JPH01273851A - Method and device for monitoring safety interrupting device for internal combustion engine - Google Patents

Abstract

PURPOSE: To perform accurate function test of an electromagnetic safety shut-off valve by actuating the electromagnetic safety shut-off valve and detect whether there is fuel injection or not when starting fuel supply in a control, device wherein the fuel supply is shut off by the electromagnetic valve when a fuel control actuator has a trouble. CONSTITUTION: In a control device 10 for inputting output data of a rotation frequency sensor 12 and an accelerator pedal position sensor 13, cooling water temperature, starting data of battery voltage or the like, a control signal is produced to actuate an electromagnetic valve 14 disposed in a fuel injection pump of a fuel control actuator 11. The actuator 11 is provided by an electromagnetic safety shut-off valve 16 actuated to shut off fuel supply when a failure is detected. In this case, a test circuit 19 is added to the control device 10 to actuate the electromagnetic safety shut-off valve 16 through an OR-gate 17 when starting fuel supply. Then, the performance of the electromagnetic safety shut-off valve 16 is judged by monitoring whether there is fuel injection or not from the output of a needle moving sensor 15 at this time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and a device for monitoring a safety shut-off device of an internal combustion engine, and more particularly to a safety shut-off valve designed as an electromagnetic safety shut-off valve for an internal combustion engine, in particular a diesel engine. (redundant)
A method and apparatus for monitoring a safety shut-off device of an internal combustion engine, wherein the fuel regulating actuator of the internal combustion engine is actuated by an electronic diesel control device, and in the event of a failure, fuel supply to the engine is interrupted by an electromagnetic safety shut-off valve. The present invention relates to a method and apparatus for monitoring safety shut-off devices.

BACKGROUND OF THE INVENTION In a known fuel injection pump for a diesel engine (DE 294 548), a pump piston arranged in the housing of the fuel injection pump is reciprocated and rotated at the same time. At this time, fuel flows from inside the housing of the injection pump, which forms the suction chamber, to the piston. From there, the fuel reaches pressure lines which communicate with the cylinders of the diesel engine, each according to the adjustment amount. A safety device is arranged in the connecting pipe connecting the suction chamber and the supply pipe of the pump piston, which prevents further supply of fuel from the suction chamber to the pump piston if a predetermined safety condition is exceeded. It is an interruption. This type of safety condition is exceeded if, for example, the adjusting lever actuated by the accelerator pedal is in the idling position and the pump pressure in the housing of the fuel injection pump is at a higher rpm than in the idling state. .

Other known emergency control devices, in particular for fuel injection systems of diesel engines (German Patent Application No. 323 819
In case No. 1), an emergency control system that can be operated manually or automatically is provided in addition to a signal processing device having a fuel supply control device. This emergency control system is provided with at least a boost pressure regulator, and when a fault is detected by the fault detection circuit, the output signal of the boost pressure regulator is used to supply the minimum amount of fuel required to drive the internal combustion engine. It can be switched to a value corresponding to the amount. It is also possible to provide a minimum value selection circuit in the emergency control system to refer to other operating conditions.

DE 196 2 570 A1 describes an adjusting device for adjusting an injection quantity control element for a fuel injection system of a diesel engine, which adjusting device is activated in the event of a fault, e.g. The circuit itself or the leads from any of the sensors are cut off, with the result that the injection quantity control member is adjusted to inject a smaller quantity. In this case, in a control method that adjusts the amount of fuel to be supplied in a direction such as this, there is a risk that the output of the internal combustion engine will be reduced and the engine will not be able to maintain operation, for example, when the road surface is poor. , a problem arises.

It is generally known to use electrical actuators actuated by electrical signals to electronically control the operation of self-igniting internal combustion engines, or diesel engines (see DE 35 31 198).
However, in this case, instead of a mechanical fuel control and controller, a central controller (SG) is used to generate the necessary regulation signals. Although the diesel engine's mechanical fuel control system is reliable in that it is error-free,
In some cases, there is a lack of ability to consider a large number of different operating conditions and environmental influences.

When using an electronic diesel control (EDC) in combination with electronic elements, there is a wide range of safety benefits, even if the individual units have the ability to identify and, in some cases, eliminate faults. Preferably, means, monitoring means and emergency running means are provided.

Therefore, a safety device for a self-ignition internal combustion engine continuously detects predetermined signals related to operating parameters of the internal combustion engine, such as the accelerator pedal position, the calculated target value of the control rod, the rotation speed, and the brake pedal position. , is known to be supplied to the controller of an electronic diesel control unit (German Patent Application No. 3301742).
(see issue).

The setpoint value of the control rod corrected by this operating parameter is simultaneously compared with the fed-back actual value of the control rod and used to determine the control deviation. If a predetermined limit value is exceeded, known safety devices stop the fuel injection pump, cut off the current in the output stage of the actuator or initiate emergency driving. However, problems may occur with this known safety device. This is because when considering safety conditions, it is not possible to refer to all possible surrounding conditions. Thus, an idle link signal can be obtained by switching the accelerator pedal to idle link, but this is not the case, for example, if the internal combustion engine is equipped with a speed regulator. Furthermore, 1. For example, in a race, or when driving at high speed and receiving a warning from a driver behind, the driver may operate the brake pedal briefly or only slightly, and at this time the accelerator pedal is not depressed. It is also possible that the engine is still in the idling position and therefore has not reached the idling position.

[Problem to be solved by the invention] An electromagnetic safety shutoff valve (ELAB) is provided as an additional (redundant) safety stop device for an internal combustion engine to ultimately stop the fuel supply in the event of a failure. In such a device for shutting off and thereby preventing continued running, the invention aims at making it possible to continuously monitor the correct functioning of the electromagnetic safety shut-off valve itself.

During normal operation, the electronic diesel control system is able to detect a fault in the fuel regulating actuator since a fault in the fuel regulating actuator continues to cause a control deviation in the controller. The electronic diesel control then cuts off the fuel supply by means of an electromagnetic safety shutoff valve via a corresponding safety logic circuit. The electromagnetic safety shut-off valve therefore serves as a safety measure and can shut down the engine in the event of a fuel regulation actuator becoming inoperable or in the event of a power stage failure, for example in an electronic diesel control system. For this reason, it is necessary to continuously monitor the electromagnetic safety shut-off valve.In this case, of course, the electromagnetic safety shut-off valve itself, like all other elements and systems, is part of the fuel supply control system. However, there is a difficulty in that it is not possible to separately test only the function of the electromagnetic safety shutoff valve.

The function of the electromagnetic safety shutoff valve is solely directed to stopping the engine. Therefore, from the standpoint of driving safety, it is natural that it is necessary or possible to control the electromagnetic safety shutoff valve temporally, that is, to test the function of the electromagnetic safety shutoff valve at predetermined time intervals when the vehicle is normally driven. Impossible. This is because this inspection itself will lead to the engine stopping.

Even the driver cannot detect the failure of the electromagnetic safety shutoff valve. This is because if the power supply is cut off, not only will there be no current flowing to the electromagnetic safety shut-off valve that may have failed, but the current supply to the fuel regulation actuator and other components will also be cut off. No current flows (
Because it will be. Furthermore, the driver or user of a vehicle equipped with such a system may not continuously pay attention to the electromagnetic safety shut-off valve, or only to the testing of certain safety elements of the vehicle's fuel supply control. That's because you can't expect much.

The present invention is to obviate the drawbacks of the prior art as mentioned above.

[Means for solving the problems] In order to solve the above problems, in the method of the present invention,
When starting fuel is supplied by the electronic diesel control device, after the fuel supply control member moves to the starting position, iii 1if1
The functionality of the electromagnetic safety isolation valve is tested by activating the safety isolation valve and testing the presence or absence of fuel injection, and the absence of fuel injection is treated as data indicating that the functionality of the electromagnetic safety isolation valve is normal. A configuration has been adopted.

Furthermore, in the device of the present invention, a test circuit is provided which responds to the starting fuel supply, and this test circuit operates an electromagnetic safety cutoff valve to interrupt the fuel supply and detect whether or not fuel is being injected. ing.

[Operation 1] Since the present invention is configured as described above, a functional test of the electromagnetic safety shutoff valve can be performed as necessary at the time of starting fuel injection.

[Example] An embodiment of the invention is shown in the drawing and is explained in detail below.

According to the basic idea of the present invention, in order to test the function of the electromagnetic safety cutoff valve during operation of the internal combustion engine, the fuel supply is cut off for 11M via the electromagnetic safety cutoff valve during fuel injection for starting. 6 As an example for clarity, in FIG. 1 a control unit of an electronic diesel control unit EDC is designated by the reference numeral 10, and a fuel regulating actuator actuated by this control unit 10 is designated by the reference numeral 11. The control device IO contains data regarding the rotation speed n from the rotation speed sensor 12, data FP regarding the accelerator pedal position from the accelerator pedal position sensor 13, and data BL (brake light) regarding the brake operation if necessary. Data as well as other data from sensors which do not need to be explained in detail here, such as regarding cooling water, battery voltage, etc., are provided. The control device 1o then activates a solenoid valve 14 arranged in the fuel injection pump of the fuel regulating actuator 11 via a schematically illustrated output stage 10a. Furthermore, what is indicated by the reference numeral 15 is a feedback device that feeds back the position of the electromagnetic valve 14. Reference numeral 16 designates an electromagnetic safety shut-off valve ELAB on the fuel regulating actuator or fuel injection pump, which is also actuated by the control device IO via a control line 16a. In this case, for example, as shown in the figure, control is performed via an OR gate 17, and this OR gate is connected to an electromagnetic safety shutoff valve ELA from a normal safety logic circuit provided in the control device IO as shown by an arrow 18.
A signal is applied to cut the current at B (and thereby prevent further fuel supply). The signal applied to this OR gate can be formed from multiple conditions detected by the safety logic circuit.

For this purpose, the electromagnetic safety shut-off valve ELAB is actuated by a test circuit 19 according to the invention, said test circuit 19 being responsive to the starting signal of the electronic diesel control and to the starting fuel supply start signal.

In current electronic diesel control systems, starting fuel supply is initiated (i.e. fuel regulation According to the invention, the required electromagnetic safety shutoff valve test is carried out after the control slider has been moved into the starting position by detecting it, for example, by the test circuit 19. It will be done. This is done by activating the electromagnetic safety shutoff valve (cutting off the power supply) via the control device. Specifically, in the embodiment shown in FIG. 1, this can be done by activating the electromagnetic safety shutoff valve L6 via the OR gate 17 coming out of the test circuit 19. Actuation in this case means turning off the current supply to the electromagnetic safety shutoff valve I6. This is because, according to a preferred embodiment, the electromagnetic safety shut-off valve interrupts the fuel supply, for example by means of a mechanical spring bias which causes the valve shut-off member to shut off the fuel supply cross-section when no current is supplied. It is. By activating the electromagnetic safety cut-off valve in this way, it is tested whether a pulse is delivered by the needle movement sensor NBF, which is provided as a feedback device, ie whether a fuel injection has taken place. The needle movement sensor NBF is configured to indicate the movement of the fuel injection nozzle needle by generating a signal corresponding to the speed of needle movement. If the needle movement sensor feeds back the presence of fuel injection when the electromagnetic safety isolation valve current is interrupted, it is concluded that either the electromagnetic safety isolation valve is faulty or the output stage that activates the electromagnetic safety isolation valve is faulty. appropriate measures can be taken. For example, the driver may be warned by an appropriate indicator lamp, or in the worst case, especially when there is no margin for safety criteria due to other malfunctions, the engine may be stopped or the fuel injection amount or maximum rotation speed may be reduced. , thereby informing the driver of the need for inspection at a repair shop when the vehicle is driven further.

It should be noted that the flow of the functions shown in the figures and explained below or the steps representing the functions do not limit the present invention.
It should be understood that it is used only to visualize the basic functions of the present invention and to illustrate the flow of specific functions as an example of implementation. The individual components and circuits can be constructed in analog, digital or hybrid technology, or alternatively, all or some areas can be program-controlled, for example by microprocessors, microcomputers, digital or analog logic circuits. It can be implemented using a corresponding area of a digital system, or it can be stored directly in a microprocessor by shaping the program flow accordingly.

FIG. 2 is a flowchart when the apparatus of the present invention is configured by software, showing the starting fuel supply section and the test function of the electromagnetic safety shutoff valve. Explanations of the terms used in the figures, the values used, and the functions indicated by each term are shown in FIG. As a result, the sequential flow of the flowchart is clear.9 Note that the specifically illustrated numerical values are merely an example, and the present invention is not limited thereto.

The function of the illustrated flowchart starts with the control device SG being activated, initialization processing being performed, and the starting counter being incremented (step ①). It is assumed that the count value of the starting counter is stored even when the control device is turned off.

The initialization process for the electromagnetic safety shutoff valve test will be explained.

The number of starts per car ranges from 5,000 to 15.
000 times. Starting counter count value a
is smaller than the respective predetermined count value X, the start-up takes place without an electromagnetic safety shut-off valve test and therefore according to a conventional electronic diesel engine control program. In that case, the flow of control is as follows: In the control that branches to the left of step Ia, which determines whether or not to conduct an electromagnetic safety shutoff valve test, starting fuel is first supplied in step II, and the primary Idle link control at the time of starting is performed in step nl, and from there the routine shifts to fuel injection amount control.

When the count value a reaches the value X, the process proceeds to the right branch of the flowchart in step 5 Ia, and an electromagnetic safety shutoff valve test is performed. In order not to make cold starting unnecessarily difficult in this case, the electromagnetic safety shutoff valve test is performed only when the cooling water temperature is TW>b (step ①). If the electromagnetic safety shutoff valve test can be performed, the electromagnetic safety shutoff valve ELAB is activated (no current) to determine whether starting fuel injection occurs. And Nl1fi safety shutoff valve E
Since the LAB test must be completed within a predetermined short time, timing is started (step V).

If a pulse from the needle movement sensor NBF is detected (step V1), it is determined that the electromagnetic safety shutoff valve ELAB has failed. If no pulse is detected, it is first determined whether the test time t, x has elapsed. If the test time Lx has not elapsed, the test can be performed again. If fuel injection is not detected by the needle movement sensor within the test time, the electromagnetic safety shutoff valve ELAB is determined to be normal. Supply current to the electromagnetic safety shutoff valve ELAB (
(in standby mode), resets the count value of the starting counter, and shifts to normal starting control.

For example, if the electromagnetic safety shutoff valve ELAB is mechanically stuck or otherwise malfunctions, it is determined based on other safety tests whether a safety-important diagnostic bit (=DIABYTE) has already been set ( step vn). If it has already been set, the engine must be stopped. In other words, by setting a=x, the next time the engine is started, the electromagnetic safety shutoff valve ELAB test will be forcibly performed, and if the electromagnetic safety shutoff valve ELAB is not stuck or the judgment bit important for safety is reset. Starting is possible only in good conditions.

If there is no other failure important for safety, the electromagnetic safety shutoff valve is placed in a standby state (that is, power is supplied), the starting counter is reset, and normal starting control is performed.

It is to be understood that all features shown in the claims, detailed description and drawings, whether used individually or in combination, do not depart from the invention.

[Effects of the Invention] As is clear from the above description, the present invention employs a configuration in which an electromagnetic safety cutoff valve that cuts fuel supply is tested every time the internal combustion engine is started a predetermined number of times. Therefore, an excellent effect can be obtained in that the necessary minimum number of tests can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the outline of the electronic control device installed in the fuel adjustment actuator, Fig. 2 is a flowchart showing the function of the electromagnetic safety shutoff valve test, and Fig. 3 shows the symbols used in Fig. 2. This is an explanatory tableau. 10...Control device II...Fuel injection adjustment member 16
...Electromagnetic safety shutoff valve 19--Test circuit diagram 3

Claims (1)

Claims: 1) A method for monitoring a safety shut-off device formed as an electromagnetic safety shut-off valve of an internal combustion engine, in particular a diesel engine, in which a fuel regulating actuator of the internal combustion engine is actuated by an electronic diesel control device, In a method of monitoring a safety shut-off device for an internal combustion engine, in which the fuel supply to the engine is interrupted by an electromagnetic safety shut-off valve when an electronic diesel control device supplies starting fuel, the fuel supply control member moves to the starting position. Later, a functional test of the electromagnetic safety shutoff valve was performed by activating the electromagnetic safety shutoff valve and testing the presence or absence of fuel injection, and the absence of fuel injection was used as data indicating that the function of the electromagnetic safety shutoff valve was normal. A method for monitoring a safety shut-off device of an internal combustion engine, characterized in that: 2) The pulse of the needle movement sensor is used to test the presence or absence of fuel injection.
The method described in section. 3) The method according to claim 1 or 2, characterized in that the functional test of the electromagnetic safety shutoff valve is repeated every time a predetermined number (x) of starting steps are performed. 4) A method according to any of claims 1 to 3, characterized in that after each electromagnetic safety shut-off valve test, a starting counter is set to a new initial value (a=0). 5) The function test of the electromagnetic safety shutoff valve is performed only when the cooling water temperature is within a predetermined range (Tw>b), according to any one of claims 1 to 4. Method. 6) If a failure of the electromagnetic safety shutoff valve is detected due to fuel injection, detect the presence of other safety-critical failures, and if other safety-critical failures of this type exist. 6. A method according to claim 1, wherein the electromagnetic safety shutoff valve test is repeated each time the internal combustion engine is stopped or restarted. 7) Needle movement sensor (
7. The method according to claim 1, wherein the function of the electromagnetic safety shutoff valve is determined to be normal only if no pulses are supplied from the NBF. 8) A device for monitoring a safety shut-off device formed as an electromagnetic safety shut-off valve of an internal combustion engine, in particular a diesel engine, in which case the fuel regulating actuator of the internal combustion engine is actuated by an electronic diesel control device and the electromagnetic safety shut-off valve is activated in the event of a failure. A device for carrying out the method according to claims 1 to 7 for monitoring a safety shut-off device of an internal combustion engine whose fuel supply to the engine is interrupted by a shut-off valve, characterized in that the test circuit (19) responsive to starting fuel supply is established,
A device for monitoring a safety shut-off device of an internal combustion engine, characterized in that the test circuit operates an electromagnetic safety shut-off valve to interrupt fuel supply and detect the presence or absence of fuel injection. 9) A detection circuit is provided for detecting the fuel injection that occurs when the electromagnetic safety shutoff valve is actuated, and the detection circuit is characterized in that it interrupts the start control in the presence of other safety-critical failures. 9. The apparatus according to claim 8. 10) A starting counter is provided, and the starting counter causes a function test of the electromagnetic safety shutoff valve to be performed every time a predetermined number (x) of starting steps are performed. The device described.