JPH0612743U - Control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] In a system in which a control unit is provided for each bank of a V-type engine, when only one control unit fails, the mixture ratio of the failed bank becomes lean and burn-in occurs. To prevent [Structure] When the microcomputer of one control unit is normal, power supply to the fail-safe unit of the other control unit is stopped (S1 → S2). Here, when the microcomputer of the other control unit is out of order, the fail-safe unit cannot function due to the stop of the power supply, and only one bank is operated. On the other hand, if both microcomputers fail, power is supplied to the fail-safe units on the other side (S3) and both fail-safe units are made to function (S4).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control device for an internal combustion engine, and more particularly to a failsafe in a control device for an internal combustion engine in which a control unit is provided for each of the two cylinder groups and at least fuel supply is controlled by the control unit.

[0002]

[Prior art]

 For example, in a V-type internal combustion engine, as shown in FIG. 2, each bank 3a, 3b of the V-type engine 3 (each cylinder group) is provided with control units 1 and 2 each having a built-in microcomputer, and each bank 3a, Some 3b are configured to electronically control the fuel supply amount, ignition timing, etc. by a different control unit.

Further, in the case of the configuration in which the fuel supply amount and the ignition timing are electronically controlled as described above, if the microcomputer fails, the fuel supply and the ignition cannot be performed, and the vehicle cannot run. Become. Therefore, a fail-safe unit (gate array) that can perform the minimum necessary control is provided, and when the microcomputer fails, the fail-safe unit is operated so that at least self-driving can be performed.

[0004]

[Problems to be solved by the device]

 By the way, since the control function of the fail-safe unit is limited, fuel and ignition are generally controlled so that the engine can be operated only at a low rotation speed. Here, as described above, in the case where two control units are provided as in the V-type engine, if one fails and the other is normal, one is normal, so high rotation and high load Although there is a possibility of operation, the bank on the side controlled by the faulty control unit at this time will perform control for low rotation and low load, so the bank on the side where the control unit is in trouble In this case, the mixture ratio becomes lean, which may cause seizure and other engine damage.

The present invention has been made in view of the above-mentioned problems, and even if the control unit fails, the operation of the mechanism can be performed at a minimum, and due to the difference in the control function between the two control units, It is an object of the present invention to provide a control device that can prevent engine damage.

[0006]

[Means for Solving the Problems]

 Therefore, the control device for an internal combustion engine according to the present invention is provided with a control unit having at least a function of controlling fuel supply to the engine for each of the two cylinder groups, and each of the two control units controls the control unit. A control device for an internal combustion engine, which has a built-in fail-safe unit with limited functions and is configured to operate the built-in fail-safe unit when the control unit main unit malfunctions. Power supply to the fail-safe unit of the other control unit is stopped during normal operation, and power is supplied to the fail-safe unit of the other control unit when the main body of one control unit fails.

[0007]

[Action]

 With this configuration, if one of the control unit main bodies fails and the built-in fail-safe unit is operated, but the other control unit main body is normal, the control unit of the faulty side is The power supply to the failsafe unit is stopped by the normal control unit.

Therefore, when only one of them fails, none of the failsafe units operate, and only the cylinder group controlled by the normal control unit is normally operated and controlled. Also, if both control unit main units fail, power is supplied to each failsafe unit, so that the failsafe units incorporated in each can be operated, and both cylinder groups can failsafe. It will be controlled by the unit.

That is, the fail-safe units are operated at the same time only when both of the two control unit bodies are out of order. One is controlled by the fail-safe unit and the other is controlled by the control unit body. The condition that occurs is not generated.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an internal configuration of two control units 1 and 2 provided for each bank 3a, 3b (for each two cylinder groups) of a V-type internal combustion engine 3 as shown in FIG. .

As shown in FIG. 1, in each of the control units 1 and 2, microcomputers (CPUs) 11a and 11b as unit bodies, and a failure determination circuit 12a for performing failure determination of the microcomputers 11a and 11b. , 12b and fail safe units (circuits for limp home) 13a, 13b for performing minimum control when the microcomputers 11a, 11b fail.

The fail-safe units 13a and 13b are composed of gate arrays and have minimum control functions of fuel supply amount and ignition timing so that the engine can be operated only at low engine speed. When the failure determination circuits 12a, 12b determine the failure of the microcomputers 11a, 11b, the control by the built-in fail-safe units 13a, 13b is actually operated.

Transistors 14a and 14b are provided in the power supply lines of the fail-safe units 13a and 13b, respectively, and these transistors 14a and 14b cause a failure in the other control unit 1 or 2, respectively. It is designed to be controlled by the judgment circuits 12a and 12b. That is, the failsafe unit is operated based on the failure judgment of the microcomputer for each control unit, but the power supply to the failsafe unit is controlled by the other control unit. Even if an attempt is made to operate the fail-safe unit due to a computer failure determination, the fail-safe unit cannot actually be operated if the power supply to the other control unit is stopped. .

Power supply control to the fail-safe units 13a and 13b via the transistors 14a and 14b is performed by the control units 1 and 2 as shown in the flowchart of FIG. First, the failure determination circuits 12a, 12b determine the failure of the microcomputers 11a, 11b (S1), and when it is determined that the failure is normal, the fail-safe unit 13a built in the other control unit 1, 2 In order to stop the power supply to 13b, the transistors 14a and 14b are turned off (S2).

Therefore, if both the microcomputers 11a and 11b are normal, the power supply to the fail-safe units 13a and 13b is stopped, but both the microcomputers 11a and 11b are normal. The microcomputer 11a, 11b can normally control the fuel supply and ignition timing for each bank.

On the other hand, when the failure determination circuits 12a, 12b determine that the microcomputers 11a, 11b have failed, the fail-safe units 13a, 13b built in the other control units 1, 2 are compared with each other. In order to supply power, the transistors 14a and 14b are turned on (S3). At this time, the operation of the fail-safe units 13a and 13b incorporated in the control unit for which the failure has been determined is instructed (S4).

For example, when one microcomputer 11a is normal and the other microcomputer 11b fails, the failure determination circuit 12a of the control unit 1 turns off the transistor 14b and supplies power to the failsafe unit 13b. Is stopped. Therefore, even if an attempt is made to operate the failsafe unit 13b in accordance with the failure judgment of the microcomputer 11b by the failure judgment circuit 12b, the failsafe unit 13b cannot be actually operated because the power supply is cut off. For this reason, one bank controlled by the control unit 2 is in an uncontrollable state (a state in which fuel supply and ignition are stopped), but in this case, the other control unit 1 is normal and the other bank is Since the control can be performed normally, the minimum engine operation can be performed by the normal operation of only one bank, and the vehicle equipped with the engine can be driven by itself.

When both the microcomputers 11a and 11b fail, the fail-safe units 13a and 13b on the other side are mutually supplied with power, and the fail-safe units included in the microcomputers 11a and 11b are self-contained. In this case, since the fail-safe units 13a and 13b work together and both banks are controlled by the fail-safe units 13a and 13b to the minimum, since 13a and 13b are operated. It is possible to drive a vehicle equipped with an engine by itself.

Here, the cylinders in one bank (cylinder group) are normally controlled, and the cylinders in the other bank (cylinder group) are minimally controlled by the failsafe units 13a and 13b. In this case, the engine may be operated at high speed and high load because normal control is applied to one bank.At this time, the other bank controls only low speed. In the cylinder of the other bank, a lean mixture ratio may occur, causing engine damage such as seizure.

However, as described above, in this embodiment, if one of the microcomputers 11a and 11b is normal, the failsafe units 13a and 13b are operated even if the other microcomputers 11a and 11b fail. No, when one bank operates normally, the other bank does not burn. Therefore, it is possible to prevent the lean combustion from occurring in the bank on the failure side as described above, thereby preventing the engine damage from occurring in the fail-safe mode, while allowing the vehicle to drive by itself when the microcomputer fails. It can be secured.

[0021]

[Effect of device]

 As described above, according to the present invention, when two control units control different cylinder groups, for example, when a control unit is provided for each bank of a V-type engine, one control unit is controlled. Is normal and the other control unit fails, the fail-safe control function of the failed control unit cannot be exerted. Even if the engine is operated under a high load, it is possible to prevent the mixture ratio in the cylinder of the bank whose fuel supply is controlled by the failure side control unit from becoming lean and causing seizure. If both fail, both fail-safe control functions can be exerted and minimum operation can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control unit according to an embodiment.

FIG. 2 is a diagram showing sharing of two control units in a V-type internal combustion engine.

FIG. 3 is a flowchart showing a fail-safe aspect of the embodiment.

[Explanation of symbols]

1, 2 Control unit 11a, 11b Microcomputer (control unit main body) 12a, 12b Failure judgment circuit 13a, 13b Fail-safe unit 14a, 14b Transistor

Claims (1)

[Scope of utility model registration request] 1. A control unit having at least a function of controlling fuel supply to an engine is individually provided for each of two cylinder groups, and each of the two control units is provided.
A control device for an internal combustion engine, comprising a fail-safe unit having a limited control function, and configured to operate the built-in fail-safe unit when the control unit main body is out of order. During normal operation, stop the power supply to the fail-safe unit of the other control unit,
A control device for an internal combustion engine, which is configured to supply power to a fail-safe unit of the other control unit when one control unit body fails.