JPH09236037A - Atmospheric pressure detecting method of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a stall caused by erroneous detection of atmospheric pressure thereafter by detecting and renewing atmospheric pressure at that time when the stall of an internal combustion engine caused by erroneous detection of atmospheric pressure is caused. SOLUTION: An engine is started on a flatland, and afterwards, it is moved up to a highland without stopping the engine, and an engine stall is caused on the highland, and when the engine is not restarted still in its stopping condition, whether or not an engine stall is caused is judged (S1). Next, whether or not a vehicle speed sensor is normal is judged (S2). Then, whether or not vehicle speed is 0km/h is judged (S3), and whether or not it is not restarted is judged (S4). Intake pipe pressure is renewed (S5) as atmospheric pressure from a supercharging pressure signal outputted by a pressure sensor. Therefore, when the engine is restarted on the highland thereafter, since operation is perfomed on a fuel injection quantity by using atmospheric pressure detected on the highland, a stall after a restart can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure detecting method for an internal combustion engine for an automobile, which detects the atmospheric pressure for air-fuel ratio control and the like.

[0002]

2. Description of the Related Art Conventionally, in a vehicle engine, a fuel injection type engine is known which is configured to determine a fuel injection amount based on an intake pressure and an engine speed.
In such an engine, a pressure sensor is attached to the intake system to detect intake pressure. Further, by using this pressure sensor, when the throttle valve is in the fully open position or in the vicinity of the fully open position during operation, as disclosed in, for example, Japanese Patent Laid-Open No. 3-199653,
It is also known that the intake pressure at that time is corrected according to the engine speed and the corrected pressure is used as the atmospheric pressure.

[0003]

By the way, as described above, when the atmospheric pressure is detected by using the pressure sensor under a specific driving condition, the intake pressure of the vehicle equipped with the turbocharger is reduced. Is pressurized, it may be difficult to use it as the atmospheric pressure even if the intake pressure is corrected.

In view of such circumstances, in an engine equipped with a turbocharger, for example, as shown in the flow chart of FIG. 3, when the first ignition switch is turned on before the engine is started, that is, the ignition switch is turned off. After the atmospheric pressure reading is initialized when the state is switched from ON to ON, the atmospheric pressure can be detected if the change in the intake pipe pressure within the predetermined time is within the predetermined value in the cranking state, etc. The ones that have been made are also known. In such an example, if the engine fails to start and the engine stops, for example, if the engine is stopped without operating the ignition switch after turning the engine on, that is, without turning off the ignition switch, restart the engine. In the configuration, the atmospheric pressure is controlled not to be detected.

In this type, when the engine is started on a level ground, atmospheric pressure is detected at that time, and when the vehicle stalls in that state, if a stall occurs, the engine is stopped with the ignition switch turned on. Will be done. When the engine is restarted from this state, the atmospheric pressure is not detected in the high altitude because it is different from the on / off condition of the ignition switch for detecting the atmospheric pressure. Therefore, even if the engine is restarted, it may stall again. In other words, normally, when the engine stalls, it is rare that the ignition switch is turned off and then turned on again to restart the engine. It is something that is not done.

An object of the present invention is to solve such a problem.

[0007]

The present invention takes the following means in order to achieve such an object. That is, the atmospheric pressure detection method for an internal combustion engine according to the present invention detects the intake pipe pressure of the internal combustion engine by a pressure sensor attached to the intake system, and determines the intake pipe pressure output by the pressure sensor under a predetermined condition as atmospheric pressure. A method for detecting the atmospheric pressure of an internal combustion engine, which detects that the internal combustion engine has stopped from the operating state and continues to stop, and when the stop continues, the intake pipe pressure at that time is detected. It is characterized in that the atmospheric pressure is detected and updated.

With such a structure, when the internal combustion engine stops completely from the operating state and is not restarted, the intake pipe pressure at that time is detected as the atmospheric pressure. , Is updated with the detected atmospheric pressure. Therefore, when the engine is restarted, it is updated to the atmospheric pressure after the internal combustion engine is stopped.For example, when the atmospheric pressure is taken into consideration in the air-fuel ratio correction control, the value of the atmospheric pressure is incorrect. Since the air-fuel ratio becomes abnormal due to the presence of the engine, it is possible to prevent the problem that the internal combustion engine is stopped immediately even if it is restarted.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention, when detecting a state in which an internal combustion engine is stopped from an operating state and is still stopped,
The intake pipe pressure is detected and updated as atmospheric pressure, and the atmospheric pressure is automatically detected immediately after the engine is stopped.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. The turbocharger schematically shown in FIG. 1 is installed in a four-cylinder engine for an automobile. The turbocharger 1 includes an exhaust turbine 2 that rotates by the energy of exhaust gas discharged from an engine.
And a compressor 3 driven by the exhaust turbine 2. Air introduced into the intake passage 5 through the air cleaner 4 can be compressed by the compressor 3 and supplied to the engine. Also,
A bypass passage 6 is provided for the exhaust turbine 2, and a waste gate valve 7 is opened and closed in the bypass passage 6 by a diaphragm type actuator 8.

The actuator 8 is a diaphragm chamber 8 biased rearward by a pressure adjusting spring (not shown).
When the pressure of the air introduced into the diaphragm chamber 8a exceeds a predetermined value defined by the pressure adjusting spring, the diaphragm 8a is displaced and the operating rod 8c moves forward. It is designed to operate in a protruding manner. The waste gate valve 7 is opened by the forward movement of the operating rod 8c. The diaphragm chamber 8b communicates with the compressor downstream side 5a of the intake passage 5 via the pressure guiding passage 9. In addition, this pressure guiding path 9
A valve body (not shown) that opens and closes the pressure release passage 10 branched from the middle of the above is operated by an electromagnetic actuator, and is switched to an open position only while a drive voltage is applied to the electromagnetic actuator. There is.

The opening / closing control valve 11 is duty-controlled by the electronic control unit 12 to be opened / closed. The electronic control unit 12 comprises a microcomputer system having a central processing unit (not shown), a memory, an input interface and an output interface. The input interface includes at least a signal a output from the throttle sensor 14 for detecting the opening degree of the throttle valve 13 interlocked with the accelerator pedal, and a pressure sensor 16 for detecting the pressure in the surge tank 15. Boosting pressure signal b, a cylinder determination signal (hereinafter referred to as N signal) G1, a crank angle reference position signal G2, and an engine speed signal output from a cam position sensor 17 for detecting the engine rotation state. c, the water temperature signal d output from the water temperature sensor 18 for detecting the engine cooling water temperature, and the vehicle speed signal e output from the vehicle speed sensor 19 for detecting the vehicle speed are respectively input. . A pulse voltage for driving is supplied from the output interface to the electromagnetic actuator of the opening / closing control valve 11.

The electronic control unit 12 has a built-in program for controlling the fuel injection amount based on the output signals from the above various sensors. In this program, the fuel injection amount is corrected according to the atmospheric pressure value. Further, in order to detect the atmospheric pressure, the intake pipe pressure of the engine is detected by the pressure sensor 16 attached to the surge tank 15, and the intake pipe pressure output by the pressure sensor 16 under a predetermined condition is detected as the atmospheric pressure. , It is detected that the engine has stopped from the operating state and continues to stop, and when the stop continues, the intake pipe pressure at that time is detected as atmospheric pressure and the atmospheric pressure is updated. It also contains a built-in program. The detected atmospheric pressure is stored in the electronic control unit 12 and is updated with the newly detected value when the atmospheric pressure is detected again under the above-mentioned conditions.

This atmospheric pressure detection program is schematically shown in FIG. Note that this program is executed with the ignition switch turned on, and even when the ignition switch is turned on when the engine is first started, when the conditions described below are satisfied. To be executed. As described above, since the atmospheric pressure is detected when the ignition switch is turned on and the conditions described below are satisfied, even in the engine in which the intake air is compressed by the turbocharger 1,
The pressure sensor 16 attached to the surge tank 15 can detect the atmospheric pressure.

First, in step S1, it is determined whether an engine stall has occurred. The determination of this stall is, for example, the last N signal G when the engine is rotating.
When the next N signal G1 is not input within a predetermined time after 1 is input to the electronic control unit 12, it is determined that the stall has occurred. Alternatively, the stall may be determined when the engine speed falls below a predetermined value. In step S2, the vehicle speed sensor 19
Is normal or not. This determination may be the same as that based on the diagnosis performed when the ignition switch is turned on. In step S3, the vehicle speed signal e
Then, it is determined whether the vehicle speed is 0 km / h. Step S4
Then, it is determined whether or not the engine is restarted based on whether or not the N signal G1 is input. In step S5, the intake pipe pressure PA is calculated from the boost pressure signal b output from the pressure sensor 16 at this time.
Update PM as atmospheric pressure.

A description will be given of a case in which the engine is started on a level ground, and then the engine is moved to a high level without being stopped, and an engine stall occurs at the high level in such a structure. That is, it is a case where after the engine is started on a flat ground, the vehicle travels to a high altitude where the atmospheric pressure is different and the engine is stopped at the high altitude. In this state, since the ignition switch is not operated, it remains in the position after starting, that is, the ignition on position. In this case, the atmospheric pressure stored in the electronic control unit 12 is detected on the flat ground and is different from that on the high ground. Therefore, at high altitudes, the fuel correction due to atmospheric pressure becomes erroneous and stall occurs.

First, when the vehicle is stopped at the time when the stall occurs and the engine is not restarted in the stopped state, steps S1 → S2 → S3 → S4 → S5 are executed, and the intake pipe pressure at that time is determined. The atmospheric pressure detected on the flat ground is updated as the atmospheric pressure. That is, the atmospheric pressure is automatically updated until the stall occurs and the engine is restarted. Therefore, when the engine is restarted in the highland after this, since the fuel injection amount is calculated using the atmospheric pressure detected in the highland, the fuel injection amount is an appropriate amount without excess or deficiency, Stall after restart can be prevented.

On the other hand, if the engine stalls when the vehicle speed is not 0 km / h and the vehicle is traveling downhill, the vehicle speed does not reach 0 km / h.
The process proceeds to steps S1 → S2 → S3 and proceeds to another routine without updating the atmospheric pressure. In this case, the engine piston is moving because the vehicle is moving because the vehicle is moving downhill even though the engine has stopped. As a result, the intake pipe pressure changes, so it is not detected as atmospheric pressure. Is.

Further, even when the vehicle is stopped, when restarted, the engine rotates, the turbocharger 1 operates, and the intake pipe pressure changes, so that the atmospheric pressure is detected and updated. Is not executed. In this case, the control proceeds to steps S1 → S2 → S3 → S4,
Move to another routine without updating the atmospheric pressure. In this way, when the engine stalls and the predetermined conditions are satisfied, the atmospheric pressure is detected and updated without operating the ignition switch, etc., so it is updated when restarting. Further, the fuel injection amount is controlled by the atmospheric pressure, and it is possible to prevent the stall from occurring again. Moreover, the atmospheric pressure is not detected during the period until the engine is started, that is, the atmospheric pressure is not detected immediately after the engine is started. The atmospheric pressure can be detected by the pressure sensor 16 attached to the tank 15.

The present invention is not limited to the above-described embodiment, but may be applied to a naturally aspirated engine in which the turbocharger 1 and the like are not mounted. In addition, the configuration of each unit is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0021]

As described above, according to the present invention, when the stall of the internal combustion engine due to the erroneous detection of the atmospheric pressure occurs, the atmospheric pressure at that time is detected and updated. It is possible to prevent stall due to erroneous detection of atmospheric pressure. Moreover, since the atmospheric pressure is detected while the internal combustion engine is stopped, it can be applied to an internal combustion engine equipped with a supercharging pressure device such as a turbocharger in the same manner as the naturally aspirated type. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a flowchart schematically showing a control procedure of the embodiment.

FIG. 3 is a flowchart schematically showing a control procedure of a conventional example.

[Explanation of symbols]

 1 ... Turbocharger 12 ... Electronic control device 15 ... Surge tank 16 ... Pressure sensor 17 ... Cam position 19 ... Vehicle speed sensor

Claims (1)

[Claims] 1. A method for detecting atmospheric pressure of an internal combustion engine, comprising detecting an intake pipe pressure of an internal combustion engine by a pressure sensor attached to an intake system, and detecting the intake pipe pressure output by the pressure sensor under a predetermined condition as atmospheric pressure. Therefore, it detects that the internal combustion engine has stopped from the operating state and continues to stop, and when the stop continues, it detects the intake pipe pressure at that time as atmospheric pressure and updates the atmospheric pressure. An atmospheric pressure detection method for an internal combustion engine, comprising: