JP3167352B2 - Engine misfire detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine misfire detecting apparatus for detecting misfires based on angular velocity fluctuations.

[0002]

2. Description of the Related Art Generally, when a misfire occurs, an engine torque is reduced and a rotation fluctuation occurs. Therefore, it is conventionally known to determine a misfire when the angular velocity fluctuation reaches a predetermined value or more. I have. By the way, when a vehicle is running on a rough road, torque is generated from the wheel side due to the influence of road surface irregularities, and when this torque is transmitted to the engine, an angular speed variation due to factors other than the above-described misfire occurs. However, there is a problem that it is difficult to determine a good misfire.

In order to solve such a problem, conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 58-184517, roughness determination is performed only for a predetermined time after detecting roughness (engine vibration). There is an engine vibration detection device configured to execute and then inhibit the roughness determination thereafter, thereby suppressing a malfunction due to road surface vibration or the like. When this engine vibration detection device is applied to the above-described engine misfire detection device, there is an advantage that a malfunction due to road surface vibration or the like can be prevented, but on the other hand, the misfire determination can be performed while the roughness determination is prohibited. Therefore, it is difficult to always perform misfire detection, and there has been a problem that quick misfire detection becomes impossible.

[0004]

According to the first aspect of the present invention, when the misfire is detected, the connection between the engine and the drive system is brought closer to the non-connection state, so that the engine is not affected by road surface vibrations. An object of the present invention is to provide an engine misfire detection device capable of performing misfire detection and performing prompt misfire detection.

According to a second aspect of the present invention, by releasing the lock-up clutch of the automatic transmission when a misfire is detected, the misfire can be detected at all times without being affected by road surface vibration. It is an object of the present invention to provide an engine misfire detection device capable of performing a misfire detection.

According to the third aspect of the present invention, by setting the slip ratio of the automatic transmission to a high slip ratio when a misfire is detected, the misfire can be always detected without being affected by road surface vibration. It is another object of the present invention to provide an engine misfire detection device capable of performing quick misfire detection.

According to a fourth aspect of the present invention, in addition to the object of the first aspect of the present invention, when a misfire is detected, a factor other than the ignition system as a cause of the misfire, such as an influence of an air-fuel ratio, is eliminated. An object of the present invention is to provide an engine misfire detection device capable of improving misfire detection accuracy.

[0008]

According to a first aspect of the present invention, there is provided an angular velocity fluctuation detecting means for detecting an angular velocity fluctuation of an engine, and wherein the angular velocity fluctuation detected by the angular velocity fluctuation detecting means is equal to or greater than a set value. An engine misfire detection device comprising misfire detection means for detecting misfire of an engine, wherein a road surface input prohibiting means for setting a connection state between the engine and a drive system to an approximate non-connection state or a non-connection state when a misfire is detected. It is a misfire detection device for an engine provided with the apparatus.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the engine is constituted by an engine with an automatic transmission, and a lock-up clutch of the automatic transmission when a misfire is detected. A misfire detection device for an engine, which is released to make the connection state between the engine and the drive system into a non-connection state.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, the slip amount between the engine with the automatic transmission and the input / output member of the torque converter converges to the target slip amount. An engine misfire detection device that sets a slip ratio of the automatic transmission to a high slip ratio when a misfire is detected, and brings a connection state between the engine and the drive system closer to a non-connection state. And

According to a fourth aspect of the present invention, in addition to the configuration of the first aspect of the present invention, there is provided an engine misfire detecting device for operating the misfire detecting means under a steady operation state of the engine. Features.

[0012]

According to the first aspect of the present invention, when the misfire is detected, the road surface input prohibiting means sets the connection state between the engine and the driving system to an approximate non-connection state or a non-connection state. The torque from the wheel side is transmitted to the engine, so that it is possible to prevent the occurrence of angular velocity fluctuation due to factors other than misfire. As a result, there is an effect that the misfire can be always detected without any influence of the road surface vibration, and the misfire can be quickly detected.

According to the invention described in claim 2 of the present invention,
When the misfire is detected, the above-mentioned road surface input prohibiting means releases the lock-up clutch of the automatic transmission, and makes the connection state between the engine and the drive system into the non-connection state.Therefore, the misfire always occurs without any influence of the road surface vibration. It is possible to perform the detection, and it is possible to execute the quick misfire detection.

According to the third aspect of the present invention,
When a misfire is detected, the road surface input prohibiting means sets the slip ratio of the automatic transmission (specifically, the slip ratio of the lock-up clutch) to a high slip ratio (a state close to the converter state), and connects the engine and the drive system. Near the uncoupled state, without any influence of road vibration,
There is an effect that misfire detection can be always performed, and quick misfire detection can be performed.

According to the invention described in claim 4 of the present invention,
In addition to the effect of the first aspect of the present invention, the misfire detection means operates under a steady operation state of the engine.
For example, the influence of the air-fuel ratio and the like can be eliminated, and as a result, there is an effect that the accuracy of misfire detection can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawing shows a misfire detecting device for a vehicle engine with an automatic transmission. In FIG. 1, an air flow meter 2 is connected to the rear of an air cleaner 1 for purifying intake air, and the air flow meter 2 detects the amount of intake air. It is configured as follows.

A throttle body 3 is connected to the rear of the above-mentioned air flow meter 2, and a throttle valve 4 as a control valve for controlling an intake air amount is disposed in a throttle chamber 4 in the throttle body 3. I have.

A surge tank 6 as an expansion chamber having a predetermined volume is connected to an intake passage downstream of the throttle valve 5, and an intake manifold 8 communicating with an intake port 7 is connected downstream of the surge tank 6. An injector 9 is provided in the intake manifold 8.

On the other hand, the above-described intake port 7 and exhaust port 12 which are appropriately communicated with the combustion chamber 11 of the vehicle engine 10 with an automatic transmission have an intake valve 13 which is opened and closed by a valve mechanism (not shown). Attach the exhaust valve 14 respectively,
Further, an ignition plug 16 having a spark gap facing the above-described combustion chamber 11 is attached to the cylinder head 15.

An O ₂ sensor 18 is disposed in an exhaust passage 17 communicating with the above-described exhaust port 12, and a catalytic converter 1 for detoxifying harmful gas is provided downstream of the exhaust passage 17.
While a so-called catalyst is connected, an engine water temperature sensor 22 is attached to a water jacket 21 formed on the outer periphery of the intake manifold 8, and a bypass passage 23 for bypassing the throttle valve 5 is provided. Is provided with an ISC valve 24 as an ISC (idle speed control) mechanism.

Incidentally, the automatic transmission 25 (hereinafter simply referred to as AT)
As shown in FIG. 2, the torque converter 26 is fixed to a front cover 28 connected to the engine output shaft 27 and one side of the case 29 and rotates integrally with the engine output shaft 27. A pump 30 and the pump 3
The pump 3 is rotatably provided on the other side of the front cover 28 and the case 29 so as to face the pump 3.
0, and is provided between the pump 30 and the turbine 31 so as to be driven when the speed ratio of the turbine speed to the pump speed is equal to or less than a predetermined value. Stator 3 that performs increasing action
2 and a lock-up clutch 33 interposed between the turbine 31 and the front cover 28 described above.

The rotation of the turbine 31 is output from the turbine shaft 34 and input to a transmission gear mechanism (not shown), and the lock-up clutch 33 is connected to the turbine shaft 34 so that the front cover 2
8, the engine output shaft 27 and the turbine shaft 34 are directly connected via the front cover 28 and the lock-up clutch 33.

A lock-up valve 36 and a converter line 3 are connected to the torque converter 26 by a main flow line 35 led from an oil pump (not shown).
7, hydraulic oil is introduced into the R chamber 38 on the turbine side,
The lock-up clutch 33 is constantly urged in the engagement direction by the pressure of the hydraulic oil, and an F chamber 39 between the lock-up clutch 33 and the front cover 28.
Is connected to a lock-up release line 40 led from the lock-up valve 36 described above, and hydraulic pressure (release pressure) is supplied from the lock-up release line 40 into the F chamber 39 described above.
Is introduced, the lock-up clutch 33 is released. Further, the torque converter 26 has a holding pressure valve 41.
A converter outline 43 for sending out the working oil to the oil cooler 42 is connected to the oil cooler 42 via the.

On the other hand, the lock-up valve 36 described above
A pressure regulating device including a spool 44 and a spring 45 for urging the spool 44 rightward in the drawing, and having the mainstream line 35 connected to both sides of the port 46 to which the lockup release line 40 is connected. A port 47 and a drain port 48 are provided.

A pilot line 49 for applying a pilot pressure to the spool 44 is connected to the right end of the lock-up valve 36 in the drawing, and a drain line 50 branched from the pilot line 49 and a tank 51. A duty solenoid valve 52 is provided between the two.

The duty solenoid valve 52 repeatedly turns ON and OFF at a predetermined duty ratio according to a control signal to open and close the drain line 50 in a very short cycle, thereby reducing the pilot pressure in the pilot line 49 to the above-described duty ratio. Adjust to the value corresponding to.

The pilot pressure is applied to the spool 44 of the lock-up valve 36 in a direction opposite to the urging force of the spring 45, and
4, the release pressure in the lock-up release line 40 acts in the same direction as the biasing force of the spring 45, and the spool 44 moves due to the relationship between the hydraulic pressure and the biasing force. The lock-up release pressure is controlled to a value corresponding to the above-mentioned pilot pressure, that is, the duty ratio of the duty solenoid valve 52, by communicating with the main flow line 35 (pressure adjustment port 47) or the drain port 48.

Here, when the duty ratio (the ON time ratio in one cycle of ON and OFF) is 0% (D = Dmin), the drain amount from the pilot line 49 becomes minimum, and
When the pilot pressure or the release pressure becomes maximum, the lockup clutch 33 is completely released (OFF),
When the duty ratio is 100% (D = Dmax), the above-mentioned drain amount becomes maximum and the pilot pressure or the release pressure becomes minimum, whereby the lock-up clutch 33 is completely engaged (ON). Then, the lock-up clutch 33 is brought into a slip state in an intermediate range of the duty ratio, and the slip amount of the lock-up clutch 33 is controlled in this region in accordance with the above-described duty ratio.

FIG. 3 shows a control circuit of the engine misfire detecting device.
O, the vehicle speed V from the vehicle speed sensor 54, the gear position detection signal from the inhibitor switch 55, the engine rotation speed Ne from the distributor 56, the rotation speed Nt of the turbine 31 from the turbine rotation sensor 57, and the crank angle from the crank angle sensor 58. Of the duty solenoid valve 5 in accordance with the program stored in the ROM
2, lock-up valve 36, lock-up clutch 3
3. Drive control of the misfire indicating lamp 61 and RAM 62
Stores necessary data such as data corresponding to the misfire determination threshold value Yo (see FIG. 6) and a map corresponding to the automatic shift diagram shown in FIG.

Here, the CPU 60 detects the angular velocity fluctuation of the engine (see the fourth step 84 in the flowchart shown in FIG. 6) and detects the current angular velocity fluctuation detected by the angular velocity fluctuation detecting means. Misfire detection means (FIG. 6) for comparing Y with a misfire determination threshold value Yo stored in the RAM 62 in advance to detect engine misfire.
And a road surface input prohibiting means for disengaging the lock-up clutch 33 of the AT 25 upon detection of a misfire and disengaging the connection between the engine and the drive system (see the flowchart shown in FIG. 5). 4th of
Step 74) and steady state determination means (see second steps 72 and 82 in the flowcharts shown in FIGS. 5 and 6) for determining whether the misfire detection condition is satisfied based on whether the engine is in a steady operation state. Doubles.

The operation of the thus configured engine misfire detection apparatus will be described below with reference to the flowcharts shown in FIGS. First, the lock-up release processing will be described with reference to the flowchart of FIG.

In a first step 71, the CPU 60 reads various necessary signals such as the engine speed Ne, the intake air amount Q, the output signal of the crank angle sensor and the like, and based on the relational expression CE = Q / Ne. To calculate the load CE.

Next, in a second step 72, the CPU 60 calculates the rotational deviation ΔNe and the load deviation ΔCE,
The engine 62 is stored in the RAM 62 in advance, and the rotation deviation threshold value α for steady state determination and the load deviation threshold value β for steady state determination are compared with the above-described calculation results. The engine steady operation is performed when ΔNe <α and ΔCE <β. Only when the process proceeds to the next third step 73,
When the engine is not operating normally, the process returns to the first step 71.

In the above-mentioned third step 73, the CPU 60 engages (ON) or disengages (OFF) the lock-up clutch 33 based on the duty ratio data of the control signal to the duty solenoid valve 52 stored in a predetermined area of the RAM 62, for example. ), The routine returns to the first step 71 when the lock-up clutch 33 is released, and returns to the fourth step 7 when the lock-up clutch 33 is engaged.
Move to 4.

In the fourth step 74, the CPU 60 releases the lock-up clutch 33 via the duty solenoid valve 52 and the lock-up valve 36 described above.

Next, a misfire detection process which is performed in parallel with the above-described lock-up release process (see FIG. 5) will be described with reference to the flowchart of FIG.

In a first step 81, the CPU 60 executes reading of various necessary signals such as the engine speed Ne, the intake air amount Q, the output signal of the crank angle sensor and the like, and based on the relational expression CE = Q / Ne. To calculate the load CE.

Next, in a second step 82, the CPU 60 calculates the rotational deviation ΔNe and the load deviation ΔCE,
The rotation deviation threshold value α for steady state determination and the load deviation threshold value β for steady state determination previously stored in the RAM 62 are compared with the above-mentioned calculation results, and the engine steady operation of ΔNe <α and ΔCE <β is performed. Only when the process proceeds to the next third step 83,
When the engine is not operating normally, the process returns to the first step 81.

In the above-mentioned third step 83, the CPU 60 calculates the angular velocity ω, and in the next fourth step 84, the CPU 60
0 calculates the angular velocity fluctuation amount Y based on the following equation. Y = ω
(I-1) -ω (i) where ω (i-1) is the previous angular velocity ω (i) is the current angular velocity.

Next, in a fifth step 85, the CPU 60 compares the angular velocity fluctuation amount Y calculated in the above-mentioned fourth step 84 with the misfire determination threshold value Yo to determine whether or not a misfire has occurred. When Yo is misfired, the process proceeds to the next sixth step 86. On the other hand, when Y <Yo is not misfired, the process returns to the first step 81. In the above-described sixth step 86, the CPU 60
Turns on the misfire indicator lamp 61 and ends a series of misfire detection processes.

As described above, when the misfire is detected, the road surface input prohibiting means (see the fourth step 74 in the flowchart of FIG. 5) releases the lock-up clutch 33 of the AT 25 to change the connection state with the engine drive system. Since the connection state is not established, torque from the wheel side is transmitted to the engine, and it is possible to prevent the occurrence of angular velocity fluctuation due to factors other than misfire. As a result, there is an effect that the misfire can be always detected without any influence of the road surface vibration, and the quick misfire can be detected.

In addition, the above-described misfire detection means (see the fifth step 85 in the flowchart of FIG. 6) operates under a steady operation state of the engine. In other words, the misfire detecting means is a steady state determining means (second step 7 in FIG. 5).
2, see the second step 82 in FIG. 6) only at the time of steady state determination, so that when a misfire is detected, factors other than the ignition system as a cause of the misfire, such as the influence of the air-fuel ratio, can be eliminated. There is an effect that the detection accuracy can be improved.

FIGS. 7 and 8 are flow charts showing another embodiment of the engine misfire detecting apparatus. 7 and 8, the circuit devices shown in FIGS. 1 to 3 and the map shown in FIG. 4 are used.

Here, the map shown in FIG. 4 shows the slip region S, the lockup region L, and the converter region C during acceleration, and the respective regions during deceleration are separately set by a map (not shown).

However, in the case of this embodiment, the CP shown in FIG.
U60 is an angular velocity fluctuation detecting means for detecting the angular velocity fluctuation of the engine (the fourth step 11 in the flowchart shown in FIG. 8).
1) and a misfire detection means (FIG. 8) for comparing the current angular velocity fluctuation amount Y detected by the angular velocity fluctuation detection means with a misfire determination threshold value Yo stored in the RAM 62 in advance to detect engine misfire. And a slip control for converging the slip amount between the input and output members of the torque converter 26 (here, the input member is the engine output shaft 27 and the output member is the turbine shaft 34) to the target slip amount. Means (see a routine R1 consisting of steps 102 to 105 in the flowchart of FIG. 7), and set the slip rate of the lock-up clutch 33 in the AT 25 to a high slip rate when a misfire is detected (in this embodiment, the duty rate D is set to an approximate minimum value). Set to
A road surface input prohibiting means (refer to a sixteenth step 106 in the flowchart of FIG. 7) for bringing the connection state between the engine and the driving system closer to the non-connection state, and whether the misfire detection condition is satisfied or not is determined based on whether the engine is in a steady operation state. (Step 11 in the flowchart of FIG. 7)
1. See second step 112 in flowchart of FIG. 8)
And also.

Next, the operation of the engine misfire detection device will be described with reference to the flowcharts shown in FIGS.

First, the duty ratio changing process will be described with reference to the flowchart of FIG. First step 91
The CPU 60 determines the engine speed Ne, the turbine speed Nt, the intake air amount Q, the vehicle speed V, the throttle opening TVO,
Various necessary signals such as a gear position signal and a crank angle sensor output signal are read.

Next, in a second step 92, the CPU 60 calculates the actual slip amount NS based on the following equation. NS = | Ne-Nt | Here, Ne is the engine speed, and Nt is the turbine speed.

Next, in a third step 93, the CPU 60 calculates a deviation ΔN of the slip amount based on the following equation. ΔN = Ns−No Here, NS is the actual slip amount, and No is the target slip amount.

Next, in a fourth step 94, the CPU 60 reads the vehicle speed V, the throttle opening TVO, the gear position signal already read in the above-mentioned first step 91 and the map previously stored in the RAM 62 (see FIG. 4). It is determined whether the current operation state is in the slip region S (see FIG. 4) of the torque converter 26 based on the following.
Then, the process proceeds to another eleventh step 101 in the slip region S.

In the above-described fifth step 95, the CPU 60 sets the deviation ΔN ′ of the previous slip amount to the deviation ΔN of the present slip amount, and then proceeds to the next sixth step 96. The CPU 60 determines whether the current operating state is in the lock-up area L (see FIG. 4) of the torque converter 26. When the current operating state is in the lock-up area L, the CPU 60 shifts to the next seventh step 97. The process proceeds to another ninth step 99.

In the above-mentioned seventh step 97, the CPU 60 calculates the rotational deviation ΔNe of the engine rotational speed Ne and the load deviation ΔCE, and then stores the rotational deviation threshold α for stationary determination stored in the RAM 62 in advance. By comparing the load deviation threshold value β for determination with the above calculation result, ΔNe <α
When the engine is in a steady state of ΔCE <β, it is considered that the misfire detection condition is satisfied, and the routine proceeds to the next ninth step 99. When the engine is not operating in a steady state, the misfire detection condition is not satisfied, and the routine proceeds to an eighth step 98.

In the above-mentioned eighth step 98, the CPU 60 sets the duty ratio D to the maximum value Dmax, while in the above-mentioned ninth step 99, the CPU 60 sets the duty ratio D to the minimum value Dmin, and In step 100, C
The PU 60 outputs a control signal to the duty solenoid valve 52.

That is, since the duty D = Dmax in the lock-up region L, the drain line 50 shown in FIG.
The amount of drain from the tank to the tank 51 is maximized, the lock-up clutch 33 is directly connected, and the
In this case, the duty ratio becomes D = min, so that the amount of drain that drains from the drain line 50 to the tank 51 in FIG. 2 is minimized, the converter is in a state where the lockup clutch 33 is completely released, and the duty ratio is D = Dmin, and lock-up clutch 3
3 is released.

By the way, if it is determined in the above-mentioned fourth step 94 that it is the slip area S, the above-described first step 94 is made.
Move to one step 101. This eleventh step 10
1, the CPU 60 determines the rotational deviation ΔN of the engine rotational speed Ne.
e and the load deviation ΔCE are calculated beforehand in the RAM
By comparing the rotation deviation threshold value α for steady-state determination and the load deviation threshold value β for steady-state determination stored in 62 with the above calculation result, engine steady operation with ΔNe <α and ΔCE <β At times, it is considered that the misfire detection condition is satisfied, and the process proceeds to the sixteenth step 106. On the other hand, when the engine is running in an unsteady state, it is considered that the misfire detection condition is not satisfied and the first routine in the routine R1 is performed.
The process proceeds to step 102 to execute slip control according to the routine R1.

This slip control is performed by the torque converter 2
The feedback control is performed so that the rotational speed deviation between the engine output shaft 27 (input member) and the turbine shaft 34 (output member), that is, the slip amount, converges to a predetermined target slip amount. This control is for preventing transmission of engine vibration to the transmission side while reducing fuel consumption deterioration when completely released.

That is, the twelfth step 102 described above
Then, the CPU 60 determines the control parameters A and B (constants or variables), and in the next thirteenth step 103, the CPU 6
0 calculates the feedback amount U (indicating the correction amount of the slip amount) based on the following equation.

U = A ・ ΔN + B ・ ΔN 'where ΔN is the actual slip amount Ns to the target slip amount No.
Is the current deviation obtained by subtracting the target slip amount No from the actual slip amount Ns.

Next, in a fourteenth step 104, the CPU 60
Calculates the duty ratio D based on the following equation.

D = D ′ + ΔD Here, D ′ is a previous duty ratio ΔD is a duty ratio correction amount set based on a map (not shown).

Next, in a fifteenth step 105, the CPU 60
Sets the deviation ΔN ′ of the previous slip amount to the deviation ΔN of the current slip amount, and then proceeds to the next tenth step 100. In this tenth step 100, the CPU 60
= D ′ + ΔD, in other words, the actual slip amount N
A control signal is output to the duty solenoid valve 52 so that s converges to the target slip amount No.

By the way, even after the slip area is determined in the fourth step 94, if it is determined in the eleventh step 101 that the misfire detection condition is satisfied, the slip control by the routine R1 is prohibited. Then, the flow shifts to the next sixteenth step 106.

In the sixteenth step 106, the CPU 60
Sets the duty ratio D to be substantially equal to the minimum duty ratio Dmin, and outputs a control signal to the duty solenoid valve 52 in the next tenth step 100 so that the duty ratio D becomes substantially equal to the above-described minimum duty ratio Dmin. Thus, the lock-up clutch 33 is set to a substantially converter state, and the connection state between the engine and the drive system is made closer to the non-connection state.

Next, a misfire detection process which is performed in parallel with the above-described duty ratio change process (see FIG. 7) will be described with reference to the flowchart of FIG. In a first step 111,
The CPU 60 reads various necessary signals such as an engine speed Ne, an intake air amount Q, and a crank angle sensor output signal, and calculates a load CE based on a relational expression of CE = Q / Ne.

Next, in a second step 112, the CPU 60 calculates the rotational deviation ΔNe and the load deviation ΔCE, and then calculates the rotational deviation threshold α for steady state determination and the load deviation for steady state stored in the RAM 62 in advance. The threshold value β is compared with the above-mentioned calculation result, and it is considered that the misfire detection condition is satisfied at the time of the engine steady operation of ΔNe <α and ΔCE <β, and the process proceeds to the next third step 113. Assuming that the misfire detection condition is not satisfied, the first step 11
Return to 1.

In the above third step 113, the CPU 60
Calculates the angular velocity ω, and in the next fourth step 114, CP
U60 calculates the angular velocity fluctuation amount Y based on the following equation. Y
= Ω (i-1) -ω (i) where ω (i-1) is the previous angular velocity ω (i) is the current angular velocity.

Next, in a fifth step 115, the CPU 60 calculates the angular velocity variation Y
Is compared with the misfire determination threshold value Yo to determine whether or not a misfire has occurred.
On the other hand, when Y <Y, the routine returns to the first step 111. In the sixth step 116 described above,
The CPU 60 turns on the misfire indicator lamp 61 and ends a series of misfire detection processes.

As described above, when the misfire is detected, the above-described road surface input prohibiting means (refer to the sixteenth step 106 in the flowchart of FIG. 7) operates the lockup clutch 33 of the AT 25.
Is set to a high slip ratio (a state close to the converter state) to bring the connected state between the engine and the drive system closer to the unconnected state, so that torque from the wheel side is transmitted to the engine and causes factors other than misfire. , The occurrence of angular velocity fluctuations can be prevented. As a result, it is possible to always perform misfire detection without being affected by road surface vibration,
There is an effect that quick misfire detection can be performed.

In addition, the above-described misfire detection means (see the fifth step 115 in the flowchart of FIG. 8) operates under a steady operation state of the engine. In other words,
This misfire detection means operates only at the time of steady-state determination by the steady-state determination means (refer to the eleventh step 101 in FIG. 7 and the second step 112 in FIG. 8). The influence of the fuel ratio and the like can be eliminated, and therefore, there is an effect that the accuracy of misfire detection can be improved.

In the correspondence between the configuration of the present invention and the above-described embodiment, the engine of the present invention corresponds to the engine 10 with the automatic transmission of the embodiment, and similarly, the automatic transmission corresponds to the AT25. The angular velocity variation detecting means of claim 1 corresponds to the fourth step 84 of the flowchart shown in FIG. 6 and the fourth step 114 of the flowchart shown in FIG. 8, and the misfire detecting means of claim 1 corresponds to the flowchart shown in FIG. The road surface input prohibiting means of claim 2 corresponds to the fifth step 85 of the flowchart shown in FIG. 8 and the fourth step 74 of the flowchart shown in FIG. Corresponds to the engine output shaft 27, the output member of claim 3 corresponds to the turbine shaft 34, and the slip control means of claim 3
The road surface input prohibiting means of claim 3 corresponds to the sixteenth step 106 of the flowchart shown in FIG. 7, but the present invention is limited to only the configuration of the above-described embodiment. For example, the sixteenth step 10 in the flowchart of FIG.
The processing in 6 may be set to D = Dmin, and may be configured to notify the driver of a misfire (misfire) by a warning means such as a buzzer instead of the misfire display.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a misfire detection device for an engine according to the present invention.

FIG. 2 is a system diagram showing a structure of a torque converter and a hydraulic circuit configuration.

FIG. 3 is a control circuit block diagram.

FIG. 4 is an explanatory diagram of a map stored in a RAM.

FIG. 5 is a flowchart showing lock-up release processing when a misfire is detected.

FIG. 6 is a flowchart showing a misfire detection process.

FIG. 7 is a flowchart showing a duty ratio changing process when a misfire is detected.

FIG. 8 is a flowchart showing a misfire detection process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine 25 ... AT 26 ... Torque converter 27 ... Engine output shaft 33 ... Lock-up clutch 34 ... Turbine shaft 74 ... Fourth step (road surface input prohibiting means) 84 ... Fourth step (angular velocity fluctuation detecting means) 85 ... Fifth Step (misfire detection means) 106 ... Sixteenth step (road surface input prohibition means) 114 ... Fourth step (angular velocity fluctuation detection means) 115 ... Fifth step (misfire detection means) R1 ... Routine (slip control means)

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiyuki Shinya 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 45/00 368 B60K 41/02 F02B 77/08 F02D 29/00 F16H 61/14

Claims (4)

(57) [Claims] An engine having an angular velocity fluctuation detecting means for detecting an angular velocity fluctuation of the engine, and a misfire detecting means for detecting a misfire of the engine when the angular velocity fluctuation detected by the angular velocity fluctuation detecting means is equal to or more than a set value. What is claimed is: 1. A misfire detection device, comprising: a road surface input prohibiting unit that sets a connection state between an engine and a drive system to an approximately non-connection state or a non-connection state when a misfire is detected. 2. The engine according to claim 1, wherein the engine is an engine with an automatic transmission, and when a misfire is detected, a lock-up clutch of the automatic transmission is released to disconnect the engine from the drive system. Engine misfire detection device. 3. An engine with an automatic transmission, and a slip control means for converging a slip amount between input and output members of the torque converter to a target slip amount, wherein the slip ratio of the automatic transmission is increased to a high slip ratio when misfire is detected. 2. The engine misfire detection device according to claim 1, wherein the setting is such that the connection state between the engine and the drive train is made closer to the non-connection state. 4. An engine misfire detecting apparatus according to claim 1, wherein said misfire detecting means is operated under a steady operation state of the engine.