JP3284718B2 - Opening / closing control device for swirl control valve - 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 opening and closing control device for a swirl control valve.

[0002]

2. Description of the Related Art As a method for obtaining stable combustion from a low speed, a swirl control valve for restricting intake air drawn into a combustion chamber in accordance with operating conditions to generate an appropriate swirl (swirl flow) in the combustion chamber. Is valid.

[0003] As a conventional swirl control valve, there is a swirl control valve which is rotatably supported on a suction passage via a rotary shaft and has a cutout formed at one end thereof so as to be offset with respect to a center line of the suction passage. The swirl control valve throttles the intake air taken into the combustion chamber when the valve is closed, thereby increasing the flow velocity of the intake air taken into the combustion chamber from the intake port, thereby generating swirl in the combustion chamber.

As a conventional swirl control valve opening / closing control device, there is provided a negative pressure actuator for driving the swirl control valve to open and close, and a solenoid valve is provided with a suction negative pressure generated downstream of the throttle valve in the intake passage as a driving pressure of the negative pressure actuator. (See JP-A-62-17318).

[0005]

However, in such a conventional swirl control valve opening / closing control apparatus, the suction negative pressure generated downstream of the throttle valve in the intake passage decreases the atmospheric pressure. When the engine is operated in a place where the atmospheric pressure is low, such as at a high altitude, the negative pressure guided to the negative pressure actuator is weakened even in a predetermined low load range in which the swirl control valve is closed. The actuator may not be able to open the swirl control valve against the built-in spring.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent an opening / closing operation failure of a swirl control valve caused by a decrease in atmospheric pressure.

[0007]

According to the first aspect of the present invention,
As shown in FIG. 1, a swirl control valve 21 for adjusting the flow rate of the intake air flowing into the combustion chamber, a negative pressure actuator 22 for opening and closing the swirl control valve 21, and a suction pressure of the intake passage 23 as an operating pressure of the negative pressure actuator 22. Valve means 25 for guiding the suction negative pressure generated downstream of the throttle valve 24, means 26 for detecting the engine load Tp, and suction negative pressure introduced into the negative pressure actuator 22 via the valve means 25 in accordance with the engine load Tp. A swirl control valve opening / closing control device including a swirl control valve opening / closing control means 27 for detecting a degree of opening TVO of a throttle valve 24, a means 32 for detecting an engine speed N, Q detecting means 33, throttle valve opening TVO and engine A means 28 for calculating an estimated value ATMMT atmospheric pressure based on the rotational speed N and the intake air amount Q,
Means 29 for determining a regulation value TpSONLMT that limits the engine operating range in which the suction negative pressure is introduced into the negative pressure actuator 22 via the valve means 25 according to the estimated value ATMMT of the atmospheric pressure.

[0008]

When the throttle valve opening TVO and the engine speed N are the same, the intake air amount is controlled based on data stored under a standard atmospheric pressure, for example, if the throttle valve opening TVO and the engine speed N are the same. The estimated value ATMMT of the atmospheric pressure can be calculated according to Q.

In response to a decrease in the suction negative pressure guided to the negative pressure actuator 22 under the same load condition with a decrease in the atmospheric pressure, the suction region in which the operation range of the negative pressure actuator 22 is located downstream of the throttle valve 24. By limiting to a low load region where the negative pressure rises sufficiently, it is possible to avoid a malfunction of the negative pressure actuator 22 when the engine is operated at a low atmospheric pressure such as at high altitude.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 2, 1 is an engine body, 10 is an intake passage, and 18 is an exhaust passage. A fuel injection valve 3 for injecting fuel is installed in the intake passage 10. Exhaust passage 18
Is provided with a three-way catalyst 19.

A swirl control valve 13 is provided immediately upstream of the intake port 12. The swirl control valve 13 has a notch that collects intake air when the valve is closed, and increases the flow rate of intake air flowing into the outer peripheral portion of the combustion chamber by passing the intake air through the notch to generate swirl in the combustion chamber. It is supposed to.

The swirl control valve 13 is driven to open and close via a diaphragm actuator (negative pressure actuator) 14. Diaphragm actuator 14
Is selectively connected to the downstream side and the upstream side of the throttle valve 5 of the intake passage 10 via a solenoid valve (valve means) 15.

When an SCV open signal is sent from the control unit 2, the solenoid valve 15 is de-energized, and is switched to a position for introducing a substantially atmospheric pressure generated upstream of the throttle valve 5 into the diaphragm chamber. As a result, the diaphragm actuator 14 is swung by the urging force of the spring interposed therein.
The control valve 13 is held at the valve open position.

When the SCV closing signal is sent from the control unit 2, the solenoid valve 15 is energized and switched to a position for introducing a suction negative pressure generated downstream of the throttle valve 5 into the diaphragm chamber. Thereby, the diaphragm actuator 14 closes the swirl control valve 13 while compressing the spring interposed therein. Intake passage 10 downstream of throttle valve 5 and solenoid valve 15
Between them, a vacuum tank 16 is installed via a one-way valve 17.

The intake passage 10 is provided with an auxiliary air amount adjusting valve 20 for guiding auxiliary air bypassing the throttle valve 5. The control unit 2 performs duty control on the opening of the auxiliary air amount control valve 20, and performs feedback control so that the idle speed of the engine matches the target value.

A control unit 2 is provided to control the injection amount from the fuel injection valve 3, the opening of the auxiliary air amount control valve 20, and the opening and closing of the swirl control valve 13. The control unit 2 performs this control
The intake air amount Q detected by the air flow sensor 4, the engine speed N detected by the speed sensor 7, the engine coolant temperature detected by the engine coolant temperature sensor 8, the opening TVO of the throttle valve 5 detected by the throttle sensor 6. ,
Each signal of the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber detected by the wide area air-fuel ratio sensor 9, the running speed of the vehicle detected by the vehicle speed sensor , the battery voltage, and the ignition switch is input.

As shown in FIG. 3, in the control unit 2, when a basic pulse width Tp of fuel injection is set to K as a constant from the intake air amount Q and the rotation speed N, Tp = K · Q / N (1) calculate.

Based on the calculated value Tp and the air-fuel ratio correction coefficient DML, the pulse width JTp of the fuel injection is calculated as JTp = Tp · DML (2).

The control unit 2 switches the target air-fuel ratio between the stoichiometric air-fuel ratio and the lean air-fuel ratio in accordance with the contents of a preset map, and performs feedback control of the actual air-fuel ratio in accordance with the detection value of the wide-range air-fuel ratio sensor 9. .

In the control unit 2, in order to control the opening and closing of the swirl control valve 13, the swirl control is basically performed according to the FLG 1 based on the fuel injection pulse width JTp and the FLG 2 based on the opening TVO of the throttle valve 5. An operation range where the valve 13 is opened and an operation range where the valve 13 is closed are determined.

If it is determined from the FLG1 map that the pulse width JTp of fuel injection becomes longer than the predetermined value TpSCV, FLG1 = 1. If it is determined that the pulse width JTp of the fuel injection is shorter than the predetermined value TpSCV-HVS, FLG1 = 0.

If it is determined from the map of FLG2 that the throttle valve opening TVO becomes larger than the predetermined value TVSCV, FLG2 = 1. Then, the throttle valve opening TVO becomes larger than a predetermined value TVSCV-HYSV.
If it is determined that the smaller, the FLG2 = 0.

When FLG1 = 1 or FLG2 = 1, an SCV open signal is sent to the solenoid valve 15. That is, under the operating condition in which at least one of the pulse width JTp of the fuel injection and the opening TVO of the throttle valve 5 is larger than the predetermined value, the swirl control valve 13
Is opened.

In the conventional apparatus, when FLG1 = 0 and FLG2 = 0, the solenoid valve 15
A CV close signal is sent. That is, the swirl control valve 13 is closed under operating conditions in which both the pulse width JTp of the fuel injection and the opening TVO of the throttle valve 5 are equal to or less than a predetermined value.

However, as shown in FIG. 5, the suction negative pressure generated downstream of the throttle valve 5 in the intake passage 10 decreases in proportion to the decrease of the atmospheric pressure. By the way, when the engine is operated, even if the pulse width JTp of the fuel injection becomes shorter than the predetermined value TpSCV, the negative pressure guided to the diaphragm actuator 14 is weakened, and the diaphragm actuator 14 closes the swirl control valve 13 against the spring. The valve cannot be driven.

According to the present invention, in response to this, the control unit 2 calculates an estimated value of atmospheric pressure (a coefficient corresponding to the air density) ATMMT based on the engine speed N, the throttle valve opening TVO and the intake air amount Q. The operation range in which the swirl control valve 13 is closed based on the calculated atmospheric pressure estimated value ATMMT is limited.

FIG. 4 shows the control contents for obtaining the estimated atmospheric pressure value ATMMT.

To explain this, a Tp value under the standard atmospheric pressure is searched according to the map of TVTp0 according to the engine speed N and the opening TVO of the throttle valve 5. In the map of TVTp0, in the operating state where the auxiliary air amount control valve 20 is fully closed under the standard atmospheric pressure, the TVT according to the engine speed N and the opening TVO of the throttle valve 5 is set.
The p value is stored in advance.

The basic pulse width Tp for fuel injection is calculated from the intake air amount Q and the rotational speed N based on the above equation (1).

A value IpISC is calculated by dividing the intake air amount Q and the auxiliary air amount ISCDuty for controlling the opening of the auxiliary air amount control valve 20 by the engine speed N.

The ratio RATIO is calculated by dividing the fuel injection pulse width TVTp0 according to the opening TVO of the throttle valve 5 under the standard atmospheric pressure by a value Tp-IpISC obtained by subtracting the value IpISC from the actual basic fuel injection pulse width Tp. I do.

Based on the map of the estimated atmospheric pressure ATMMT, the estimated atmospheric pressure ATMMT is retrieved according to the ratio RATIO. The map of the estimated atmospheric pressure value ATMMT is represented by the ratio RAT
An atmospheric pressure estimated value ATMMT corresponding to IO is stored in advance.

Returning now to the control flow chart shown in FIG.
According to the SCW map, the fuel injection pulse width Tp for generating the required negative pressure under the standard atmospheric pressure according to the engine speed N
Search SCW. In the map of TpSCW, the fuel injection pulse width TpSCW for generating the required negative pressure according to the engine speed N under the standard atmospheric pressure is stored in advance.

A correction coefficient KTpATMM is retrieved from the KTpATMM map according to the estimated atmospheric pressure value ATMMT. The map of KTpATMM is the estimated atmospheric pressure ATM
A correction coefficient KTpATMM corresponding to MT is stored in advance.

The swirl control valve 13
Is calculated as TpSONLMT = TpSCW.KTpATMM (3).

If it is determined from the FLG3 map that the basic pulse width Tp of fuel injection becomes longer than the regulation value TpSONLMT + HVS, FLG3 = 1. Then, the basic pulse width Tp of the fuel injection becomes equal to the regulation value TpSONL.
If it is determined to be shorter than MT, FLG3 = 0.

FLG1 = 0 and FLG2 = 0 and FLG
When 3 = 0, an SCV close signal is sent to the solenoid valve 15. That is, the pulse width JTp of the fuel injection
And the basic pulse width Tp of the fuel injection even under the operating condition in which both the opening TVO of the throttle valve 5 is equal to or less than the predetermined value.
Is not sent to the solenoid valve 15 as long as the pressure does not fall below the regulation value TpSONLMT based on the atmospheric pressure.

In this manner, even under the same load condition, the closed area of the swirl control valve 13 is shifted downstream from the throttle valve 5 in response to the decrease in the negative pressure guided to the diaphragm actuator 14 as the atmospheric pressure decreases. The diaphragm actuator 14 closes the swirl control valve 13 against the spring by restricting the swirl control valve 13 to a low load region in which the suction negative pressure generated on the side is sufficiently increased.
Can move . When the engine is operated in a place where the atmospheric pressure is low, such as at a high altitude, it is possible to avoid the malfunction of the diaphragm actuator 14 and prevent the engine operability from deteriorating.

[0040]

As described above, the swirl control valve opening / closing control device according to the first aspect calculates the estimated value ATMMT of the atmospheric pressure based on the throttle valve opening TVO, the engine speed N and the intake air amount Q. However, in response to the decrease in the suction negative pressure guided to the negative pressure actuator under the same load condition as the atmospheric pressure decreases, the suction negative pressure generated in the operation range of the negative pressure actuator downstream of the throttle valve is sufficient. When the engine is operated at low atmospheric pressure, such as at high altitudes, the operation of the negative pressure actuator can be avoided, and the engine operability deteriorates. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the invention described in claim 1;

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart showing the same control contents.

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

FIG. 5 is a characteristic diagram showing a relationship between atmospheric pressure and suction negative pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Swirl control valve 22 Negative pressure actuator 23 Intake passage 24 Throttle valve 25 Valve means 26 Engine load detecting means 27 Swirl control valve opening / closing controlling means 28 Atmospheric pressure estimated value calculating means 29 Regulation value determining means 33 Throttle valve opening detecting means 32 Engine speed detecting means 31 Intake air amount detecting means

Claims (1)

(57) [Claims] A swirl control valve for adjusting the speed of intake air flowing into the combustion chamber; a negative pressure actuator for opening and closing the swirl control valve; and a driving pressure of the negative pressure actuator generated downstream of the throttle valve in the intake passage. A swirl control valve opening / closing control device, comprising: a valve means for guiding a suction negative pressure; and a swirl control valve opening / closing control means for introducing a suction negative pressure to the negative pressure actuator via the valve means in accordance with an engine operating state. Means for detecting the opening degree TVO of the valve, means for detecting the engine speed N, means for detecting the intake air amount Q, and a large amount based on the throttle valve opening TVO, the engine speed N and the intake air amount Q. Means for calculating an estimated value ATMMT of atmospheric pressure; and an estimated value AT of atmospheric pressure. Switching controlgear of the swirl control valve, characterized in that it comprises a means for determining a regulated value TpSONLMT to limit the engine operating region for introducing an intake negative pressure through the valve means to the vacuum actuator in response to MT.