JP2002147290A - Exhaust gas recirculation device for vehicular engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of black smoke during a vehicular start and to resolve insufficient torque during the start. SOLUTION: This exhaust gas recirculation device for the engine is provided with an EGR pipe 18 connected to manifolds 12 and 14 of the engine 11, an EGR valve provided in the EGR pipe 18, a controller 24 controlling the EGR valve, a clutch sensor 31 detecting an engagement/disengagement state of a clutch, a speed sensor 32 detecting traveling speed of a vehicle, a position sensor 33 provided in a transmission of the vehicle and detecting a shift position of the transmission, and an accelerator sensor 29 detecting a stepped-on amount of an accelerator pedal. The controller 24 closes the EGR valve when the clutch sensor detects a disengaged state of the clutch, the speed sensor detects zero traveling speed, the position sensor detects a shift position other than neutral, and the accelerator sensor detects a predetermined stepped-on amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for a vehicle engine that extracts a part of exhaust gas from an exhaust system and recirculates the exhaust gas to an intake system to reduce NOx. More specifically, the present invention relates to an exhaust gas recirculation system for a vehicle engine provided in a vehicle having a pedal operating clutch.

[0002]

2. Description of the Related Art Conventionally, as an exhaust gas recirculation device of this type, an EGR valve is provided on an EGR pipe branched from an exhaust manifold of an engine and connected to an intake manifold.
There is known a configuration in which a controller controls an EGR valve based on a rotation speed and a load of an engine. In this system, the controller opens the EGR valve in a steady driving state, recirculates a part of the exhaust gas to the intake system, lowers the maximum combustion temperature by the heat capacity of the exhaust gas, reduces NOx, and reduces the However, by closing the EGR valve and stopping the recirculation of exhaust gas to eliminate the shortage of air in the engine, the emission of black smoke from the engine is reduced.

[0003] However, if the accelerator pedal is suddenly depressed and sudden acceleration is performed in order to pass a vehicle traveling ahead from a steady driving state, the fuel injection amount increases immediately with the depression of the accelerator pedal, but the accelerator pedal is depressed. The EGR valve will not close unless it is relatively depressed and the controller recognizes that the load is high,
At the time of rapid acceleration in a steady running state, although the fuel injection amount sharply increases, there is a problem that the timing of closing the EGR valve and stopping the operation of EGR is delayed.

In general, if the closing of the EGR valve is delayed with respect to an increase in the fuel injection amount, the balance between air and fuel in the cylinder is lost, which temporarily deteriorates combustion and causes black smoke to be generated in the exhaust gas. There are issues involved. That is, in performing black smoke countermeasures at the time of the transient stop of the operation of the EGR, it is important how quick the acceleration is recognized. Particularly, in the electronic control fuel injection pump of the variable prestroke type, the governor control is given priority. It is said that the rank is high, the recognition of sudden acceleration is slow, and the rate of black smoke generation during transition is high.

[0005] To solve this problem, the EGR of the engine is designed to delay the timing of increasing the fuel when the accelerator pedal is depressed for rapid acceleration.
An apparatus has been proposed (JP-A-11-350069).
In this EGR device, when the accelerator pedal is rapidly depressed in the EGR operation state to perform rapid acceleration, the timing of increasing the fuel is delayed, and the amount of fuel injection is increased together with the closing of the EGR valve, so that black smoke during transition is increased. We try to suppress the occurrence of.

[0006]

However, the above-mentioned EG
The R device has a problem that the timing of increasing the fuel is delayed even when the vehicle is started from a stopped state, and the torque at the time of starting the vehicle is insufficient, which causes a problem that the vehicle actually starts running. An object of the present invention is to provide an exhaust gas recirculation system for a vehicle engine that can suppress the generation of black smoke at the time of starting the vehicle and can eliminate the insufficient torque at the time of starting.

[0007]

The invention according to claim 1 is
As shown in FIG. 1, an exhaust gas recirculation device for an engine 11 provided in a vehicle having a pedal operating clutch,
E having one end connected to the exhaust manifold 14 of the engine and the other end connected to the intake manifold 12 of the engine 11
GR pipe 18 and EGR provided on EGR pipe 18
This is an improvement in an engine exhaust gas recirculation system including an EGR valve 19 that opens and closes a pipe 18 and a controller 24 that controls the EGR valve 19. Its characteristic configuration is that a clutch sensor 31 for detecting the disconnected state of the clutch is provided.
A speed sensor 32 for detecting a traveling speed of the vehicle, a position sensor 33 provided in a transmission of the vehicle for detecting a shift position of the transmission, and an accelerator sensor 29 for detecting an amount of depression of an accelerator pedal. 24
Means that the clutch sensor 31 detects the disengaged state of the clutch,
The speed sensor 32 detects zero traveling speed, the position sensor 33 detects a shift position other than neutral, and the accelerator sensor 29 controls to close the EGR valve 19 when detecting a predetermined stepping amount.

In the exhaust gas recirculation system for a vehicle engine according to the present invention, it is determined that the engine 11 is in an idling state when the vehicle is stopped or that the vehicle is in a steady running state and the controller 24 is in a transient state. When not detecting, the controller 24 opens the EGR valve 19 and connects the EGR pipe 18. For this reason, the exhaust manifold 14
Is supplied to the intake manifold 12 through the EGR pipe 18, the temperature of the combustion gas in the combustion chamber of the engine 11 decreases, and the reaction between nitrogen and oxygen is suppressed,
NOx emissions are reduced.

On the other hand, if the driver depresses the clutch pedal to start the stopped vehicle, shifts the transmission lever, and then gradually releases the clutch pedal while depressing the accelerator pedal, the vehicle actually starts. Previously, the clutch sensor 31 detects the disengaged state of the clutch, the speed sensor 32 detects the traveling speed of zero, the position sensor 33 detects a shift position other than the neutral position, and the accelerator sensor 29 detects a predetermined depression amount. A condition arises. When this state occurs, the controller 24 closes the EGR valve 19 and stops the operation of the EGR. For this reason, when the fuel injection amount increases due to depression of the accelerator pedal when the vehicle starts, the EGR valve 1
The closing of No. 9 is not delayed, and the balance between air and fuel in the cylinder is maintained when the vehicle starts moving, thereby preventing the generation of black smoke. Further, since the fuel injection amount increases in accordance with the depression amount of the accelerator pedal, the shortage of torque at the time of starting the vehicle is eliminated, and the occurrence of the backlash of the vehicle is avoided.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a vehicle engine. The engine 11 is a diesel engine 11 provided in a vehicle having a pedal operating clutch. The intake port of the diesel engine 11 is connected to an intake pipe 13 via an intake manifold 12, and the exhaust port is connected to an exhaust manifold 14 via an exhaust manifold 14. Exhaust pipe 16 is connected. An exhaust gas recirculation device 17 is provided between the intake manifold 12 and the exhaust manifold 14. This exhaust gas recirculation device 17
An EGR pipe 18 having one end connected to the exhaust manifold 14 and the other end connected to the intake manifold 12;
An EGR valve 19 provided on the pipe 18 and a controller 24 for controlling the EGR valve 19 based on the rotation speed and load of the engine 11 are provided. Here, reference numeral 22 in FIG. 1 denotes an air cleaner provided at the tip of the intake pipe 13.

An EGR pipe 18 is connected to the intake manifold 12 and the exhaust manifold 14 by bypassing the engine 11, and an EGR valve 19 is connected to an EGR valve near the intake manifold 12.
The GR pipe 18 is provided. As the EGR valve 19 in this embodiment, a motor-operated valve that adjusts the opening of the EGR valve 19 by driving a valve body (not shown) by a motor 21 is used. The EGR valve 19 passes through an EGR pipe 18 and exhaust manifold. It is configured to adjust the flow rate of the exhaust gas that is recirculated from the intake manifold 12 to the intake manifold 12.
The EGR valve 19 may be an air-driven valve or the like instead of such an electric valve. Here, reference numeral 26 in FIG. 1 denotes exhaust gas (EGR) which is recirculated to the intake manifold 12.
EGR cooler for cooling gas).

The engine 11 is provided with a rotation sensor 28 for detecting the rotation speed. The vehicle is provided with an accelerator sensor 29 for detecting the amount of depression of an accelerator pedal (not shown). The load of the engine 11 is detected by the accelerator sensor 29 as the amount of depression of the accelerator pedal. The control input of the controller 24 is connected to the detection outputs of the rotation sensor 28 and the accelerator sensor 29, and the control output of the controller 24 is connected to the motor 21 via a drive circuit (not shown). The controller 24 is provided with a memory 24a.
The timing at which the EGR valve 19 is opened or closed according to changes in the rotation speed and load of the engine is stored as a map.

On the other hand, a not-shown pedal operation clutch is provided with a clutch sensor 31 for detecting the disconnected state of the clutch.
Is provided, and the vehicle is provided with a speed sensor 32 for detecting its running speed. A transmission (not shown) of the vehicle is provided with a position sensor 33 for detecting a shift position of the transmission. Clutch sensor 31 and speed sensor 3
2 and respective detection outputs of the position sensor 33 are connected to control inputs of a controller 24, and the controller 24 is configured to control the EGR valve 19 based on these respective detection outputs.

When the controller 24 of the exhaust gas recirculation device configured as described above does not detect a transition state, for example, an idle state when the vehicle is stopped, or a truck (not shown) runs on a flat ground at a constant speed. Sometimes
The controller 24 is configured to open the EGR valve 19 by performing a comparison operation between the respective detection outputs of the rotation sensor 28 and the accelerator sensor 29 and a map stored in the memory 24a. When the EGR valve 19 is opened, the EGR pipe 18 communicates and the exhaust gas from the exhaust manifold 14
The air is supplied to the intake manifold 12 via the R pipe 18. As a result, the temperature of the combustion gas in the combustion chamber of the engine 11 decreases, and the reaction between nitrogen and oxygen is suppressed.
x emission can be reduced.

Next, the control of the controller when starting the vehicle from the idle state when the vehicle is stopped will be described with reference to FIG. In the idle state when the vehicle is stopped, the clutch sensor 31
Detects the clutch connection state, the speed sensor 32 detects the traveling speed of zero, and the position sensor 33 detects the neutral position (FIGS. 2A, 2B, and 2C).
(C)). A driver who wants to start the vehicle from this state first depresses a clutch pedal (not shown) and shifts a transmission lever. Then, as shown in FIG. 2B, the clutch sensor 31 detects the disengaged state of the clutch, and as shown in FIG. 2C, the position sensor 33 detects a shift position other than the neutral position. Then, the driver gradually depresses the clutch pedal while depressing the accelerator pedal. In this state, the clutch sensor 31
Detects the disengaged state of the clutch, but when the accelerator pedal is depressed, the accelerator sensor 29 detects a predetermined depression amount as shown in FIG. 2D. Thus, before the vehicle actually starts, the clutch sensor 31 detects the disengaged state of the clutch, the speed sensor 32 detects the traveling speed of zero, the position sensor 33 detects the shift position other than the neutral position, and A state occurs where the sensor 29 detects a predetermined stepping amount. When this state occurs, the controller 24 closes the EGR valve 19 as shown in FIG.

Thereafter, the accelerator pedal is further depressed, and the depressing amount of the clutch pedal is further reduced, and the power of the engine 11 is transmitted to the wheels of the vehicle, whereby the vehicle actually starts to move. As shown in FIG. 2D, when the accelerator pedal is further depressed, the fuel injection amount increases. At the same time, the EGR valve 19 closes as shown in FIG.
Deactivate the GR. For this reason, the EGR valve 19
Is not delayed with the increase in fuel injection amount,
When the vehicle starts moving, the balance between air and fuel in the cylinder is maintained, and the generation of black smoke is prevented. Further, since the fuel injection amount increases in accordance with the depression amount of the accelerator pedal, the shortage of torque at the time of starting the vehicle is eliminated, and the occurrence of the backlash of the vehicle is avoided. In the above-described embodiment, an example in which the engine is mounted on a truck as a vehicle is shown. However, the vehicle may be a passenger car or a special construction vehicle used at a construction site as long as the vehicle has a pedal operation clutch. Good.

[0017]

As described above, according to the present invention, the clutch sensor for detecting the disengagement state of the clutch, the speed sensor for detecting the running speed of the vehicle, and the transmission sensor provided in the transmission of the vehicle are provided. A position sensor that detects the shift position, and an accelerator sensor that detects the amount of depression of the accelerator pedal, a clutch sensor detects the disengagement of the clutch, a speed sensor detects zero traveling speed, and a position sensor other than neutral When the shift position is detected and the accelerator sensor detects a predetermined depression amount, the controller is configured to close the EGR valve, so that the clutch pedal is depressed to start the stopped vehicle and the transmission lever is shifted. And then gradually depress the clutch pedal while depressing the accelerator pedal, the vehicle actually starts Before the EGR valve is closed, the closing of the EGR valve is not delayed with respect to the increase in the fuel injection amount due to the depression of the accelerator pedal, and the air-fuel balance in the cylinder is maintained when the vehicle starts moving. The generation of black smoke is prevented. Also, since the fuel injection amount increases according to the accelerator pedal depression amount,
Insufficient torque at the time of starting the vehicle is eliminated, and it is possible to prevent the start of the vehicle from being sluggish.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an exhaust gas recirculation device of the present invention.

FIG. 2 is a diagram showing a control state of a controller at the time of starting.

[Explanation of symbols]

 11 engine 12 intake manifold 14 exhaust manifold 18 EGR pipe 19 EGR valve 24 controller 29 accelerator sensor 31 clutch sensor 32 speed sensor 33 position sensor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Kasai 3-1-1, Hinodai, Hino-shi, Tokyo Hino Motors Co., Ltd. (72) Eiji Suzuki 3-1-1, Hinodai, Hino-shi, Tokyo Hino Motors F-term in stock (reference) 3G062 AA01 AA03 CA04 DA02 EA10 EB15 FA01 FA23 GA04 GA25 GA28 GA31 3G092 AA02 AA17 AB03 AC01 DC10 EA02 EA13 EA21 EA28 FA05 FA15 FA26 GA12 GB01 HD07X HF08Z HF12Z HF15Z03 AB 03A06 DB10 DB11 EA00 EC02 FA01 FA11 FA12 FB02

Claims (1)

[Claims] An exhaust gas recirculation device for an engine (11) provided in a vehicle having a pedal operating clutch, wherein one end is connected to an exhaust manifold (14) of the engine (11) and the other end is connected to the engine (11). An EGR pipe (18) connected to the intake manifold (12) of (11), and an EGR valve (19) provided on the EGR pipe (18) for opening and closing the EGR pipe (18)
A controller (24) for controlling the EGR valve (19)
An exhaust gas recirculation device for a vehicle engine, comprising: a clutch sensor (31) for detecting a disconnected state of the clutch.
A speed sensor (32) for detecting a traveling speed of the vehicle; a position sensor (33) provided in a transmission of the vehicle for detecting a shift position of the transmission; and an accelerator for detecting an amount of depression of an accelerator pedal. Sensor (2
9), wherein the controller (24) is such that the clutch sensor (31) detects the disengaged state of the clutch, the speed sensor (32) detects the traveling speed of zero, and the position sensor (33) is neutral. An exhaust gas recirculation system for a vehicle engine, wherein the EGR valve (19) is controlled to close when the accelerator sensor (29) detects a predetermined depression amount by detecting a shift position other than the above.