JP3475603B2 - Engine intake characteristics control 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 improvement in an engine intake air quality control device.

[0002]

2. Description of the Related Art In order to prevent the fuel evaporated in a fuel tank of a vehicle from being released into the atmosphere, the evaporated fuel is adsorbed by activated carbon in a canister when the engine is stopped, and it is taken in during operation of the engine. A canister purge system is provided in which vaporized fuel is desorbed from the activated carbon in the canister by the outside air introduced into the canister using the suction negative pressure generated in the pipe to guide it to the intake passage.

For example, an engine canister purge system disclosed in Japanese Utility Model Laid-Open No. 3-271554 includes a purge passage connecting a canister and an intake passage downstream of a throttle valve, and a purge control valve for opening and closing the purge passage. The amount of purge gas introduced into the intake passage via the purge control valve is adjusted in accordance with the operating state of.

[0004]

However, such a conventional engine canister purge system has the following problems.
The valve body of the purge control valve may stick due to an adhesive substance such as carbon, which may cause a stick.
When the purge control valve is left open due to this stick and the valve closing operation becomes impossible, a large amount of evaporated fuel is introduced into the intake passage depending on the operating conditions immediately after startup, and is sucked into the combustion chamber of the engine. As a result, the air-fuel ratio of the air-fuel mixture to be disturbed may be disturbed, and an engine stall may occur in which the operation of the engine is stopped.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and to provide an intake characteristic control device for an engine, which copes with a failure of a purge control valve or the like and secures the drivability of the engine.

[0006]

According to a first aspect of the present invention, there is provided an intake air quality control device for an engine, comprising: a transportation passage 102 for transporting an additive substance that influences the intake air characteristic to an intake passage 101, as shown in FIG. Intake property control valve 103 which is interposed in the transport passage 102 and regulates the transport amount of the additive substance
And the intake property control valve 10 in the transportation passage 102.
3, a cut valve 104 which is installed in series with the valve 3 to open and close the transportation passage 102, an intake property control means 105 which controls the opening of the intake property control valve 103 and the opening and closing of the cut valve 104 according to operating conditions, and a cut valve 104
There the engine stall detecting means 106 for detecting that the engine stall in the operating state of being opened transport passage 102 occurs, cut
Operating state in which the valve 104 opens the transportation passage 102
The number of engine stalls, CPENST, at which a stall occurred
Intake property control when the value exceeds PCENST
The valve 103 is diagnosed as abnormal and cut.
Fail-seal that shuts off the valve to block the transport of additive substances
And a fail-safe control.
The means is the last engine stall number CPEN even after the engine is stopped.
ST is stored in memory and engine operation is restarted.
The number of stallings, CPENST, is reduced each time
The number of times CPENST is less than the predetermined value PRENST
Restarts the transport of the additive through the cut valve if
It will be configured .

According to another aspect of the present invention, there is provided an intake characteristic control device for an engine, wherein an additive substance having an influence on the intake characteristic is added to the intake passage 1.
01 to the transportation passage 102 and to the transportation passage 102
Intake property control that is installed to control the transport rate of additive substances
Control valve 103 and the transfer passage 102 to the intake property control.
The transport passage 102 is installed in series with the roll valve 103.
A cut valve 104 for opening and closing a suction according to the operating conditions
Opening and cut valve of temper control valve 103
The intake characteristics control means 105 for controlling the opening and closing of the 104, mosquitoes
Operating condition in which the control valve 104 has opened the transportation passage 102
Detection engine that detects the occurrence of engine stall
The stage 106 and the cut valve 104 open the transportation passage 102.
Number of engine stalls that caused an engine stall in the running condition
Suck when PENST exceeds a specified value PCENST
Abnormality in the temper control valve 103
After that, the cut valve is closed to block the transport of additive substances.
And a fail-safe control means 107 for disconnection, the full
The fail-safe control means ensures that the vehicle speed is below a predetermined value.
Or the engine stall that occurred when the engine was idle
The number of times is not added to the number of times of stalling .

[0008]

[0009]

According to a third aspect of the present invention, there is provided an intake characteristic control device for an engine according to the first or second aspect , further comprising a canister which communicates with a fuel tank and adsorbs evaporated fuel, and the canister serves as the transportation passage. A purge passage for introducing the desorbed evaporated fuel into the intake passage is provided, and the operation time in which the cut valve as the fail-safe control means opens the purge passage is within a predetermined time TMPEST # and the purge passage is opened. When the engine stall count CPENST at which the engine stall occurs exceeds a predetermined value PCENST, it is diagnosed that an abnormality has occurred in the intake property control valve, and the cut valve is closed to interrupt the introduction of the evaporated fuel.

[0011]

In the engine intake air quality control device according to claim 1, the fail-safe control means 107 adds the engine stall count CPENST in which the engine stall occurs in the operating state in which the cut valve 104 opens the transportation passage 102 ,
The stalling count CPENST is greater than or equal to the predetermined value PCENST
Abnormality in the intake characteristics control valve 103 when it becomes is diagnosed as occurring, closes the cut valve 104
Blocking trafficking of additive material Te. As a result, a large amount of the additive substance can be prevented from being introduced all at once into the intake passage, and the engine properties can be prevented from being disturbed by disturbing the properties of the fuel sucked into the combustion chamber of the engine. Fail-safe control means
Is the number of engine stalls CP each time the engine is restarted.
There is no increase in the number of engine stalls by reducing ENST.
If the control valve returns to normal,
Then open the cut valve to restart the transport of the additive substance.
You can

In the engine intake air quality control device according to claim 2, the fail-safe control means 107 is
Operating state in which the valve 104 opens the transportation passage 102
Add the number of stallings that occurred at
However, the stalling count CPENST is less than or equal to a predetermined value PCENST.
If it goes up, the intake property control valve 103
It is diagnosed that an abnormality has occurred, and the cut valve 104 is closed.
Valve to block additional material transport. This allows a large amount of
Prevents the additive substance from being introduced all at once into the intake passage,
Ensues by disturbing the properties of the fuel drawn into the combustion chamber of the engine
Can be prevented. In addition, fail-safe system
The control means is such that the speed of the vehicle is below a predetermined value or
The number of stalls that occurred when Jin's idle stalls
Since it is not added to the number, the clutch operation error occurs when the vehicle starts.
The number of stallings caused by storms etc.
It is possible to avoid adding to T and obtain high diagnostic accuracy.
It

[0013]

[0014]

According to a third aspect of the invention, the intake air of the engine is
If the engine stalls repeatedly during purging immediately after startup in the property control device , it is diagnosed as a failure of the intake property control valve and the opening operation of the cut valve is prohibited to prevent the canister from operating when the engine is stopped. A large amount of vaporized fuel adsorbed on the engine is prevented from being introduced all at once into the intake passage, and a sudden change in the amount of vaporized fuel disturbs the air-fuel ratio of the air-fuel mixture drawn into the combustion chamber of the engine, causing an engine stall. Can be prevented.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an engine 1 mounted on an automobile sucks intake air (mixture) into a cylinder 4 from an intake passage 3 as an intake valve is opened, and the intake air is compressed by a piston 5. After igniting and burning through the spark plug, the exhaust gas is discharged to the exhaust passage 9 as the exhaust valve is opened, and these steps are continuously repeated.

An injector 14 for injecting fuel and a throttle valve 17 for throttled intake air in association with an accelerator pedal are provided in the middle of the intake passage 3, and an air flow meter 18 for detecting the intake air amount is provided upstream thereof. To be

A three-way catalytic converter (not shown) is installed in the exhaust passage 9 to oxidize HC and CO in the exhaust and reduce NOx.

In FIG. 1, 20 is a fuel tank, and 2 is a canister for adsorbing the evaporated fuel generated in the fuel tank 20. The fuel evaporated in the fuel tank 20 is guided to the canister 2 via the charge passage 19 and adsorbed on the activated carbon 8 in the canister 2.

A purge passage (transport passage) 6 for introducing a purge gas containing evaporated fuel desorbed from the canister 2 into the intake passage 3 is provided.

A purge control valve (intake property control valve) 7 and a purge cut valve (cut valve) 10 are provided in series in the middle of the purge passage 6. When both the purge control valve 7 and the purge cut valve 10 are opened, the fresh air introduced into the canister 2 becomes the purge gas (additive substance) containing the evaporated fuel desorbed from the activated carbon 8, and passes through the purge passage 6 and the intake passage 3
Inhaled into.

The purge control valve 7 is driven by a step motor and its opening is continuously adjusted to adjust the amount of purge gas transported.

The purge cut valve 10 is driven to open and close via a diaphragm actuator, and when negative suction pressure is introduced to the diaphragm actuator via the solenoid valve 11, the purge passage 6 is opened, and the diaphragm actuator is opened via the solenoid valve 11. When the atmospheric pressure is introduced, the purge passage 6 is blocked by the urging force of the return spring.

A control unit 13 for controlling the opening / closing operation of the purge control valve 7 and the purge cut valve 10, the fuel injection amount from the injector 14, etc.
Is provided.

The control unit 13 inputs the intake air amount Qa detected by the air flow meter 18, the engine speed N detected by the engine speed sensor 19, the cooling water temperature Tw detected by the cooling water temperature sensor, and the like. Then, the basic fuel injection amount Tp is calculated according to the operating state.

An O ₂ sensor 16 is installed in the middle of the exhaust passage 9. The control unit 13 includes an O ₂ sensor 16
Input the output VO ₂ according to the oxygen concentration in the exhaust gas detected at, and feedback control the fuel injection amount so that the air-fuel mixture becomes the stoichiometric air-fuel ratio, and maximize the conversion efficiency of the three-way catalyst 15. To maintain.

In the fuel injection control, the basic injection amount Tp is calculated based on the detected intake air amount Qa and the engine speed N.
Tp = K · Qa / N (1) However, after calculating from K; a constant, the final fuel is adjusted so that the air-fuel ratio falls within a narrow range around the stoichiometric air-fuel ratio in the predetermined stoichiometric range. The fuel injection amount is feedback-controlled by calculating the fuel injection amount Ti by the following equation.

Ti = Tp × α × COEF + Ts (2) where α is the air-fuel ratio feedback correction coefficient, COEF
Is the sum of various correction coefficients using the cooling water temperature Tw as a parameter, and Ts is the invalid injection pulse width.

A pulse signal corresponding to the calculated fuel injection amount Ti is output to each injector 14 to control the fuel injection.

The control unit 13 inputs the vehicle speed detected by the vehicle speed sensor 21, the signal from the idle switch 22 and the like, opens and closes the purge control valve 7 and the purge cut valve 10 according to the operating conditions, and outputs from the canister 2. The purging gas is introduced into the intake passage 3.

The timing chart of FIG. 2 shows an example of controlling the purge rate to the intake passage 3 and the purge cut valve 10.

To explain this, after the engine 1 is started, the purge rate is gradually increased for the purpose of preventing engine stalling. And when the elapsed time from the start of purging exceeds a predetermined time, in order to obtain a constant purging rate,
The opening degree of the purge control valve 7 is continuously adjusted. This allows the canister 2 to operate while the engine 1 is stopped.
A large amount of the evaporated fuel adsorbed inside is prevented from being introduced into the intake passage 3 at once, and a sudden change in the evaporated fuel amount is prevented from disturbing the air-fuel ratio of the air-fuel mixture sucked into the combustion chamber of the engine. .

Further, under the purge cut condition such that the vehicle speed becomes 0, for example, the purge cut valve 10 is closed and the introduction of the evaporated fuel is stopped while the vehicle is stopped.

By the way, in the canister purge system of the engine 1 as described above, the purge control valve 7 is used.
There is a possibility that a valve element driven by the step motor of (3) sticks by an adhesive substance such as carbon, that is, a so-called stick occurs. When the purge control valve 7 remains open and the valve closing operation becomes impossible due to this stick, a large amount of evaporated fuel is introduced into the intake passage and is sucked into the combustion chamber of the engine 1 depending on operating conditions. This may disturb the air-fuel ratio of the air-fuel mixture and may cause engine stall that stops the operation of the engine 1.

In response to this, the present invention provides an operation in which the purge cut valve 10 opens the purge passage 6 after the engine is started for a predetermined time TMPEST # and the purge cut valve 10 opens the purge passage 6. In the state
The stalling count CPENST generated by the stalling is added, and the stalling count CPENST is a predetermined value PCENST #.
When it becomes the above, it is diagnosed that an abnormality has occurred in the purge control valve 7, and the purge cut valve 10 is closed to perform the fail-safe control for interrupting the introduction of the evaporated fuel.

The timing chart of FIG. 3 shows an example of control for prohibiting the opening of the purge cut valve 10 when an abnormality occurs in which the opening of the purge control valve 7 cannot be adjusted.

Explaining this, when the vehicle speed exceeds a predetermined value (for example, 8 km / h), the purge cut valve 10 is opened, and the purge that introduces the evaporated fuel from the canister 2 into the intake passage 3 is performed.

The stalling count CPENST, which is a count of the number of engine stalls during the purge, is a predetermined value PCE.
When NST # is exceeded, it is considered that the purge control valve 7 has an abnormality in which the opening cannot be adjusted, and fail-safe control is performed to close the purge cut valve 10.

The flowchart of FIG. 4 shows a routine for prohibiting the opening of the purge cut valve 10 when an abnormality occurs in which the opening degree of the purge control valve 7 cannot be adjusted. The routine is executed by the control unit 13 at regular intervals. It

Explaining this, first, at step 1, it is judged whether or not the ignition switch is turned from OFF to ON.

Ignition switch from OFF to ON
At the time of starting, the process proceeds to step 2 and the engine stop count CPENST counted in the previous operation is decreased by one.

Then, in step 3, the purge time when the purge cut valve 10 is opened is the predetermined time TMPES.
Determine if T # is within.

While the purge time TMPEST # has not elapsed for the predetermined time, the routine proceeds to step 4, where it is determined whether an engine stall in which the engine speed of the engine 1 becomes 0 occurs.

When the engine stall occurs, the routine proceeds to step 5 where the number of times of stall CPENST, for example, two times CPENSTG # is added.

Subsequently, the routine proceeds to step 6, where it is judged whether or not purging is prohibited, and if purging is not prohibited, step 9 is carried out.
And the stalling count CPENST reaches a predetermined value PCENS.
It is determined whether T # or more.

If the number of engine stalls CPENST is greater than or equal to the predetermined value PCENST #, the process proceeds to step 8 to set the mode in which purging is prohibited.

On the other hand, if it is determined in step 6 that purging is prohibited, the process proceeds to step 7 and the engine stall count CPEN
It is determined whether ST is greater than or equal to a predetermined value PCENST #.

If the number of engine stalls CPENST is greater than or equal to the predetermined value PCENST #, the process proceeds to step 8 and the purge prohibit mode is continued.

The stalling count CPENST is a predetermined value PRE
If it is smaller than NST #, the routine proceeds to step 10 to cancel the purge prohibition mode.

As a result, if the engine stall occurs repeatedly during the purge immediately after the engine is started, it is diagnosed that the purge control valve 7 is out of order, and the opening operation of the purge cut valve 10 is prohibited. A large amount of evaporated fuel adsorbed in the canister 2 at the time of operation stop is prevented from being introduced into the intake passage 3 all at once, and a rapid change in the amount of evaporated fuel disturbs the air-fuel ratio of the air-fuel mixture sucked into the combustion chamber of the engine. It is possible to prevent an engine stall.

Further, since the diagnosis of the purge control valve 7 is performed during the purge in which the purge cut valve 10 is opened in step 3, it is not performed when the vehicle speed is equal to or lower than a predetermined value or when the vehicle is idling. It is possible to avoid adding an engine stall that occurs due to a clutch operation error, etc., to the engine stall count CPENST when the vehicle starts running, and to obtain high diagnostic accuracy.

An EGR passage (not shown) connecting the exhaust passage 9 and the intake passage 3 is provided. An EGR control valve for opening and closing the EGR passage and an EGR cut valve are installed in series in the EGR passage. Control unit 13
Controls the opening of the EGR control valve according to the operating conditions of the engine. As a result, the amount of inactive EGR gas introduced into the intake passage 3 is adjusted to suppress the generation of NOx.

However, even in such an EGR system of the engine 1, there is a possibility that a stick of the valve body of the EGR control valve sticks. If the stick causes the EGR control valve to remain open and the valve closing operation becomes impossible, a large amount of EGR gas is introduced into the intake passage depending on operating conditions and is mixed into the combustion chamber of the engine 1. This may disturb the air-fuel ratio of the air and cause an engine stall that stops the operation of the engine.

In response to this, after the engine is started, the number of engine stalls in which an engine stall has occurred is added in an operating state in which the EGR cut valve opens the EGR passage, and when the number of engine stalls exceeds a predetermined value, EGR control is performed. It is diagnosed that an abnormality has occurred in the valve, and the EGR cut valve is closed to perform fail-safe control for cutting off the introduction of EGR gas.

[0056]

As described above, in the engine intake air quality control device according to the first aspect, the cut valve has the transport passage.
The engine stall occurs when the engine stalls when the
Add the number CPENST
When the value exceeds the specified value PCENST, the intake property control
It is diagnosed that an abnormality has occurred in the roll valve, and when the abnormality occurs , the transport of the additive substance is blocked through the cut valve to prevent a large amount of the additive substance from being introduced into the intake passage, and the combustion chamber of the engine. It is possible to prevent the engine from being disturbed by disturbing the property of the fuel sucked into the engine. Also,
Whenever the operation of the engine is restarted,
By reducing it, the control valve will operate normally.
When returning, open the cut valve to transport the additive substance.
It can be restarted.

According to another aspect of the present invention, there is provided an engine intake air quality control apparatus, wherein the vehicle speed is equal to or lower than a predetermined value, or
The number of stallings that occurred when the engine was idle
Since it is not added to, the clutch operation mistake when starting the vehicle
The number of stallings caused by the number of stallings CPENST
Is added, and high diagnostic accuracy is obtained.
It

[0058]

[0059]

According to the third aspect of the present invention, in the engine canister purge system, when the engine stall occurs repeatedly during the purge immediately after the engine is started, it is diagnosed as a failure of the intake property control valve, and the cut valve is opened. By prohibiting the valve operation, a large amount of evaporated fuel adsorbed in the canister is prevented from being introduced into the intake passage at once when the engine is stopped, and a sudden change in the amount of evaporated fuel is sucked into the combustion chamber of the engine. It is possible to prevent engine stalling by disturbing the air-fuel ratio of the air-fuel mixture.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a timing chart of purge control during normal operation.

FIG. 3 is a timing chart when the purge control valve fails.

FIG. 4 is a flowchart showing the same control contents.

FIG. 5 is a claim correspondence diagram showing the invention according to claim 1;

[Explanation of symbols]

1 engine 2 canister 3 intake passage 6 Purge passage 7 Purge control valve 9 exhaust passage 10 Purge cut valve 13 Control unit 14 injectors 101 Intake passage 102 transportation corridor 103 Intake air quality control valve 104 cut valve 105 Intake property control means 106 stalling detection means 107 Fail-safe control means

Continuation of front page (56) Reference JP-A-6-101544 (JP, A) JP-A-6-101580 (JP, A) JP-A-5-272418 (JP, A) JP-A-7-174051 (JP , A) JP 61-104143 (JP, A) JP 7-189818 (JP, A) JP 6-221207 (JP, A) JP 7-139438 (JP, A) 63-57341 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02D 41/00 F02M 25/08

Claims (3)

(57) [Claims] 1. A transport passage for transporting an additive substance that affects the intake property to an intake passage, an intake property control valve interposed in the transport passage for adjusting the transport amount of the additive substance, and an intake property control for the transport passage. A cut valve that is installed in series with the valve to open and close the transport passage, an intake property control means that controls the opening of the intake property control valve and the opening and closing of the cut valve according to operating conditions, and the cut valve opens the transport passage. An engine stall detecting means for detecting the occurrence of engine stall in the operating condition and an operating condition in which the cut valve opens the transportation passage.
The number of engine stalls that occured is a predetermined value PCE
Intake property control valve when NST or more
After diagnosing that something abnormal has occurred, close the cut valve.
And a fail-safe control means that cuts off the transport of additive substances
The failsafe control means records the previous engine stall count CPENST even after the engine is stopped.
Each time the engine is restarted,
Reduce the number of stalling times CPENST, and reduce the number of stalling times CP
When ENST is less than the predetermined value PRENST
With the configuration that restarts the transport of the additive substance through the cut valve,
An intake characteristic control device for an engine characterized by the above . 2. An additive substance which affects the intake property is introduced into the intake gas.
A transport passage for transporting to the passage and an intake air that is interposed in the transport passage and regulates the transport amount of the additive substance
The property control valve is installed in series with the intake property control valve in the transport passage.
And the cut valve that opens and closes the transportation passage, and the opening degree of the intake property control valve according to operating conditions.
The intake property control means that controls the opening and closing of the cut valve and the operating state when the cut valve opens the transportation passage
And engine stall detecting means for detecting that the bets occurs, Enns in operating condition the cut valve was opened the transporting channel
The number of engine stalls that occured is a predetermined value PCE
Intake property control valve when NST or more
After diagnosing that something abnormal has occurred, close the cut valve.
And a fail-safe control means that cuts off the transport of additive substances
The fail-safe control means is configured such that the vehicle speed is equal to or lower than a predetermined value or the engine eye
Set the number of stallings that occurred at the time of dollars to the stalling count
An engine intake air quality control device characterized in that it does not add . 3. A fuel tank is communicated with and adsorbs evaporated fuel.
Equipped with a canister, the evaporated fuel desorbed from the canister as the transport passage.
Is equipped with a purge passage that introduces a cut valve into the intake passage.
Operation time when the passage is opened for a predetermined time TMPEST #
The engine is stalled within the operating range and the purge passage is open.
The number of engine stalls that occurred occurs CPENST is a predetermined value PCEN
When it becomes ST or more, it becomes the intake property control valve
Diagnose that something is wrong and close the cut valve.
It is characterized in that the introduction of evaporative fuel is blocked.
An intake air quality control device for an engine according to claim 1 or 2.
Place