JPS58204941A - Fuel injection controller of diesel engine - Google Patents

Abstract

PURPOSE:To improve operative efficiency of an engine, by providing a sensor detecting the atmospheric pressure and performing optimum combustion also in case of running operation on the highland. CONSTITUTION:Speed of an engine is detected by a speed sensor 2. A rack position of a fuel injection pump 3 is detected by a rack position sensor 4. A rotary phase angle of the pump 3 is detected by a phase angle sensor 5. Temperature of the outside air is detected by an air temperature sensor 6 and the atmospheric pressure is detected by an air pressure sensor 7. These detection signals are fed out to a CPU22 through an input interface 21. Said signals especially a fuel injection amount in accordance with temperature and pressure of the outside air are stored in memory unit 23. In this way, also in case of running operation on the highland with the lean atmosphere, a fuel injection amount is automatically controlled in accordance with a reduced amount of oxygen in intake air, and combustion of the engine can be optimized similarly to the case of running operation on the flatland.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a device for varying the maximum amount of fuel injection of a diesel engine of a vehicle according to conditions.

[Description of prior art]

When diesel engine vehicles drive at high altitudes, the atmosphere becomes thinner, so with conventional fuel injection control devices, the amount of fuel injected is relatively excessive compared to the oxygen in the engine's intake air, causing deterioration of combustion. It was happening.

[Purpose of the invention]

The present invention solves the above problems, and provides a fuel injection control device for a diesel engine that can automatically control the optimum fuel injection amount according to the outside pressure even when the atmosphere becomes thin. With the goal.

[Summary of the invention]

The present invention is characterized in that it is equipped with an atmospheric pressure sensor that detects external atmospheric pressure as an electrical signal, and that the detection signal of this atmospheric pressure sensor is taken in as input information to the control circuit means that controls the maximum load of the fuel injection pump.

[Explanation based on examples]

An explanation will be given below based on the drawings of the embodiment.

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

In FIG. 1, a diesel engine 1 includes a rotation sensor 2 that detects the rotation speed of the engine, and a fuel injection pump 3.
The fuel injection pump 3 includes a rack position sensor 4 that detects the rack position of the fuel injection pump 3, and a phase angle sensor 5 that detects the rotational phase angle of the fuel injection pump 3. Further, a vehicle equipped with this diesel engine 1 is equipped with an air temperature sensor 6 that detects outside air temperature, and an air pressure sensor 7 that detects outside air pressure.

FIG. 2 is a configuration diagram showing an example of this atmospheric pressure sensor 7. As shown in FIG.

10 is a vacuum confinement chamber, and 11 is an external pressure measurement chamber. A diaphragm 12 is stretched between the two chambers 10S11. This vacuum sealed chamber 10 is sealed to a high vacuum by a diaphragm 12, and this diaphragm 12 is held by an adjustment spring 13 so that a reference displacement is achieved when the pressure to be measured is 1 atm.

Inside the external pressure measurement chamber 11, an iron core 16 is provided on a rod 15 that is vertically disposed on the diaphragm 12.

This iron core 16 constitutes a differential transformer 18 together with a coil 17 wound around the outer periphery of the external pressure measuring chamber 11 . This differential transformer IB is designed so that the output potential becomes zero when the outside pressure is 1 atm.

□ Returning to FIG. 1, the detection outputs from each of the sensors 2.4 to 7 are taken out as electrical signals and guided to the input interface 21 of the microcomputer 20. This input interface 21 converts these electrical signals into a predetermined information signal level and sends it to the CPU 22. C
A storage device 23 is connected to the PU 22 . This storage device 23 stores fuel injection conditions for obtaining optimal startability and engine output characteristics from the starting conditions and running conditions given to the diesel engine 1. In particular, the optimal maximum amount of fuel injection according to outside temperature and outside pressure is stored.

The CPU 22 processes the outputs from each of the sensors 2.4 to 7 as input information, and outputs the output from the output interface 24.
via the hydraulic control valve 26 and the stopper control device 27
gives control output to. This hydraulic control valve 26 changes the hydraulic pressure to a fuel injection angle control device 29 inserted between a timing gear 28 and a rotating shaft of the fuel injection pump 3, thereby causing the rotation of the timing gear 28 and the rotation of the fuel injection pump 3. Phase 1″ with: Controls the difference.

Further, the stopper control bag fi27 includes a control circuit 31, an electromagnetic device 32, and a stopper 33, as shown in FIG. Reference numeral 34 denotes a control rack, which is movable left and right as shown by arrows in the figure, and when it moves to the left, the fuel injection amount increases, and when it moves to the right. A stopper 33 provided at the left end of the control rack 34 regulates the maximum amount of fuel injection, and is used to control the electromagnetic device 32.
It is configured so that it can move left and right while rotating.

In such a device, when the outside air pressure is normally 1 atm, a detection signal from the air pressure sensor 7 is given from the CPU 22 to the stopper control device 27, and the stopper 33 is placed at the regular position PO in FIG. 4. Next, when the vehicle travels at a high altitude and the outside pressure becomes less than 1 atmosphere, the stopper control device 27 moves the stopper 33 to a position to the right of the home position PO (FIG. 3). As a result, the maximum injection amount of the fuel injection pump 3 is suppressed, and even if the amount of oxygen in the intake air is reduced, there will be no oversupply of fuel.

Note that if the outside temperature changes significantly and the zero point of the barometric pressure sensor 7 fluctuates, the CP'U2
2 is a stopper control device 2 that compensates the output of the atmospheric pressure sensor 7.
It is desirable to give it to 7.

Further, as shown in FIG. 5, when the diesel engine 1 is started at a low temperature, the stopper control device 2 receives the output from the air temperature sensor 6.
7 to move the stopper 33 to the left (
3), the startability can be improved.

〔Effect of the invention〕

As described above, according to the present invention, by incorporating the detection output of the barometric pressure sensor into the control input of the conventionally provided fuel injection control device, even when driving at high altitudes where the atmosphere is thin, the intake air can be reduced. The fuel injection amount is automatically controlled according to the reduced amount of oxygen, which has the excellent effect of optimizing engine combustion in the same way as when driving on flat ground.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram showing an example of the atmospheric pressure sensor. FIG. 3 is a configuration diagram of the stopper control device. FIGS. 4 and 5 are control characteristic diagrams. 1--Diesel engine, 2-Revolution sensor, 3-Fuel injection pump, 4-Rack position sensor, 5-Phase angle sensor, 6-Air temperature sensor, 7-Atmospheric pressure sensor, 20-=Microcomputer, 27-Stopper Control device, 33-stopper, 34-control rack. Patent applicant Naotaka Ide, agent of Hino Motors Co., Ltd., patent attorney. Go 1 Figure 1 Figure 2

Claims (1)

[Scope of Claims] (11) Information including the rotational speed of the engine, the load of the fuel injection pump, the rotational phase angle of the fuel injection pump, and the outside air temperature is used as input information to determine the fuel injection timing of the engine and the maximum speed of the fuel injection pump. A fuel injection control device for a diesel engine equipped with a control circuit means for automatically controlling a load, comprising an air pressure sensor that detects outside air pressure as an electrical signal, and the control circuit means using the detection signal of the air pressure sensor as the input information. A fuel injection control device for a diesel engine, characterized in that it is incorporated into a diesel engine.