KR19990061292A - Exhaust gas recirculation control device - Google Patents

Abstract

In the present invention, a part of the exhaust gas is bypassed by an intake pipe to remove particulate matter and nitrogen oxides NO _X The present invention relates to an exhaust gas recirculation control apparatus and an exhaust gas recirculation control apparatus for controlling an exhaust gas recirculation control apparatus and an exhaust gas recirculation control apparatus for controlling an exhaust gas recirculation control apparatus and an exhaust gas recirculation control apparatus, , A lever position sensor, a water temperature sensor and a vehicle speed sensor, and relatively corrects the signals to operate the first and second solenoid valves step by step according to the deviation of the respective positions and set values, And a control means for controlling the throttle valve and the EGR actuator to operate so as to optimize the response speed in response to situations such as low load and high load conditions so as to maximize the generation amount of soot, To a recirculation control apparatus and a method thereof.

Description

Exhaust gas recirculation control device

The present invention bypasses a part of the exhaust gas with an intake pipe to remove particulate matter and nitrogen oxide ( NO _X The present invention relates to an exhaust gas recirculation control apparatus and an exhaust gas recirculation control method for controlling an exhaust gas recirculation control apparatus and an exhaust gas recirculation control apparatus for reducing air pollution by optimizing the response speed in response to a situation such as a low load condition and a high load condition, The present invention relates to an exhaust gas recirculation control apparatus capable of contributing to prevention of exhaust gas recirculation.

Generally, as shown in Figs. 1 and 2, an exhaust gas recirculation (EGR) control apparatus bypasses a part of the exhaust gas with an intake pipe to generate particulate matter and nitrogen oxides NO _X Control function to reduce the EGR-control function.

The conventional configuration is as follows.

Reference numeral 1 denotes a diesel engine main body, to which an EGR passage 4 branched from the exhaust passage 3 of the engine body 1 is connected. The EGR passage 4 is opened and closed by an EGR valve 5A which functions as a driven device driven by a pressure-loaded actuator 5. The actuator 5 includes a pressure chamber 5a and a movable partition wall 5b partitioning the pressure chamber 5a and displacing in accordance with the pressure of the pressure chamber and a spring 5c for biasing the movable partition wall in one direction ). The stem of the EGR valve 5A is connected to the movable partition wall 5b and imparts a humidification in the closing direction by the spring 5c. The pressure chamber 5a is connected to a solenoid valve 7 which functions as a pressure regulating valve via a negative pressure output passage 6. [ The solenoid valve 7 is connected to a vacuum pump 9 as a second pressure source for generating a second pressure (negative pressure) via a negative pressure passage 8 as a second pressure supply passage.

A large-diameter orifice 8a and a small-diameter orifice 8b are formed in the negative pressure passage 8, respectively. The solenoid valve 7 comprises a coil 10 and a valve body 11 which is moved by the coil.

The solenoid valve 7 is connected to one end of an atmospheric release passage 2 which functions as a first pressure supply passage. The other end of the atmospheric release passage 12 is opened to the atmosphere as a first pressure source for generating a first pressure (atmospheric pressure). A small-diameter orifice is formed in the atmospheric release passage (12). The operation of the solenoid valve 7 is such that when the valve body 11 closes the negative pressure passage, the negative pressure output passage 6 and the atmospheric release passage 12 communicate with each other and the pressure chamber 5a of the actuator 5 is atmospheric pressure Thereby moving the EGR valve 5A and closing the EGR passage 4 as indicated by the broken line. When the valve body 11 closes the atmosphere opening passage 12, a negative pressure is supplied to the pressure chamber 5a of the actuator 95 to move the EGR valve 5A so that the EGR passage 4 It opens together.

Further, the solenoid valve 7 is controlled to be dewy, so that the negative pressure of the vacuum pump 99 is continuously supplied to the actuator 5. The solenoid valve 7 is connected to a control unit 13 composed of a computer as a control means. The engine operation state detection signal from the water temperature sensor 14 of the engine body 1 and the lever position sensor 16 and the rotation sensor 17 of the fuel injection pump 15 are applied to the control unit 13 . The timing control solenoid valve 18 of the fuel injection pump 15 is connected to the control unit 13.

The control unit 13 controls the solenoid valve 7 such that the first pressure (atmospheric pressure or negative pressure) and the second pressure (negative pressure or atmospheric pressure) alternately act in the pressure chamber 5a, (Negative pressure or atmospheric pressure) is continuously applied to the pressure chamber 5a so that the pressure of the pressure chamber is increased from the set value to the second pressure (Negative pressure or atmospheric pressure) of the pressure chamber continuously acts to change the pressure of the pressure chamber from the set value toward the second pressure (negative pressure or atmospheric pressure).

At this time, in order to prevent the generation of soot during operation in the diesel engine, it is necessary to control so that there is always a little excess air in all the operating conditions. Particularly, under the low load condition, since the excess air ratio is large, NO _X , There is little effect unless a large amount of EGR is supplied in comparison with a high load condition.

Due to the constraints of these conditions, the conventional EGR-control is based on the engine speed / load characteristic diagram, as shown in Fig. Exhaust gas should not be mixed in the intake air when the specific operating condition is, for example, cold running or the engine coolant temperature is very high. In order to prevent this, the recalculation rate is determined in consideration of the basic characteristics as well as the correction characteristics.

In addition, when the speed of the diesel vehicle is rapidly accelerated, the amount of consumed fuel is rapidly increased due to the decrease in the response speed of the solenoid valve 7, while the consumed air amount is not increased in proportion to the amount of consumed fuel Accordingly, a large amount of soot is discharged due to the excessive fuel consumption, and in particular, in an EGR-controlled engine, an excessive amount of soot is generated as compared with the above case.

Thus, in order to prevent soot, it is necessary to reduce the supply amount of EGR. That is, in the operation transient state, it is necessary to timely control the EGR in accordance with the operation state of the engine.

Conventionally, the electronic control of EGR uses a EGR valve with a potentiometer to feedback how much the valve has actually moved with respect to the target value and compensate by controlling the pressure while being separated from the target value, It is a duties system that automatically opens the control pressure by releasing the pressure supplied to the EGR valve periodically to the atmosphere, that is, by controlling the duties.

In addition, the feedback system has a problem in that the system cost is increased and the durability of the EGR actuator as an EGR actuator or an EGR valve as a driven device. In addition to the problem that the responsiveness is lowered because the EGR valve is opened to the atmosphere or the pressure is supplied to the EGR valve, the valve is subjected to ripple and the durability of the valve is lowered. At the same time, The diameter of the throttle valve provided between the atmospheric side and the pressure source may be reduced, but the response gradually deteriorates.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an EGR control engine that optimizes the response speed in response to situations such as low load and high load conditions, And an exhaust gas recirculation control device capable of contributing to the prevention of air pollution.

In order to attain the above object, an exhaust gas recirculation control apparatus according to the present invention comprises a vehicle speed sensor for converting a rotation of a differential case of a transmission into an electric pulse, a water temperature sensor of an engine body for detecting a water temperature in the engine, An EGR actuator connected in communication with a first solenoid valve operated in accordance with a negative pressure by a vacuum pump and controlling an amount of recirculated exhaust gas, and an EGR actuator which controls the amount of air supplied to the combustion chamber through the EGR actuator, And a throttle valve operated by the second solenoid valve in accordance with the detected throttle position of the accelerator pedal. The exhaust gas recirculation control apparatus includes an accelerating position detecting sensor coupled to the accelerator pedal to detect a throttle angle position of the accelerator pedal, A lever position sensor, a water temperature sensor, and a vehicle speed sensor, And control means for controlling the throttle valve and the EGR actuator to operate in a multi-step manner by operating the first and second solenoid valves step by step in accordance with the deviation of the respective values and the set values, .

1 is a systematic diagram schematically showing a conventional exhaust gas recirculation control apparatus.

2 is a block diagram of an exhaust gas recirculation control apparatus according to an embodiment of the present invention.

3 is a control flow diagram according to an embodiment of the present invention;

DESCRIPTION OF THE REFERENCE NUMERALS

5: EGR actuator 5A: EGR valve

7: first solenoid valve 9: vacuum pump

14: Water temperature sensor 15: Fuel injection pump

16: rotation sensor 17: lever position sensor

20: throttle valve 21: second solenoid valve

30: control means 31:

33: Command ECU: Electronic control unit

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate like elements to those of the prior art, and redundant description is omitted. FIG. 2 is a block diagram of an exhaust gas recirculation control apparatus according to an embodiment of the present invention, and FIG. 3 is a control flowchart according to an embodiment of the present invention.

Reference sign S is an angle-of-inclination sensor that is coupled to the accelerator pedal to detect the angular position of the accelerator pedal.

The accelerator pedal depression angular position detection sensor S is electrically connected to a determination section that receives the detection signal of the accelerator pedal depression degree from the depressed angle position detection sensor S and determines the degree of depression of the accelerator pedal .

In addition, the judging section 31 judges whether the accelerator pedal depression degree (WTS _K ) And a first set value (WTS ₀ ) And outputs the first estimate < RTI ID = 0.0 & (WTS _K ) Lt; RTI ID = 0.0 > (WTS ₀ ) (Electronic control unit) that controls the second solenoid valve to be operated / deactivated in a multi-step manner according to a greater degree to control the opening degree of the EGR valve 5A of the EGR actuator 5 to be changed.

Further, the judging section 31 judges whether or not the second estimated value of the cooling water temperature of the engine estimated by the water temperature sensor (AP _K ) Lt; RTI ID = 0.0 > (AP ₀ ) Of the fuel injection pump 15, and the third estimated value < RTI ID = 0.0 > (LPS _K ) And a third set value (LPS ₀ ) The third estimate < RTI ID = 0.0 > (LPS _K ) Lt; / RTI > (LPS ₀ ) Of the fuel injection pump (15), and the fourth estimated value < RTI ID = 0.0 > (EN _K ) And a fourth set value (EN ₀ ) Lt; RTI ID = 0.0 > (EN _K ) Lt; RTI ID = 0.0 > (EN ₀ ) The first solenoid valve 7 and the second solenoid valve 21 are operated in a multistage manner in accordance with the deviation between the respective estimated values and the respective set values so that the EGR actuator 5 with respect to the intake manifold 5 The opening degree of the EGR valve 5A, and the degree of opening of the throttle valve.

The control means 30 receives detection signals from the steering angle sensor S, the lever position sensor 17, the water temperature sensor and the vehicle speed sensor, and relatively corrects the signals, And actuates the throttle valve 20 and the EGR actuator 5 in a multistage manner by operating the first and second solenoid valves 7 and 21 step by step according to the degree of deviation of the throttle valve.

Next, the operation and effect of the present invention configured as described above will be described.

First, when the driver depresses the accelerator pedal for instantaneous acceleration, the amount of depression of the accelerator pedal is measured by the accelerator pedal depressed angle position detecting sensor S coupled to the accelerator pedal, and the signal is sent to the deciding section 31.

When the amount of the depression of the accelerator pedal is transmitted to the judging unit 31, the judging unit judges that the first estimated value (WTS _K ) And a first set value < RTI ID = 0.0 > (WTS ₀ ) .

At this time, if the difference between the estimated value and the set value is determined to be positive, the determination unit 31 instructs the control unit 30 to determine that the vehicle is in the acceleration state.

In the command section 33 of the control means 30, when it is determined that the vehicle is in the accelerated state, the ECU including the control means 30 independently drives the second solenoid valve 21 to the estimated value and the set value It is instructed to increase the number of steps in accordance with the degree of deviation.

Further, the second estimation value of the cooling water temperature of the engine estimated by the water temperature sensor 14 in the determination section 31 (AP _K ) And a second set value (AP ₀ ) Lt; RTI ID = 0.0 > (AP _K ) Lt; RTI ID = 0.0 > (AP ₀ ) The degree of opening of the first solenoid valve 7 and the second solenoid valve 21 is increased in a multistage manner in accordance with the degree of the deviation and the opening degree of the throttle valve 20 and the EGR valve 5A And also increases in conjunction with the degree.

Further, the third estimated value estimated by the lever position sensor 17 of the fuel injection pump 15 (LPS _K ) And a fourth set value (EN ₀ ) The third estimate < RTI ID = 0.0 > (LPS _K ) Lt; / RTI > (LPS ₀ ) And the fourth estimated value estimated by the rotation sensor 16 of the fuel injection pump 15, (EN _K ) And a fourth set value (EN ₀ ) Lt; RTI ID = 0.0 > (EN _K ) Lt; RTI ID = 0.0 > (EN ₀ ) The degree of opening of the throttle valve 20 and the EGR valve 5A is independently increased in multiple stages according to the degree of the deviation.

At this time, in accordance with the operation of the throttle valve 20 and the EGR valve 5A, the opening degree of the EGR valve 5A is changed stepwise according to the operation of the EGR actuator 5 that responds to the negative pressure of the vacuum pump 9 , The control operation is always performed so that there is always a little excess air in all the operating conditions.

As a result, when the driver depresses the accelerator pedal during the instantaneous acceleration, the acceleration state is detected as fast as possible by the accelerator pedal angular position detecting sensor S and the second solenoid valve is immediately operated by the ECU, It is possible to secure the response performance.

Accordingly, the intake air amount is increased stepwise in proportion to the degree of change of the operating condition according to the acceleration state, NO _X And the amount of unburned gas can be reduced to suppress the generation of black smoke as much as possible.

As described above, according to the exhaust gas recirculation control apparatus of the present invention, it is possible to optimize the response speed in response to situations such as low load and high load conditions, to minimize the generation of soot, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention may be embodied otherwise without departing from the scope or spirit of the invention as disclosed in the accompanying claims.

Claims (2)

A water temperature sensor of an engine body for detecting a water temperature in the engine, a lever position sensor of a fuel pump, and a first solenoid operated in accordance with a negative pressure by a vacuum pump, An EGR actuator connected in communication with the valve and controlling the amount of recirculated exhaust gas, an exhaust gas control valve controlling the amount of air supplied to the combustion chamber through the EGR actuator and operated by the second solenoid valve in accordance with the negative pressure, In the recirculation control device, An angular position detection sensor coupled to the accelerator pedal to detect the angular position of the accelerator pedal, And the first and second solenoid valves are operated in accordance with the degree of deviation between the respective positions and the set values, And a control means for controlling the throttle valve and the EGR actuator to operate in a multistage manner by operating the exhaust gas recirculation control device. The method according to claim 1, Wherein, Wherein the first estimated value is greater than or equal to a predetermined value by comparing the estimated first estimated value with a first set value set by itself, receiving a detection signal of the degree of depression of the accelerator pedal from the answer position detecting sensor, The second estimated value of the engine coolant temperature estimated by the fuel injection pump is less than a second set value that is set by itself and the third estimated value estimated by the lever position sensor of the fuel injection pump is compared with a third set value set by itself, The fourth estimated value estimated by the rotation sensor of the fuel injection pump is compared with the fourth estimated value set by itself, and when the fourth estimated value exceeds the predetermined value by the predetermined value or more, And the opening degree of the EGR valve of the EGR actuator with respect to the intake manifold and the degree of opening of the EGR valve with respect to the intake manifold, Exhaust gas recirculation control device, characterized in that for controlling the opening degree of the valve individually.