JPH0517147U - EGR control device for de-asel engine - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] When the exhaust brake is operated in a diesel engine equipped with a negative pressure control EGR valve, the exhaust escapes through the valve and prevents the performance of the exhaust brake from deteriorating. . [Structure] EGR composed of main body 4 and diaphragm chamber 5
And exhaust gas recirculation system provided with a valve 3, an exhaust Shiyatta 16 etc., connected to the air tank 14 via a solenoid valve 13 for EGR valve and the negative pressure chamber 5b of the EGR valve by the air circuit L _2, the operation of the exhaust brake The solenoid valve is linked to EG
It is controlled by the R controller. As a result, the air pressure is applied to the negative pressure chamber of the EGR valve so that the EGR valve is not opened by the pressure of the exhaust gas.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an EGR control device for a diesel engine provided with an exhaust gas recirculation device having a negative pressure control EGR valve and an exhaust brake device.

[0002]

[Prior Art]

 Various types of exhaust gas recirculation are known, and the present applicant has proposed an exhaust brake device for a multi-cylinder engine in Japanese Utility Model Laid-Open No. 2-67048, and further includes an exhaust gas recirculation device and an exhaust brake device. Diesel engines are known.

[0003]

[Problems to be solved by the device]

 In a diesel engine that recirculates exhaust gas, if the exhaust outlet is located upstream of the exhaust brake shutter, the pressure inside the engine will escape through the EGR valve when the exhaust brake is activated, and The performance may be impaired.

An object of the present invention is to provide an EGR control device for a diesel engine that prevents deterioration of exhaust brake performance.

[0005]

[Means for Solving the Problems]

 According to the present invention, in a diesel engine provided with an exhaust gas recirculation device equipped with a negative pressure control EGR valve and an exhaust brake device, the negative pressure side of the EGR valve is connected to an air source via an electromagnetic valve by an air circuit. Control means is provided which is connected and opens the solenoid valve in conjunction with the operation of the exhaust brake.

The control means is composed of an EGR controller formed of a microcomputer, and when the exhaust brake switch is ON and the engine speed is equal to or higher than a predetermined value (for example, 600 rpm), the EGR control is stopped. It is preferable to control the EGR valve so that it returns to the closed position.

[0007]

[Action]

 In the diesel engine EGR control device configured as described above, when the exhaust brake switch is ON and the engine speed is equal to or higher than the predetermined value, the EGR controller closes the EGR valve and opens the solenoid valve. Air pressure is applied to the negative pressure side of the EGR valve to prevent the EGR valve from opening with the pressure of the exhaust gas to prevent the exhaust gas from recirculating.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a main body 4 of an EGR valve, generally designated by 3, is provided in a recirculation passage 2 branched from the exhaust pipe 1 upstream of the exhaust shutter 16 for recirculating exhaust gas in the direction of the arrow. ing. The main body 4 is connected to a diaphragm 6 provided in a diaphragm chamber 5 and is urged by a spring 7 in a valve closing direction. The chamber 5a on the main body side of the diaphragm chamber 5 is opened to the atmosphere by the atmosphere opening pipe 8 through the orifice 9. The negative pressure chamber 5b on the side opposite to the chamber 5a is composed of a three-way valve open to the atmosphere by the vacuum circuit L1, and the PCM valve 10 for the EGR valve and the surge tank 11 which open the negative pressure chamber 5b to the atmosphere at the time of OFF. It is connected to the vacuum pump 12 via. An air circuit L2 is branched from between the negative pressure chamber 5b of the vacuum circuit L1 and the PCM valve 10, and the air circuit L2 is connected to the air tank 14 via an EGR valve solenoid valve 13 that opens when it is turned on. ing.

An exhaust shutter 16 is connected to the air tank 14 via an exhaust shutter electromagnetic valve 15 that is closed when the air circuit L3 is turned on. The intake shutter PCM valve 18 (FIG. 2) of the EGR valve PCM valve 10, EGR valve solenoid valve 14, exhaust shutter solenoid valve 15, and intake shutter 17, which are opened when the electric circuit is turned on, are electrically connected to the electric circuits E1 and E2, respectively. It is connected to the EGR controller 20 which is a control means by E3 and E4.

An engine rotation sensor 30, an engine load sensor 31, a key switch 32, an exhaust brake switch 33, an engine water temperature sensor 34, and an air flow sensor 35 are connected to the EGR controller 20, respectively.

In FIG. 2, the EGR controller 20 is composed of a microcomputer, and is connected to an exhaust brake switch 33, an engine load sensor 31 and a key switch 32, an exhaust brake operation determining means 21, an engine load sensor 31, and a key switch. 32, an engine rotation sensor 30, an engine water temperature sensor 34, and an EGR control means 23 to which an air flow sensor 35 is connected, and the exhaust brake operation determination means 21 via the EGR control operation determination means 22 is an EGR control means 23. It is connected to the. The exhaust brake actuation determination means 21 and the EGR control means 23 respectively include an electromagnetic valve actuation means 24, an EGR valve PCM valve actuation means 25, an EGR valve solenoid valve actuation means 26, and an intake shutter actuation means 27 such as an exhaust shutter. The exhaust shutter solenoid valve 15, the EGR valve PCM valve 10, the EGR valve solenoid valve 13 and the intake shutter PCM valve 17 are connected to these means 24, 25, 26 and 27, respectively. There is.

Next, the operation will be described with reference to FIG.

The EGR controller 20 determines whether the key switch 32 is ON (step S1), and if YES, determines whether the exhaust brake switch 33 is ON (step S2). If YES, it is determined based on the signal from the engine speed sensor 30 whether the engine speed N is higher than a predetermined value N1 (for example, a speed 600 rpm slightly higher than the idling speed 450 rpm) (step S3). . If YES, the exhaust shutter solenoid valve 15 is turned on, the exhaust shutter 16 is closed, and the exhaust brake is operated (step S4). Next, the EGR valve PCM valve 10 is turned off to communicate the negative pressure chamber 5b with the atmosphere (step S5), the EGR valve solenoid valve 13 is opened, and the positive pressure of the air tank 14 is applied to the chamber 5b to apply the EGR valve. 3 is prevented from opening due to exhaust pressure (step S6), the intake shutter PCM valve 17 is turned off, the intake shutter 16 is closed (step S7), and the process returns.

On the other hand, if steps S1 and S2 are NO, the exhaust shutter solenoid valve 15 is OFF to open the exhaust shutter 16 (step S8), the EGR control is performed (step S9), and the process returns.

FIG. 4 shows a specific example in which the present invention is applied to a V-type engine. In the figure, reference numeral 19 is a muffler, 36 is a clutch switch, and 37 is an accelerator switch.

[0017]

[Effect of the device]

 Since the present invention is configured as described above, it is possible to prevent the exhaust brake performance from deteriorating when the exhaust brake operates and the EGR valve opens to recirculate exhaust gas.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a control block diagram.

FIG. 3 is a control flowchart.

FIG. 4 is an overall configuration diagram showing a specific example of the present invention.

[Explanation of symbols]

 2 ... Recirculation passage 3 ... EGR valve 5b ... Negative pressure chamber 10 ... EGR valve PCM valve 13 ... EGR valve solenoid valve 15 ... Exhaust shutter solenoid valve 16 ... Exhaust shutter 20 ... EGR controller

Claims (1)

[Scope of utility model registration request] 1. In a diesel engine provided with an exhaust gas recirculation device equipped with a negative pressure control EGR valve and an exhaust brake device, the negative pressure side of the EGR valve is connected to an air source via an electromagnetic valve by an air circuit, An EGR control device for a diesel engine, characterized in that control means for opening the solenoid valve is provided in association with the operation of the exhaust brake.