JPH0338419B2 - - Google Patents

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, so-called electromagnetic pickups are often used. Detection of the engine rotation angle is fundamental to control, and control is impossible without it. However, in the previous models, only one was provided, and problems such as disconnection of the electromagnetic pickup coil, disconnection of the wire harness that connects the electromagnetic pickup and the electrical control circuit that determines the injection amount, and poor contact of the connector could occur. failures 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 case 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 the conditions are bad, it will end up in a dangerous situation such as overrun. In addition, some devices have built-in logic that stops the engine using high-class equipment, but although this can avoid primary dangers such as overruns, it is possible to prevent the failure from occurring on expressways, on winter mountain roads, or far away. If this occurs in a remote field or at a hydraulic power source during work, there will be a secondary danger of not being able to evacuate, drive on your own in a vast area, or secure pressure, which can also result in loss of life. This could become a related issue. No countermeasures were taken into consideration at all.

In the present invention, when the rotation angle sensor malfunctions and accurate rotation angle information cannot be obtained, the control device that detects this switches to the second rotation angle sensor and uses another rotation angle detection means to obtain rotation angle information. The purpose is to enable continuation of operation by obtaining the following conditions. Here, the second rotation angle sensor may be any sensor that can substantially detect the rotation angle of the engine, and an auxiliary device such as an alternator that operates in synchronization with the engine may be used.

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

In FIG. 1, 1 is an injector, 2 is a high pressure source, 3 is a low pressure source, and 4 is a control device. The injector 1 consists of a spool valve 5, a plunger 8, a piston 9, a nozzle 10, first, second, and third solenoid valves 11, 12, 13, a throttle 22, and a check valve 24, and the pressure sources 2 and 3 are pumps. 20
1,301, relief valves 202,302, filters 203,303, and pressure accumulators 204,304 constitute a normal constant hydraulic pressure source. The control device 4 is also connected to various sensors (not shown) and to the three electromagnetic valves 11, 12, and 13.

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

To describe the operation of the system according to the present invention described above, the control device 4
A control signal is output from the solenoid valves 11, 12, and 13. The spool valve 5 is actuated by the electromagnetic valves 11 and 12, 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 solenoid valve 13 in accordance with the electrical signal calculated and output by the control device, introducing the injection fuel in the state shown in Fig. 1, and controlling this time. . At this time, a throttle 22 is provided to reduce the rate of change in the injection amount with respect to time. In addition, the injection timing is controlled by the solenoid valve 1 according to the electrical signal calculated and output by the control device.
1 is activated, and by moving the spool valve 5, the timing at which 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 explanation, 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. The injector 1 shown here as an example is already common and its operation is well known, so
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 within the permissible frequency range, and check whether there is an impossible change by comparing with the previous value. If this is determined to be normal, the engine speed is calculated from the rotation angle information, and then the optimal injection amount is calculated by adding corrections based on this 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 injector 1
The operation timings of the solenoid valves 11, 12, and 13 are calculated. Then, an operation signal is output for the solenoid valve that matches the operation timing with respect to the rotational position of the engine known from the early rotation angle information and the top mark sensor. Return to each sensor reading again,
Operation is performed by repeating this loop. By the way, when the previous rotation angle sensor is determined to be abnormal, the control goes into failure mode and processes to switch the rotation angle information, specifically which sensor's output to use as rotation angle information, and the rotation angle used for various calculations. Rewrite the flags that control changes to parameters and calculation expressions for . As a result, by using normal rotation angle information from now on,
And calculations are performed accordingly. The calculation output is performed sequentially in the same steps as during normal operation, the loop goes around, and operation continues. At this time, although not shown, it is desirable to turn on an indicator lamp to notify the operator of the rotation angle sensor and the abnormality.

What should be noted here is that as mentioned above, the quality of the information is generally degraded as the second rotation angle sensor uses engine auxiliary equipment (alternator, etc.), so the operating conditions are narrower than normal. This may result in poor performance or reduced performance.

If a sensor with the same performance level is used as the second rotation angle sensor, the same operation as in normal operation can be continued by controlling as in the above-described embodiment. In this case, by comparing and calculating the information on the two, it is possible to perform normal operation, and when an abnormality is detected, to operate with only the remaining normal one as in the normal operation in the above-described embodiment. In this case, more precise abnormality diagnosis can be made. Note that various sensors capable of substantially detecting the rotation angle of the enzan can be used as the second rotation angle sensor.
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 without using a digital computer. Of course, this is also possible, 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 computer, but this may be done by hardware in the input circuit, or it may also be done manually by the driver. In this case, it is necessary to stop the engine once. There is.

It is obvious that the present invention can be applied to systems in which the injector type, configuration and number of hydraulic power sources, hydraulic oil, number and types of sensors, sensing items, etc. shown in the embodiment are changed.

As an effect of the present invention, according to the present invention, when the first crank angle detection means for detecting crank angle information fails and accurate angle information cannot be obtained, the control device that detects this malfunctions. Since the crank angle information detected by the second crank angle detection means is used to control the operation of the injector based on this crank angle information and the position information of the earlier crank, it is possible to prevent failures in normal times. At the same time, the operation of the injector plunger can be controlled with excellent precision using both the engine reference position and crank angle information, making it possible to continue operation.

Further, according to the present invention, operation can be continued with highly accurate control using both the reference position of the engine and the crank angle information both when the means for detecting the crank angle is in normal operation and when there is a failure.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the fuel injection device, Fig. 2 is a diagram showing an example of the configuration when the fuel injection device is used in a 6-cylinder engine, and Fig. 3 is an example of the control flow of the control device. This is a flowchart showing the following. Explanation of symbols, 1... Injector, 2, 3...
Pressure source, 4...Control device, 5...Spool valve, 8
... Plunger, 9 ... Piston, 10 ... Nozzle, 11, 12, 13 ... First, second, third solenoid valve.

Claims (1)

[Claims] 1. Various sensors that detect the operating state of the engine, etc.; A control device that is connected to the sensor and operates based on the information; and A plunger that is electrically controlled by the control device. In a fuel injection device comprising an electronically controlled injector provided for each cylinder that pressurizes fuel and injects the fuel, a crank position detection means detects crank position information indicating a specific rotational reference position of an engine; , a first crank angle detection means for detecting a crank angle occurring during each fuel injection, and a second crank angle detection means for detecting a crank angle occurring during each fuel injection. ,
The control device selects normal information from among the crank angle information detected by the first crank angle detecting means and the second crank angle detecting means, and uses the normal information as crank angle information. A fuel injection device characterized in that the operation of a plunger of the injector is controlled based on the position information of the crank and the position information of the crank.