JPH0763126A - Diesel engine with EGR - Google Patents

Abstract

(57) [Abstract] [Objective] To reduce NOx and particulate matter emitted from the diesel engine, a particulate filter with a sub chamber, EGR, and a catalyst for removing NOx is installed to clean the exhaust gas. Try. A turbocharger 5 is attached to an engine 1 having a piston 12 provided with a sub chamber 2, and an EGR passage 70 and an exhaust gas passage 51 of the intake pipe 3 and the turbocharger 5 are provided. A bypass channel 9 is installed between them. Then, the main filter 6 for collecting the particulate matter contains a material having a catalytic action, the temperature is monitored by the temperature sensor 61, and the catalytic action is controlled by controlling the pressure air from the bypass passage 9 and the energization to the main filter 6. Keep the optimum temperature of.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine with EGR for reducing nitrogen oxides and particulate matter contained in exhaust gas of a diesel engine for cleaning.

[0002]

2. Description of the Related Art A diesel engine is a heterogeneous combustion in which fuel is injected into a high temperature air by adiabatic compression to perform combustion. Therefore, CO and HC emissions are small, but nitrogen oxides (NOx) are emitted. A large amount of particulates are discharged. When the turbocharger is attached to the diesel engine, the amount of air supplied is large, so the amount of exhaust smoke is relatively small and the amount of exhaust smoke is reduced, but NO.
The technology to reduce the generation of x has not been completed.

On the other hand, recently, a technique for reducing the amount of NOx by using zeolite or alumina as a catalyst has been developed.

[0004]

With the above catalyst, NO
The technology for reducing x is extremely sensitive to the temperature of the reaction, and the temperature of the exhaust gas is 1 when the diesel engine burns.
Since the temperature greatly changes from 00 ° C to 700 ° C, there is a problem that it is difficult to maintain the optimum catalytic reaction temperature.

The present invention is intended to solve such a conventional problem, and its purpose is to mount a sub-combustion chamber, a turbocharger and an EGR mechanism on a diesel engine and use a catalyst to make it suitable. It is an object of the present invention to provide a diesel engine with an EGR that keeps the reaction temperature and also arranges a particulate filter to reduce pollutants in exhaust gas for cleaning.

[0006]

In order to achieve the above-mentioned object, according to the present invention, a sub-combustion chamber for pre-combusting fuel,
A turbocharger that is driven by the exhaust gas to compress the intake air of the engine, a bypass flow passage that joins a part of the intake air of the engine to the exhaust gas flow of the turbocharger and its control valve, and the above-mentioned target A main filter which is arranged in the downstream of the pumper and which contains a material for catalytically removing nitrogen oxides and which has a current-carrying terminal for incineration of particulates; and the above-mentioned catalytic action by monitoring the internal temperature of the main filter. Control means for maintaining an appropriate temperature of the engine, an EGR passage for recirculating a part of the exhaust gas of the engine and its passage valve, and a particulate having an energizing terminal for heating arranged in the EGR passage.
There is provided a diesel engine with EGR including a sub-filter for filtering.

[0007]

[Operation] Diesel engine, auxiliary combustion chamber, turbocharger
In addition to mounting an EGR mechanism that recirculates the exhaust gas, a particulate filter contains a material that has a catalytic action, so the NOx components and particulates in the exhaust gas are reduced, and the exhaust gas is cleaned. Can be realized.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an EGR equipped disc according to the present invention.
FIG. 3 is a configuration block diagram showing an embodiment of a zel engine.

Reference numeral 1 in the figure is an engine, which is a cylinder 1.
1 and a piston 12, and a top portion of the piston 12 is provided with a sub combustion chamber (sub chamber) 2 for pre-combusting fuel. The sub-chamber 2 has an opening 21 having a predetermined hole diameter with respect to the outer diameter of the injection nozzle 13 hanging from the upper portion of the cylinder 11.
And a plurality of radial communication holes 22 penetrating from the upper side wall of the sub-chamber 2 toward the inner wall of the cylinder 11, which communicate with the main combustion chamber.

The cylinder head 14 has an intake port 31 having an intake valve 30 and an exhaust port 4 having an exhaust valve 40.
1, and an intake pipe 3 communicating with the intake port 31.
And a turbocharger 5 serving as a supercharging mechanism between the exhaust pipe 4 communicating with the exhaust port 41 and NOx in the exhaust gas passage 51 of the turbocharger 5. On the other hand, a main filter 6 containing zeolite or alumina having a catalytic action is connected to reduce NOx and particulates in exhaust gas. Reference numeral 61 is a temperature sensor for detecting the internal temperature of the main filter 6, and 62 is a heating terminal for supplying electric power for heating to the conductive filter element, both of which are connected to the control device 8. . Further, in order to supply a part of the fuel to the exhaust gas passage 51 to the main filter 6 to promote the catalytic action, the injection nozzle 63
And the fuel pump 64 are attached, and the fuel from the fuel pump 65 is supplied to the main filter 6 according to a command from the control device 8.

Reference numeral 7 is a sub-filter, which includes the exhaust pipe 4 to the intake pipe 3
Is provided in the middle of the EGR flow path 70 that serves as an exhaust gas recirculation path, and filters exhaust gas passing through the flow path, and is provided with a heating energizing terminal 71, and an actuator is provided upstream of the filter. A flow path valve 72 having a switch 73 is attached.

Reference numeral 9 denotes a bypass flow passage, which is an intake port of the engine 1.
A control valve 91 operated by an actuator 92 is attached in a flow path from the engine 31 to the exhaust gas path 51 of the turbocharger 5, and when the control valve 91 is opened when the engine 1 is under heavy load, intake air The air on the port side is guided to the exhaust gas passage 51 so that the exhaust gas temperature is lowered. The operation command to the actuator 92 and the actuator 73, and the energization command to the energizing terminal 71 of the sub filter 7 are issued from the control device 8.

Next, the operation of this embodiment thus constructed will be described. First, the fuel spray injected from the injection nozzle 13 into the sub-chamber 2 is ignited by the compressed air of high temperature due to the compression of the piston 12 to form a flame, and the plurality of communication holes 2
2 reaches every corner of the cylinder side wall, mixes with air and burns explosively.

Then, the burned gas is guided to the turbocharger 5 through the exhaust pipe 4, and the energy thereof compresses the air to pump it to the intake port 31 through the intake pipe 3. The exhaust gas from the turbocharger 5 is sent to the main filter 6 via the exhaust gas passage 51, and the particulates in the exhaust gas are filtered and released to the atmosphere.

During this time, when the engine 1 is under a light load, EG
The flow passage valve 72 of the R flow passage 70 is opened, NOx of the combustion gas is reduced due to the reflux gas passing through the flow passage, reaches the main filter 6, the particulates are filtered, and the catalytic action of the filter element is provided. As a result, NOx can be further reduced. In this case, since the exhaust gas temperature is low at a light load, the temperature signal from the temperature sensor 61 of the main filter 6 is checked and the temperature of the filter element is 320
The energization of the heating terminal 62 is controlled so that the temperature becomes ± 50 ° C., and the temperature is kept at the optimum temperature for the catalytic action.

Then, when the engine load becomes large, the control valve 91 of the bypass flow passage 9 from the intake port 31 to the outlet of the turbocharger is opened, and the overcharge of the turbocharger 5 which is active under high load is opened. A part of the supply air is introduced into the main filter 6. Therefore, the filter temperature of the main filter 6 which is heated by the high temperature exhaust gas at the time of high load is lowered and NOx is reduced by adjusting the opening of the control valve 91 to a temperature suitable for the catalytic action. . Incidentally. In this case EG
Since the sub-filter 7 of the R flow path 70 has a high gas temperature and a small amount thereof, the filter can be easily heated, and the carbon deposited by energizing the energizing terminal 71 can be incinerated, and this incineration can also be performed. The concentration of CO2 increases and EGR
Therefore, NOx can be reduced.

[0017]

According to the present invention as in the above embodiments,
In order to reduce NOx in the exhaust gas of diesel engines, a combustion system with a subchamber at the top of the piston is used, an EGR mechanism that recirculates the exhaust gas is used, and a zeolite or alumina that has a catalytic action is included in the main filter. Since the temperature is maintained at an appropriate temperature regardless of the size of the engine load, the amount of NOx in the exhaust gas is greatly reduced, and the particulates are collected by the main filter at the final stage of the exhaust flow, The effect is to reduce the release to.

[Brief description of drawings]

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

[Explanation of symbols]

 1 ... Engine 2 ... Sub-combustion chamber 3 ... Intake pipe 5 ... Turbocharger 6 ... Main filter 7 ... Sub filter 8 ... Control device 9 ... Bypass flow path 61 ... Temperature sensor 70 ... EGR flow path 72 ... Flow path valve 91 ... Control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F01N 3/02 301 Z 341 CPE F 3/20 ZAB L 3/24 ZAB E L S T

Claims (3)

[Claims] 1. A sub-combustion chamber for pre-combusting fuel, a turbocharger which is driven by exhaust gas to compress intake air of an engine, and a part of intake air of the engine exhaust gas of the turbocharger. And a control valve therefor, which is joined to the flow, and a particulate material which is disposed downstream of the turbocharger and which catalytically removes nitrogen oxides.
A main filter having an energizing terminal for incineration, control means for maintaining an appropriate temperature for the catalytic action by monitoring the internal temperature of the main filter, an EGR passage for recirculating a part of engine exhaust gas, and its A diesel engine with EGR, comprising: a flow passage valve; and a sub filter for particulate filtration, which is disposed in the EGR flow passage and has a heating energizing terminal. 2. The control means controls opening / closing of a control valve of the bypass flow path and a flow path valve of the EGR flow path, and energization control to a main filter and a sub filter according to an engine load. A diesel engine with EGR according to claim 1. 3. The diesel engine with EGR according to claim 1, wherein at least one of zeolite and alumina is used as the material having the catalytic action.