CN106762241A - A kind of engine exhaust-gas recirculating system - Google Patents

Abstract

The invention discloses an engine exhaust gas recirculation system, which relates to a vehicle. The engine exhaust gas recirculation system passes through the engine provided with an intake port and an exhaust port, including an intake pipeline, an exhaust pipeline, an EGR pipeline and a throttle valve. The invention sets a throttle valve in the exhaust gas recirculation system of the engine, increases the pressure difference of the EGR system, and increases the application of the EGR technology on the supercharged gasoline engine. The air intake pipeline is arranged before the air intake. The exhaust pipeline is arranged behind the exhaust port. The EGR line is connected between the intake line and the exhaust line. The throttle valve is located near the end of the exhaust line and is used to increase the pressure difference of the engine exhaust gas recirculation system. In the invention, the throttle valve is arranged on the exhaust side of the engine, and the throttle valve has ample space for arrangement and is easy to fix. By adjusting the opening of the throttle valve, the pressure of the EGR exhaust gas outlet point behind the front catalytic converter is increased. Under the same pressure of the EGR exhaust gas outlet point, the pressure difference of the EGR system is increased to meet the needs of the engine.

Description

An engine exhaust gas recirculation system

technical field

The invention relates to the technical field of vehicles, in particular to an engine exhaust gas recirculation system.

Background technique

EGR technology plays an important role in engine fuel saving and emission reduction. With the increasingly stringent fuel consumption and emission regulations, the application of EGR technology on supercharged gasoline engines has gradually become a trend. Applying EGR to supercharged gasoline engines Technology will inevitably become a mainstream of engine technology upgrades in major OEMs.

The application of EGR technology on supercharged gasoline engines is mainly divided into two technical routes: high-pressure EGR and low-pressure EGR. The high-pressure EGR technical solution for gasoline engines is relatively mature, but its contribution to the fuel consumption of the engine and the vehicle is relatively small. Low-pressure EGR has more advantages in terms of fuel economy and is currently a relatively cutting-edge and mainstream engine technology upgrade route.

In the development process of the low-pressure EGR system, the insufficient pressure difference of the EGR system is an important problem affecting the application of the low-pressure EGR technology. Insufficient pressure difference of the EGR system will cause the flow of EGR exhaust gas to fail to meet the needs of the engine, resulting in engine knocking and other abnormal working conditions of the engine, which may lead to engine damage or engine performance that does not meet the requirements. Solving the pressure difference problem of the low-pressure EGR system of the supercharged engine is a difficult problem that must be solved when the low-pressure EGR technology is applied to the supercharged gasoline engine.

Contents of the invention

The object of the present invention is to provide an engine exhaust gas recirculation system capable of increasing the pressure difference of the EGR system.

In particular, the present invention provides an engine exhaust gas recirculation system through an engine, wherein the engine has an intake port and an exhaust port, comprising:

an air intake pipeline, arranged before the air intake port, for gas inflow of the engine;

An exhaust pipeline, arranged behind the exhaust port, is used to discharge exhaust gas from the engine;

The EGR pipeline is connected between the intake pipeline and the exhaust pipeline, and is used to send part of the exhaust gas discharged from the exhaust pipeline into the intake pipeline after exhaust gas recirculation, so as to reusing a portion of exhaust gases from said engine; and

A throttle valve is arranged near the end of the exhaust pipe for increasing the pressure difference of the exhaust gas recirculation system of the engine.

Further, the intake pipeline includes an intake pipeline, and a turbocharger, an intercooler, a throttle valve and an intake manifold connected in sequence through the intake pipeline, wherein fresh air passes through the intake pipeline After entering the turbocharger, it passes through the intercooler, the throttle valve and the intake manifold to the intake port of the engine,

Wherein, the turbocharger has two groups of air inlets and outlets, wherein one group of inlets and outlets is connected to the intake pipeline, and the other group of inlets and outlets is connected to the exhaust pipeline.

Further, the exhaust pipeline includes an exhaust pipe, and an exhaust manifold, the turbocharger, a front catalytic converter, a rear catalytic converter, an auxiliary muffler and a main muffler connected in sequence through the exhaust duct device,

Wherein, the throttle valve is arranged at the exhaust pipe between the secondary muffler and the main muffler.

Further, one end of the EGR pipeline is connected to the exhaust pipe between the front catalytic converter and the rear catalytic converter, and the other end is connected to the intake pipe before the turbocharger , the other end of the EGR pipeline is connected to the intake pipeline via a tee piece,

Wherein, the exhaust gas generated in the engine flows through the exhaust manifold, the turbocharger and the front catalytic converter and is divided into two parts, and a part of the exhaust gas passes through the rear catalytic converter and the auxiliary muffler , the throttle valve and the main muffler are discharged, and another part of the exhaust gas is recirculated through the EGR pipeline and then sent to the intake pipeline.

Further, according to the flow direction of the exhaust gas, the EGR pipeline includes an EGR filter screen, an EGR cooler and an EGR valve connected in sequence through the pipeline.

Further, a temperature sensor is further arranged between the EGR valve and the EGR cooler, and a pressure difference sensor is arranged on both sides of the EGR valve.

Further, the throttle valve is an electric throttle valve.

Further, the throttle valve is a mechanical throttle valve.

Further, a pressure sensor is arranged before the throttle valve.

Further, the engine is a supercharged gasoline engine.

The invention sets a throttle valve in the exhaust gas recirculation system of the engine, increases the pressure difference of the EGR system, and increases the application of the EGR technology on the supercharged gasoline engine.

Further, the present invention arranges the throttle valve on the exhaust side of the engine, and the throttle valve has ample space for arrangement and is easy to fix; by adjusting the opening degree of the throttle valve, the EGR exhaust gas outlet point after the front catalytic converter is increased. Pressure, in the case of the same pressure at the outlet point of EGR exhaust gas, increase the pressure difference of the EGR system to meet the needs of the engine.

Further, the location of the throttle valve has a lower temperature near the main muffler, and the lower temperature has lower requirements on the material of the throttle valve. A mechanical throttle valve that meets the design requirements can be selected. As far as the valve is concerned, the cost of the throttle valve can be reduced; it ensures that the low-pressure EGR technology has a large working range on the supercharged gasoline engine, thereby improving the low-pressure EGR technology on the supercharged gasoline engine under the premise of ensuring the feasibility of the application The fuel-saving effect of the application has promoted the application of low-pressure EGR technology in supercharged gasoline engines.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of illustration and not limitation with reference to the accompanying drawings. The same reference numerals in the drawings designate the same or similar parts or parts. In the attached picture:

FIG. 1 is a schematic structural view of an engine exhaust gas recirculation system according to an embodiment of the present invention.

detailed description

Fig. 1 shows a schematic structural diagram of an engine exhaust gas recirculation system in an embodiment of the present invention. It can be seen from the figure that the engine exhaust gas recirculation system passes through the engine 10 and is used for circulating the gas entering the engine 10 and the gas flowing out of the engine 10 . Wherein the engine 10 has an intake port and an exhaust port. The engine exhaust gas recirculation system includes an intake pipe 20 , an exhaust pipe 30 , an EGR pipe 40 and a throttle valve 50 . The present invention arranges the throttle valve 50 in the exhaust gas recirculation system of the engine, increases the pressure difference of the EGR system, and increases the application of the EGR technology on the supercharged gasoline engine.

As shown in FIG. 1 , the flow direction indicated by the hollow arrow a in the figure is the flow direction of the gas in the intake pipeline 20 . The air intake pipeline 20 is arranged before the air intake port for gas inflow of the engine 10 . The flow direction of the gas indicated by the solid arrow b shown in the figure is the flow direction of the gas in the exhaust pipeline 30 . As can be seen from FIG. 1 , the exhaust pipeline 30 is arranged behind the exhaust port, and is used for exhaust gas of the engine 10 to be discharged. The flow direction of the gas indicated by the dotted arrow c shown in the figure is the flow direction of the gas in the EGR pipeline 40 . As shown in FIG. 1 , the EGR pipeline 40 is connected between the intake pipeline 20 and the exhaust pipeline 30 , and is used to recirculate part of the exhaust gas discharged from the exhaust pipeline 30 and send it to into the intake pipe 20, so that part of the exhaust gas discharged from the engine 10 can be reused. Wherein, the throttle valve 50 is arranged near the end of the exhaust pipeline 30 for increasing the pressure difference of the exhaust gas recirculation system of the engine. Preferably, the connection between the EGR pipeline 40 and the exhaust pipeline 30 is arranged in front of the throttle valve 50 . Wherein, the front and back mentioned in the present invention are both defined according to the flow direction of the gas. In the present invention, the throttle valve 50 is arranged on the exhaust side of the engine 10, and the throttle valve 50 has ample space for arrangement and is easy to fix. During the use of the system of the present invention, the opening degree of the throttle valve 50 can be adjusted to increase the pressure of the EGR exhaust gas outlet point behind the front catalytic converter. Under the same situation of the EGR exhaust gas outlet point pressure, the pressure difference of the EGR system can be increased. Make it meet the requirements of the engine 10 .

The intake pipeline 20 includes an intake pipeline 21, and a turbocharger 22, an intercooler 23, a throttle valve 24 and an intake manifold 25 connected in sequence through the intake pipeline 21, wherein the intake gas passes through the The intake pipe 21 enters the turbocharger 22 and passes through the intercooler 23 , the throttle valve 24 and the intake manifold 25 to the intake port of the engine 10 after being pressurized.

Wherein, the turbocharger 22 has two groups of air inlets and outlets, namely a first air inlet 221 , a first air outlet 222 , a second air inlet 223 and a second air outlet 224 . One group of air inlets and outlets, that is, the first air inlet 221 and the first air outlet 222 are connected in the air intake pipeline 20, and another group of air inlets and outlets, that is, the second air inlet 223 and the second air outlet 224 are connected in the exhaust line 30.

As a specific embodiment, as can be seen in FIG. 1 , the intake gas first enters the first air inlet 221 from the intake pipe 21 and then enters the turbocharger 22, and is supercharged by the turbocharger 22 and then passes through the first air outlet. 222 out, then through the intercooler 23, the throttle valve 24 and the intake manifold 25, and then through the air intake of the engine 10, and then enter the engine 10 through the air intake for combustion of the engine 10.

The exhaust pipeline 30 includes an exhaust pipeline 31, and an exhaust manifold 32, a turbocharger 22, a front catalytic converter 33, a rear catalytic converter 34, a secondary muffler 35 and a main The muffler 36 , wherein the throttle valve 50 is arranged at the exhaust pipe between the secondary muffler 35 and the main muffler 36 .

One end of the EGR pipeline 40 is connected to the exhaust pipe 31 between the front catalytic converter 33 and the rear catalytic converter 34, and the other end is connected to the intake pipe before the turbocharger 22. At the gas pipeline 21 , the other end of the EGR pipeline 40 is connected to the intake pipeline 21 via a tee piece 60 . The gas flowing out of the EGR pipeline 40 enters the turbocharger 22 after being mixed with the fresh air entering the intake pipeline 20 at the tee 60 .

Wherein, the exhaust pipeline 30 passes through the second air inlet 223 and the second air outlet 224 of the turbocharger 22 . Wherein, the exhaust gas produced by the engine 10 enters the turbocharger 22 after passing through the exhaust manifold 32 and the second air inlet 223 of the turbocharger 22 , and then enters into the turbocharger 22 through the second intake port 223 of the turbocharger 22 . The second air outlet 224 comes out, and is divided into two parts after being catalyzed by the front catalytic converter 33, and a part of exhaust gas passes through the rear catalytic converter 34, the secondary muffler 35, the throttle valve 50 and the main muffler 36 After exhausting, another part of the exhaust gas is recirculated through the EGR pipeline 40 and then sent into the intake pipeline 20 .

The EGR pipeline 40 includes an EGR filter 41 , an EGR cooler 42 and an EGR valve 43 sequentially connected through the pipeline according to the flow direction of the exhaust gas. A temperature sensor 44 is also provided between the EGR valve 43 and the EGR cooler 42 , and a differential pressure sensor 45 is provided on both sides of the EGR valve 43 .

As a preferred embodiment, generally, the throttle valve 50 is an electric throttle valve.

As another example, because the throttle valve 50 is arranged at the tail end of the exhaust pipe 31 close to the main muffler 36, the temperature at this position is lower, and the lower temperature requires lower materials for the throttle valve 50. A mechanical throttle valve that meets the design requirements can be selected, which can reduce the cost of the throttle valve 50 compared with the electric valve. In order to monitor the effectiveness of the mechanical throttle, a pressure sensor 51 is arranged upstream of the mechanical throttle.

As an embodiment, the engine 10 is a supercharged gasoline engine. The invention ensures that the low-pressure EGR technology has a larger working range on the supercharged gasoline engine, thereby improving the fuel-saving effect of the low-pressure EGR technology applied to the supercharged gasoline engine under the premise of ensuring the feasibility of the application, and further promotes Application of low-pressure EGR technology on supercharged gasoline engine. So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. a kind of engine exhaust-gas recirculating system, by engine, wherein, there is air inlet and exhaust at the engine Mouthful, including：

Air inlet pipeline, before being arranged at the air inlet, the gas for the engine is flowed into；

Gas exhaust piping, is arranged at after the exhaust outlet, for the waste gas discharge of the engine；

EGR line, is connected between the air inlet pipeline and the gas exhaust piping, for the portion that will be discharged at the gas exhaust piping Point waste gas send into after waste gas recycling in the air inlet pipeline, so that the portion of engine discharge is repeated profit With；With

Choke valve, is set, the pressure difference for increasing the engine exhaust-gas recirculating system near the gas exhaust piping end.

2. engine exhaust-gas recirculating system according to claim 1, it is characterised in that

The air inlet pipeline includes admission line, and turbocharger, charge air cooler, the section being sequentially connected through the admission line Valve and inlet manifold, wherein, air inlet gas through the admission line enter it is described it is turbocharger supercharged after through cold in described Device, the air throttle and the inlet manifold to the engine air inlet,

Wherein, the turbocharger has two groups of air inlet/outlets, and one of which air inlet/outlet is connected in the air inlet pipeline, Another set air inlet/outlet is connected in the gas exhaust piping.

3. engine exhaust-gas recirculating system according to claim 2, it is characterised in that the gas exhaust piping includes exhaust Pipeline, and be sequentially connected through the discharge duct exhaust manifold, the turbocharger, preceding catalyst converter, after catalyst converter, pair Muffler and main muffler,

Wherein, the choke valve is arranged at the discharge duct between the secondary muffler and the main muffler.

4. engine exhaust-gas recirculating system according to claim 3, it is characterised in that one end of the EGR line connects It is connected at the discharge duct between the preceding catalyst converter and the rear catalyst converter, the other end is connected to the turbocharger At the admission line before, the other end of the EGR line is connected with the admission line through three-way piece,

Wherein, the waste gas for being produced in the engine flows through the exhaust manifold, the turbocharger and the preceding catalyst converter After be divided into two parts, a part of waste gas is after described after catalyst converter, the secondary muffler, the choke valve and the main muffler Discharge, another part waste gas is sent into the air inlet pipeline after carrying out waste gas recycling through the EGR line.

5. engine exhaust-gas recirculating system according to claim 4, it is characterised in that according to described in exhaust gas flow direction EGR line includes the EGR filter screens, cooler for recycled exhaust gas and the EGR valve that are sequentially connected with through pipeline.

6. engine exhaust-gas recirculating system according to claim 5, it is characterised in that the EGR valve is cold with the EGR But temperature sensor is additionally provided between device, the both sides of the EGR valve are provided with differential pressure pickup.

7. the engine exhaust-gas recirculating system according to any one of claim 1-6, it is characterised in that the choke valve It is electric throttle valve.

8. the engine exhaust-gas recirculating system according to any one of claim 1-6, it is characterised in that the choke valve It is mechanical throttle damper.

9. engine exhaust-gas recirculating system according to claim 8, it is characterised in that be provided with before the choke valve Pressure sensor.

10. the engine exhaust-gas recirculating system according to any one of claim 1-9, it is characterised in that described to start Machine is gasoline supercharging engine.