CN203560008U - Exhaust gas recirculation system for diesel engine - Google Patents

Abstract

The utility model discloses an exhaust gas recirculation system for a diesel engine, which is used for overcoming adverse effects on the diesel engine performance, caused by a conventional diesel engine exhaust gas recirculation system. The exhaust gas recirculation system comprises an exhaust manifold, a supercharger, an oxidation catalyst, a diesel particle catcher, an EGR (exhaust gas recirculation) valve, an EGR cooler, an air filter and an air intake manifold, wherein the supercharger is an exhaust gas turbo-supercharger equipped with a supercharger turbine motor and a supercharge gas compressor; the exhaust manifold, the supercharger turbine motor, the oxidation catalyst and the diesel particle catcher are connected onto an exhaust pipeline of the diesel engine in sequence. The exhaust gas recirculation system is characterized in that the EGR valve and the EGR cooler are connected in series between the diesel particle catcher and the air filter, an EGR air inlet is additionally formed in the air filter, and an air outlet of the EGR cooler is communicated with the EGR air inlet of the air filter. According to the utility model, the air snatch phenomenon with the supercharger can be avoided, and the particles in the exhaust gas can be further removed, so as to prolong the working life of the diesel engine.

Description

A diesel engine exhaust gas recirculation system

technical field

The utility model relates to an exhaust gas recirculation system of an engine, in particular to an exhaust gas recirculation system of a vehicle-mounted diesel engine, and belongs to the technical field of internal combustion engines.

Background technique

With the continuous increase of global car ownership, the problem of air pollution caused by vehicle exhaust has become increasingly prominent, so the emission regulations of countries around the world are becoming more and more stringent. In order to meet the requirements of automobile energy saving and emission reduction, the engine exhaust gas recirculation (ie EGR) system has become the mainstream configuration of modern automobiles. The high-temperature oxygen-enriched environment generated by Nox can achieve the purpose of reducing Nox emissions.

At present, there are two ways to take air in the EGR system of a diesel engine. One is the high-pressure EGR system shown in Figure 1, which takes air from the exhaust pipeline before the supercharger 9, and exhaust gas and air are in the exhaust pipe behind the throttle valve. Mixing at the main pipe of the intake manifold 10; the second is the low-pressure EGR system shown in Figure 2, which takes gas from the back of the diesel particulate filter (ie DPF) located behind the turbocharger turbine, and the EGR outlet is connected to the booster. In the intake pipeline before the compressor 9 compressor 9-1. Since the amount of exhaust gas in the high-pressure EGR system will increase with the emission demand, the improvement of the exhaust gas recycling rate will cause more exhaust gas to be introduced into the intake manifold 10 before the supercharger 9, so that the exhaust gas volume used by the supercharger 9 Reduced, can not meet the engine intake pressure requirements, and the particulate matter and incomplete combustion products in the high-pressure EGR exhaust gas are likely to cause intake pipe blockage and abnormal wear of the engine cylinder, shortening the engine life; the low-pressure EGR system is taken from the rear end of the DPF After the exhaust gas drives the supercharger turbine to do work, its pressure is greatly reduced. In order to reduce the back pressure of the engine exhaust system, the DPF filter effect installed after the supercharger turbine is weakened, so the exhaust gas entering the supercharger compressor Smaller particles remaining in the exhaust can impact the aluminum blades of the supercharger compressor, adversely affecting overall engine performance.

Utility model content

The purpose of this utility model is to provide a diesel engine exhaust gas recirculation system which can not only avoid the occurrence of gas grabbing with the supercharger, but also solve the problem that the particulate matter in the exhaust gas has an adverse effect on the overall performance of the engine. .

Problem described in the utility model is realized with following technical scheme:

A diesel engine exhaust gas recirculation system, which includes an exhaust manifold, a supercharger, an oxidation catalyst, a diesel particulate filter, an EGR valve, an EGR cooler, an air filter and an intake manifold, the supercharger It is an exhaust gas turbocharger equipped with a turbocharger turbine and a supercharger compressor, and the exhaust manifold, turbocharger turbine, oxidation catalyst and diesel particulate filter are sequentially connected to the exhaust pipe of the engine On the road, it is special in that: the EGR valve and the EGR cooler are connected in series between the diesel particulate filter and the air filter, the air filter is provided with an EGR inlet, and the EGR cooler outlet is connected to the EGR of the air filter. The air port is connected.

In the exhaust gas recirculation system of the above diesel engine, the air filter is provided with a filter screen at the EGR air inlet.

In the exhaust gas recirculation system of the above diesel engine, the EGR inlet of the air filter communicates with the fresh air inlet, and they are located below the filter element of the air filter, and an air outlet of the air filter is arranged above the filter element of the air filter.

In the exhaust gas recirculation system of the above diesel engine, the air outlet of the air filter communicates with the air inlet of the supercharger compressor, and the air outlet of the supercharger compressor communicates with the intake manifold.

The exhaust gas recirculation system of the above-mentioned diesel engine, the circulation route of the recirculated exhaust gas is: engine cylinder head→exhaust manifold→supercharger turbine→oxidation catalyst→diesel particulate filter→EGR valve→EGR cooler→air filter→ Supercharger compressor → intake manifold → engine cylinder head.

In the utility model, after the exhaust gas of the engine drives the supercharger turbine to do work, it is then treated by the oxidation catalyst and the diesel particle trap, not only the temperature and pressure are greatly reduced, but also the larger particulate matter in the exhaust gas is removed, so The EGR valve takes air from the back of the diesel particulate filter, which not only overcomes the phenomenon of grabbing air with the supercharger, but also reduces the temperature of the exhaust gas that participates in combustion again. After being filtered by the filter at the EGR inlet of the air filter, the particulate matter in the exhaust gas is Further removal reduces the impact of exhaust gas on the blades of the supercharger compressor and improves the overall performance of the engine.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described.

Fig. 1 is an exhaust flow route diagram of an existing diesel engine high-pressure EGR system;

Fig. 2 is the exhaust gas flow route diagram of the existing diesel engine low-pressure EGR system;

Fig. 3 is a waste gas flow route diagram of the utility model;

Fig. 4 is a structural schematic diagram of the air filter of the present invention.

The list of labels in the figure is: 1. Engine cylinder head, 2. Exhaust manifold, 3. Oxidation catalyst, 4. Diesel particulate filter, 5. EGR valve, 6. EGR cooler, 7. Air filter, 7-1. EGR inlet, 7-2. Fresh air inlet, 7-3. Air filter outlet, 7-4. Air filter element, 7-5. Filter screen, 8. Engine intake pipe, 9, supercharger, 9-1, supercharger worm gear, 9-2, supercharger compressor, 10, intake manifold.

Detailed ways

Referring to Fig. 3, the utility model comprises an exhaust manifold 2, a supercharger 9, an oxidation catalyst 3, a diesel particulate filter 4, an EGR valve 5, an EGR cooler 6, an air filter 7 and an intake manifold 10, The supercharger 9 is an exhaust gas turbocharger provided with a supercharger turbine 9-1 and a supercharger compressor 9-2, and the exhaust manifold 2, the supercharger turbine 9-1, the oxygen The catalytic converter 3 and the diesel particulate filter 4 are sequentially connected to the exhaust pipe of the engine, and the EGR valve 5 and the EGR cooler 6 are connected in series between the diesel particulate filter 4 and the air filter 7; the circulation of the recirculated exhaust gas The route is: engine cylinder head 1→exhaust manifold 2→supercharger turbine 9-1→oxidation catalyst 3→diesel particulate filter 4→EGR valve 5→EGR cooler 6→air filter 7→supercharger Compressor 9-2→intake manifold 10→engine cylinder head 1; fresh air enters the air filter fresh air inlet 7-2 of the air filter 7 through the intake pipe 8, and passes through the air filter element 7 together with the recirculated exhaust gas -4 After being filtered, enter the supercharger compressor 9-2 for supercharging, and the mixture of supercharged fresh air and recirculated exhaust gas enters the engine combustion chamber through the intake manifold 10.

Referring to Fig. 4, the air filter 7 of the present utility model is provided with an EGR air inlet 7-1, and the air outlet of the EGR cooler 6 communicates with the EGR air inlet 7-1 of the air filter 7, and the EGR air inlet 7-1 A filter screen 7-5 is provided at the place, and the EGR air inlet 7-1 communicates with the fresh air inlet 7-2 of the air filter 7, and they are located below the air filter element 7-4 and above the air filter element 7-4 The air filter outlet 7-3 is set, and the air filter outlet 7-3 communicates with the air inlet of the supercharger compressor 9-2, and the air outlet of the supercharger compressor 9-2 is connected with the intake manifold. Tube 10 communicates.

Referring to Fig. 3 and Fig. 4, in the utility model, after the exhaust gas of the engine drives the supercharger turbine 9-1 to do work, it is then processed by the oxidation catalyst 3 and the diesel particulate filter 4, not only its temperature and pressure are greatly reduced , and the larger particulate matter in the exhaust gas is removed, so the EGR valve 5 takes air from the back of the diesel particulate filter 4, which not only overcomes the phenomenon of grabbing air with the supercharger 9, but also reduces the temperature of the exhaust gas that participates in combustion again, and at the same time reduces The total intake air temperature is increased, the fuel combustion efficiency is improved, and the high-temperature oxygen-enriched environment on which Nox generation depends is further destroyed, which is beneficial to the improvement of engine emission performance; the exhaust gas entering the EGR system passes through the EGR intake port 7 of the air filter 7 - After filtering by 1 filter 7-4, the particulate matter in the exhaust gas is further removed, which not only reduces the impact of exhaust gas on the blades of the turbocharger compressor 7-2, but also reduces the pollution of the engine intake pipe and cylinder, improving the The overall performance of the engine prolongs the working life of the engine.

Claims (5)

1. A diesel engine exhaust gas recirculation system, which includes an exhaust manifold (2), a supercharger (9), an oxidation catalyst (3), a diesel particulate filter (4), an EGR valve (5), EGR cooler (6), air filter (7) and intake manifold (10), the supercharger (9) is equipped with a supercharger turbine (9-1) and a supercharger compressor (9- 2) The exhaust gas turbocharger, the exhaust manifold (2), the turbocharger turbine (9-1), the oxidation catalyst (3) and the diesel particulate filter (4) are sequentially connected to the engine On the exhaust pipeline, the feature is that the EGR valve (5) and the EGR cooler (6) are connected in series between the diesel particulate filter (4) and the air filter (7), and the air filter (7) is additionally The EGR air inlet (7-1), the air outlet of the EGR cooler (6) communicates with the EGR air inlet (7-1) of the air filter (7). 2. The diesel engine exhaust gas recirculation system according to claim 1, characterized in that the air filter (7) is provided with a filter screen (7-5) at the EGR inlet (7-1). 3. The diesel engine exhaust gas recirculation system according to claim 2, characterized in that the EGR inlet (7-1) of the air filter (7) and the fresh air intake of the air filter (7) The ports (7-2) are connected, they are located below the air filter element (7-4), and the air filter outlet (7-3) is arranged above the air filter element (7-4). 4. A diesel engine exhaust gas recirculation system according to claim 3, characterized in that the air filter outlet (7-3) communicates with the air inlet of the supercharger compressor (9-2), The air outlet of the supercharger compressor (9-2) communicates with the intake manifold (10). 5. A diesel engine exhaust gas recirculation system according to claim 4, characterized in that the circulation route of the recirculated exhaust gas is: engine cylinder head (1) - exhaust manifold (2) - supercharger Turbine (9-1)--oxidation catalyst (3)--diesel particulate filter (4)--EGR valve (5)--EGR cooler (6)--air filter (7)--boost Air compressor (9-2)--intake manifold (10)--engine cylinder head (1).

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