JPS6123847A - Fuel controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To keep off any reverse rotation of an engine so easily and smoothly, by installing a hydraulic detecting device, which generates an oil pressure drop detecting signal for a hydraulic pump of an electric governor, and a controller setting a desired injection quantity to zero at a specified occasion. CONSTITUTION:A hydraulic pump 14 is driven by a Diesel engine 13, and it produces oil pressure corresponding to a direction of rotation in this engine. A hydraulic switch 3 generates an oil pressure drop detection signal when oil pressure in the hydraulic pump 14 becomes below the specified value. A controller 4 calculates a desired injection quantity of the engine according to a detection signal out of a driving state detector 2, while it sets the desired injection quantity to zero when the oil pressure is below the specified value. Thus, the engine is stopped and its reverse rotation is preventable so easily and accurately without installing any exclusive valve or the like for fuel interception.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel control device for an internal combustion engine having a reverse rotation prevention function for a diesel engine.

[Conventional technology]

Conventionally, when a diesel engine is cranked in the opposite direction, the engine often reverses, causing problems such as damage to the engine. To prevent this, as shown in Japanese Patent Publication No. 5-22619, an oil pressure switch detects a drop in oil pressure, determines whether the engine is rotating in reverse, and drives a fuel cutoff actuator to stop the engine. A device has been proposed to do this.

[Purpose of the invention]

The present invention further improves the conventional device described above, and organically combines an engine reversal prevention function with an electronically controlled fuel injection device called an electric governor. By determining that the rotation is in the reverse direction when the engine's rotation is reduced to The purpose is to be able to reliably stop the engine and prevent reverse rotation.

〔Example〕

Hereinafter, the present invention will be explained with reference to an embodiment shown in the drawings. 1st
The figure shows its overall configuration. 14 is a diesel engine 13
A hydraulic pump such as an oil pump for transporting lubricating oil that is driven by - and generates hydraulic pressure corresponding to the forward rotation direction of this engine; 2 is an oil pressure switch that generates a drop detection signal, and 2 is various operating state detectors that detect the operating state of the diesel engine as electrical signals (e.g., rotation speed sensor, accelerator operation amount sensor, intake pressure sensor, intake temperature sensor, cooling water temperature sensor). sensors, etc.).

10 is an actuator such as a near solenoid for operating the control rack of the fuel injection pump 12, and 11 is a real position detector such as a differential transformer type for detecting the position of the control rank of the injection pump.

Further, reference numeral 4 receives signals from a stark signal detector 1 that determines whether or not the engine is starting, an operating state detector 2, and an oil pressure switch 3, and an internal microcomputer unit 6 determines a target injection amount to the engine. This is a controller that determines the target position of the control rank and controls the current flowing to the actuator 10. It shapes the signal from the operating state detector and converts it into an A/D converter.
A waveform shaping and A/D conversion circuit 5 converts the target position signal of the control rack from the microcomputer section 6, a D/A conversion circuit 7 converts the control rack target position signal from the microcomputer section 6 to D/A, and compares this target position with the detected actual position. , a servo amplifier 8 that outputs a signal according to the deviation between the two, and a drive circuit 9 that drives the actuator 10 using this signal.

Next, the operation of the device having the above configuration will be explained in Figures 2 to 6.
This will be explained using figures. FIG. 2 is a flowchart showing a series of processes performed by the microcomputer.

First, in step 100, the starter signal is ON or OFF.
Determine whether it is FF and check whether it is "at startup". If it is determined that it is "at the time of starting", a target injection amount is calculated in step 102. If it is determined that "other than when starting", the process proceeds to step 101. In step 101, it is determined whether the oil pressure generated by the hydraulic pump is equal to or higher than a predetermined value. This means whether the oil pressure switch is “ON” or “OFF”.
For example, as shown in Figure 3,
When the oil pressure exceeds a predetermined value and the oil pressure switch 3 turns "ON," an Ov level signal is sent to the CPU 6b in the microcomputer section 6 via the buffer 6a, and when the oil pressure becomes less than a predetermined value, the oil pressure switch turns "OFF." Then the CPU will get 10v
8 levels are input, and the 0N10FF of the oil pressure switch is determined by this level determination.

That is, in this step, it is determined whether the diesel engine is rotating in the forward direction. If the determination result is "forward rotation", the process advances to step 102; if the determination result is "reverse rotation", the process advances to step 103, where the target injection amount is set to "zero", which is a feature of the present invention.
and set.

When the engine is rotating in the forward direction or at the time of starting, the target injection amount is calculated in accordance with the operating state in step 102 as described above. That is, as shown in Fig. 4, the basic injection amount is determined by searching for a governor pattern determined by the rotation speed and accelerator amount.
Furthermore, as shown in Figure 5, the basic maximum injection amount is determined by searching for the basic maximum injection amount pattern determined by the rotation speed, and this is corrected for intake pressure and intake temperature to determine the final maximum injection amount. The target injection amount is obtained by selecting the minimum value between the basic injection amount and the basic injection amount.

Next, in step 104, an analog servo command voltage indicating the target position of the control rank is determined from the target injection amount and rotation speed obtained as above.

This can be obtained by searching for a command injection amount analog signal pattern determined by the rotational speed and target injection amount as shown in FIG.

Finally, in step 105, the analog servo command voltage is output to the D/A converter.

Incidentally, forward rotation or reverse rotation may be indicated by a lamp 3a as shown in FIG. 3 or the like.

〔Effect of the invention〕

As described above, according to the present invention, the oil pressure generated by the hydraulic pump in the electric governor system of a diesel engine is monitored via the oil pressure switch, and when the oil pressure is below a predetermined value (
In the case of reverse rotation), by commanding the target injection amount to "zero", reverse rotation of the engine can be easily and smoothly prevented without a dedicated valve for fuel cutoff.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a flowchart showing the processing procedure in the microcomputer section of FIG. 1, and FIG. 3 is a detailed configuration diagram of the oil pressure switch in FIG. 1. 4 to 6 are characteristic diagrams for explaining the injection amount control characteristics of the present invention. ■... Starter signal detector, 2... Operating status detector, 3... Oil pressure switch, 4... Controller, 6... Microcomputer section, 12... Injection pump, 13...
...Diesel engine, 14...Hydraulic pump.

Claims (1)

[Claims] A hydraulic pump that is driven by a diesel engine and generates hydraulic pressure corresponding to the rotational direction of the engine; an oil pressure detection means that generates an oil pressure drop detection signal when the oil pressure generated by the hydraulic pump becomes less than a predetermined value; Operating state detection means for detecting the operating state as an electrical signal; starting operation detection means for detecting whether the engine is in a starting operating state; and calculating a target injection amount of the engine in accordance with the operating state detection signal. A fuel control device for an internal combustion engine, further comprising a controller that sets the target injection amount to zero when the engine is not in the starting operation state and the oil pressure is below a predetermined value.