Vehicle-mounted engine control apparatus

• US 7,962,274 B2
• Filed: 03/31/2008
• Issued: 06/14/2011
• Est. Priority Date: 07/27/2007
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yonezawa, Shiro, Hashimoto, Koji, Tsunekazu, Shoso
• Primary Examiner(s): Cronin; Stephen K
• Assistant Examiner(s): Hoang; Johnny H
• Application Number:
  US12/059,829
• Publication Number:
  US 20090030587A1
• Time in Patent Office: 1,170 Days
• Field of Search: 701101-105, 701/110, 701112-115, 123/458, 123/496, 123/497, 7311422-11425, 731/144.1, 731/144.5, 731/144.9, 731/146.3
• US Class Current: 701/103
• CPC Class Codes: F02D 2041/227 Limping Home, i.e. taking specific engine control measures at abnormal conditions
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/105 using asynchronous injection
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue
• CPC Class Codes: F02D 41/28 Interface circuits

Abstract

In an vehicle-mounted engine control apparatus according to the present invention, a restart inspection mechanism, which is simpler than an activation inspection mechanism, is provided, and the mechanism to be applied is selected by an initialization determination device. The contents of the restart inspection are limited to malfunction items detected by a periodic code inspector during driving of the vehicle. As a result, the time required to restart a microprocessor when a malfunction occurs is shortened.

Claims

1. An vehicle-mounted engine control apparatus comprising:

a microprocessor for controlling an engine driving device, in response to an operation status of a driving-condition detection sensor in a multicylinder vehicle engine;

a fuel injection control means for collaborating with the microprocessor so as to sequentially open and drive a fuel injection valve, in synchronization with an operation status of a crank angle sensor;

a program memory incorporating self-diagnosis means for initializing and restarting the microprocessor in the case where a malfunction occurs;

a RAM memory that is always supplied with electric power from an on-vehicle battery and a partial region of which is utilized as a keep memory for maintaining a storage state even in the case where a power switch is opened; and

a data memory in which, during a delayed power-supply period after the power switch is opened, important data that has been stored in a specific region of the RAM memory and transferred thereto is stored,

wherein the program memory further incorporates a control program including an activation inspection means or a restart inspection means that is selected by an initialization determination means and followed by an initialization means for performing writing setting of a predetermined default value for the RAM memory;

wherein the initialization determination means is a means for determining whether the activation inspection means, which is performed when an engine is activated, is to be performed or the restart inspection means, which is performed when a malfunction occurs in the microprocessor while the engine is running, is to be performed;

wherein the activation inspection means comprises a plurality of means, among self-diagnosis means, including a transfer inspection means for transferring content of the data memory to the RAM memory and detecting whether or not any bit information has intruded in the transferred data and whether or not any bit information in the transferred data has been lost, a code inspection means for detecting whether or not any bit information has intruded in the program memory and whether or not any bit information in the program memory has been lost, a reading/writing inspection means for inspecting whether or not reading from and writing in the RAM memory are normally performed, and

a disconnection inspection means for inspecting a power-supply circuit for an air-intake-valve driving actuator;

wherein the restart inspection means is a memory inspection means that includes at least one of the code inspection means for detecting whether or not any bit information has intruded in the program memory and whether or not any bit information in the program memory has been lost and the reading/writing inspection means for inspecting whether or not reading from and writing in the RAM memory are normally performed, and that is configured with self-diagnosis items that are simplified compared with the activation inspection means;

wherein the self-diagnosis means further include a periodic code inspection means that is approximately periodically performed during the operation of the microprocessor, with regard to partial regions of the program memory and the RAM memory, that resets the microprocessor so as to perform initialization and restart thereof when the occurrence of intrusion or loss of bit information is detected, and that sets a malfunction occurrence flag for a malfunction in the program memory or in the RAM memory; and

wherein the memory inspection means performed in the restart inspection means is to make inspection of a memory corresponding to the kind of the malfunction occurrence flag.

2. The vehicle-mounted engine control apparatus according to claim 1, wherein the program memory further incorporates a valve opening level control means for the air-intake-valve driving actuator and a control program corresponding to a limp-home drive means for driving and controlling an engine while the valve opening level control means is halted, and an external diagnosis circuit and a malfunction storage/determination circuit are added to the microprocessor;

wherein the external diagnosis circuit is formed of at least one of a watchdog timer that, when the period of a watchdog signal generated by the microprocessor exceeds a predetermined threshold value, generates a reset output so as to initialize and restart the microprocessor and a monitoring/controlling circuit that monitors controlling operation of the microprocessor and when a malfunction is detected, generates a main-portion-malfunction detection signal so as to initialize and restart the microprocessor;

wherein the malfunction storage/determination circuit is a counter circuit that counts an occurrence number of a reset signal inputted from the external diagnosis circuit to the microprocessor and an occurrence number of a self-checked-malfunction detection signal generated by the self-diagnosis means, and when the counted number exceeds a predetermined value, interrupts the electric power for the air-intake-valve driving actuator so as to make the limp-home drive means effective; and

wherein the counted present value of the counter circuit is reset by an initial pulse generated when the power switch is turned on, and

the microprocessor is activated by being initialized by the initial pulse.

3. The vehicle-mounted engine control apparatus according to claim 1,

wherein the program memory further incorporates a control program corresponding to an asynchronous fuel injection control means;

wherein the asynchronous fuel injection control means is to shorten the time period between the preliminary stage in which initialization by at least the restart inspection means is completed, cylinder discrimination based on the crank angle sensor is completed, and then fuel injection control, which is in conjunction with and in synchronization with the operation of the crank angle sensor, is sequentially performed for each of the cylinders and the stage in which preliminary concurrent injection is performed for a plurality of cylinders, the microprocessor is reset, and then'"'"'the engine is driven again; and

wherein the asynchronous fuel injection control means utilizes at least one of a first asynchronous fuel injection control means for performing at once concurrent injection for every cylinder, in conjunction with the operations of the crank angle sensor, and a second asynchronous fuel injection control means for performing at once concurrent group injection only for a cylinder group that incorporates a cylinder in which the fuel is required to be injected, after discrimination of the cylinder group, which is configured with cylinders among which injection timings differ by at least two strokes, is performed.

4. The vehicle-mounted engine control apparatus according to claim 1, wherein the initialization determination means is determined based on the logic state of an initial flag;

the initial flag is set by a flag setting means after the activation inspection means is performed, and reset when the power switch is turned on; and

when the initial flag has not been set, the activation inspection means is performed, but when the initial flag has been set, the restart inspection means is performed.

5. The vehicle-mounted engine control apparatus according to claim 1, wherein the initialization determination means is determined based on the content of a determination memory,

wherein a specific address in the RAM memory is designated to the determination memory;

after the activation inspection means is performed, a first specific numerical value is written in the determination memory by a determination memory setting means; and

during a delayed power-supply period after the power switch is opened, a second specific numerical value other than the first specific numerical value is written in determination memory by a determination memory rewriting means, and

wherein, in the case where the content of the determination memory is a value other than the first specific numerical value, the activation inspection means is performed; and

in the case where the content of the determination memory coincides with the first specific numerical value, the restart inspection means is performed.

6. The vehicle-mounted engine control apparatus according to claim 5, wherein the program memory further incorporates a control program corresponding to an instantaneous-power-failure processing means;

and

wherein the instantaneous-power-failure processing means is a means that is caused to operate by an interrupt signal of top priority being inputted to the microprocessor when the power switch is closed and the terminal voltage of the power source abnormally decreases, and that writes in the determination memory the second specific numerical value or a third specific numerical value, other than the first specific numerical value.

7. The vehicle-mounted engine control apparatus according to claim 1, wherein, in the periodic code inspection means, the code inspection means for the program memory is divided into a plurality of blocks and then the plurality of blocks is performed;

the malfunction occurrence flag related to a malfunction in the program memory includes a plurality of flags corresponding to the respective inspection blocks; and

in the restart inspection means, code inspection on the program memory related to the block corresponding to a generated malfunction flag is performed.

8. The vehicle-mounted engine control apparatus according to claim 1, wherein, in the restart inspection means, memory inspection on the RAM memory is performed when the malfunction occurrence flag related to the RAM memory is activated by the periodic code inspection means, and memory inspections on both the program memory and the RAM memory are performed when the malfunction occurrence flag related to the program memory is activated.

9. The vehicle-mounted engine control apparatus according to claim 3, wherein, in the case where the vehicle-mounted engine is a port-injection-type multicylinder engine, the asynchronous fuel injection control means performed following the restart inspection means includes an early-injection determination means;

and the early-injection determination means is a means that operates so as to make the first asynchronous fuel injection control means effective, when memory inspection on the program memory is performed in the restart inspection means, and that makes the second asynchronous fuel injection control means effective, in the case where only memory inspection on the RAM memory is performed in the restart inspection means.

10. The vehicle-mounted engine control apparatus according to claim 3, wherein, in the case where the vehicle-mounted engine is a port-injection-type multicylinder engine, asynchronous injection necessity determination means that operates following the activation inspection means is provided;

and the asynchronous injection necessity determination means is a determination means for making the asynchronous fuel injection control means effective, when the engine rotation speed is the same as or lower than a predetermined value, the environmental temperature is the same as or lower than a predetermined value, and the voltage of an on-vehicle battery is the same as or lower than a predetermined value, and

wherein the asynchronous fuel injection control means that is performed based on the asynchronous injection necessity determination means includes an early-injection determination means;

the early-injection determination means makes the first asynchronous fuel injection control means effective, in the case where the ambient temperature and the voltage of the on-vehicle battery are each the same as or lower than the predetermined value, i.e., in inadequate conditions; and

in the case where the ambient temperature and the voltage of the on-vehicle battery are each the same or higher than the predetermined value, i.e., in adequate conditions, the early-injection determination means makes the second asynchronous fuel injection control means effective.

11. The vehicle-mounted engine control apparatus according to claim 3, wherein, in the case where the vehicle-mounted engine is a port-injection-type multicylinder engine, the first asynchronous fuel injection control means is a late control means in which, at the first fuel injection timing after the operation of cylinder discrimination control is started, fuel injection for every cylinder is performed, or an early control means in which, at the fuel injection timing immediately before the operation of the cylinder discrimination control is started, fuel injection for every cylinder is performed, and at the first fuel injection timing after the operation of the cylinder discrimination control is started, the fuel injection for every cylinder is interrupted.

12. The vehicle-mounted engine control apparatus according to claim 3, wherein, in the case where the vehicle-mounted engine is a direct-injection-type multicylinder engine, the asynchronous fuel injection control means utilizes only the second asynchronous fuel injection control means is utilized.

13. The vehicle-mounted engine control apparatus according to claim 2, wherein the monitoring/controlling circuit is serially connected to the microprocessor and is formed of an integrated circuit element including a buffer memory to which the program memory transfers control constants and a calculation circuit unit;

and part of a driving-condition detection sensor and part of an engine driving device are connected to the monitoring/controlling circuit,

wherein the monitoring/controlling circuit performs serial communication with the microprocessor, with regard to input/output signals, and generates an inquiry signal intended for the microprocessor; and

in the case where an answer signal, from the microprocessor, to the inquiry signal does not coincide with correct-solution information that has been preliminarily transferred from the program memory to the buffer memory, the monitoring/controlling circuit generates a main-portion-malfunction detection signal so as to reset and restart the microprocessor, and

wherein, when a malfunction occurs in the serial communication with the monitoring/controlling circuit, the microprocessor generates the assist-portion-malfunction detection signal, so that the malfunction storage/determination circuit adds and counts the occurrence of the malfunction; and

furthermore, based on the assist-portion-malfunction detection signal, the monitoring/controlling circuit initializes the buffer memory.

14. The vehicle-mounted engine control apparatus according to claim 2, wherein the monitoring/controlling circuit is formed of an auxiliary microprocessor serially connected to the microprocessor;

the auxiliary microprocessor includes an auxiliary program memory and an auxiliary RAM memory that collaborate therewith;

the program memory transfers control constants to the auxiliary RAM memory;

part of a driving-condition detection sensor and part of an engine driving device are connected to the auxiliary microprocessor;

the auxiliary microprocessor serially communicates with the microprocessor with regard to input and output signals and generates an inquiry signal intended for the microprocessor, and in the case where an answer signal, from the microprocessor, to the inquiry signal does not coincide with correct-solution information that has been preliminarily transferred from the program memory to the auxiliary RAM memory, the auxiliary microprocessor generates a main-portion-malfunction detection signal so as to reset and restart the microprocessor, and

wherein, when the pulse width of a watchdog signal generated by the auxiliary microprocessor exceeds a predetermined value, the microprocessor generates a assist-portion-malfunction detection signal, so that the malfunction storage/determination circuit adds and counts the occurrence of a malfunction; and

at the same time, based on the assist-portion-malfunction detection signal, the auxiliary microprocessor initializes the auxiliary RAM memory.