JPH10131776A - Boost pressure control device for engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in a drivability while improving response of a supercharger by setting a timing lag until opening control is started to an opening/closing control valve, and delaying opening control of the opening/ closing valve for a prescribed time by control means. SOLUTION: In an engine with a supercharger, a throttle valve 6 is arranged on the way of an air feed passage 4 arranged downstream from a supercharger. A bypass passage 8 is arranged to bypass a throttle valve, and an opening/ closing control valve 10 is arranged on the way of the bypass passage 8. In the case where the opening/closing control valve 10 is opened at the time of deceleration and the throttle valve 6 is bypassed, a time lag until opening control is started is set to the opening/closing control valve 10, and opening control of the opening/closing control valve 10 is delayed for a prescribed time by control means 12. It is thus possible to eliminate disorder feeling in a series of motions from an accelerating operation to a brake operation while improving response of the supercharger, and it is also possible to prevent deterioration of drivability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control device for a supercharged engine, and more particularly to a control device for controlling a supercharging pressure control device to open and close a control valve so as to bypass air supply during deceleration. Only by controlling the opening and closing control valve to delay the opening control, the response of the turbocharger can be improved, and a series of movements from the accelerator operation to the brake operation is less likely to be uncomfortable than normal, and drivability is improved. The present invention relates to a supercharging pressure control device for a supercharged engine that can prevent deterioration.

[0002]

2. Description of the Related Art Some engines are provided with a supercharger in which a turbine is swirled by exhaust gas and a compressor is rotated by the swirling force of the turbine to pressurize and supply an air-fuel mixture.

An example of a supercharging pressure control device for the supercharged engine is disclosed in Japanese Patent Application Laid-Open No. 59-28042. The deceleration control device for a turbocharged internal combustion engine disclosed in this publication provides a turbocharged internal combustion engine having a throttle valve responsive to an accelerator pedal on the outlet side of a compressor of the turbocharger. Is held at a predetermined value equal to or greater than the idle opening. Further, in a turbocharged internal combustion engine having a throttle valve responsive to an accelerator pedal on an outlet side of a compressor of a turbocharger, and controlling a fuel ignition timing at a required advance angle determined according to predetermined engine operating conditions. A throttle valve holding device that holds the opening of the throttle valve at a predetermined value equal to or greater than the idle opening when the engine decelerates while the turbocharger is operating, and requests ignition timing when the engine decelerates while the turbocharger is operating. The turbocharger is maintained at a high speed even during deceleration, eliminating the response delay during reacceleration.

[0004]

A conventional supercharging pressure control system for a supercharged engine is disclosed in Japanese Patent Application Laid-Open No. Sho 59-28042. The ignition timing is maintained at a predetermined value equal to or larger than the opening degree, and the ignition timing is advanced when the engine is decelerated during the operation of the turbocharger.

[0005] A holding device for holding the throttle opening at a predetermined value is turned on regardless of deceleration.

In order to improve the response of the supercharger, there is a method in which supercharged air is guided to an exhaust manifold and the discharged raw gas is burned to rotate a turbine.

However, since the throttle opening is not closed below a certain value at the time of deceleration, the effect of the engine brake at the moment of closing is weak (see FIG. 3 (a)), and a trigger for braking can be made by the engine brake. This has an adverse effect on the driver's feeling of stepping on the brake pedal and is inconvenient.

In addition, when there is a certain amount of air, the engine output cannot be sufficiently reduced with a small advance angle, and conversely, when the engine is in a retarded state in which the engine output is sufficiently reduced, compression is lost. If the ignition is performed or the ignition is not performed, there is a disadvantage that the ignition state becomes unstable and the afterburning fire becomes unstable.

Further, the gas passing through the cylinder is:
Due to the extremely rich state, that is, the over-rich state, even if the state returns to the normal state, the effect remains, and the ignition state of the engine itself deteriorates, which is disadvantageous in practical use.

Furthermore, in order to apply the engine brake, the operation of opening the throttle valve after the engine brake has been applied once with the fully-closed opening unchanged (idle opening) is referred to as the operation of the throttle valve. If it is intended to realize this only by opening the throttle valve to a predetermined opening after fully closing it once, a device such as a fly pie wire is required, so that the cost becomes large and economical In addition, when opening and closing the throttle valve using an actuator, the slack of the throttle cable may have an adverse effect, and improvements have been made.

[0011]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention supplies air from a supercharger to an engine and a throttle in a supply passage downstream of the supercharger. In a turbocharged engine provided with a valve, a bypass passage for bypassing the throttle valve is provided, an opening / closing control valve is provided in the middle of the bypass passage, and the opening / closing control valve is opened during deceleration to control the air supply. In this case, a control means is provided for setting a time lag until the start of the opening control in the opening / closing control valve and delaying the opening control of the opening / closing control valve by a predetermined time.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
In the case of controlling the opening and closing control valve to open and bypass the air supply during deceleration, a time lag until the start of the opening control is set in the opening and closing control valve, and the control means delays the opening control of the opening and closing control valve by a predetermined time. In addition to improving control, the response of the turbocharger is improved, and a series of movements from the accelerator operation to the brake operation are less likely to be uncomfortable than normal operations, thereby preventing deterioration in drivability.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. In FIG. 2, reference numeral 2 denotes a supercharging pressure control device for a supercharged engine (not shown), and reference numeral 4 denotes a supply passage between the supercharger and the engine.

The supercharged engine supplies air from a supercharger (not shown) to an engine (not shown), and a throttle valve 6 is provided in the air supply passage 4 downstream of the supercharger. Provided.

A bypass passage 8 for bypassing the throttle valve 6 is provided, and an opening / closing control valve (ABV) 10 is provided in the middle of the bypass passage 8, and the opening / closing control valve 10 is opened during deceleration to bypass the air supply. In order to control the opening / closing control valve 10, a control unit (ECM) 12 for setting a time lag until the start of the opening control and delaying the opening control of the opening / closing control valve 10 by a predetermined time is provided.

More specifically, when the control means 12 sets a time lag until the start of the opening control in the on-off control valve 10, the control means 12 may use a potential time lag generated when a route is formed, Control means 12 according to
A predetermined time, which is a time lag, is set in a timer (not shown) of the above, and the opening control of the opening / closing control valve 10 is delayed by the predetermined time.

When the control means 12 controls the opening and closing of the open / close control valve 10 to control the air supply to be bypassed at the time of deceleration, the control means 12 controls the ignition of the engine to be thinned simultaneously with the start of the open control of the open / close control valve 10. It also has functions.

As shown in FIG. 2, when the open / close control valve 10 is provided in the middle of the bypass passage 8, the open / close control valve 10
The pressure chamber 14 is opened to the atmosphere, and a diaphragm chamber 16 is provided in communication with the air supply passage 4 downstream of the bypass passage 8 by a pressure passage 18.
A spring 22 for urging the valve body 20 in the closing direction of the bypass passage 8 is provided therein.

Further, a pressure switching valve (VSV) 24 is provided in the middle of the pressure passage 18, and the control means 12 is connected to the pressure switching valve 24.

The opening / closing control valve 10 is opened by the air supply pipe pressure downstream of the throttle valve 6, and uses the atmospheric pressure during the closing operation.

That is, the pressure switching valve 24 is switched so that the air supply passage 4 downstream of the throttle valve 6 and the diaphragm chamber 16 of the on-off control valve 10 communicate with each other in response to a control signal from the control means 12 during deceleration. The operation (see symbols a and b in FIG. 2) is performed, and the opening / closing control valve 10 is opened by applying the air supply pipe pressure in the negative pressure state, which is the pre-throttle pressure, to the diaphragm chamber 16.

The pressure switching valve 24 performs a switching operation to release the diaphragm chamber 16 of the on-off control valve 10 to the atmosphere in response to a control signal from the control means 12 during non-deceleration (FIG. 2).
), And the open / close control valve 1 is actuated by the action of the atmosphere on the diaphragm chamber 16 by the urging force of the spring 22.
0 is closed.

The control means 12 includes various signals such as an exhaust temperature signal, a brake switch signal, a clutch switch signal, a throttle opening signal, a boost (intake pressure) signal, a gear position signal, a vehicle speed signal, and an engine speed Ne signal. Is entered.

The engine brake becomes difficult to operate by opening the fully-closed opening, and the fully-closed opening remains unchanged (idle opening). (A potential and physical time lag or a predetermined time set when the route is formed). In other words, the brake operation is started after the momentary braking of the engine is started, so that the feeling of pressing the brake pedal of the driver is not significantly affected. That is, if the accelerator pedal is opened from the beginning, braking is not applied when the accelerator pedal is released, and the timing is delayed.

In order to maintain the rotation of the supercharger, it is necessary to bypass a large amount of air (a maximum air amount of 20).
%). The output of the engine that has absorbed such an amount cannot be reduced by a slight retard, and it is necessary to perform the ignition thinning (cut). For example, in four cylinders
If the cylinder is cut, the output will be less than 1/4 (because it is responsible for the mechanical loss of three cylinders). By combining this ignition thinning with a slight retard, it is possible to reduce the output to such a degree that engine stall does not occur. Further, since one cylinder is normally ignited, it becomes a pilot flame for burning the raw gas discharged from the other cylinders. Then, the raw gas reduces the thermal load of the cylinder, the exhaust manifold, and the like due to the thinning out of the ignition, which is effective for durability under a high load.

Further, since the throttle valve 6 is only bypassed, the engine is the same as the throttle valve 6 being opened, and the air-fuel ratio becomes as mapped in the program, and the air-fuel ratio ( (A / F) As the environment, it is not ignited but keeps the best condition.

Next, the operation will be described with reference to the control flowchart of the supercharging pressure control device 2 for the supercharged engine shown in FIG.

When the control program is started, it is determined (100) whether or not the engine speed N is equal to or higher than the set engine speed N1.
In the case of S, the determination (102) as to whether or not the throttle valve 6 has suddenly closed is made by the equation dThrθ / dt ≦ (dθ / dt) 1, and if the determination (100) is NO, the pressure Ignition recovery for turning off the switching valve (VSV) 24 or normal control is performed (104).

On the other hand, if the judgment (102) as to whether or not the throttle valve 6 has suddenly closed (YES) is made (102), the judgment is made as to whether or not the throttle opening Thrθ is smaller than the set throttle opening Thrθ1 (106). When it is determined that the throttle valve 6 has suddenly closed (NO) (102), the process returns to the ignition mode where the pressure switching valve (VSV) 24 is turned off or performs normal control (104). Move to

In the judgment (106) as to whether or not the throttle opening Thr.theta. Has become equal to or less than the set throttle opening Thr.theta.1, if the judgment (106) is YES, a potential time lag or a predetermined time which becomes a preset time lag. After delaying the opening control of the opening / closing control valve 10 by a predetermined time after the elapse of, the pressure switching valve (VSV) 24 is turned ON by a control signal from the control means 12 to turn the pressure switching valve (VSV) 24 on the downstream side of the throttle valve 6. The air supply passage 4 is communicated with the diaphragm chamber 16 of the open / close control valve 10, and the open / close control valve 10 is opened by applying a negative pressure air supply pipe pressure to the diaphragm chamber 16. At this time, ignition thinning (retard) is also performed (108).

If the above determination (106) is NO, the process is shifted to the ignition recovery for turning off the pressure switching valve (VSV) 24 or the process (104) for performing the normal control.

After the opening of the opening / closing control valve 10, it is determined whether or not the opening degree of the throttle valve 6 has suddenly returned (11).
0) is determined by the equation dThrθ / dt ≧ (dθ / dt) 2, and if the determination (110) is NO, the determination of the OFF operation timing of the pressure switching valve (VSV) 24 (11)
2), and if the determination (110) is YES, return to ignition by turning off the pressure switching valve (VSV) 24;
Alternatively, the process is shifted to the process (104) for performing the normal control.

The OF of the pressure switching valve (VSV) 24
The determination of the F operation timing (112) is for determining whether or not the elapsed time T has become equal to or longer than the set elapsed time T1. If the determination (112) is NO, the elapsed time T is set to the set elapsed time T1. It repeats until it becomes above, judgment (112)
Is YES, the pressure switching valve (VSV) 24
Is turned off, and the process proceeds to the process (104) for performing normal control.

Thus, as shown in FIG. 3B, the response of the supercharger can be improved, which is practically advantageous.

At the moment of deceleration, as shown in FIG. 3 (b), the engine brake is activated, and after a lapse of a predetermined time, the opening / closing control valve 10 is controlled to open. Is less likely to be uncomfortable than normal movements, and the drivability can be prevented from deteriorating.

Further, the control means 12 includes the on-off control valve 1
By performing the ignition thinning at the same time as the start of the opening control of 0, at least one of the cylinders is reliably ignited, and a kind of fire for afterburning can be secured.

Furthermore, the opening / closing control valve 10 is opened by the air supply pipe pressure downstream of the throttle valve 6 and the atmospheric pressure is used during the closing operation. This is performed by the change of the air supply pipe pressure and the atmosphere, and FIG.
As shown in the figure, so-called self-feedback can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and various application modifications are possible.

For example, in the embodiment of the present invention, when the opening / closing control valve 10 is opened, the air supply pipe pressure downstream of the throttle valve 6 is used, and the atmospheric pressure is used during the closing operation. However, the open / close control valve 3
When the valve 2 is opened, the air supply pipe pressure downstream of the throttle valve 6 may be used, and the air supply pipe pressure upstream of the throttle valve 6 may be used during the closing operation.

That is, as shown in FIG. 4, when the opening / closing control valve 10 is provided in the middle of the bypass passage 8, the diaphragm chamber 16 of the opening / closing control valve 32 is connected to the air supply passage downstream of the bypass passage 8 by the pressure passage 18. Contact 4
A spring 22 that urges the valve body 20 in the closing direction of the bypass passage 8 is provided in the diaphragm chamber 18.

A pressure switching valve (VSV) 24 is provided in the pressure passage 18 and the control means 12 is connected to the pressure switching valve 24.

A pressure intake passage 34 is provided for connecting the opening of the pressure switching valve 24 (see FIG. 4C) to the air supply passage 4 upstream of the on-off control valve 32. The pressure chamber 14 of the opening / closing control valve 10 is provided in the middle of 34 in communication.

Then, at the time of deceleration, the pressure switching valve 24 is connected to the air supply passage 4 downstream of the throttle valve 6 and the diaphragm chamber 16 of the opening / closing control valve 10 by a control signal from the control means 12. A switching operation (see FIGS. 4A and 4B) is performed to apply a negative pressure air supply pipe pressure to the diaphragm chamber 16 to open the opening / closing control valve 10 and, at the time of non-deceleration, by a control signal from the control means 12. Pressure chamber 14 of opening / closing control valve 10 and diaphragm chamber 1
6, the switching operation of the pressure switching valve 24 to apply the air supply pipe pressure upstream of the on-off control valve 32 (FIG.
Then, the same air supply pipe pressure is applied to the pressure chamber 14 and the diaphragm chamber 16 to close the on-off control valve 10 by the urging force of the spring 22.

As a result, the opening / closing operation of the opening / closing control valve 10 is performed only by the change in the supply pipe pressure, and so-called self-feedback can be reliably performed.

[0046]

As described above in detail, according to the present invention, the supercharger is provided in which the air supply from the supercharger is supplied to the engine and the throttle valve is provided in the air supply passage downstream of the supercharger. In the engine-equipped engine, a bypass passage that bypasses the throttle valve is provided, an opening / closing control valve is provided in the bypass passage, and the opening / closing control valve is opened when the deceleration decelerates and the air supply is bypassed. Since a control means for setting a time lag until the start of control and delaying the opening control of the on-off control valve by a predetermined time is provided, the response of the supercharger can be improved, which is practically advantageous. In addition, the engine brake is effective at the moment of deceleration, and after a predetermined time has elapsed, the opening / closing control valve is controlled to open, so that a series of movements from the accelerator operation to the brake operation is more uncomfortable than normal. Unlikely to occur,
This can prevent deterioration of drivability.

[Brief description of the drawings]

FIG. 1 is a control flowchart of a supercharging pressure control device for a supercharged engine according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a supercharging pressure control device of the supercharged engine.

3 shows a time chart of a supercharging pressure control device of a supercharged engine, wherein (a) is a conventional time chart and (b)
Is a time chart of the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a supercharging pressure control device of a supercharged engine showing another embodiment of the present invention.

[Explanation of symbols]

 2 Supercharging pressure control device for supercharged engine 4 Supply air passage 6 Throttle valve 8 Bypass passage 10 Opening / closing control valve (ABV) 12 Control means (ECM) 14 Pressure chamber 16 Diaphragm chamber 18 Pressure passage 20 Valve body 22 Spring 24 Pressure switching valve (VSV)

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 43/00 301 F02P 9/00 304D F02P 9/00 304 F02D 33/00 318C

Claims (4)

[Claims] In a supercharged engine provided with a throttle valve in the middle of an air supply passage downstream of the supercharger while supplying air from the supercharger to the engine, a bypass for bypassing the throttle valve is provided. A passage is provided, and an opening / closing control valve is provided in the middle of the bypass passage. When the opening / closing control valve is opened at the time of deceleration and control is performed so as to bypass the air supply, a time lag until the start of the opening control is set in this opening / closing control valve. A supercharging pressure control device for a supercharged engine, further comprising control means for performing control so as to delay opening control of an on-off control valve by a predetermined time. 2. The control device according to claim 1, wherein the control means controls the opening of the open / close control valve to bypass the air supply at the time of deceleration. The supercharging pressure control device for a supercharged engine according to claim 1, which is a means. 3. The opening / closing control valve according to claim 1, wherein the opening / closing control valve is an opening / closing control valve that is opened by an air supply pipe pressure downstream of a throttle valve and uses atmospheric pressure during a closing operation. Item 3. A supercharging pressure control device for a supercharged engine according to Item 2. 4. The open / close control valve, which is opened by an air supply pipe pressure downstream of the throttle valve and uses an air supply pipe pressure upstream of the throttle valve during a closing operation. Claim 1 in the range of
Or a supercharging pressure control device for a supercharged engine according to claim 2.