuit that receives an injection control pulse from the CPU and supplies a drive signal to the corresponding injection valve, 31.32...3n is an electromagnetic valve coil for driving each injection valve; 41. ．． 41...4n is a switch, 51.
52...5 n is an energization detection circuit consisting of a comparison circuit, 6
is a display circuit.

Since the above n systems are completely independently controlled by CP IJ 1, only the operation of the first system at the top will be explained.

; When the injection valve drive circuit 21 is performing the compression operation, the switch 41 is closed and the injection valve is operated.
Periodically sucks current from 1. As this current is absorbed, the voltage at the left end of the coil 31 decreases, and the quasi-voltage Vr
When the voltage falls below ef, the 1 energization detection circuit 51 outputs a "1" signal to CI) U1.

When the voltage at the left end of the coil 31 increases to the reference voltage V ref again due to the stop of the energization drive, the 2 energization detection circuit 5
1 outputs a ``0'' signal to the CPUI.

The CPU inspects the output of the energization detection port 11'351 after a predetermined period of time has elapsed from the end of the injection control pulse, and confirms that "
0'', it is determined that the injection valve drive amount iI'821 is normal, and the switch 41 is kept closed.

If a failure occurs in the injection valve drive circuit 21 and current continues to be sucked from the coil 31, the output of the energization detection circuit 51 will be "1" even after a predetermined period of time has elapsed from the end of the injection control pulse.
``holds the state. If the CPU detects this, the control signal connected to the switch 41'' is sent to the switch 41 by the control signal.
Leave 1 by 1°. As a result, the failed injection valve drive circuit 21 is disconnected from the injection system of f(', 1, and the operation of the first injection valve stops. This stoppage of operation of the first injection valve is indicated on the display circuit 6. be done.

The operation is exactly the same for the second to nth systems.

An example of stopping the operation of the injection valve has been described above.

The energization detection circuit 5 indicates that the continuous injection state has occurred due to the failure R.
1 may be detected and the operation of the fuel pump in this system may be stopped.

In addition, the energization detection circuit 51 may detect that a continuous injection state occurs due to a failure, and in this case, if the number of revolutions exceeds a predetermined number, the fuel supply may be stopped. Yes, because it can only run at low speeds, it prevents the catalyst and engine from overheating.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a means for detecting that each fuel injector is in a continuous injection state, and a means for detecting that each fuel injector is in a continuous injection state, and a means for continuously cutting the fuel injector according to the detection result. ', 2: i'
Since the structure is equipped with lv (means for suppressing the operation of the injection system or the entire system), it has the advantage of being able to automatically and automatically prevent overflow of the medium and fire.

[Brief explanation of the drawing]

The figure is a block diagram of an embodiment of the present invention. 1 is the CPU, 2L 22-2n is the injection valve drive circuit, 3i
, 32...3n is a coil of a solenoid valve for driving an injection valve, 41
．． 42...4n is a switch. 5], 52, . Patent applicant Fujitsu Ten Co., Ltd.

Claims (1)

[Scope of Claims] An electronically controlled fuel injection device of an independent injection type that includes a fuel injection valve for each cylinder and controls each fuel injection valve independently. An electronic device characterized by comprising means for detecting that each fuel injection valve has entered a continuous injection state, and means for suppressing the operation of the fuel injection system or the entire system that has entered the continuous injection state according to the detection result. Control fuel injector.