CN104791147A - Particulate matter removing device of marine heavy-duty diesel engine EGR system - Google Patents

Abstract

A marine heavy-duty diesel engine EGR system particle removal device in the technical field of internal combustion engines, including a conical turbine outlet pipe, a shuttle-shaped volume chamber, a spiral blade, an EGR pipe, an EGR valve, a conical turbine outlet pipe, a shuttle-shaped volume chamber, and a rear exhaust pipe. The air pipes are connected together in turn, the spiral blades are arranged in the conical turbine outlet pipe through the spiral blade fixing bracket to form a spiral air passage, the air inlet of the EGR pipe is arranged in the shuttle-shaped volume cavity, and the air outlet of the EGR pipe is arranged in the front inlet. Intratracheal. The invention can obtain relatively clean tail gas as the gas source of the EGR system, and reduces the pollution of particulate matters to the air compressor and the intake system of the engine. The invention has reasonable design and simple structure, and is suitable for the low-voltage circuit connection method of EGR.

Description

Marine heavy-duty diesel engine EGR system particulate matter removal device

technical field

The invention relates to a particulate removal device for an EGR system of a marine heavy-duty diesel engine, in particular to a particulate removal device for an EGR system of a heavy-duty diesel engine with intake turbocharging and intake intercooling.

Background technique

Exhaust gas recirculation (EGR) technology has long been considered an effective measure to reduce NOx emissions. But when EGR technology is applied to diesel engine, it will bring some problems. Since the diesel engine adopts the direct injection compression ignition method in the cylinder, there is a diffusion combustion zone in the combustion of the mixture, which will lead to the formation of particulate matter, especially in marine diesel engines that use heavy fuel oil as the main fuel. High particulate matter emissions will not only pollute the atmosphere, but also cause blockage of the EGR system, wear of the intake valve and valve seat, and serious problems such as poor valve sealing.

Supercharged intercooled diesel engine According to the different EGR circuits, the EGR system can be divided into low-pressure circuit connection method and high-pressure circuit connection method. In the low-pressure circuit connection method, an external pipe is used to connect the turbine outlet of the exhaust gas turbocharger with the compressor inlet, and an EGR valve is installed on the circuit to control the flow of EGR. This method is very easy to obtain an appropriate pressure difference, and it is easy to realize in the large speed range of the diesel engine. However, since the exhaust gas flows through the compressor of the supercharger and the supercharged intercooler, the particulate matter in the exhaust gas is likely to cause corrosion of the supercharger and fouling of the intercooler, reducing the reliability and life of the diesel engine. In the high-pressure circuit connection method, the inlet of the turbine is connected to the outlet of the compressor. Since the exhaust gas does not pass through the compressor and intercooler, damage to the compressor and intercooler is avoided, but it will inevitably cause wear on the intake valve and valve seat.

At present, the methods to reduce particulate matter are mainly to increase the direct injection pressure, adopt new combustion modes such as homogeneous compression ignition, and adopt DPF. Increasing the injection pressure can improve oil-gas mixing and reduce particle emissions to a certain extent, but the improvement effect is limited when the load is high; the homogeneous compression ignition technology has its own defects such as difficult to effectively control the ignition time and large cycle fluctuations, and its experimental certification still needs to be completed. A certain period of time; DPF technology is a relatively mature particle removal technology, but on heavy-duty marine diesel engines, the existing DPF will be blocked quickly, resulting in increased exhaust back pressure, DPF requires frequent regeneration, and is not practical.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned technologies, the present invention provides a simple method for effectively reducing the particle content of the EGR circuit for the EGR system of the low-pressure circuit connection method. The basic principle is to use the inhomogeneity of the quality of the exhaust components to arrange a spiral air passage in the exhaust pipe after the exhaust gas flows through the exhaust turbine. After the airflow passes through, it rotates at a high speed to cause the particles to produce centrifugal effect, and the EGR system pipe only recovers the part of the exhaust gas with less intermediate particle content.

The present invention is achieved through the following technical solutions, intercooler, diesel engine, compressor, turbine, conical turbine outlet pipe, shuttle-shaped volume chamber, rear end exhaust pipe, spiral blade, EGR pipeline, EGR valve, Front intake pipe, screw blade fixing bracket, diesel engine is connected with compressor and turbine through intake and exhaust pipelines, intercooler is arranged on the intake pipeline between diesel engine and compressor, and the air outlet of front intake pipe passes through the intake pipeline It is connected with the air inlet of the compressor, and the conical turbine outlet pipe, the shuttle-shaped volume cavity, and the rear exhaust pipe are connected together in turn, and the outlet of the turbine passes through the exhaust pipe and the air inlet of the conical turbine outlet pipe. The spiral blades are arranged in the conical turbine outlet pipe through the spiral blade fixing bracket to form a spiral air passage, the air inlet of the EGR pipe is arranged in the shuttle-shaped volume chamber, and the center line of the air inlet of the EGR pipe and the shuttle-shaped volume chamber The internal exhaust gas flows in parallel, the air outlet of the EGR pipe is arranged in the front intake pipe, and the EGR valve is arranged on the EGR pipe.

Further, in the present invention, the cross-sections of the conical turbine outlet pipe, the shuttle-shaped volume chamber, and the rear exhaust pipe are all circular, and the center line of the air inlet of the EGR pipeline coincides with the axis of the shuttle-shaped volume chamber, and the conical The turbine outlet pipe is a tapered nozzle, and the EGR valve is a solenoid valve.

Compared with the prior art, the present invention has the following beneficial effects: relatively clean tail gas can be obtained as the gas source of the EGR system, reducing the pollution of particulate matter to the compressor and engine intake system; the design is reasonable, the structure is simple, and the development cost is low. Low.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Among them: 1. Conical turbine outlet pipe, 2. Shuttle volume cavity, 3. Rear exhaust pipe, 4. Spiral blade, 5. EGR pipe, 6. EGR valve, 7. Front intake pipe, 8. Spiral blade Fixed bracket, 9, intercooler, 10, diesel engine, 11, air compressor, 12, turbine.

Detailed ways

The embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. This embodiment is based on the technical solution of the present invention, and provides detailed implementation methods and specific operating procedures, but the scope of protection of the present invention is not limited to the following embodiments. .

Example

As shown in Figure 1, the present invention includes a conical turbine outlet pipe 1, a shuttle-shaped volume chamber 2, a rear exhaust pipe 3, a spiral blade 4, an EGR pipeline 5, an EGR valve 6, a front air intake pipe 7, and a spiral blade fixing bracket 8. Intercooler 9, diesel engine 10, compressor 11, turbine 12, diesel engine 10 is connected to compressor 11 and turbine 12 through intake and exhaust pipelines, intercooler 9 is arranged between diesel engine 10 and compressor 11 On the air intake pipeline, the air outlet of the front air inlet pipe 7 is connected to the air inlet of the compressor 11 through the air inlet pipe, and the conical turbine air outlet pipe 1, the shuttle-shaped volume chamber 2, and the rear exhaust pipe 3 are connected together in sequence, The air outlet of the turbine 12 is connected to the air inlet of the conical turbine air outlet pipe 1 through the exhaust pipeline, the spiral blade 4 is arranged in the conical turbine air outlet pipe 1 through the helical blade fixing bracket 8 to form a spiral air passage, and the EGR pipe 5 The air inlet of the EGR pipe 5 is arranged in the shuttle-shaped volume chamber 2, the center line of the air inlet of the EGR pipe 5 is parallel to the exhaust flow in the shuttle-shaped volume chamber 2, the air outlet of the EGR pipe 5 is arranged in the front air intake pipe 7, and the EGR valve 6 is arranged on the EGR pipe 5; the cross-sections of the conical turbine outlet pipe 1, the shuttle-shaped volume chamber 2, and the rear exhaust pipe 3 are all circular, and the center line of the air inlet of the EGR pipe 5 is in line with the shuttle-shaped volume chamber 2 The axes coincide, the conical turbine outlet pipe 1 is a tapered nozzle, and the EGR valve 6 is a solenoid valve.

The working process of the present invention is: (1) after the exhaust gas flows through the turbine 12 from the exhaust valve, it enters the conical turbine outlet pipe 1, and the helical blade 4 is fixed in the pipe, and the exhaust gas is generated under the guidance of the helical blade 4 Rotate and continue to flow forward; the pipe is designed to be tapered, which is equivalent to a tapered nozzle, and the subsonic exhaust is accelerated. (2) The high-speed rotating exhaust enters the shuttle-shaped volume chamber 2, where the larger soot particles in the exhaust will move to the periphery under the action of centrifugal force; Large soot particles are mainly distributed in the outer ring area, while the gas in the middle is relatively clean. At this time, the horizontal EGR pipe 5 extending into the volume chamber will collect the clean gas in the middle part in a timely manner, and the remaining exhaust gas will be discharged with Air duct exhaust. (3) The relatively clean exhaust gas entering the EGR pipeline 5 is mixed with the fresh air in the front intake pipe 7 under the control of the EGR valve 6, and finally flows into the cylinder after being supercharged by the compressor 11 and intercooled by the intercooler 9.

Claims (2)

1. a large diesel engine egr system particulate matter removal device peculiar to vessel, comprise intercooler (9), diesel engine (10), gas compressor (11), turbine (12), diesel engine (10) is by intake and exhaust pipeline and gas compressor (11), turbine (12) is connected, intercooler (9) is arranged in diesel engine (10), on air inlet pipeline between gas compressor (11), characterized by further comprising, conical turbine steam outlet pipe (1), fusiformis cavity volume (2), rear end outlet pipe (3), helical blade (4), EGR pipe road (5), EGR valve (6), front end airflow pipe (7), helical blade fixed support (8), the air outlet of front end airflow pipe (7) is connected by the suction port of air inlet pipeline with gas compressor (11), conical turbine steam outlet pipe (1), fusiformis cavity volume (2), rear end outlet pipe (3) is connected in turn, the air outlet of turbine (12) is connected by the suction port of gas exhaust piping with conical turbine steam outlet pipe (1), helical blade (4) is arranged in conical turbine steam outlet pipe (1) by helical blade fixed support (8) and forms helical intake, the suction port in EGR pipe road (5) is arranged in fusiformis cavity volume (2), the suction port center line in EGR pipe road (5) with fusiformis cavity volume (2) interior exhaust stream to parallel, the air outlet in EGR pipe road (5) is arranged in front end airflow pipe (7), EGR valve (6) is arranged on EGR pipe road (5).

2. large diesel engine egr system particulate matter removal device peculiar to vessel according to claim 1, it is characterized in that the cross section of conical turbine steam outlet pipe (1), fusiformis cavity volume (2), rear end outlet pipe (3) is circle, the suction port center line in EGR pipe road (5) and the dead in line of fusiformis cavity volume (2), conical turbine steam outlet pipe (1) is convergent jet pipe, and EGR valve (6) is solenoid valve.