JPH11236829A - Method and device for warming up engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for warming up an engine capable of effecting sufficient warming-up of the engine even during running by effecting exhaust throttle at an intermediate valve opening between full closing and full opening during running of an engine in a cold-down state, improving combustion of an engine, and effecting a warming-up of an exhaust throttle. SOLUTION: In warming-up of an engine 1, opening and closing of an exhaust throttle valve 8 are controlled at least in a three-stage valve opening. When it is detected that the engine 1 is in a cold-down state and during idle running, the exhaust throttle valve 8 is brought into a full closing state of a first stage. Further, when it is detected that the engine 1 is in a cold-down state and during non-idle running, the exhaust throttle valve 8 is brought into a half-opening state of a second state. When it is detected that the engine 1 is not in a cold- down state, control is effected such that the exhaust throttle valve 8 is brought into a full opening state of a third stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling a warm-up system in an engine of an automobile or the like.

[0002]

2. Description of the Related Art As a warming-up method for warming a cold engine at the start of operation of a conventional engine of an automobile or the like, an exhaust throttle valve is provided in an exhaust passage and a cooling water is used to confirm that the engine is in a cold state. The temperature is detected by a cold state detecting means such as a thermoswitch for detecting the temperature, and the exhaust throttle valve is fully closed to narrow the exhaust passage, thereby increasing the exhaust pressure, that is, increasing the passage friction (passage resistance) to warm the passage. The method of working is adopted.

[0003] The term "fully closed" of the exhaust throttle valve used herein does not mean that the exhaust passage is fully closed.
Even if the exhaust throttle valve is fully closed, it only means that the exhaust passage is narrowed and that a certain amount of exhaust can be passed.Mechanically, for example, a through hole is formed in a part of the exhaust throttle valve. Or a valve closing amount is adjusted so that the exhaust passage is not completely closed, so that a part of the exhaust passage can be secured even when the exhaust throttle valve is fully closed.

[0004] Even if the exhaust pressure rises due to the full closing of the exhaust throttle valve, the amount of fuel injected into the combustion chamber is increased so that the engine speed does not decrease, so that the amount of generated heat increases. Warm-up can be promoted. Further, since the amount of exhaust gas discharged from the exhaust pipe is reduced by fully closing the exhaust throttle valve, the amount of heat radiation from the exhaust pipe can be reduced, and the amount of heat for heating the engine coolant can be increased. . It is also possible to promote warming up of the engine by increasing the amount of heat transferred to warming up the engine.

However, in this conventional warming-up system, when the accelerator is depressed to start running from a cold state, the temperature of the cooling water is increased despite the increase in fuel injection and the amount of heat generated by the engine. Since the vehicle travels in the warm-up mode because it is low, that is, in the exhaust throttle state with the exhaust throttle valve closed, exhaust becomes insufficient and the amount of residual exhaust gas in the cylinder increases, which is similar to excessive EGR. State. Therefore, there is a problem that combustion is deteriorated, a large amount of smoke is generated, and fuel consumption is reduced.

[0006] In order to solve this problem, Japanese Patent Publication No.
Japanese Patent No. 9291 discloses a warm-up promotion in which the exhaust throttle at the time of warm-up is controlled not only by the measured value of the cooling water temperature but also by the vehicle speed, and when the vehicle speed exceeds a predetermined vehicle speed, the exhaust throttle is released. An apparatus is described.

[0007]

However, in this warm-up promoting device, the exhaust throttle valve is controlled to open and close only in two stages, that is, fully open and fully closed. (8 km / h or less), there is a problem that the exhaust throttling can be performed only at a speed of 8 km / h, and the warm-up promotion during the running of the vehicle cannot be substantially performed.

In addition, when the operation of the engine is started in the cold state and the running state is shifted before the warming-up is completed, the exhaust throttle is released during the increase in the vehicle speed and the fully closed state is shifted to the fully opened state. Since the engine speed changes rapidly and accelerates rapidly, there is a problem that acceleration shock occurs and riding comfort is poor. The present invention has been made in order to solve the above-described problem, and an object of the present invention is to provide an exhaust throttle valve used for warming up an engine with a valve opening intermediate between a fully closed state and a fully opened state, so that an exhaust throttle valve in a cold state is provided. During traveling, the exhaust throttle with this intermediate valve opening is performed to improve engine combustion and also exhibit the warming effect of the exhaust throttle, so that the engine can be sufficiently warmed up even during traveling. Machine method and apparatus.

[0009]

An engine warming method for achieving the above object is provided by an engine controller for controlling the operation of the engine, wherein the engine controller controls the operation of the engine from a cold state detecting means for detecting a cold state of the engine. A signal and an idle signal from idle detection means for detecting an idle operation state are input to control an exhaust throttle valve provided in an exhaust passage,

The exhaust throttle valve is controlled to open and close to at least three levels of valve opening in which the valve opening increases in the order of first, second, and third, and the cold state detecting means determines that the engine is in a cold state. And, when the idle detecting means detects that the idle operation is being performed, the exhaust throttle valve is set to the first stage valve opening,

When the cold state detecting means detects that the engine is in a cold state and the idle detecting means detects that the engine is not operating idle, the exhaust throttle valve is set to the second stage. A valve opening degree, and when the cold state detecting means detects that the engine is not in a cold state, the engine is warmed up by controlling the exhaust throttle valve to the third stage valve opening degree. is there.

According to this method, when the vehicle in the cold state is warmed up, when the vehicle is stopped, that is, in the idling state, the exhaust throttle valve can be fully closed to increase the warming effect, and the accelerator can be depressed. When the idling detection device shifts to a running state in which a non-idle state is detected, the exhaust throttle valve can be half-opened to warm up while dealing with an increase in the amount of exhaust gas accompanying an increase in the amount of fuel injection. After the warm-up is completed, the exhaust throttle valve is fully opened to allow normal engine operation without exhaust throttle.

Further, in addition to the above control, the intake throttle valve provided in the intake passage is controlled to be closed when the cold state detecting means detects that the engine is in a cold state. By using this intake throttle together with the exhaust throttle, the exhaust throttle increases the amount of fuel injection due to the increase in friction, and at the same time, increases part of the mechanical noise and combustion noise, that is, releases these noises from the intake pipe to the outside. The amount of noise can be reduced by narrowing the intake pipe with the intake throttle, and the noise of the engine during warm-up can be reduced.

Further, since cold air, which is low-temperature outside air, is sucked in each time of intake, the cylinder temperature during warm-up is reduced by the cold air. However, the amount of the cold air can be reduced by the intake throttle. Therefore, a decrease in the cylinder temperature can be reduced, and the warm-up of the engine can be further promoted.

Further, an engine warming device for warming up by this method is provided in an exhaust passage of an engine having a cold state detecting means for detecting a cold state of the engine and an idle detecting means for detecting an idling operation state. First, second,
In addition to providing an exhaust throttle valve that changes in at least three stages in which the valve opening increases in a third order,

When the cold state detecting means detects that the engine is in a cold state and the idle detecting means detects that the engine is idling, the exhaust throttle valve is set to the first stage valve opening. ,

When the cold state detecting means detects that the engine is in a cold state and the idle detecting means detects that the engine is not operating at idle, the exhaust throttle valve is set to the second stage valve opening degree. And an engine controller that controls opening and closing of the exhaust throttle valve so that the exhaust throttle valve has a third-stage valve opening when the cold state detection unit detects that the engine is not in a cold state. Be composed.

According to this warming-up device, when the vehicle is stopped, that is, idling, the exhaust throttle valve is fully closed,
The warm-up effect can be increased, and when the accelerator is depressed and the idling detection device detects a non-idle state, the exhaust throttle valve is half-opened and the amount of exhaust gas increases with an increase in fuel injection amount. After the warm-up is completed, the exhaust throttle valve can be fully opened and normal engine operation without exhaust throttle can be performed.

Further, in order to perform the three-stage opening / closing operation of the exhaust throttle valve, the opening / closing mechanism of the exhaust throttle valve is switched to a first outlet and a second outlet by a negative pressure source and an operation signal, and the negative pressure is switched. First and second negative pressure switching valves communicating with a pressure inlet; and an actuator for inputting a negative pressure and a negative pressure to open and close the exhaust throttle valve, wherein the first negative pressure switching valve has a negative pressure inlet. Is connected to the negative pressure source, the first outlet is connected to the negative pressure inlet of the second negative pressure switching valve, and in the second negative pressure switching valve, the first outlet is connected to the actuator, and the second An outlet is connected to the actuator via the pressure reducing valve.

This pressure reducing valve is a pressure regulating valve that reduces a negative pressure input from a negative pressure source and outputs a negative pressure intermediate to the atmospheric pressure. The configuration of the opening / closing device for the exhaust throttle valve is a simple and inexpensive device. The exhaust throttle valve is a first combination of a negative pressure pump, a negative pressure switching valve, a pressure reducing valve and an actuator.
Opening and closing can be controlled in three stages, namely, fully closed, second stage, half open, and third stage, fully open, so that it can be constructed at a low cost and is a relatively simple combination of equipment having excellent heat resistance. Since the opening and closing of the valve can be controlled by simple control, high reliability for the opening and closing operation of the valve can be obtained.

According to this configuration, this occurs when a step motor, a duty control valve, or the like is employed.
It is possible to avoid a problem such as an operation failure due to high heat from the exhaust passage and a problem that the device is expensive.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method and apparatus for warming up an engine according to the present invention will be described with reference to the drawings. However, since FIGS. 1 to 4 are diagrams for explaining the present invention, illustrations other than the devices and flowcharts according to the present invention are omitted.

[Structure of Apparatus (FIG. 1)] As shown in FIG. 1, in a supercharged engine 1 having a warm-up device for the engine 1, a compressor 3 of the supercharger is provided in an intake passage 2, A turbine 6 of this supercharger is provided in an exhaust passage 5, and the energy of the exhaust gas
, And the rotation of the turbine 6 drives the compressor 3 to compress and supply fresh air A to the intake passage 2.

An exhaust throttle valve 8 is provided in the exhaust passage 7 on the downstream side of the turbine 6 of the supercharger, and devices 20, 21, 22, 23, 24 for opening and closing the exhaust throttle valve 8 are provided. As a result, the exhaust throttle valve 8 is set to the first (fully closed), the second (half open),
Opening / closing operation is performed in at least three stages of valve opening in which the valve opening increases in the order of third (fully open). Further, an intake throttle valve 4 whose opening degree is adjusted by a step motor 31 called an intake throttle is provided in the intake passage 2 on the downstream side of the compressor 3 of the supercharger. [Exhaust throttle valve opening / closing device]

Opening / closing devices 20, 21, 2 for the exhaust throttle valve 8
2, 23, 24 are negative pressure pumps (VP: vacuum pumps) 2
0, a first negative pressure switching valve (VSV1: vacuum switching valve) 21, a second negative pressure switching valve (VSV2) 22, a pressure reducing valve 23, and an actuator 24 called an exhaust throttle.

The pipe 25 from the negative pressure pump 20 is
It is connected to the negative pressure inlet (inlet side port) P11 of the first negative pressure switching valve (VSV1) 21 composed of a directional control valve having more ports than the port, and communicates with the negative pressure inlet P11 when the operation (operation) signal is ON. The first outlet (first outlet side port) P12 is connected to a negative pressure inlet (inlet side port) P21 of a second negative pressure switching valve (VSV2) 22. Further, when the operation signal is OFF, the second outlet (second outlet side port) P which communicates with the negative pressure inlet P11.
13 is an exhaust port open to the atmosphere.

The second negative pressure switching valve (VSV2) 22 connects an actuator 24 to a first outlet (first outlet side port) P22 communicating with the negative pressure inlet P21 when the operation signal is ON, and operates. When the signal is OFF, a second outlet (second outlet side port) P23 communicating with the negative pressure inlet P21 is connected to an inlet side P31 of a pressure reducing valve (VRV: vacuum regulating valve) 23 which is a pressure regulating valve. The outlet side P32 of the pressure reducing valve 23 is connected to the actuator 24.

When the operation signal is turned on, the first and second negative pressure switching valves 21 and 22 move the internal valves against the urging force of an internal spring (not shown), so that the first outlet P12 or P22 becomes negative. When the operation signal is turned off, the second outlet P13 is communicated with the pressure inlet P11 or P21 by the biasing force of the internal spring.
Alternatively, P23 is configured to communicate with the negative pressure P11 or P21.

The negative pressure pump 31, which is a negative pressure source,
The negative pressure pump for controlling the EGR valve (not shown) may be shared or another negative pressure source may be used. [Engine Control Device] And, as sensors for engine control, an accelerator opening sensor (not shown) linked with the accelerator pedal 11 near the accelerator pedal 11,
An idle switch (idle detecting means) for detecting an idle state or a non-idle state is provided, and a warm-up switch (QWS: quick warm-up switch) for manually turning on / off a warm-up mode is provided in the driver's seat. .

Further, a cooling water temperature sensor (cooling state detecting means) 12 for detecting a cooling water temperature Tw is provided on a cylinder head of the engine body 10, and a toothed rotation plate 13 of a toothed rotating unit 13 is provided below the engine body 10 in a unit time. A rotation speed sensor 14 for detecting the number of passages, that is, the rotation speed Ne of the engine 10, is provided.
An engine controller 9 called an engine control module (ECM) for controlling the operation of the engine according to programs and data input in advance by receiving signals from these and other sensors is provided.

[Other Configurations] An air cleaner 32 is provided on the inlet side of the intake passage 2, and an air cleaner 32 is provided on the outlet side of the exhaust passage 7.
A muffler 26 is provided. If necessary, an EGR device, an intercooler, a catalytic converter for exhaust gas, and the like, which are not shown in FIG. 1, may be provided to improve exhaust gas measures and engine performance. [Control of Exhaust Throttle Valve and Intake Throttle Valve] Next, control of the exhaust throttle valve 8 and the intake throttle valve 4 will be described with reference to flowcharts of FIGS.

First, the subroutine relating to the warming-up method of the present invention involves three steps, one for warming-up mode determination, one for exhaust throttle control, and one for intake throttle control. These subroutines are provided by an engine controller (ECM) for controlling the engine.
) Is repeatedly called and executed in the engine operation program in 9).

[Determination of Warm-up Mode and Setting of Warm-up Mode Flag (FIG. 2)] First, in the warm-up mode determination subroutine shown in FIG. Then, the warm-up switch signal Qws, the coolant temperature (cooler signal) Tw, the engine rotation speed Ne, and the accelerator opening Ac are read.

In the next step S12, a warm-up switch signal Qws from a warm-up switch (not shown)
It is determined whether the state is N (warm up) or OFF (do not warm up). If the determination is ON, the process proceeds to step S13. In step S13, it is determined whether or not the coolant temperature Tw detected by the coolant temperature sensor 12 is lower than a predetermined warm-up stop temperature TwL.
go to.

In step S14, it is determined whether or not the engine rotation speed Ne detected by the rotation speed sensor 14 is between the rotation stop rotation speed NeL at which the idle operation is stalled and the warm-up stop rotation speed NeH. If the answer is YES, the process goes to step S15. Step S
At 15, it is determined whether or not the accelerator opening Ac detected by the accelerator opening sensor (not shown) is smaller than the warm-up stop accelerator opening AcL. Fq is set to 1 (ON) and the routine returns.

If any one of steps S12, S13, S14, and S15 is NO, the process goes to step S17, sets the warm-up mode flag Fq to 0 (OFF), and returns. The value of the warm-up stop rotation speed NeH is, for example, 1 in an engine having a rated rotation speed of 3600 rpm.
The rotation speed is set at a medium speed of 700 to 2000 rpm, and the warm-up stop accelerator opening AcL is set to, for example, 25% or more of the fully opened state. That is, in the operating range exceeding these values, the exhaust pressure rises remarkably,
It is desirable that the exhaust throttle valve 8 be fully opened.

[Exhaust Throttle Control] Next, in the exhaust throttle control subroutine shown in FIG. 3, if it is called from the engine operation program and started, step S21 is executed.
Then, it is determined whether or not the warm-up mode flag Fq set in the above-described warm-up mode determination subroutine is 1 (ON), and in the case of YES of ON, the exhaust throttle is performed. Go to step S22.

In step S22, it is determined whether or not a signal (idle signal) Is of an idle switch (not shown) indicates that the accelerator 11 is not depressed, that is, whether the accelerator 11 is in the ON state during idle operation. If so, the exhaust throttle valve 8 is opened at the first stage, that is, fully closed to perform exhaust throttle, and the operation (operation) signal Vs1 to the first negative pressure switching valve (VSV1) is turned on in step S23. And the second
The operation signal Vs2 to the negative pressure switching valve (VSV2) is turned off, and the routine returns.

Note that, instead of the idle switch, the idle determination may be made based on the detection value of the accelerator opening sensor. By the ON and OFF signals, the negative pressure from the negative pressure pump 20 passes through the ports P11 and P12 of the first negative pressure switching valve 21 and the ports P21 and P22 of the second negative pressure switching valve 22, and the exhaust throttle valve 8 And the exhaust throttle valve 8 is set to the first-stage valve opening degree, that is, fully closed.

If the determination in step S22 is NO, that is, if the idle switch is depressed during the non-idling operation in the OFF state, that is, if the vehicle is running, the exhaust throttle valve 8 is set to the second-stage valve opening degree, The exhaust throttle is performed by half opening (half closing), and both the operation signal Vs1 and the operation signal Vs2 are turned on in step S24, and the routine returns. This 2
By the two ON signals, the negative pressure from the negative pressure pump 20 is changed to the ports P11 and P12 of the first negative pressure switching valve 21 and the second negative pressure switching valve 22.
The intermediate negative pressure is applied to the actuator 24 of the exhaust throttle valve 8 from the ports P21 and P23 through the pressure reducing valve 23 (VRV), and the exhaust throttle valve 8 is opened to the second stage, that is, half-open.

If the determination in step S21 is NO, the exhaust throttle valve 8 is not opened and the exhaust throttle valve 8 is fully opened, and the operation signal to the first negative pressure switching valve (VSV1) is determined in step S25. Both Vs1 and the operation signal Vs2 to the second negative pressure switching valve (VSV2) are turned off, and the routine returns.

The negative pressure from the negative pressure pump 20 is switched from the port P11 of the first negative pressure switching valve 21 to the exhaust port on the atmosphere opening side of P13 by the two OFF signals, more specifically, the OFF signal of Vs1. Since no negative pressure is applied to the actuator 24 of the exhaust throttle valve 8, the exhaust throttle valve 8 is fully opened by the urging force of a spring (not shown) inside the actuator 24.

[Inlet throttle control] Finally, in the intake throttle control subroutine shown in FIG. 4, if called from the engine operation program and started, step S31 is executed.
Then, it is determined whether or not the warm-up mode flag Fq set in the warm-up mode determination subroutine is 1 (ON), and if YES at 1, the intake throttle is performed. Go to S32.

In step S32, the control target valve opening SvT for a signal for operating the step motor 31 which is the actuator of the intake throttle valve 4 is set to the valve opening SvC when the valve is closed. Degree SvT and current valve opening degree Sv
Step motor with the difference ΔSv from 1 as the indicated amount SvM
Output to 31. With this output, the step motor 31
Opens or closes the valve by the indicated amount SvM from the current degree of valve opening Sv1 to perform the intake throttle or maintain the intake throttle state. Thereafter, the current valve opening Sv1 is replaced with the control target valve opening SvT, and the routine returns.

If the determination in step S31 is NO, that is, if the warm-up mode flag Fq is 0, the flow proceeds to step S33. In this step S33, the control target valve opening SvT for the signal for operating the step motor 31 is calculated as follows:
The valve opening SvO at the time of valve opening is set, and the control target valve opening S
The difference ΔSv between vT and the current valve opening Sv1 is determined by the indicated amount SvM.
To the step motor 31. With this output, the step motor 31 opens or closes the valve by the instructed amount SvM from the current valve opening Sv1 to release the intake throttle or maintain the release state. Then, the current valve opening S
v1 is replaced by the control target valve opening SvT, and the routine returns.

In the example of the valve opening degree SvC when the valve is closed and the valve opening degree SvO when the valve is opened, the stepping motor 31 that controls the valve in 0 to 11 stages has the valve opening degree SvO when the valve is opened.
At this stage, the valve opening SvC when the valve is closed becomes a signal corresponding to the ninth stage.

[Summary of Control] In summary, these controls include a warm-up switch signal Qws, a cooling water temperature (cooling signal) Tw, an engine rotation speed Ne, an accelerator opening Ac,
Read the idle switch (idle signal) Is,
An operation signal V to the first negative pressure switching valve 21 regarding the exhaust throttle valve 8
s1, a control for outputting an operation signal Vs2 to the second negative pressure switching valve 22 and an instruction amount SvM for the intake throttle valve 4.

Then, the warm-up mode (Fq = 1 (ON))
During idle operation (IS = ON), the first negative pressure switching valve 21
Is turned on, the second negative pressure switching valve 22 is turned off, and the negative pressure supplied from the negative pressure pump 20 is supplied to the actuator 24, and the exhaust throttle valve is opposed to the urging force of an internal spring (not shown) of the actuator 24. 8 is fully closed, and the intake throttle valve 4 is closed to warm up.

In the warm-up mode (Fq = 1 (ON)) and during non-idling operation (IS = OFF), the first negative pressure switching valve
21 is turned ON, the second negative pressure switching valve 22 is turned ON, and the negative pressure supplied to the actuator 24 is set to a negative pressure intermediate to the atmospheric pressure.
The exhaust throttle valve 8 is half-opened and the intake throttle valve 4 is closed and warmed up by the balance with the biasing force of the spring inside the actuator 24.

Further, in the non-warm-up mode (Fq = 0)
In (OFF)), the first negative pressure switching valve 21 is turned off and the second negative pressure switching valve 22 is turned off to cut the negative pressure supplied to the actuator 24, and the exhaust is performed by the urging force of the spring inside the actuator 24. The throttle valve 8 is fully opened, and the intake throttle valve 4 is opened to warm up. [Effect of exhaust throttle]

According to the above-described engine warm-up method and the engine warm-up device having the above-described configuration, when the vehicle in the cold state is warmed up, the exhaust throttle valve 8 is stopped in the stopped state, that is, in the idling state. Can be fully closed to increase the warm-up effect, and when the accelerator 11 is depressed to shift to a running state in which the idle detection device detects a non-idle state, the exhaust throttle valve 8 is half-opened to reduce the fuel injection amount. The warm-up can be performed while coping with the increase in the exhaust gas amount accompanying the increase. After the warm-up is completed, the exhaust throttle valve 8 can be fully opened to perform the normal engine operation without the exhaust throttle.

In other words, the exhaust throttle valve 8 used for warming up the engine 1 is provided with a valve opening between the fully closed (first stage) and the fully opened (third stage) (second stage) so that the exhaust throttle valve 8 can be cooled from the cold state. In the shifted traveling state, the exhaust throttle of the intermediate valve opening is performed to improve the combustion of the engine 1 and to exert the warming effect of the exhaust throttle, thereby sufficiently warming up the running engine 1. be able to.

[Effect of Combined Use of Inlet Restrictor] Also, the combined use of the intake restrictor increases the in-cylinder pressure in accordance with the increase in the injection caused by the increase in the friction caused by the exhaust restrictor. Combustion noise such as combustion noise increases, but these noises can reduce the amount of noise emitted from the intake pipe.

Further, the intake throttle causes cold air to enter the cylinder from the intake pipe, lowering the temperature inside the cylinder and deteriorating the warm-up performance. However, by restricting the intake pipe, the amount of cold air is reduced. It is possible to suppress a decrease in the temperature in the cylinder and a deterioration in the warm-up property. Further, in this embodiment, the intake throttle is performed in two stages of opening and closing the valve. However, similarly to the exhaust throttle, the intake throttle is finely performed in three or more stages of valve opening in accordance with the operating state of the engine. You may.

[Effects of Opening / Closing Mechanism of Exhaust Throttle Valve] Further, the opening / closing mechanism of the exhaust throttle valve 8 can be replaced by a simple and inexpensive device such as a negative pressure pump (VP) 20, negative pressure switching valves (VSV) 21, 22. The exhaust throttle valve 8 can be controlled to open and close in three stages: fully closed (first stage), half open (second stage), and fully open (third stage) by a combination of a pressure reducing valve (VRV) 23 and an actuator 24. The mechanism can be configured at a low cost, and it is excellent in heat resistance, and the opening and closing of the exhaust throttle valve 8 can be controlled by relatively simple control. Therefore, high reliability of the opening and closing operation of the exhaust throttle valve 8 can be obtained. .

According to this configuration, it is possible to avoid the problem of operation failure due to high heat from the exhaust passage and the problem of high cost which occur when a step motor is employed, and to adjust the opening degree of the EGR valve. A problem that occurs when a duty control valve (EVRV: Electric Vacuum Regulating Valve) used for control and the like is adopted, that is, the response speed is slow, a time lag occurs, the problem that it is weak to heat, and the cost is high. Problems can be avoided.

[0057]

According to the engine warm-up method and the engine warm-up device of the present invention, when a vehicle in a cold state is warmed up, the vehicle is stopped, that is, idling.
When the exhaust throttle valve is fully closed, the warm-up effect can be increased, and when the accelerator is depressed and the idle detection device moves to a running state in which a non-idle state is detected, the exhaust throttle valve is half-opened, and the fuel injection amount is increased. It is possible to perform warm-up while coping with the increase in the amount of exhaust gas accompanying the increase in the exhaust gas. After the warm-up is completed, the exhaust throttle valve can be fully opened and normal engine operation without exhaust throttle can be performed.

That is, according to the engine warm-up method and the engine warm-up device of the present invention, the exhaust throttle is provided with an intermediate valve opening, and in the running state, the exhaust throttle is performed at the intermediate valve opening. In addition to improving the combustion of the engine, the warm-up effect of the exhaust throttle is also exerted, and the engine during running can be sufficiently warmed up, and the amount of smoke generated during warm-up running can be reduced.

By using the intake throttle together, the amount of combustion noise, such as engine noise and explosion combustion noise, which increase due to the exhaust throttle, can be reduced from the intake pipe, and the amount of cold air entering from the intake pipe can be reduced. , It is possible to suppress a decrease in the temperature in the cylinder due to cold air and a deterioration in warm-up properties, and further promote warm-up.

Further, the opening and closing mechanism of the exhaust throttle valve is a low-cost, simple, and excellent heat-resistant device, such as a negative pressure pump,
With a combination of a negative pressure switching valve, a pressure reducing valve, and an actuator, the opening and closing operation of the exhaust throttle valve in three stages of closing (first stage), half opening (second stage), and opening (third stage) can be performed by simple control. Therefore, the exhaust throttle mechanism can be configured at a low cost, and these devices are also excellent in heat resistance, and can control the opening and closing of the valve with relatively simple control. High reliability can be obtained. According to this configuration, it is possible to avoid problems such as a malfunction due to high heat from the exhaust passage and a problem of high cost, which occur when a step motor is employed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an engine warm-up device according to the present invention.

FIG. 2 is a diagram showing a warm-up mode determination subroutine of the engine warm-up method according to the present invention.

FIG. 3 is a diagram illustrating an exhaust throttle control subroutine of the engine warm-up method according to the present invention.

FIG. 4 is a diagram showing an intake throttle control subroutine of the engine warm-up method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Supercharger compressor 4 Intake throttle valve 5, 7 Exhaust passage 6 Turbocharger turbine 8 Exhaust throttle valve 9 Engine controller 10 Engine body 11 Accelerator pedal 12 Cooling water temperature sensor (cooling state detecting means) 13 Toothed rotating plate 14 Rotation speed sensor 20 Negative pressure pump 21 First negative pressure switching valve
(VSV1) 22 Second negative pressure switching valve (VSV2) 23 Pressure reducing valve (VRV) 24 Actuator 26 Muffler 31 Step motor 32 Air cleaner P11, P21 Negative pressure inlet P12, P22 First outlet P13, P23 Second outlet

Claims (4)

[Claims] An engine controller for controlling operation of an engine is supplied with a cold signal from a cold state detecting means for detecting a cold state of the engine and an idle signal from an idle detecting means for detecting an idling operation state, and exhausts the engine. Controlling the exhaust throttle valve provided in the passage and controlling opening and closing of the exhaust throttle valve to at least three stages of valve opening in which the valve opening increases in the first, second, and third order, When the means detects that the engine is in a cold state, and when the idle detecting means detects that the idling operation is being performed, the exhaust throttle valve is set to the first-stage valve opening degree; When the detecting means detects that the engine is in a cold state and the idle detecting means detects that the engine is not operating in an idle state, the exhaust throttle valve is set to the second stage. When the cold state detection means detects that the engine is not in a cold state, the exhaust throttle valve is set to the third position.
A method for warming up an engine that controls the valve opening in stages. 2. The warm-up of an engine according to claim 1, wherein the intake throttle valve provided in the intake passage is controlled to be closed when the cold state detecting means detects that the engine is in a cold state. Method. 3. An engine provided with a cold state detecting means for detecting a cold state of the engine and an idle detecting means for detecting an idling state of the engine.
An exhaust throttle valve that changes in at least three stages in which the valve opening degree increases in a third order is provided, and the cold state detecting means detects that the engine is in a cold state, and the idle detecting means is in idle operation. When it is detected, the exhaust throttle valve is set to the first-stage valve opening degree, the cold state detecting means detects that the engine is in a cold state, and the idle detecting means is in non-idle operation. Is detected, the exhaust throttle valve is set to the second position.
When the cold state detection means detects that the engine is not in a cold state, the exhaust throttle valve is controlled to open and close so that the exhaust throttle valve has a third stage valve opening degree. Engine warm-up device with engine controller. 4. A first and a second switch for switching between the first outlet and the second outlet by a negative pressure source and an operation signal to communicate with the negative pressure inlet in order to perform the three-stage opening and closing operation of the exhaust throttle valve.
A negative pressure switching valve, an actuator for inputting a negative pressure and a negative pressure to open and close the exhaust throttle valve, wherein the first negative pressure switching valve has a negative pressure inlet at the negative pressure source, a first outlet Is connected to the negative pressure inlet of the second negative pressure switching valve, respectively, and in the second negative pressure switching valve, a first outlet is connected to the actuator, and a second outlet is connected to the actuator via the pressure reducing valve. 4. The engine warm-up device according to claim 3, wherein the device is connected to an actuator.