JP2962030B2 - Engine fail-safe with electronic throttle control - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fail-safe device for an engine with an electronic throttle control device. 2. Description of the Related Art An electronic throttle control device for an engine includes a throttle actuator for opening and closing a throttle valve by a motor or the like, a throttle control module with a built-in microcomputer for controlling the throttle actuator based on an accelerator opening and the like. Is provided. Conventionally, as a fail-safe device of the electronic throttle control device, a failure of a throttle control system is self-diagnosed based on a sensor signal inputted thereto in a throttle control module, and the failure is diagnosed when a failure is detected. Some fail-safe logics are executed in accordance with the part or mode. However, in such a conventional fail-safe device, the self-diagnosis and the execution of the fail-safe logic in the throttle control module are performed. Failure may not be detected due to disconnection of the signal input line or the like. The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of a calculation for controlling a throttle actuator.
It is an object of the present invention to be able to perform appropriate fail-safe processing even when a failure of a failure detection by a control module to be performed or an abnormality of the control module itself occurs. Accordingly, as shown in FIG. 1, the present invention provides a throttle actuator for opening and closing a throttle valve, and a first control for performing an operation for controlling the throttle actuator. Module and calculation for fuel injection amount control or ignition timing control
A second control module that, in the electronic throttle control system with engine equipped with the first con
The first control module is added to the troll module.
Control based on sensor signals input directly to
System failure and diagnose the result of the diagnosis by the second controller.
Self-diagnosis means for outputting to the roll module;
When the result is a failure, the throttle actuator
The opening / closing drive of the throttle valve by the
While providing a first fail-safe means, wherein the second co
Control module, the second control module
Throttle control based on sensor signals input directly to the
Auxiliary diagnostic means for diagnosing a failure of the control system;
The diagnosis result input from the roll module is not a failure
Even if the diagnosis result by the auxiliary diagnosis means is
In case of failure, control the fuel injection amount or ignition timing
Second fail-safe means for reducing engine output;
To provide a fail-safe device for an engine with an electronic throttle control device. In the above configuration, the first control module
Module, based on the sensor signal input directly to this
To diagnose a failure in the throttle control system, and
In the event of an obstacle, the throttle
Stop the open / close drive of the throttle valve and fail-safe
Do. Further, the sensor signal input to the first control module is also input to the second control module,
Similarly to the first control module, the second control module diagnoses a failure in the throttle control system and compares the result with the self-diagnosis result of the first control module.
When the first control module does not detect a failure and the second control module detects a failure,
Assuming that the first control module cannot perform a normal failure diagnosis, the second control module lowers the engine output due to fuel cut or ignition timing retard of a part of the cylinders to perform fail-safe. An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows the device configuration. First, a throttle actuator for opening and closing the throttle valve 1 for adjusting the intake air amount of the engine will be described. A throttle valve return spring 2 for urging the throttle valve 1 in a closing direction is acted on. An accelerator drum 5 connected to an accelerator pedal 3 via a wire 4 is rotatably disposed on one end side of a valve shaft of the throttle valve 1, and the accelerator drum 5 has an accelerator drum return for urging the accelerator drum 5 in a closing direction. The spring 6 is operated. [0010] A first electromagnetic clutch 7 is interposed between the accelerator drum 5 and the throttle valve 1. The first electromagnetic clutch 7 is in a connected state when not energized and is in an open state when energized (normally closed). Also, on the other end of the valve shaft of the throttle valve 1,
A motor drum 9 driven by a DC motor 8 is rotatably arranged. A second electromagnetic clutch 10 is interposed between the motor drum 9 and the throttle valve 1.
The second electromagnetic clutch 10 is in an open state when not energized and in a connected state when energized (normally open). Therefore,
By energizing the first and second electromagnetic clutches 7 and 10, only the second electromagnetic clutch 10 is brought into the connected state, and the DC motor 8 can control opening and closing of the throttle valve 1, and the first and second electromagnetic clutches 7 and 10 can be controlled. By shutting off the power supply to 10, the throttle valve 1 can be directly opened and closed by the accelerator pedal 3 with only the first electromagnetic clutch 7 in the connected state. The throttle actuator (DC motor 8, first and second electromagnetic clutches 7, 10) is provided with a throttle.
Tool control module 20 (first control module)
Joule), to which signals are input from the following 11 to 18 sensor switches. In addition, below
Is TCM20 for the throttle control module 20
Will be explained. Reference numerals 11 and 12 denote accelerator sensors (dual system), which detect the accelerator opening Acc based on the rotation angle of the accelerator drum 5 and the depression angle of the accelerator pedal 3 by the output voltage of a potentiometer. Reference numeral 13 denotes a throttle sensor, which detects the throttle opening Tvo from the rotation angle of the throttle valve 1 based on the output voltage of a potentiometer. A vehicle speed sensor 14 outputs a pulse signal having a frequency proportional to the vehicle speed Vsp by an electromagnetic pickup or the like provided on a transmission output shaft. 15 is automatic constant vehicle speed control (ASCD control)
Is an ASCD set switch for instructing the start of the operation. Reference numeral 16 denotes an ASCD cancel switch for instructing cancellation of the automatic constant vehicle speed control (ASCD control). 17
Is an accelerator limit switch that is turned off only when the accelerator pedal 3 is not operated. Reference numeral 18 denotes a brake limit switch that is turned on only when a brake pedal (not shown) is not operated. The TCM 20 is composed of the following 21 to 24 blocks. 21 is a one-chip microcomputer, CPU,
ROM, RAM, A / D port, digital port, various timers, etc. are built in. When the system is normal, the microcomputer 21 outputs a CLUTCH signal instructing energization of the first and second electromagnetic clutches 7 and 10, and further calculates a target throttle opening based on various sensor / switch signals. The DIR signal indicating the forward / reverse rotation direction of the DC motor 8 and the D signal indicating the drive current of the DC motor 8 so that the actual throttle opening matches the target throttle opening.
Outputs UTY signal. When the system fails, the motor control signals (DIR, DUTY) and the clutch control signal (CLU)
TCH) is initialized, that is, an output for instructing interruption of the motor drive current and the clutch drive current is performed, and the DC motor 8
From the throttle control by the accelerator pedal 3 to the throttle direct drive. Reference numeral 22 denotes a DC motor drive circuit, which is a motor control signal (DIR, D
Based on (UTY), the motor drive current and the current direction are controlled such that only one of the pair of power transistors at the diagonal positions of the DC motor drive bridge circuit is turned on. Reference numeral 23 denotes a self-holding relay circuit,
Is turned on only after the set switch 15 is pressed.
Thereafter, the on state is maintained until the cancel switch 16 is pressed or the brake pedal is depressed to turn off the brake limit switch 18 or until the ignition switch (not shown) is turned off. Reference numeral 24 denotes an electromagnetic clutch drive circuit, which is a clutch control signal (CL
The power transistor is turned on / off based on (UTCH). The power transistor, the first electromagnetic clutch 7, and the second electromagnetic clutch 10 are connected in series. FIG. 3 shows a control operation performed by the microcomputer 21 of the TCM 20, which is executed at regular intervals (for example, 10 msec). At P1, self-diagnosis of a system failure is performed based on a sensor / switch signal or the like. This part corresponds to the self-diagnosis means. In P2, the determination is made based on the result of P1, and if there is a failure, the process proceeds to P3. In P3, the motor control signals (DIR, DU)
TY) and the clutch control signal (CLUTCH) are initialized to zero. Then, the process proceeds to P17 to be described later, and the output is turned off. This part corresponds to the first fail-safe means.
You. As a result, the drive current to the DC motor 8 is cut off and the rotation stops, and the first and second electromagnetic clutches 7 and
When the power supply to 10 is cut off, the first electromagnetic clutch 7 is engaged, and the second electromagnetic clutch 10 is released, so that the throttle control by the DC motor 8 is shifted to the throttle direct drive by the accelerator pedal 3. In this case, TC
The fault diagnostic signal FS _TCM output from M20 is set to 1 indicating a fault. In the normal state, the process proceeds to P4 and thereafter, and as the throttle control by the DC motor 8, the automatic constant vehicle speed control (ASCD control) without the accelerator pedal or the driving force characteristic seasoning control with the accelerator pedal depressed (ASCD control). Accelerator-by-wire control). In P4 to P6, the accelerator opening Ac
c, the throttle opening Tvo and the vehicle speed Vsp are read from each sensor and calculated. Then, the process proceeds to P7. At P7, it is determined from the value of the flag switch Fmode whether ASCD control or accelerator-by-wire control has been performed. If Fmode = 1 (during accelerator-by-wire control), the process proceeds to P8, where Fmode =
If 0 (during ASCD control), the process proceeds to P11. During the accelerator-by-wire control, at P8, it is determined whether the set switch 15 for instructing the start of the ASCD control has been turned on. If it is turned on, the process proceeds to P9 to start ASCD control; otherwise, to P15 to continue accelerator-by-wire control.
Proceed to. When shifting to the ASCD control, a flag switch Fmode = 0 is set at P9, and at the next P10, the current vehicle speed Vsp is stored as the target vehicle speed Vspr. And P
Proceed to 13. In P13, the calculation of the ASCD control is performed. That is, using a known control method such as PID control, a vehicle speed deviation (Vspr-Vs) between the current vehicle speed Vsp and the target vehicle speed Vspr.
The target throttle opening Tvor is calculated from p). Then, the process proceeds to P16. At P16, calculation of throttle servo control is performed. That is, the current throttle opening Tvo and the target throttle opening Tvo are determined by using a known control method such as PID control.
A DIR signal indicating a motor rotation direction and a DUTY signal indicating a motor drive current are calculated based on a throttle opening deviation (Tvor−Tvo) from vor. And P
Proceed to 17. At P17, the above-mentioned DIR and DUTY are written into a predetermined I / O register of the microcomputer 21, and these are output. During the ASCD control, at P11, it is determined whether or not the cancel switch 16 for instructing the cancellation of the ASCD control is turned on. If it is turned on, the process proceeds to P14 for starting the accelerator-by-wire control, and if not, the process proceeds to P12. At P12, it is determined whether or not the brake pedal is depressed from the on / off state of the brake limit switch 18. If the brake pedal is depressed, proceed to P14 to start accelerator-by-wire control;
Proceed to P13 to continue SCD control. When shifting to the accelerator-by-wire control, at P14, the flag switch Fmode =
Set 1 Then, the process proceeds to P15. At P15, an operation of accelerator-by-wire control is performed. That is, the target throttle opening Tvor is calculated from the current accelerator opening Acc based on the accelerator opening-throttle opening correspondence map predetermined in consideration of the characteristics of the engine and the vehicle. Then, the process proceeds to the calculation of the throttle servo control of P16 and the output of P17. As described above, in the normal state, the first and second electromagnetic clutches 7 and 10 are energized,
The first electromagnetic clutch 7 is in the released state, the second electromagnetic clutch
10 is connected, and the throttle control (ASCD control or accelerator-by-wire control) by the DC motor 8 is performed. On the other hand, the engine control module shown in FIG.
The fuel tank 31 (second control module) performs arithmetic processing based on signals from various sensors to control the fuel injection amount and the ignition timing.
Control output to In the following, the engine control
The module 30 will be described as an ECM 30. Here, the signals of the accelerator sensors 11 and 12, the throttle sensor 13 and the vehicle speed sensor 14 input to the TCM 20 are also input to the ECM 30, and the TCM 20 and the ECM 30 are connected by a communication line 40 to enable transmission and reception of signals. I have. Then, a diagnosis routine shown in FIG. 4 is executed at predetermined time intervals (for example, 10 msec) by a microcomputer built in the ECM 30. At P21, the accelerator opening Acc is read based on the signals from the accelerator sensors 21 and 22. In P22, the value of the throttle opening Tvo1 is calculated by calculation based on the read value of the accelerator opening Acc. At P23, the throttle opening Tvo is read based on the signal from the throttle sensor 23. In P24, P
The throttle opening Tvo1 calculated in 22 is compared with the value of the actual throttle opening Tvo read in P23. If they do not match, it is regarded as a failure, and the program proceeds to P25. At P25, a failure diagnosis signal FS _TCM which is a self-diagnosis result is read from the _{TCM 20} . At P26, it is determined whether the read fault diagnosis signal FS _TCM from the _{TCM 20} is 1 indicating a fault, and if FS _TCM = 0 (if the _TCM 20 determines that it is normal), the process proceeds to P27. That is, EC
When a failure is detected in M30 and no failure is detected in TCM20, it is considered that TCM20 cannot perform a normal failure diagnosis, and the process proceeds to P27. At P27, the output of the engine is reduced by cutting off the fuel of some of the cylinders, that is, by stopping the output of the fuel injection pulse signal to the fuel injection valves 31 of some of the cylinders. Or, by delaying the ignition timing of some or all cylinders,
The output of the engine is reduced by delaying the output of the ignition signal to 32. The portions P21 to P26 correspond to auxiliary diagnostic means, and the portion P27 corresponds to the second phase due to a decrease in engine output.
This is equivalent to a safe method . According to the present invention as described above, according to the present invention, the
Directly input to this in one control module
Diagnosis of throttle control system failure based on sensor signal
When the diagnosis result indicates a failure, the throttle
The opening and closing of the throttle valve by the tutor is stopped.
Thus, while fail-safe can be performed, a sensor signal input to the first control module is input to the second control module, and a self-diagnosis result of the first control module is input to the second control module, Diagnosis of throttle control system first
Not only the control module but also the second control module can be used to check the diagnosis result of the first control module. Therefore, when the normal failure diagnosis cannot be performed by the first control module, the second control module By performing the engine output reduction processing by the module, the effect of ensuring fail-safe performance can be obtained.

[Brief description of the drawings] FIG. 1 is a block diagram showing the configuration of the present invention. FIG. 2 is a system diagram showing one embodiment of the present invention. FIG. 3 is a flowchart showing processing contents of TCM. FIG. 4 is a flowchart showing processing contents of ECM. [Explanation of symbols] 1 Throttle valve 3 accelerator pedal 7 First electromagnetic clutch 8 DC motor 10 Second electromagnetic clutch 11,12 Accelerator sensor 13 Throttle sensor 14 Vehicle speed sensor 20 TCM (Throttle control module) 30 ECM (Engine Control Module) 40 Communication line

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/00-45/00 395

Claims (1)

(57) [Claims] A throttle actuator for opening and closing a throttle valve, a first control module for performing an operation for controlling the throttle actuator, and a fuel injection amount
Second control for performing calculations for control or ignition timing control
An engine with an electronic throttle control device comprising: a first control module;
Based on sensor signals input directly to the
Diagnose the failure of the rottle control system, and
Self-diagnosis means for outputting to the second control module
When the diagnosis result indicates a failure, the throttle
Opening / closing drive of the throttle valve by an actuator
And first fail-safe means for canceling
On the other hand, the second control module has the second control
Based on sensor signals input directly to the
Auxiliary diagnostic means for diagnosing a failure of the rottle control system;
The diagnostic result input from the first control module is
Even when it is not a failure, diagnosis by the auxiliary diagnostic means
If the disconnection result is a failure, the fuel injection amount or ignition timing
Second fail-safe to reduce engine output by controlling
Failsafe device for an electronic throttle control system with an engine, characterized by comprising a full unit.