JP2000257498A - Self-diagnostic system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent misdiagnosis by detecting faults, while the engine of an automatic stop vehicle is operating, and deciding fault when integrated value of fault detection is above the first setting value, and prohibiting engine stop for the predetermined period, when the integrated value is larger than the second setting value (< the first setting value). SOLUTION: In controlling an engine 2 by a controller 16, when diagnosis conditions and range conditions are satisfied, monitor clamp, a process to fix a correction factor of air-fuel ratio to a certain value when air-fuel ratio correction reaches the limit of rich or lean side, is detected. Every time the monitor clamp is detected, an integrated value N is added, and results of the addition made is compared with a setting value CMC1. When N>=CMC1, an engine stop prohibit flag is set to 1 to make the engine stop. Next, the integrated value N and a setting value CMC2 (>CMC1) are compared. When N>=CMC2, NG deciding processing is conducted, and then engine stop prohibit process is canceled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle self-diagnosis device having a function of automatically stopping an engine when engine output is not required.

[0002]

2. Description of the Related Art An engine and a motor (a rotating electric machine serving both as an electric motor and a generator) as power sources for a vehicle.
A hybrid vehicle having both of them and running with one or both driving forces is known (for example, “Automotive Engineering” VOL.46 No.7 199 issued by Railway Japan Co., Ltd.)
(June 19, pp. 39-52). In such a hybrid vehicle, the engine is stopped when the engine output is unnecessary, such as when the vehicle is running only by the motor or when the vehicle is stopped. In addition to a hybrid vehicle, in a so-called idle stop vehicle, the engine is stopped when the vehicle stops to save fuel consumption.

There is known a self-diagnosis device which automatically detects an abnormality of an engine so that a mechanic can easily grasp the cause of a failure or the like. If the present invention is applied to a vehicle in which the engine is temporarily stopped, there arises a problem that accurate failure diagnosis cannot be performed. In other words, it is conceivable to provide a backup circuit for storing the abnormality detection history just before the engine is stopped, and to take over the stored contents after the engine is started. In addition, there is a possibility that the accuracy of diagnosis may be reduced or erroneous diagnosis may be caused due to a change in the atmospheric condition during the stop of the engine.

The present invention has been made in view of such a problem, and aims to solve the conventional problem by temporarily prohibiting the stop of the engine when a probability of abnormality occurs. I have to.

[0005]

According to a first aspect of the present invention, there is provided an engine automatic stop vehicle for automatically stopping an engine when output is not required. A failure determination device that performs a failure determination when is equal to or greater than a first set value; and a failure determination device that determines whether the integrated value is equal to or greater than a second set value that is set to be smaller than the first set value. An engine stop prohibition device that prohibits automatic stop for a predetermined period is provided.

According to a second aspect of the present invention, there is provided the engine stop prohibiting device according to one of the following conditions: when a predetermined stop prohibition time has elapsed, or when an integrated value of abnormality detection becomes equal to or greater than a first set value. The engine stop prohibition is released when the condition is satisfied.

According to a third aspect of the present invention, the first aspect of the present invention is applied to an idle stop vehicle that automatically stops idle operation when the vehicle is stopped.

According to a fourth aspect of the present invention, there is provided a hybrid according to the first aspect of the present invention, further comprising a rotating electric machine as a power source in addition to the engine, wherein the engine is stopped when the driving state by the engine is not required. Applies to vehicles.

According to a fifth aspect of the present invention, a monitor clamp state of the air-fuel ratio control device for performing feedback control of the fuel supply amount based on a signal from the exhaust oxygen sensor or the air-fuel ratio sensor in the failure determination device according to the first aspect of the present invention. When detection of is detected, integration of abnormality detection is performed.

According to a sixth aspect of the present invention, the engine stop prohibiting device according to the fifth aspect of the present invention includes an engine control device for increasing the load or the rotational speed of the engine during the engine stop prohibiting period.

According to a seventh aspect of the present invention, the engine stop prohibition device according to the fifth aspect of the invention corrects a shift schedule of the automatic transmission in a direction in which the engine speed is relatively increased during the engine stop prohibition period. The device was provided.

[0012]

According to the first and second aspects of the present invention, the failure determination device determines whether the integrated value of abnormality detection during engine operation is equal to the first value.
Is determined to have failed when the set value is reached. After the failure is determined, the automatic stop of the engine is generally performed when a predetermined stop condition is satisfied and when the engine is determined to require no engine output. However, if the integrated value of abnormality detection is the second
If it is not less than the set value and less than the first set value, the engine stop control is temporarily prohibited by the engine stop prohibition device. As a result, the abnormality detection is continued under the condition in which the abnormality is detected and the occurrence of the failure is predicted. Therefore, when the abnormality has occurred, it is necessary to more reliably detect the abnormality and make a highly accurate failure determination. Becomes possible.

The period during which the engine stop is prohibited is set, for example, until a predetermined time elapses as described in the second aspect of the present invention or until the integrated value of the abnormality detection becomes equal to or more than the first set value. can do. If the first set value is not reached even after a certain period of time has elapsed after the integrated value has become equal to or larger than the second set value, it can be considered that no serious failure has occurred, and the engine is stopped. Release the ban. Further, if the integrated value reaches the first set value, a failure determination is made. Therefore, it is not necessary to prohibit the engine from being stopped any longer. Deterioration of fuel efficiency and exhaust performance can be minimized.

According to a third aspect of the present invention, there is provided a vehicle for automatically stopping an engine.
Alternatively, as described in the invention of the fourth aspect, an idle-stop vehicle that automatically stops idle operation when the vehicle is stopped, or a rotating electric machine as a power source in addition to the engine and stops the engine when the driving state is not required by the engine. According to the present invention, the self-diagnosis of the engine can be performed more appropriately in these vehicles.

According to the fifth aspect of the present invention, the abnormality detection is integrated when the monitor clamp state of the air-fuel ratio control device for feedback-controlling the fuel supply amount based on the signal from the exhaust oxygen sensor or the air-fuel ratio sensor is detected. The monitor clamp detects a deviation from a target air-fuel ratio based on a signal from an air-fuel ratio sensor and corrects a fuel supply amount to the engine in a direction approaching the target air-fuel ratio in accordance with the deviation. This is a state in which the correction coefficient reaches a limit value at which further correction cannot be performed due to a system failure or the like, and is kept constant. This monitor clamp is integrated for each control cycle, and when a certain amount, that is, in this case, exceeds the first set value, it is determined that a failure has occurred, and thereafter, for example, the air-fuel ratio control by an open loop is performed. An air-fuel ratio abnormality represented by a monitor clamp is an abnormality that should be detected with the highest priority in engines that require precise fuel control.
It is important to accurately perform this failure determination from the viewpoint of minimizing deterioration of fuel efficiency and exhaust performance of the engine.
Therefore, according to the present invention, the failure determination can be performed with higher accuracy, and the original purpose of the failure diagnosis can be better achieved.

According to a sixth aspect of the present invention, the engine stop prohibiting device according to the fifth aspect of the present invention includes an engine control device for increasing the load or the rotation speed of the engine during the engine stop prohibiting period. When the monitor clamp is generated, the frequency of detection as an abnormality increases as the load or rotation speed of the engine increases, and the failure can be determined in a shorter time, so that the accuracy of the failure determination is improved. .

According to a seventh aspect of the present invention, there is provided the engine stop prohibiting device according to the fifth aspect of the present invention, wherein the shift schedule of the automatic transmission is corrected in a direction in which the engine speed is relatively increased during the engine stop prohibition period. A device is provided. By correcting the shift schedule of the automatic transmission in a direction in which the engine speed is relatively increased, the engine speed under the same operating conditions is increased as compared to before the shift schedule is changed. Thus, it is possible to increase the accuracy of failure detection.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. First, FIGS. 1 and 2 show a configuration example of a hybrid vehicle to which the present invention can be applied. This is a parallel-type hybrid vehicle that travels using the power of one or both of an engine and a motor according to traveling conditions. The power train of this vehicle includes a motor 1, an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a reduction gear 6, a differential gear 7, and driving wheels 8. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other. Motor 1 and engine 2
Are connected to each other via a reduction gear (not shown) having a predetermined rotation ratio. The output shaft of the clutch 3, the output shaft of the motor 4, and the input shaft of the continuously variable transmission 5 are connected to each other.

When the clutch 3 is engaged, the engine 2 and the motor 4
Is the propulsion source of the vehicle, and when the clutch 3 is released, only the motor 4 is the propulsion source of the vehicle. The driving force of the engine 2 or the motor 4 is controlled by a continuously variable transmission 5, a reduction gear 6, and a differential gear 7.
Is transmitted to the drive wheels 8 via the Pressure oil is supplied from the hydraulic device 9 to the continuously variable transmission 5 to clamp and lubricate the belt.

The motor 1 is mainly used for starting the engine and generating power, and the motor 4 is mainly used for power running and regenerative operation at the time of deceleration. The motor 10 is for driving the oil pump of the hydraulic device 9. However, when the clutch 3 is engaged, the motor 1 can be used for powering and braking of the vehicle,
The motor 4 can be used for starting the engine or generating power.
The clutch 3 is an electromagnetic powder clutch, and its transmission torque can be adjusted by current control.

The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. When a DC electric motor is used for the motors 1, 4, and 10, a DC / DC converter is used instead of the inverter. The inverters 11 to 13 are connected to a high-power battery 15 via a common DC link 14, convert DC power of the high-power battery 15 into AC power, supply the AC power to the motors 1, 4, 10, and Is converted into DC power to charge the high-power battery 15. Inverter 1
Since 1 to 13 are connected to each other via the DC link 14, the electric power generated by the motor during the regenerative operation can be directly supplied to the motor during the power running operation without passing through the high-power battery 15.

Reference numeral 16 denotes a controller having functions of various control circuits such as a failure determination device and an engine stop prohibiting device of the present invention. The controller 16 includes a microcomputer and its peripheral parts and various actuators.
It controls the rotation speed and output torque of the motors 1, 4, and 10, the speed ratio of the continuously variable transmission 5, the fuel injection amount and injection timing of the engine 2, the ignition timing, and the like.

As shown in FIG. 2, the controller 16 includes a key switch 20, a select lever switch 21,
Accelerator pedal sensor 22, brake switch 23, vehicle speed sensor 24, battery temperature sensor 25, battery SO
A C detection device 26, an engine speed sensor 27, and a throttle opening sensor 28 are connected. The selector lever switch 21 is provided for parking P, neutral N, and reverse R.
And P, N, depending on the set position of a select lever (not shown) for switching to any range of drive D.
One of the switches R and D is turned on.

The accelerator pedal sensor 22 detects the amount of depression of the accelerator pedal, and the brake switch 23 detects the state of depression of the brake pedal. Vehicle speed sensor 24
Detects the running speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the high-power battery 15. The battery SOC detection device 26 detects an SOC (State Of Charge) that is a representative value of the actual capacity of the high-power battery 15. The engine speed sensor 27 detects the speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.

The controller 16 further includes an engine 2
Fuel injection device 30, ignition device 31, variable valve operating device 32
Are connected. The controller 16 controls the fuel injection device 30 to supply and stop the fuel to the engine 2 and adjust the fuel injection amount and the injection timing.
1 to control the ignition timing of the engine 2. Also,
The controller 16 controls the variable valve operating device 32 to adjust the operating states of the intake and exhaust valves of the engine 2. The controller 16 is supplied with power from a low-voltage auxiliary battery 33.

The above is an example of a basic configuration of a hybrid vehicle to which the present invention can be applied. In the present invention, self-diagnosis of an engine in a vehicle in which the engine is automatically stopped during operation such as the hybrid vehicle is described. It aims to improve accuracy. An embodiment of the control contents of the controller 16 for this purpose will be described below with reference to FIGS.

FIG. 3 is a flowchart showing an outline of the engine stop prohibition control according to the present invention. This control is performed by the controller 1
6 is executed periodically as part of vehicle / engine control. In this control, initially, an engine stop prohibition flag #EGOPR, a counter integrated value N of the number of monitor clamps, and a timer value T of an elapsed time from the start of engine stop prohibition are set.
Are initialized to 0 (step 301). # Above
EGOPR is referred to in an engine stop control (not shown). When #EGOPR is 0, engine stop is permitted.
When it is 1, stopping the engine is prohibited.

Next, it is determined whether the diagnosis condition and the region condition are satisfied (steps 302 and 303). The diagnosis condition is whether or not the engine is in an operating state in which the engine can be diagnosed. For example, when the engine is forcibly stopped by a driver's key switch operation or the like during the diagnosis, the subsequent diagnosis becomes impossible. The above #EGOPR, N, and T are initialized to prepare for the next and subsequent diagnoses (step 304). Further, since this control is based on the detection of a monitor clamp indicating an abnormal state of the air-fuel ratio feedback control, the engine rotation sensor 27 and the throttle opening degree are determined as operating conditions under which the air-fuel ratio feedback control is performed as a region condition. The determination is made based on the operation state signal from the sensor 28 or the like. When the engine is detected to be in an operation range where the air-fuel ratio feedback control is not performed, for example, during deceleration fuel cut or idling, no diagnosis is performed.

When the diagnosis condition and the region condition are satisfied, a monitor clamp is detected next (step 30).
5). The monitor clamp is a process for clamping the air-fuel ratio correction coefficient to a constant value when the air-fuel ratio correction reaches the limit on the rich side or lean side as described above. In general, in the air-fuel ratio feedback control of the engine, as shown in the following equation, the fuel supply amount Te is changed to a basic fuel amount Tp determined from a map search based on the engine speed and the intake air amount to various values determined by the coolant temperature or the like. It is determined by multiplying the correction coefficient Co by the air-fuel ratio correction coefficient ALPHA.

Te = Tp · Co · ALPHA The air-fuel ratio correction coefficient ALPHA is based on the deviation between the actual air-fuel ratio detected by the exhaust oxygen sensor or the air-fuel ratio sensor and the target air-fuel ratio, and the actual air-fuel ratio approaches the target air-fuel ratio. In this case, a correction amount for Te is given. The correction range is set to, for example, 1.25 to 0.75. If the air-fuel ratio is biased to the rich side due to a failure of the air-fuel ratio sensor or the like, the ALPHA
≦ 0.75 or ALPHA biased toward the lean side
When ≧ 1.25, further correction is impossible, and ALPHA = 1 is clamped to temporarily stop the feedback control.

In this control, each time the monitor clamp is detected, the integrated value N is added (step 306), the addition result is compared with the set value CMC1, and the monitor clamp detection process is repeated until N ≧ CMC1. (Step 308). The set value CMC1 corresponds to the second set value of the present invention, and is set to one or more appropriate values as a reference value of the number of monitor clamp occurrences at which failure occurrence is predicted. Here, if N ≧ CMC1, the engine stop prohibition flag #EGOPR is set to 1 to prohibit the engine from stopping, and then the integrated value N and the set value CMC2 are set.
(Where CMC2> CMC1) (steps 309 and 310). The set value CMC2 is the first value of the present invention.
And is a reference value for making a final failure determination with respect to the number of monitor clamp occurrences. Since it is not necessary to compare the integrated value N with the set value CMC1 after # EGOPR = 1, #EGOPR is referred to before the comparison by CMC1 (step 30).
7), when # EGOPR = 1, the comparison with CMC1 is bypassed, and the process directly proceeds to the comparison with CMC2.

Since the set value CMC2 is an original failure judgment reference value for the number of monitor clamp occurrences, N ≧ CMC
When the flag is 2, the NG determination process, for example, the process of turning on the monitor lamp of the self-diagnosis device, and then the flag #
EGOPR is reset to release the prohibition of the engine stop, and the integrated value N and the timer value T are initialized to 0, thereby terminating the failure diagnosis (step 314). In contrast, N
While <CMC2, the timer value T is updated (added), and the above processing is repeated until T reaches the reference value TMCON (steps 311 and 312).

If the timer value T reaches the reference value TMCON before the integrated value N of the number of monitor clamps reaches the set value CMC2, this indicates that the number of monitor clamp occurrences is CMC1.
Means that the frequency of occurrence of the monitor clamp after that is low is low, and it can be determined that it is not a serious failure state at present. Therefore, the flag #EGOPR is reset to cancel the prohibition of the engine stop, and the integrated value N After the timer value T is initialized to 0, the process returns to the beginning of the diagnostic processing (step 302) and starts a new diagnostic processing (step 313). If the integrated value N becomes equal to or larger than the set value CMC2 before the timer value T reaches the reference value TMCON, the error is determined as NG as described above.
A determination process (step 314) is performed.

FIG. 4 or FIG. 5 shows an example of a control operation by the engine stop prohibition control. Each of these shows a case of a rich abnormality in which the air-fuel ratio correction coefficient ALPHA reaches a limit value smaller than 1 (shown as “100%” in the figure). In addition, since CMC is set to 1, the flag #EGOPR is set to 1 with the first monitor clamp occurrence.
Is set to prohibit stopping the engine (ENG).

FIG. 4 shows that the timer value T is changed to the reference value TMC before the monitor clamp integrated value N reaches the set value CMC2 after the engine stop is inhibited by the first monitor clamp.
In this case, the prohibition of the engine stop is released (# EGOPR = 0) without performing the diagnosis NG process as described above. On the other hand, FIG. 5 shows a case where the monitor clamp integrated value N reaches the set value CMC2 before the timer value T reaches the reference value TMCON after the engine stop is inhibited by the first monitor clamp, and In this case, NG is determined when N = CMC2, and the prohibition of engine stop is released.

[Brief description of the drawings]

FIG.

FIG. 2 is a schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.

FIG. 3 is a flowchart showing one embodiment of control according to the present invention.

FIG.

FIG. 5 is an explanatory diagram of a control operation example by the control of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 motor 2 engine 3 clutch 4 motor (rotary electric machine) 5 continuously variable transmission 9 hydraulic device 10 hydraulic pressure generation motor 15 battery 16 controller 19 DC / DC converter 20 key switch 21 select lever switch 22 accelerator pedal sensor 23 brake switch 24 vehicle speed Sensor 25 Battery temperature sensor 26 Battery SOC detection device 27 Engine speed sensor 28 Throttle opening sensor 33 Auxiliary battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02D 17/00 F02D 41/22 301G 5H115 29/02 321 F16H 61/10 41/22 301 B60K 9/00 Z F16H 61/10 F term (reference) 3G084 AA00 BA02 BA03 BA13 BA15 BA17 BA32 BA33 CA07 DA27 DA28 EA07 EA11 EB12 EB22 EC01 FA03 FA05 FA06 FA10 FA20 FA26 FA29 FA33 3G092 AB02 AC02 AC03 BA03 BA09 BB01 BB01 CA01 EA01 EA02 EA02 EB04 EC01 FA30 FB06 GA10 HA06Z HD05Z HE01Z HE08Z HF02Z HF12Z HF21Z HF26Z 3G093 AA07 BA22 CA00 CA12 DA01 DA05 DA06 DA13 DB05 DB11 DB15 EA00 EA02 NEEA EA03 EA13 EB03 FA07 FA11 FB03 FB01 FB02 PE01Z PE08Z PF01Z PF03Z PF05Z PF08Z PG01Z 3J052 AA11 BA13 DA02 DA03 EA04 FA01 FB31 GC04 GC13 G C23 GC46 GC64 LA01 5H115 PG04 PI15 PI16 PI29 PU02 PU08 PU22 PU24 PU25 PU29 PV02 PV09 QN02 QN12 RB08 RE01 RE05 RE20 SE05 SE08 TB01 TE02 TE03 TE04 TI01 TI10 TO21 TO23 TR20

Claims (7)

[Claims] In an automatic stop vehicle for automatically stopping an engine when output is not required, when an abnormality during operation of the engine is detected and an integrated value of the abnormality detection becomes equal to or greater than a first set value. A failure determination device that performs a failure determination on the engine; and an engine stop that prohibits the automatic stop of the engine for a predetermined period when the integrated value is equal to or greater than a second set value that is set smaller than the first set value. A self-diagnosis device for a vehicle, comprising a prohibition device. 2. The engine stop prohibition device according to claim 1, wherein when a predetermined stop prohibition time elapses or when an integrated value of abnormality detection becomes equal to or more than a first set value, the engine stop prohibition device is activated. The vehicle self-diagnosis device according to claim 1, wherein the stop prohibition of the vehicle is released. 3. The self-diagnosis device for a vehicle according to claim 1, wherein the vehicle with the engine automatically stopped is an idle stop vehicle that automatically stops idle operation when the vehicle is stopped. 4. The hybrid vehicle according to claim 1, wherein the engine automatic stop vehicle is provided with a rotating electric machine as a power source in addition to the engine, and stops the engine when the vehicle is in an operation state in which no driving force is required by the engine. A self-diagnosis device for a vehicle according to the above. 5. The failure determination device according to claim 1, wherein when the monitor clamp state of the air-fuel ratio control device for feedback-controlling the fuel supply amount based on a signal from the exhaust oxygen sensor or the air-fuel ratio sensor is detected, the abnormality detection is integrated. Item 2. The vehicle self-diagnosis device according to Item 1. 6. The vehicle self-diagnosis device according to claim 5, wherein the engine stop prohibition device includes an engine control device that increases an engine load or a rotation speed during the engine stop prohibition period. 7. The vehicle according to claim 5, wherein the engine stop prohibition device includes a shift schedule correction device that corrects a shift schedule of the automatic transmission in a direction in which the engine speed increases relatively during the engine stop prohibition period. Diagnostic device.