JPH07189708A - Swirl control valve opening/closing control device - Google Patents

Abstract

PURPOSE:To prevent the opening/closing operation failure of a swirl control valve generated in association with the lowering of atomospheric pressure. CONSTITUTION:A swirl control valve opening/closing control device is provided with an opening/closing control means 27 for a swirl control valve 21 for leading intake negative pressure into a negative pressure actuator 22 through a valve means 25 according to the operating state of an engine. This swirl control valve opening/closing control device is further provided with a means 28 for computing the atmospheric pressure estimate ATMMT on the basis of the throttle valve opening TVO, engine speed N and intake air quantity Q, and a means 29 for determining the regulation value TpSONLMT for limiting an engine load area where intake negative pressure is led into the negative pressure actuator 22 through the valve means 25 according to the atmospheric pressure estimate ATMMT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an opening / closing control device for swirl control valves.

[0002]

2. Description of the Related Art As a method for obtaining stable combustion even at low speeds, a swirl control valve that throttles intake air taken into a combustion chamber according to operating conditions is provided to generate an appropriate swirl (swirl flow) in the combustion chamber. Is effective.

As a conventional swirl control valve, there is a swirl control valve that is rotatably supported in an intake passage via a rotary shaft and has a notch formed at one end thereof offset from the center line of the intake passage. When the swirl control valve is closed, the intake air sucked into the combustion chamber is throttled to increase the flow velocity of the intake air sucked into the combustion chamber from the intake port to generate swirl in the combustion chamber.

As a conventional open / close control device for a swirl control valve, a negative pressure actuator for opening / closing the swirl control valve is provided, and a suction negative pressure generated downstream of a throttle valve in an intake passage as a driving pressure of the negative pressure actuator is a solenoid valve. There is one that is guided through the above (see Japanese Patent Application Laid-Open No. 62-17318).

[0005]

However, in such a conventional control device for opening and closing a swirl control valve, the suction negative pressure generated downstream of the throttle valve in the intake passage is reduced in atmospheric pressure. Since the pressure decreases proportionally, when the engine is operated in a place where the atmospheric pressure is low, such as in highlands, the negative pressure introduced to the negative pressure actuator weakens even in the prescribed low load range where the swirl control valve is closed. The actuator may not be able to drive the swirl control valve to open against the built-in spring.

The present invention focuses on the above-mentioned problems, and an object of the present invention is to prevent defective opening / closing operation of a swirl control valve caused by a decrease in atmospheric pressure.

[0007]

The invention according to claim 1 is
As shown in FIG. 1, a swirl control valve 21 that adjusts the flow velocity of the intake air flowing into the combustion chamber, a negative pressure actuator 22 that drives the swirl control valve 21 to open and close, and an operating pressure of the negative pressure actuator 22 in the intake passage 23. A valve means 25 for guiding the suction negative pressure generated on the downstream side of the throttle valve 24, a means 26 for detecting the engine load Tp, and a suction negative pressure introduced into the negative pressure actuator 22 via the valve means 25 according to the engine load Tp. In the open / close control device for a swirl control valve including the open / close control means 27 for the swirl control valve 21, a means 31 for detecting the opening TVO of the throttle valve 24, a means 32 for detecting the engine speed N, and an intake air amount. Q detection 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,
And 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 in accordance with the estimated atmospheric pressure value ATMMT.

[0008]

When the throttle valve opening TVO and the engine speed N are in the same condition, the swirl control valve opening / closing control apparatus according to claim 1 is based on prestored data, for example, under standard atmospheric pressure. The estimated value ATMMT of atmospheric pressure can be calculated according to Q.

In response to a decrease in the suction negative pressure introduced to the negative pressure actuator 22 under the same load condition as the atmospheric pressure decreases, the suction pressure generated in the operation range of the negative pressure actuator 22 on the downstream side of the throttle valve 24. By limiting to a low load region where the negative pressure sufficiently rises, it is possible to avoid the malfunction of the negative pressure actuator 22 when the engine is operated in a place where the atmospheric pressure is low, such as in highlands.

[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
A three-way catalyst 19 is installed in.

A swirl control valve 13 is installed immediately upstream of the intake port 12. The swirl control valve 13 has a cutout portion that collects intake air when the valve is closed. By passing the intake air through the cutout portion, the flow velocity of intake air flowing into the outer peripheral portion of the combustion chamber is increased, and swirl is generated in the combustion chamber. It is supposed to do.

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

When the control unit 2 sends an SCV open signal to the solenoid valve 15, the solenoid valve 15 is brought into a non-energized state and switched to a position for introducing substantially atmospheric pressure generated upstream of the throttle valve 5 into the diaphragm chamber. As a result, the diaphragm actuator 14 holds the throttle valve 5 in the open position by the urging force of the spring interposed therein.

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

Further, the intake passage 10 is provided with an auxiliary air amount adjusting valve 20 for guiding the auxiliary air bypassing the throttle valve 5. The control unit 2 duty-controls the opening degree 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 degree of the auxiliary air amount control valve 20, and the opening / closing of the swirl control valve 13. The control unit 2 is for 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 cooling water temperature detected by the engine cooling water temperature sensor 8, and the opening TVO of the throttle valve 5 detected by the throttle sensor 6. ,
The air-fuel ratio of the air-fuel mixture supplied to the combustion chamber detected by the wide-range air-fuel ratio sensor 9, the traveling speed of the vehicle detected by the vehicle speed sensor 10, the battery voltage, and the ignition switch signals are input.

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

Based on the calculated value Tp and the fuel-air ratio correction coefficient DML, the fuel injection pulse width JTp 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 according to the contents of the preset map, and feedback-controls the actual air-fuel ratio according to the detection value of the wide range air-fuel ratio sensor 9. .

In order to control the opening and closing of the swirl control valve 13, the control unit 2 basically controls the swirl control according to FLG1 based on the pulse width JTp of fuel injection and FLG2 based on the opening TVO of the throttle valve 5. The operating range in which the valve 13 is opened and the operating range in which the valve 13 is closed are determined.

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

When it is determined from the FLG2 map that the throttle valve opening TVO exceeds the predetermined value TVSCV and becomes large, FLG2 = 1. When it is determined that the throttle valve opening TVO is shorter than the predetermined value TVSCV-HYSV, FLG2 = 0.

When FLG1 = 1 or FLG2 = 1, the 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 fuel injection and the opening TVO of the throttle valve 5 is larger than a predetermined value, the swirl control valve 13
Open.

By the way, in the conventional device, when FLG1 = 0 and FLG2 = 0, the solenoid valve 15 receives an S
A CV close signal is sent. That is, the swirl control valve 13 is closed under operating conditions in which both the fuel injection pulse width JTp and the opening degree 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 on the downstream side of the throttle valve 5 in the intake passage 10 decreases in proportion to the decrease in the atmospheric pressure, so that the atmospheric pressure in highlands is low. By the way, when the engine is operated, even if the pulse width JTp of fuel injection becomes shorter than the predetermined value TpSCV, the negative pressure guided to the diaphragm actuator 14 weakens, 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 (a coefficient corresponding to the air density) ATMMT of the atmospheric pressure based on the engine speed N, the throttle valve opening TVO and the intake air amount Q. The operating 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.

Explaining this, the Tp value under the standard atmospheric pressure is searched according to the engine speed N and the opening TVO of the throttle valve 5 from the map of TVTp0. The map of TVTp0 shows T corresponding to the engine speed N and the opening TVO of the throttle valve 5 in the operating state in which the auxiliary air amount control valve 20 is fully closed under the standard atmospheric pressure.
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 degree 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 corresponding to the opening TVO of the throttle valve 5 under the standard atmospheric pressure by the value Tp-IpISC obtained by subtracting the value IpISC from the actual basic fuel injection pulse width Tp. To do.

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

Returning now to the control flow chart shown in FIG. 3, Tp
The fuel injection pulse width Tp for generating the required negative pressure under the standard atmospheric pressure according to the engine speed N from the SCW map
Search for 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 standard atmospheric pressure is stored in advance.

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

The swirl control valve 13
The restriction value TpSONLMT that limits the valve closing range of is calculated as TpSONLMT = TpSCW · KTpATMM (3).

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

FLG1 = 0 and FLG2 = 0 and FLG
When 3 = 0, the SCV close signal is sent to the solenoid valve 15. That is, the pulse width JTp of fuel injection
And the opening degree TVO of the throttle valve 5 both become equal to or less than a predetermined value, the basic pulse width Tp of fuel injection Tp
The SCV close signal is not sent to the solenoid valve 15 as long as is not less than the regulation value TpSONLMT based on the atmospheric pressure.

In this way, even under the same load condition, the negative pressure introduced to the diaphragm actuator 14 weakens as the atmospheric pressure decreases, so that the closed range of the swirl control valve 13 is located downstream of the throttle valve 5. The diaphragm actuator 14 can drive the swirl control valve 13 to open against the spring by limiting to a low load region where the suction negative pressure generated on the side is sufficiently increased. When the engine is operated in a place where the atmospheric pressure is low such as in highlands, it is possible to prevent the diaphragm actuator 14 from malfunctioning and prevent the engine drivability from deteriorating.

[0040]

As described above, in the swirl control valve opening / closing control apparatus according to the first aspect, the estimated atmospheric pressure value ATMMT is calculated based on the throttle valve opening TVO, the engine speed N and the intake air amount Q. However, the suction negative pressure introduced to the negative pressure actuator weakens under the same load condition as the atmospheric pressure decreases, so that the suction negative pressure generated in the operating range of the negative pressure actuator downstream from the throttle valve is sufficient. Since the configuration is limited to the operating range that rises to above, when the engine is operated in a place where the atmospheric pressure is low, such as in highlands, it prevents the negative pressure actuator from malfunctioning and deteriorates the engine drivability. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to claims of the invention according to 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]

 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 Open / Close Control Means 28 Atmospheric Pressure Estimated Value Calculating Means 29 Regulatory Value Determining Means 33 Throttle Valve Opening Detecting Means 32 Engine speed detecting means 31 Intake air amount detecting means

Claims (1)

[Claims] 1. A swirl control valve for adjusting the speed of intake air flowing into a combustion chamber, a negative pressure actuator for opening and closing the swirl control valve, and a driving pressure of the negative pressure actuator, which is generated downstream of a throttle valve in an 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 into a negative pressure actuator via the valve means in accordance with an engine operating state. A means for detecting the valve opening TVO, a means for detecting the engine speed N, a means for detecting the intake air amount Q, and a large value based on the throttle valve opening TVO, the engine speed N and the intake air amount Q. Means for calculating the atmospheric pressure estimated value ATMMT, and atmospheric pressure estimated value AT 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.