JPS5851234A - Fuel injection system for internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable to continue the operation of the engine in spite of the trouble of one of a plurality of detecting means by a method wherein a plurality of detecting means for detecting the crank angle of the engine are equipped and an injector is controlled by selecting a right information among those of said means by a control unit. CONSTITUTION:When a control signal, formed by the control unit 4 inputting the output signals of various kinds of sensors, is outputted to solenoid valves 11-13, the spool valve 5 of the injector 1 is operated by the solenoid valves 11, 12 and a hydraulic pressure impressed on a piston 9 driving a plunger 8 is controlled. The plunger 8 increases the hydraulic pressure supplied from a pressure source 2 to supply to and inject from a nozzle 10 while the injecting amount is controlled by the valve opening time of the solenoid valve 13. In the above-described system, a plurality of rotating angle sensors are provided in the above-described sensors and the control unit 4 is constituted so that the right and normal information from among the informations of said sensors is selected to generate the control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device for an internal combustion engine, and more particularly to an electronically controlled injection device having a control device with a safety mechanism in case a rotation angle sensor fails.

Various electronically controlled fuel injection devices have been proposed in the past. The most important sensor in injection control is the engine rotation angle sensor.

Most commonly, a so-called electromagnetic pickup is often used. Detection of the engine rotation angle is fundamental to control), and control is impossible without this. However, the table shows that in the previous models, only one was provided, and the electromagnetic pickup coil was disconnected, the wire harness connecting the electromagnetic pickup and the electrical control circuit that determined the injection amount was disconnected, and the connector came into contact. Failures such as defects were not sufficiently considered, and only attention was paid to improving reliability up to the manufacturing stage. Even particularly high-grade equipment only stopped the engine in the event of a failure. If there is no control logic in the event of a failure, the engine will become uncontrollable due to some kind of failure, and the engine will go into an uncontrolled state, and if conditions are bad, it will fall into a dangerous situation such as overrun. There are also high-class devices that have built-in logic to stop the engine, but I'm not sure about this.

Although primary dangers such as overruns can be avoided, for example, if a breakdown occurs on a highway, a winter mountain road, a faraway field, a hydraulic power source during work, etc. A secondary danger of self-travelling and inability to secure pressure arises, which could also lead to problems that could be life-threatening. This measure was not considered at all.

In the present invention, when the rotation angle sensor malfunctions and accurate rotation angle information cannot be obtained, the control device detects this and switches to the second rotation angle sensor, and then uses another rotation angle detection means. The purpose is to enable continuation of operation by obtaining rotation angle information. Here, if the second rotation angle sensor is the same, operation can be continued at exactly the same level, and failure detection itself can be accurately grasped by comparing the two. However, this has the disadvantage of increasing costs. If cost is important, you can use a secondary rotation angle sensor that operates in synchronization with the engine, such as an alternator, or use another control system, such as a simple rotation speed sensor for display. In particular, the system is designed to allow continued operation only at a level that compromises performance.

FIG. 1 shows an example of an electronically controlled hydraulically driven diesel injection system that can be used in the present invention.

In Fig. 1, 1 is an injector, 2 is a high pressure source, and 3
indicates a low-pressure pressure source, and 4 comprehensively indicates a control device. The injector 1 includes a spool valve 5, a plunger 8, a piston 9, a nozzle 10, and a first. Second. Sixth solenoid valve 11.12.13
The pressure sources 2 and 3, including the throttle valve 22 and check valve 24, constitute a normal constant hydraulic pressure source consisting of a pump 201, 301, relief valves 202, 302, filters 203, 303, and pressure accumulators 204, 304. . Further, the control device 4 is connected to various sensors (not shown), and is connected to the three solenoid valves 11.1.
2.13 is connected.

FIG. 2 shows an example of the configuration of a six-cylinder engine according to the present invention. The engine 100 includes a spool valve 5 and a plunger 8 shown in FIG.
, six injectors 1 including pistons 9, nozzles 10, solenoid valves 11, 12, 13, etc., and an engine 100.
is equipped with sensors for crank angle, water temperature, etc., and is connected to the control device 4. On the other hand, the hydraulic power source 2 shown in FIG.
The pressure piping from 3 is connected to each injector 1, and the installed pressure sensor is connected to the control device 4. The control device 4 is composed mainly of a microcomputer (including a solenoid valve drive circuit, etc.), detects the state of the engine using various sensors, and performs control according to a program 2.

The operation of the system according to the present invention described above will be described. Control signals are output from the control device 4 to the electromagnetic valves 11, 12, and 13 in accordance with information from various sensors. Solenoid valve 11.1
2 actuates the spool valve 5, thereby controlling the hydraulic pressure applied to the piston 9 that drives the plunger 8. The plungers 8 and 9 increase the pressure of the hydraulic pressure supplied from the pressure source 2, and supply it to the nozzle 10 for injection. The injection amount is controlled by opening and closing the electromagnetic valve 13 in accordance with an electric signal calculated and output by the control device, introducing fuel for injection in the state shown in FIG. 1, and controlling this time. At this time, a diaphragm 22 is provided to reduce the rate of change in the injection amount with respect to time.

The injection timing is controlled by operating the electromagnetic valve 11 in accordance with an electric signal calculated and output by the control device, and by moving the spool valve 5, the timing at which the hydraulic pressure from the pressure source 2 is applied to the piston 9 is changed. Strictly speaking, injection begins with a certain mechanical delay. Therefore, it can be controlled by the electrical signal.

As is clear from the above description, all injection operations such as injection amount and injection timing are controlled by electrical signals based on calculations of the control device, and crank position information is essential for operating each electromagnetic valve. Since the injector 1 shown here as an example is already common and its operation is well known, further detailed explanation will be omitted.

Next, the calculation and control method performed by the control device will be explained with reference to FIG. The control device reads information from each sensor at an optimal cycle to constantly monitor the engine's status. It is determined whether this information is normal based on the most important information from the rotation angle sensor. For example, in the case of an electromagnetic pickup, it is known to check the output amplitude range, check the level against the permissible frequency range, and check whether there is an unavoidable change by comparing with the previous value. If it is determined that the engine 1 is normal, the engine speed is calculated from the rotation angle information, and then the optimum injection amount is calculated by adding corrections based on the engine speed, the accelerator position, and various pressures and temperatures. Further, the optimum injection timing is calculated in the same manner. Based on this information, the operation timing of the solenoid valves 11, 12, and 13 of the injector 1 is calculated. Then, an operating signal is output for the solenoid valve that matches the operating timing with respect to the rotational position of the engine determined from the rotation angle information and the top mark sensor. The operation is continued by repeating this loop until each senna is read again. By the way, when the previous rotation angle sensor is determined to be abnormal, the control goes into failure mode.The rotation angle information is switched, specifically, which sensor's output is used as the rotation angle information, and the output is used for various calculations. Rewrite the flag that controls the change of the parameter calculation formula for the rotation angle. As a result, normal rotation angle information can be used thereafter, and calculations can be performed accordingly. The calculation output is performed sequentially in the same steps as during normal operation, the loop is completed, and operation continues. At this time, although not shown, it is desirable to turn on an indicator lamp to notify the operator of an abnormality in the one-rotation angle sensor.

What should be noted here is that as mentioned above, the second rotation angle sensor uses engine supplementary power (alternator, etc.), so the quality of the information is generally lower, so the operating conditions are narrower than under normal conditions. If the range becomes too low, the performance will deteriorate.

If a sensor with the same performance level is used as the second rotation angle sensor, the same operation as in the normal state can be continued by controlling as in the above-described embodiment. Furthermore, in this case, by comparing and calculating the information on both, it is also possible to carry out normal operation and, when an abnormality is detected, to operate with only the remaining normal one as in the normal operation of the above-described embodiment. In this case, a more precise abnormality diagnosis can be made. It is clear that a more reliable safety function can be provided by further expanding this and equipping a plurality of sensors of the same type, diverted sensors, or substitute sensors as rotation angle information sources.

Furthermore, in this case, it can be made even safer and more reliable by incorporating majority logic as an extension of the other embodiments.

Also, from another point of view, it is of course possible to create a program using interrupts by using the control flow shown in Figure 3 in the same way as a general method, and furthermore, it is possible to create a program using interrupts using analog circuits without using a digital computer. Of course, it is also possible to combine them, and it goes without saying that a combination thereof is also possible.

In the embodiment, the switching process was performed by selecting information inside the converter, but this may be done by hardware using the input circuit, or it may also be done manually by the driver. In this case, the engine may be stopped once. There is a need.

Injector type and hydraulic source configuration shown as examples,
It is clear that the present invention can be applied to systems in which the number, hydraulic oil sensors, number, type, sensing items, etc. are changed.

The effects of the present invention include: 1. A fuel injection device comprising: 1. various sensors such as a rotation angle sensor and an accelerator position sensor; 2. a control device connected to each sensor; and 3. an injector controlled by the control device. By equipping a plurality of rotation angle sensors as rotation angle information sources and incorporating logic for switching in the event of a failure, rotation angle information can be obtained and operation can be continued even in the event of a failure.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the fuel injection device;
The figure shows a configuration example when the fuel injection device is used in a six-cylinder engine, and FIG. 6 is a flowchart showing an example of the control flow of the control device. Explanation of symbols 1...Injector 2.3...Pressure source 4.
...Control device 5...Spool valve 8...
Plunger 9...Stone 10...Nozzle

Claims (1)

[Claims] Various sensors that detect the operating status of the engine, a control device that is connected to the sensor and operates based on the information, and an electronically controlled injector that is controlled by the control device in synchronization with the shift flank angle. What is claimed is: 1. A fuel injection device comprising a plurality of means for detecting the crank angle of an engine, the control device selecting normal information from the means for control.