JPS5874867A - Fuel injection controlling method for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable to prevent occurrence of an accident such as overrun of an engine, by operating a valve mechanism for controlling operation of a fuel metering actuator or a driving system for feeding fuel under pressure under the trouble mode in case that some trouble is caused at a portion of an injection means in its fuel increasing state. CONSTITUTION:When a solenoid valve 12 is closed and a solenoid valve 13 is opened in response to the output signal of a control means 30, a piston 9 and a plunger 8 are depressed for injection of fuel. Here, the quantity of injected fuel is controlled on the basis of the valve opening time of the third solenoid valve 13 of a fuel metering actuator. With such an arrangement, if the valve 13 becomes inoperable in its valve opened state, the valve opening timing of the solenoid valve 12 is delayed from the normal timing and current supply to the solenoid valve 13 is stopped. From the next cycle timing on, the valve 12 is opened retroactively according to the timing in advance of the above delay time from the normal valve opening time of the valve 13. Thus, fuel can be supplied although the fuel metering accuracy is not so good, and overrun of the engine due to the above trouble can be prevented without stopping operation of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a fuel injection device for an internal combustion engine, particularly a diesel engine, when the fuel injection device fails.

Electronically controlled fuel injection devices have been widely used until now, and they consist of a pressure delivery system consisting of a diesel engine and a syringe, an injection nozzle, a valve mechanism that mainly controls the operation of the pressure delivery system, and a valve mechanism that adjusts the injection amount. Each cylinder is equipped with an injector device that is operated by a control signal from a control device based on information from various detectors. Many of these types use electromagnetic valves for the valve mechanism that controls the pressure feeding system and the actuator that adjusts the injection amount for ease of control. A solenoid valve exclusively for metering is installed. However, solenoid valves have a higher failure rate than other functional parts, and stopping at tt, when the metering solenoid valve opens, is extremely dangerous as it can lead to engine overrun. In conventional control methods configured to operate (stop)
Even if a cylinder fails, the engine will stop because it will cause abnormal vibrations and other operational problems. Therefore, the first danger can be avoided, but if the breakdown was on a highway, a mountain road in winter, or a field on the horizon, there would be a second danger, that is, the inability to drive. However, the problem arises that it is not easy to return home due to accidents. Therefore, modern vehicles are required to have driving performance that allows them to return to their destination as far as possible, even if the situation is poor. Conventional methods, of course, cannot satisfy this requirement.

This invention provides a fuel that can continue operating without damaging the engine even if a part of the injector device for a cylinder, for example, a metering solenoid valve (actuator) opens and enters a valve state. The purpose of this invention is to provide an injection control method.

In the present invention, when it is detected that the actuator for metering control in the injector device for each cylinder is in a fuel supply ready state and has failed, at least the operation of the failed injector device is stopped. Switches to failure mode F operation without any problem, controls the amount of fuel supplied to the pump operating oil chamber below the sylanger via the failed actuator, and controls the operation of the valve mechanism that allows the piston and f-tension to rise. I try to measure it by doing this.

Therefore, even if a failure occurs in a part of the injector device of a certain cylinder, there is no need to stop engine operation, and even if acceleration/deceleration performance deteriorates, a state close to normal operation can be maintained, and the engine Damage to the engine due to parts y or abnormal vibrations can also be avoided.

The present invention will be explained in detail with reference to the drawings below. In FIG. 1, numeral 1 indicates an injector device provided for each cylinder;
2' indicates a high pressure source, and 3 indicates a low pressure source as a whole.

The injector 1 has a switching valve 5, such as a line valve, which slides from side to side in the figure while maintaining oil tightness inside the bore 4. Aro,
8. A small-diameter syringe that slides up and down in a substantially integral state while maintaining oil tightness inside 7. A large-diameter gas cylinder 9 and an injection nozzle 10 that receives the fuel pressure-fed from the sylanger 8
and three solenoid valves 11, 12, and 13. The inside of the pore 4 in a part of the switching valve 5 forms a switching valve operating oil chamber 14, and this chamber 14 communicates with the low-pressure pressure source 3 via a solenoid valve 11, which is a two-way on-off valve, and piping 15. , is also connected to a fuel redaper tank 16 via a solenoid valve 12, which is also a two-way on-off valve. On the opposite side of the hydraulic fluid chamber 14, a spring 17 presses the switching valve 5 to the left in the figure, that is, in a direction that makes the hydraulic fluid chamber 14 smaller. A gas cylinder hydraulic oil chamber 18 is formed by the inside of the pore 4 in the intermediate small diameter portion of the switching valve 5 and the l aa T above the piston 9. This gas stone hydraulic oil chamber 18 is.

Depending on which of the two positions, left and right, the switching valve 5 is in communication with the two ports 19 and 20. One of the ports 1-) 19 is returned to the high-pressure source 2 via a pipe 21, and the other port 20 is returned to the tank 16 via a restriction 22. A pump hydraulic oil chamber 23 formed in the pore 6 on the lower side of the syringe 8 communicates with the nozzle 10, and also includes a check valve 24 and the above-mentioned metering solenoid valve 13, which is a two-way on-off valve.
It communicates with a low pressure source 3 via. The input I-to of the control device 30 is electrically connected to various sensors (not shown),
And the output ports are the three electromagnetic valves 11.12. II
K are electrically connected and send control signals to them.

Pressure sources 2 and 3 are f pump 201.301, relief valve 20
2, 302, Fiyata 203, 303, Aki-tool mul- tators 204, 304 constitute a normal constant oil pressure source.

The operation of the QIHC system described above is as follows:
In the illustrated position, the solenoid valve 11 is closed and the solenoid valve 12 is open, so the high pressure source 2 is separated from the switching valve operating oil chamber 14 and this chamber 14
communicates with Redeemer Tank 16. Therefore, spring 1
Therefore, when the switching valve 5 is in the left position, the L/-) 20 is in communication with the piston hydraulic oil chamber 18, and becomes a path through which the fuel in this chamber 18 can be released into the tank 16. In this state, when a signal giving the solenoid valve 13 an opening time corresponding to the injection amount is input from the control device 30, the valve is opened for this period as shown in the figure, and the fuel from the low pressure source 3 is transferred to the check valve 24. The oil is introduced into the pump hydraulic oil chamber 23 through the pump and filled with a predetermined amount, and then the metering solenoid valve 13 is closed. At this time, Zestone 9
．． Siranjar 8 rises.

When the electromagnetic valve 11- is switched to open and the solenoid valve 12 is switched to close, the hydraulic pressure from the pressure source 3 acts on the switching valve operating chamber 14 through the conduit 15, and at the same time, this chamber 14 is separated from the reduction tank 16. As a result, the switching valve 5 moves to the right in the figure against the spring 17, closing the port 20 and opening the port 19.

Thus, the hydraulic pressure from the high ε source 2 is guided to the piston hydraulic oil chamber 18 through the piping 21, and this hydraulic pressure moves the Vp stone 9 and the sylanger 8 downward. At this time, an extremely high pressure is generated in the pump working oil chamber 23, which theoretically increases the pressure in the pump chamber 23 to twice the piston-silanger sectional area ratio of the oil pressure of the pressure source 2. This ultra-high pressure fuel is prevented from flowing back by the check valve 24, is supplied to the nozzle 10, and is injected into a combustion chamber of an internal combustion engine (not shown).

The above is the operation during normal operation, and this will be further explained along the timing diagram of FIG. 2. jI2 solenoid valve 12
When the valve is closed and the first solenoid valve 11 is opened at the timing, the spool is moved to the right by hydraulic pressure, and the piston syringe is subsequently depressed. Therefore, inject fuel. Next, at tine B, the first solenoid valve 11 is closed, and the spool that opens the second solenoid valve 12 is pushed back to the left, and the second solenoid valve 12 is closed. In this state, the third electromagnetic valve is opened at timing 0, and during this period, the sylanger and piston are pushed up and the injected fuel is introduced. What is shown in FIG. 1 is the state during this period. timing p
Then, when the solenoid valve -3 is closed, timing A of the next cycle is reached again in that state. It can be seen that the control of the injection amount is carried out in the time indicated by (2). Therefore, in the case of partial load, the controlled valve opening time becomes W as shown by the broken line in the figure.

Next, a method of controlling a failure cage will be explained using a similar Tysender diagram (FIG. 3). What should be noted here is that the third solenoid valve does not operate when it is opened. Therefore, the third solenoid valve is not energized and is not shown in the figure. The first solenoid valve is opened at the timing shown in the figure, and the process leading to injection is the same as normal operation. Therefore, the opening of the second solenoid valve is delayed (as compared to normal operation), and this delay time is quantitatively calculated by going backwards from the timing of the next cycle by approximately the control valve opening time OD of normal operation. timing B
Decide and then open the gate. Since the third electromagnetic valve is already open, the injected fuel is introduced at the same time as the spool moves to the left in this state, and the introduction ends at the timing of the next cycle, that is, the injection timing.Therefore, the control of the injection amount is B ( In this motor, the metering accuracy is poor during acceleration and deceleration, as described above. This is because the timing of B is determined by anticipating that the control time B is the injection timing of the next cycle, and when accelerating and decelerating, the timing of B is the same as that expected in the tie electric terminal B. This is because it will change. However, it is sufficient for the purpose of somehow continuing to operate the engine.

Next, the overall control flow will be explained. After setting the initial conditions, input various Senna information. Examples include TDC mark, engine speed, accelerator position, cooling water temperature, lubricating oil temperature, intake air temperature, intake air pressure, exhaust temperature, pressure source pressure, etc.

As will be described later, an abnormality in the metering solenoid valve 13 is detected based on the sensor information, and if there is no failure, the controller 30 normally calculates the metering and timing of the cage, and performs control as shown in FIG. do. Then, the senna information is input again, and calculations are performed moment by moment through this loop. When a failure is discovered, the metering and timing calculations are performed to perform control as shown in FIG. 3. In a system where the faulty cylinder can be identified, if only the faulty cylinder is detected, then all cylinders may be counted. As an example of a method for detecting a failure, a method that generates a pulse at every constant rotational speed is used to detect the instantaneous rotational speed. The control device 30 monitors this and considers it to be abnormal when the rotational fluctuation for each explosion exceeds the determined rotational speed. Alternatively, there is a method of providing feedback on the amount of intake by installing a stopper position sensor.

The present invention can be applied to any case in which metering and pressure feeding are controlled by separate actuators, such as the solenoid valve 11.
't 12 can be used with a 2-position, 3-port type, and of course can also be applied to a linear direct-acting type that moves the suzo IvS itself directly by electromagnetic force without operating it with a hydraulic or solenoid valve. can. It goes without saying that the configuration, number, and type of hydraulic fluid of the pressure sources are not limited, and the present invention is applicable to any mechanical improvements, such as installing a slotted circuit in the sylanger. It is obvious that it can be done. Furthermore, although a digital control circuit is used in the embodiment, it is of course possible to implement this with an analog/4G circuit. In addition, the metering solenoid valve may be of a different type, and its placement may be upstream or downstream of the throttle valve 22, and in either case, the metering solenoid valve may be located on the inlet side of the metering fuel. It doesn't matter if there is.

It is important to note here that if there is a failure in a part of the metering circuit other than the solenoid valve, such as when the throttle valve falls off, it may be mistakenly detected as a failure in the solenoid valve, depending on the system configuration. In such a system, if only that cylinder is operated in the failure mode, the metering solenoid valve remains closed and that cylinder stops operating. In order to avoid the stoppage of the operation, use the same method to control the control timing shown in Figure 5 when the stoppage of the operation is detected, and change the opening time of the metering solenoid valve from CD to OD'. What is necessary is to move to a second failure mode that shortens the time.

As mentioned above, in the present invention, the pumping drive system.

Each cylinder is equipped with an injector device that has a valve mechanism that controls its operation and a separate actuator for metering, inputs various sensor information, and outputs signals that control the valve mechanism and actuator from the control device. In a fuel injection system, when a part of the injector device fails in a state where fuel can be supplied, that is, when the injection amount increases, the valve mechanism that controls the actuator for metering or the operation of the pressure feeding drive system is operated in a failure mode. This enables metering without stopping engine operation and avoids dangers such as over-run caused by malfunctions.

Moreover, when three digital circuits are used, this method basically allows control fa without adding or changing configuration 2.
It also has the effect of being possible only by changing Migtum.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 112 is a control/operation timing diagram in normal mode, and FIG. 3 is a control/operation timing diagram in failure mode. FIG. 4 is a flowchart showing the overall control flow. FIG. 5 is a control operation timing diagram in a failure mode in another embodiment of the present invention. 1... Injector device 2.3... Pressure source 5...
・Switching valve 8-・Silanger 9...Stone 10・-Injection nozzle 11.12-・・1st.
2nd electromagnetic valve 13 - Attacheator for metering (fifth electromagnetic valve) 30 - Control device. Agents Asamura and Akira 4 people Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] (1) A pressure delivery system that includes a VP stone and a sylanger connected to the VP stone, and that pumps fuel in a pump operating oil chamber below the syringe under pressure by the VP stone, and an injection system that injects the pressure-fed fuel. A nozzle and a valve mechanism that controls the vertical movement of the piston and syringe by changing the oil pressure in the piston hydraulic oil chamber above the piston. The actuator below the f ranger is an actuator that adjusts the amount of fuel supplied to the hydraulic oil chamber, that is, the amount of fuel injection.
In a fuel injection control method for an internal combustion engine in which each cylinder is provided with an injector device that is operated (by a control signal from a control device based on information from a detector that detects the operating state of the engine), a part of the injector device is When a failure occurs in a state in which fuel can be supplied, at least the operation of the failed injector device is controlled in the failure mode V by controlling the operation of the metering actuator or the valve mechanism. A fuel injection control method for an internal combustion engine, the method comprising controlling an injection amount. (2. The fuel injection control method according to claim 1, wherein the control of the operation of the valve mechanism in the failure mode operation reduces the hydraulic pressure in the piston hydraulic oil chamber above the piston, causing the syringe to rise. Controls the amount of fuel supplied to the pump hydraulic chamber below the plunger through the faulty metering actuator so that the available timing starts a predetermined time before the regular fuel injection timing. (3) A fuel injection control method for an internal combustion engine, characterized in that: (3) A fuel injection control method for an internal combustion engine, characterized in that the actuator is constituted by a solenoid valve. Control method.