JP2005016400A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a control device for an internal combustion engine providing retreating travel by using small and inexpensive solenoid valves. <P>SOLUTION: At the time of retreating travel when failures of an ETV 3 or an electric motor 3a, which is an intake throttle means, are detected by a failure detecting means 13e, the intake amount supplied to each cylinder 1a can be individually controlled by the individual solenoid valves 14 provided for each of the cylinders 1a, and intake amount variation of each of the cylinders 1a can be eliminated. In addition, the individual solenoid valves 14 controlling the intake amount of each of the cylinders 1a may be operated corresponding to each of the cylinders 1a, and solenoid valves of large size or having highly durable reliability are not required. Small solenoid valves enabling high speed response can be adopted, making it possible to provide an inexpensive device as a whole. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device related to control of the intake air amount of an internal combustion engine, and more particularly to a control device for an internal combustion engine for performing retreat travel when a part of the functions of the control device fails.
[0002]
[Prior art]
As the prior art, an electronically controlled throttle valve (hereinafter referred to as ETV) that electronically controls the intake air amount to the internal combustion engine is known, but when any trouble occurs in this type of ETV, There is a so-called limp home mechanism that performs evacuation operation to a repair shop. For example, when a problem occurs in the electronic control of the ETV provided in the intake manifold portion of the internal combustion engine having a plurality of cylinders, the motor is cut off and is energized by the rotating shaft of the butterfly valve that rotates the ETV. It is comprised so that it may return to an intermediate opening degree by two springs. The reason why the intermediate opening is set is to enable normal traveling in an urban area.
[0003]
In the ETV system that returns to the intermediate opening, the spring force that is urged at the boundary of the intermediate opening is different in the normal use state. Therefore, the motor that rotates against the spring force and rotates the butterfly is controlled. Gain is not constant. For this reason, a system is also known in which a butterfly is urged by a single spring so that the butterfly is fully closed in the event of a failure, and air necessary for the evacuation operation is supplied from an individual bypass passage that bypasses the butterfly.
[0004]
Furthermore, the intake throttle means for controlling the intake amount to the internal combustion engine having a plurality of cylinders is arranged in the independent intake pipe of each cylinder, and the intake responsiveness is only superior to the case where it is arranged in the collecting section of the intake pipe. In other words, it is known that the pumping loss of the engine is reduced and the fuel consumption is improved. Further, when the intake throttle means is provided in the independent intake pipe, the intake air amount control gain at a low opening of the valve becomes large and stable intake air amount control becomes difficult. Therefore, each independent intake pipe is communicated. It is disclosed that a communication pipe is provided and the balance of the intake air amount is obtained through the communication pipe (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2529692 (2nd page, FIG. 3)
[0006]
[Problems to be solved by the invention]
However, the prior art has the following problems. In the ETV system that returns to the intermediate opening, the internal combustion engine outputs in accordance with the amount of intake air that is regulated by the intermediate opening. For example, deceleration or stopping during the evacuation operation depends on the braking force. Therefore, when a great load is applied to the brake, a problem due to overheating of the brake occurs. In order to prevent the vehicle from being disabled as a result of this, an intermediate opening is set to an intake amount that allows retreating in an urban area.
[0007]
However, for example, a failure during high-speed traveling or a failure during traveling on an uphill road may cause a case where a sufficient internal combustion engine output cannot be obtained due to a shortage of intake air at a set intermediate opening. As a result, in the evacuation operation, a situation may occur in which the relative speed with other vehicles traveling on the road cannot be ensured. On the other hand, in the method of supplying from the individual bypass passage, it is conceivable to control the intake air amount during the evacuation operation with, for example, a linear solenoid valve or an ON / OFF duty solenoid valve. Therefore, a large solenoid valve for controlling a large amount of intake air is necessary, and an expensive limp home mechanism has to be used.
[0008]
In addition, the duty solenoid valve controls the intake air amount with a single solenoid valve. If the duty solenoid valve is turned ON / OFF in a cycle that is not synchronized with the rotational speed of the internal combustion engine, the intake air amount to each cylinder will differ, causing combustion spots or torque fluctuations. As a result, stable evacuation traveling becomes difficult. In order to perform bypass intake air amount control in synchronization with rotation, or to reduce intake variation to each cylinder while being asynchronous with rotation, ON / OFF control at high frequency is required, and durability reliability is high. It had to be an expensive limp home mechanism. Further, even in a device provided with a communication pipe, the intake air amount from the communication pipe is controlled by a single electromagnetic valve, and it is necessary to use a large-sized and highly reliable electromagnetic valve.
[0009]
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain an internal combustion engine control device that provides retreat travel using a small and inexpensive electromagnetic valve.
[0010]
[Means for Solving the Problems]
An internal combustion engine control apparatus according to the present invention includes an independent intake pipe connected to each cylinder of an internal combustion engine having a plurality of cylinders, a throttle unit for adjusting an intake air amount provided in each of the independent intake pipes, Intake throttle means for operating the throttle portion in conjunction, an individual bypass passage that bypasses the throttle portion of the independent intake pipe, an individual solenoid valve that adjusts the intake air amount that passes through the individual bypass passage, and an intake air amount of the independent intake pipe An intake air amount detecting means for detecting the intake air amount, a control means for adjusting an intake air amount supplied to each cylinder based on a detection result of the intake air amount detecting means and a set target intake air amount, and the intake air throttle means or the throttle portion A control unit for an internal combustion engine that detects a failure of the internal combustion engine, wherein the control unit normally has each throttle unit provided in an independent intake pipe based on the target intake air amount. The When a failure is detected by the failure detection means, the energization to the intake throttle means is cut off, the opening of the throttle portion is mechanically closed, and the control is switched to the control by the individual solenoid valve It is.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a control device for an internal combustion engine according to the present invention, and shows a case of four cylinders. The internal combustion engine 1 has a plurality of cylinders 1a, and an independent intake pipe 2 and an independent exhaust pipe 7 are connected to each of the plurality of cylinders 1a. Each independent intake pipe 2 has an intake valve 1b, and each independent exhaust pipe 7 has an exhaust valve 1c.
[0012]
Further, the independent intake pipe 2 is provided with an electronically controlled throttle valve 3 (hereinafter referred to as ETV 3) for electronically controlling the intake amount of each cylinder 1a. The electric motor 3a controls the intake air amount by moving the intake throttle valve of the ETV 3 in conjunction with it. Here, ETV3 corresponds to a throttle part, and the electric motor 3a corresponds to an intake throttle means. The ETV 3 is urged to return to the fully closed position mechanically by a return spring (not shown) when the electric motor 3a is not energized.
[0013]
An injection valve 4 that injects fuel toward each intake valve is provided downstream of the ETV 3. An air cleaner 6 is provided upstream of the intake air collecting portion 5 of each independent intake pipe 2. Furthermore, an air-fuel ratio sensor 9 that detects the air-fuel ratio of the internal combustion engine 1 is provided in the exhaust collecting portion 8 of the independent exhaust pipe 7. The internal combustion engine 1 is provided with a cylinder identification sensor 10 for determining the combustion stroke of each cylinder 1a and the rotational speed of the internal combustion engine 1 as cylinder identification means.
[0014]
Further, an individual bypass passage 11 for bypassing each intake throttle valve of the ETV 3 and allowing bypass air to flow in from the intake air collecting portion 5 is provided, and an individual electromagnetic valve 14 is arranged in the individual bypass passage 11 as an actuator for controlling the air flow rate. ing. The flow rate of air passing through the individual solenoid valve 14 is set so that the vehicle has a supply capacity of an intake flow rate for one cylinder that is sufficient when the vehicle is in a high load such as traveling on an uphill road or traveling at a high speed. Moreover, although the intake pressure sensor 12 which is an intake amount detection means is installed in each independent intake pipe 2, you may switch and measure for every stroke of each cylinder 1a.
[0015]
The control means 13 is a control means for calculating and controlling the intake air amount, the fuel amount and the ignition timing to the internal combustion engine 1, and the ETV control means 13a, the fuel amount control means 13b, the electromagnetic valve control means 13c and the intake air amount control described below. Each control means of the means 13d is included. Here, the intake air amount control means 13d calculates the amount of air charged into each cylinder 1a based on a target intake air amount set by an instruction of an accelerator pedal (not shown) operated by the driver. The intake air amount control means 13d controls the ETV 3 via the ETV control means 13a, and controls the individual electromagnetic valve 14 via the electromagnetic valve control means 13c.
[0016]
Further, the intake air amount control means 13d includes a failure detection means 13e, and the failure detection means 13e detects a failure of the ETV 3, the electric motor 3a, and the ETV control means 13a. When the failure detection means 13e detects a failure including the ETV 3, the ETV control means 13a stops energizing the motor 3a, and the electromagnetic valve control means 13c controls the individual electromagnetic valve 14 to control the individual bypass passage 11. Via each of the cylinders 1a.
[0017]
Normally, the air that has passed through the air cleaner 6 is supplied to each independent intake pipe 2 as the amount of air limited by the ETV 3 or the individual electromagnetic valve 14, and the intake pressure of the supplied air is detected by the intake pressure sensor 12. The fuel amount control means 13 b calculates an appropriate fuel amount for each cylinder based on the detection results of the intake pressure sensor 12 and the cylinder identification sensor 10, and controls the injection valve 4.
[0018]
The fuel amount control means 13b receives the output of the air-fuel ratio sensor 9 provided in the exhaust collecting portion 8 and performs a feedback control to precisely adjust the fuel amount. Further, the fuel amount control means 13b has ignition control means (not shown), and MBT (Minimum Spark Advance for Best) corresponding to a predetermined environment of the internal combustion engine.
Torque) or ignition control near MBT.
[0019]
The control by the individual bypass passage 11 and the individual electromagnetic valve 14 is effective not only in the case where a failure including the ETV 3 is detected by the failure detection means 13e but also in the intake air amount control at a low load such as idle. That is, the intake air amount control at the time of low load such as idling is performed by the individual electromagnetic valve 14 provided individually corresponding to the independent intake pipe 2 so as to compensate for the intake variation caused by the ETV 3. By feeding back the output value of the intake pressure sensor 12 provided individually, individual control can be performed for each independent intake pipe 2. Further, by feeding back the output of the air-fuel ratio sensor 9 provided in the exhaust collecting portion 8, the air-fuel ratio and the output of the internal combustion engine 1 can be controlled with higher accuracy.
[0020]
In particular, in the present invention, by using the cylinder identification sensor 10, the air flowing from the individual bypass passage 11 can be controlled to be supplied in synchronization with the rotation of the internal combustion engine 1, in other words, each stroke of the internal combustion engine 1. Therefore, there is little variation in the amount of intake air actually sucked into each cylinder 1a of the internal combustion engine 1, and the accuracy of measurement by the intake pressure sensor 12 is improved. Further, if the intake air amount through the individual bypass passage 11 is supplied while the intake valve 1b is closed as much as possible, the pumping loss of the internal combustion engine 1 is reduced. Therefore, the greater the supply capacity from the individual bypass passage 11, the better the fuel efficiency. Inhalation is possible.
[0021]
In the configuration of the present invention that performs the above operation, when the failure detection means 13e detects a failure including the ETV3 while the vehicle is running, the energization to the electric motor 3a is stopped and the ETV3 is applied by the biasing force of the spring. And the output control of the internal combustion engine 1 is performed only by the flow rate of the individual bypass passage 11. However, since the individual solenoid valve 14 performs duty control in synchronization with the rotation based on the detection result of the cylinder identification sensor 10, the charging intake air amount to each cylinder 1a from the high load to the low load within the setting range of the bypass flow rate. Can be controlled stably.
[0022]
Furthermore, since the range from the high load to the low load can be stably controlled as described above, smooth retreat travel according to the accelerator opening degree indicating the driver's intention is possible even during retreat travel. Since the individual bypass passages 11 are provided for each cylinder 1a, the individual solenoid valves 14 corresponding to the cylinders 1a can be made smaller than the solenoid valves required for collectively controlling the bypass flow rate, and can respond quickly. Therefore, even when a sudden failure occurs during high-speed driving or uphill driving, it is possible to perform evacuation while suppressing variations in intake air amount for each cylinder.
[0023]
According to the present embodiment, the intake air amount supplied to each cylinder can be individually controlled by the solenoid valve provided for each cylinder even during the retreat travel, and the intake air amount variation for each cylinder is eliminated. be able to. In addition, the solenoid valve that controls the intake air amount for each cylinder only needs to operate for each cylinder, and does not require a large or highly reliable one, but adopts a small solenoid valve that can respond quickly. Therefore, it is possible to provide an inexpensive apparatus as a whole.
[0024]
Furthermore, by setting the maximum value of the amount of intake air supplied to each cylinder from the individual bypass passage to an amount capable of traveling on an uphill road or traveling at high speed, the intake air amount can be controlled according to the engine demand output during the evacuation operation, The output control can be performed over a wide range from the idle state to the uphill traveling or the high speed traveling. As a result, even during retreating, deceleration or stopping can be performed without relying on the brake, and problems due to overheating of the brake can be prevented.
[0025]
Furthermore, since the amount of intake air supplied through the individual bypass passage can be controlled in synchronization with the rotation of the internal combustion engine, the variation in the amount of intake air actually taken into each cylinder of the internal combustion engine can be reduced, and the intake air can be reduced. The accuracy of measurement by the barometric sensor is also improved. In particular, by supplying air while the intake valve is closed, pumping loss can be reduced and intake with good fuel efficiency can be achieved.
[0026]
【The invention's effect】
As described above, according to the present invention, by providing an individual bypass passage that bypasses the throttle portion of the independent intake pipe and performing intake air amount control by the individual solenoid valve, retreat travel using a small and inexpensive solenoid valve is performed. The provided control device for an internal combustion engine can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a control device for an internal combustion engine according to the present invention.
[Explanation of Symbols] 1 Internal combustion engine, 1a cylinder, 1b Intake valve, 1c Exhaust valve, 2 Independent intake pipe, 3 ETV, 3a Electric motor, 4 Injection valve, 5 Intake collecting part, 6 Air cleaner, 7 Independent exhaust pipe, 8 Exhaust collecting unit, 9 air-fuel ratio sensor, 10 cylinder identification sensor, 11 individual bypass passage, 12 intake pressure sensor, 13 control means, 13a ETV control means, 13b fuel amount control means, 13c electromagnetic valve control means, 13d intake air amount control means , 13e Failure detection means, 14 Individual solenoid valve.

Claims (5)

An independent intake pipe connected to each cylinder of an internal combustion engine having a plurality of cylinders;
A throttle that adjusts the intake air amount provided in each of the independent intake pipes;
An intake throttle means for operating each throttle section in conjunction with each other;
An individual bypass passage for bypassing the throttle portion of the independent intake pipe;
An individual solenoid valve for adjusting the amount of intake air passing through the individual bypass passage;
An intake air amount detecting means for detecting an intake air amount of the independent intake pipe;
Control means for adjusting the amount of intake air supplied to each cylinder based on the detection result of the intake air amount detection means and the set target intake air amount;
A control device for an internal combustion engine comprising a failure detection means for detecting a failure of the intake throttle means or the throttle portion,
Normally, the control means causes the intake throttle means to operate each throttle portion provided in the independent intake pipe based on the target intake air amount,
When a failure is detected by the failure detection means, the energization to the intake throttle means is cut off, the opening of the throttle portion is mechanically closed, and the control is switched to the control by the individual solenoid valve. Control device for internal combustion engine. The control device for an internal combustion engine according to claim 1,
When the failure is detected by the failure detection means, the control means controls the individual electromagnetic valve according to the change in the target intake air amount so as to pass through the individual bypass passage and supply the intake air to each cylinder. A control apparatus for an internal combustion engine, wherein a retraction operation is performed by adjusting an amount. The control apparatus for an internal combustion engine according to claim 1 or 2,
The control device for an internal combustion engine, wherein the individual bypass passage and the individual solenoid valve have a supply capacity of an air flow rate required when a vehicle on which the internal combustion engine is mounted travels on an uphill road or travels at a high speed. The control apparatus for an internal combustion engine according to any one of claims 1 to 3,
The internal combustion engine includes cylinder identification means for detecting a combustion stroke of each cylinder,
The control device for an internal combustion engine, wherein the control means performs an intake air amount control that passes through the individual bypass passage by the individual electromagnetic valve based on a combustion stroke of each cylinder detected by the cylinder identification means. The control apparatus for an internal combustion engine according to claim 4,
The control means detects a closing period of each intake valve based on a combustion stroke of each cylinder detected by the cylinder identification means, and detects intake air amount control passing through the individual bypass passage by the individual electromagnetic valve. Further, the control apparatus for an internal combustion engine is performed in synchronization with a closing period of each intake valve.

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