JPH05321735A - Self-diagnosis device for engine power supply voltage abnormality - Google Patents

Abstract

(57) [Abstract] [Purpose] In a vehicle that uses an electronically controlled fuel injection two-cycle engine, diagnoses the occurrence of power supply voltage abnormality in order to prevent engine seizure due to power supply voltage abnormality. [Configuration] An upper limit power supply voltage V _{1 at} which a minimum engine speed N _{C at} which an engine burns due to a decrease in power supply voltage exists,
The lower limit power supply voltage V ₂ that can correct the decrease in injection amount due to the decrease in power supply voltage is specified. The output V of the voltage detecting means and the output N of the engine speed detecting means are N> N _C , and
If V <V ₁ , it is diagnosed as a voltage abnormality at high rotation. If N <N _C and V <V ₂ , it is diagnosed that the voltage is abnormal during low rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-diagnosis device for an abnormal power supply voltage of an electronically controlled fuel injection two-cycle engine.

[0002]

2. Description of the Related Art Even in a vehicle equipped with an electronically controlled fuel injection engine, the power supply voltage is not constant. Therefore, in order to eliminate the change in the fuel injection amount with respect to the fluctuation of the power supply voltage, the injection amount is corrected with respect to the fluctuation of the power supply voltage. .. However, rather than a power supply voltage fluctuation, a power supply voltage drop state may occur. For example, if the generator of a vehicle equipped with an electronically controlled fuel injection two-cycle engine fails, the voltage applied to the system, especially the fuel pump, will drop. The discharge flow rate and power consumption of the fuel pump depend on the voltage, and the discharge flow rate decreases as the voltage decreases. Therefore, due to the decrease in applied voltage,
A sufficient amount of fuel does not flow in the fuel system, the fuel injection amount from the injection nozzle decreases, and the air-fuel ratio increases. When the air-fuel ratio increases and the air-fuel mixture becomes lean, the two-cycle engine may cause seizure in the high speed rotation range.

As a countermeasure against the applied voltage drop, there is, for example, US Pat. No. 4,643,153. This patent is to correct the fuel injection amount with respect to the applied voltage drop, and is effective in the range of voltage drop that can be corrected, but when the applied voltage drop that cannot be corrected occurs like a generator failure. Is not valid.

[0004]

The problem to be solved is that there is no effective countermeasure when the applied voltage drop that cannot be corrected occurs due to a generator failure.

[0005]

SUMMARY OF THE INVENTION A self-fault diagnosing device of the present invention for an abnormal power supply voltage of an electronically controlled injection engine includes a power supply voltage detection means, an engine speed detection means, a storage means for setting and storing an abnormality determination factor, and the storage. The means are a lower limit engine speed N _C of the engine speed corresponding to seizure of the engine due to a decrease in the power supply voltage, an upper limit power supply voltage V ₁ of the power supply voltage corresponding to seizure of the engine due to a decrease in the power supply voltage, and a power supply voltage. At least the lower limit power supply voltage V _{2 of the} power supply voltage corresponding to the correction of the decrease in the fuel injection amount due to the decrease in the engine speed N _A detected by the engine speed detecting means.
Of the power supply voltage detection means in response to the first determination means for determining the magnitude of the lower limit rotation speed N _C and the first determination means output N _A > N _C. The second power supply voltage V _A and the upper power supply voltage V ₁ are determined by the second determination means and the first determination means in response to the determination output of N _A <N _C. It is characterized in that a third judging means for judging the magnitude of the power supply voltage V _A detected by the voltage detecting means and the lower limit power supply voltage V ₂ is provided.

[0006]

FIG. 3 is an explanatory diagram of the operation of the self-diagnosis apparatus of the present invention. The reason why the abnormality in the voltage due to the large decrease in the power supply voltage is diagnosed is in the area where the engine speed and the power supply voltage are hatched. If it exists in. An upper limit power supply voltage V _{1 at} which there is a minimum engine speed N _{C at} which the engine burns due to a decrease in power supply voltage, and a lower limit power supply voltage V ₂ that can correct a decrease in fuel injection amount due to a decrease in power supply voltage are defined.
If the output V _A of the voltage detection means and the output N _A of the engine speed detection means are N _A > N _C and V _A <V ₁ ,
It is diagnosed that the voltage is abnormal at the time of high rotation, N _A <N _C , and V _A
If <V ₂ , it is diagnosed that the voltage is abnormal at low speed. Within the hatched area in Fig. 3, the abnormal voltage during high rotation is N _C
─ In the area on the right side of line A, the abnormal voltage during low rotation is N _C ─ A
It corresponds to the area to the left of the line.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a block diagram of a self-diagnosis apparatus of the present invention for abnormal power supply voltage of an electronically controlled injection engine. 1
Is a 2-cycle engine body, 2 is an intake pipe, 3 is an exhaust pipe,
4 is a fuel injection nozzle, 5 is an air cleaner, 6 is an atmospheric pressure sensor, 7 is a throttle valve, 8 is a throttle opening sensor provided in the throttle body, and 9 is an electronic control unit (EC).
U) and 10 are ignition units including a distributor and an ignition plug exposed in the cylinder head, and 11 is a battery. In the case of the present embodiment, the engine speed is set to 1 for ignition of the ignition coil included in the ignition unit 10.
The next signal is directly taken into the ECU 9 and calculated from the input interval of the ignition primary signal.

FIG. 1 is a flow chart showing a failure diagnosis routine of the self-diagnosis apparatus of the present invention for abnormal power supply voltage of an electronically controlled injection engine. Step S1 is a process for detecting flag ON. If the flag is not on, the process proceeds to step S2, and the power supply voltage V _A is detected by using the power supply voltage detecting means. Instead of the power supply voltage V _A , the applied voltage V of the fuel system is detected by using the applied voltage detection means of the fuel system.
_F may be detected. Next, in step S3, the engine speed detection means detects the engine speed N _A. In step S4, the comparison means for comparing the engine speed N _A detected in step S3 with the specific engine speed N _C compares the magnitudes of N _A and N _C. Step S4
If N _A > N _C , the process proceeds to step S5.
In step S5, the power supply voltage V _A detected in step S2, or the applied voltage V _F of the fuel system and the first voltage V ₁
By comparing means and, V _A, or comparing the magnitude of V _F and V _1. If V _A <V ₁ or V _F <V ₁ , it is determined that the voltage is abnormal during high rotation. Then, in step S6, the occurrence of an abnormality is notified to the driver by means of an abnormality occurrence warning means such as a warning lamp. This abnormality occurrence warning means is not cleared until the power is turned off. If N _A > N _{C is} not satisfied in step S4, the process proceeds to step S7. In step S7, the power supply voltage V detected in step S2
The magnitude of V _A or V _F and V ₂ is compared by a comparison means of _A or the applied voltage V _F of the fuel system and the second voltage V ₂ . If V _A <V ₂ or V _F <V ₂ , it is determined that the voltage is abnormal during low rotation, and the abnormality occurrence warning means notifies the driver of the occurrence of abnormality in step S8.

[0009]

As described above, the self-diagnosis device for the abnormal power supply voltage of the present invention is a serious trouble when the applied voltage of the fuel system is lowered due to a battery voltage drop, a generator failure, or the like. It is possible to notify the driver of the occurrence of the voltage abnormality before the occurrence of the error and at the stage where the power supply voltage can be corrected.

[Brief description of drawings]

FIG. 1 is a flowchart showing a failure diagnosis routine of a self-diagnosis apparatus of the present invention for abnormal power supply voltage of an electronically controlled injection engine.

FIG. 2 is a configuration diagram of a self-diagnosis apparatus of the present invention for a power supply voltage abnormality of an electronically controlled injection engine.

FIG. 3 is an operation explanatory view of the self-diagnosis device of the present invention with respect to a power supply voltage abnormality of the electronically controlled injection engine.

[Explanation of symbols]

 1 2 cycle engine body 2 intake pipe 3 exhaust pipe 4 fuel injection nozzle 5 air cleaner 6 atmospheric pressure sensor 7 throttle valve 8 throttle opening sensor 9 electronic control unit (ECU) 10 ignition unit 11 battery

Claims (1)

[Claims] 1. An electronically controlled fuel injection device is adopted.
In a self-diagnosis device for a power supply voltage abnormality of a cycle engine, a power supply voltage detection means, an engine speed detection means, a storage means for setting and storing an abnormality determination factor, the storage means responds to engine burn-in due to a decrease in power supply voltage. The lower limit engine speed N _C of the engine speed, the upper limit power supply voltage V ₁ of the power supply voltage corresponding to engine burn-in due to the decrease of the power supply voltage, and the power supply corresponding to the correction of the fuel injection amount decrease due to the decrease of the power supply voltage. _A first determination unit that stores at least a lower limit power supply voltage V _{2 of the} voltage and determines the magnitude of the engine speed N _A detected by the engine speed detection unit and the lower limit speed N _C ; In response to the determination output that the determination means is N _A > N _C , the magnitude of the power supply voltage V _A detected by the power supply voltage detection means and the upper limit power supply voltage V ₁ is determined. Second determination means, in response to the determination output of the first determination means that N _A <N _C , the power supply voltage V _A detected by the power supply voltage detection means and the lower limit power supply voltage V ₂ A self-diagnosis apparatus for a power supply voltage abnormality, comprising a third determining means for determining the magnitude of the.