JP2002188525A - Exhaust gas recirculating device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the further purification of an exhaust gas when an engine is started in cold/low temperature, in an exhaust gas recirculating device for the engine. SOLUTION: An exhaust gas recirculating pipe is opened to an intake pipe along a tangent of its section, so as to make the exhaust gas, supplied to the intake pipe by the exhaust gas recirculating pipe, generate a turning flow in the intake pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation device for an engine.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open Nos. 10-047170 and 10-299589 disclose an engine having an intake pipe and an exhaust pipe, and an exhaust gas recirculation pipe connecting the exhaust pipe and the intake pipe. An exhaust gas recirculation device for an engine including an exhaust gas recirculation valve inserted into an exhaust gas recirculation pipe is disclosed.

On the other hand, in an engine using gasoline as fuel, an idle-up operation is performed in which more fuel is supplied to the engine when the engine is idling at a cold / low temperature than when the engine is idling at a steady state. Conventionally,
Various environmental measures have been taken for the engine, and fuel efficiency and NOx emissions have been improved. However, during the idle-up operation, the engine (body / cooling water /
Since the oil is in a low temperature state, various problems caused by poor combustion and relatively large friction loss of various parts of the engine have not been easily improved. Further, if the start / stop of the engine is repeated at the time of cold / low temperature, the fuel efficiency deteriorates due to the idle-up, and the NOx emission increases.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exhaust gas recirculation system for an engine, in which the exhaust gas is further cleaned at the time of cold / cold start of the engine.

[0005]

A first technical means for solving the above problems is an engine having an intake pipe and an exhaust pipe, an exhaust gas recirculation pipe connecting the exhaust pipe and the intake pipe, and an exhaust gas recirculation pipe. In an exhaust gas recirculation apparatus for an engine having an exhaust gas recirculation valve inserted into a gas recirculation pipe, the exhaust gas is supplied so that the exhaust gas supplied to the intake pipe by the exhaust gas recirculation pipe generates a swirling flow in the intake pipe. That is, the return pipe is provided for the intake pipe.

A second technical means for solving the above problem is that, in addition to the first technical means, an exhaust gas recirculation pipe is opened to an intake pipe along a tangent to a cross section of the intake pipe. . That is, a structure in which the exhaust gas generates a swirling flow in the intake pipe is concrete.

[0007]

FIG. 1 is a sectional view of an exhaust gas recirculation system for an engine according to an embodiment of the present invention. This device is
An engine 13 having an intake pipe 11 and an exhaust pipe 12; and an exhaust gas recirculation pipe 14 connecting the exhaust pipe 11 and the intake pipe 12.
And the exhaust gas recirculation valve 1 inserted in the exhaust gas recirculation pipe 14.
5, the preheat catalyst 1 inserted in the exhaust pipe at a position upstream of the branch of the exhaust pipe 12 and the exhaust gas recirculation pipe 14.
6 is provided. Then, the exhaust gas recirculation pipe 14 is connected as shown in FIG.
As shown in FIG.
It has an opening. The exhaust gas recirculation pipe 14 and the intake pipe 1
The joint 1 may be anywhere on the intake pipe 11, and may be joined on, for example, an intake manifold.

The operation of the exhaust gas recirculation system for an engine having the above configuration will be described below. Air is drawn into the combustion chamber 18 of the engine 13 from an air cleaner (not shown) via the intake pipe 11. Fuel (gasoline, light oil, various engine fuels such as alcohol and natural gas) is supplied to the combustion chamber 18 by appropriate means (not shown) (fuel injection means to the intake pipe 11 and the combustion chamber 18). The fuel burns with the air in the combustion chamber 18. Then, the combustion products are exhausted from the exhaust pipe 12 to the outside as exhaust gas.
When various sensors determine that the engine is in a cold / low temperature state, the control means (not shown) controls the exhaust gas recirculation valve 1
Open 5. Therefore, a part of the exhaust gas flowing through the exhaust pipe 12 flows into the exhaust gas recirculation pipe 14 after passing through the preheat catalyst 16.

As described above, the exhaust gas recirculation pipe 14 is opened to the intake pipe 11 along the tangent to the cross section of the intake pipe 11. Accordingly, the recirculated exhaust gas flowing from the exhaust gas recirculation pipe 14 to the intake pipe 11 generates a swirling flow 17 in the intake pipe 11 as shown in FIG. That is, since the high-temperature recirculated exhaust gas flows along the inner peripheral wall of the intake pipe 11, the intake pipe 11
Can be heated.

The high-temperature recirculated exhaust gas having the swirling flow directly flows into the combustion chamber 18 via an intake valve (not shown), and flows along the inner peripheral wall of the combustion chamber 18 as shown in FIG. The wall surface of the combustion chamber 18 can be warmed. The ignition plug (not shown) is generally located substantially at the center of the combustion chamber 18, and the recirculated exhaust gas is hardly involved, so that the combustion in the combustion chamber 18 is not impaired. In FIG. 3, 19 is an intake port, 2
Although 0 indicates each exhaust port, the number of each port is not limited to one and may be any number.

The opening and closing of the exhaust gas recirculation valve 15 is controlled appropriately not only when the engine is cold / low temperature, but also according to other conditions of the engine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an exhaust gas recirculation device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a top view of the combustion chamber 18 in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Exhaust gas recirculation apparatus 11 ... Intake pipe 12 ... Exhaust pipe 13 ... Engine 14 ... Exhaust gas recirculation pipe 15 ... Exhaust gas recirculation valve

Claims (2)

[Claims] An exhaust system for an engine, comprising: an engine having an intake pipe and an exhaust pipe; an exhaust gas recirculation pipe connecting the exhaust pipe and the intake pipe; and an exhaust gas recirculation valve inserted into the exhaust gas recirculation pipe. An engine, wherein the exhaust gas recirculation pipe is disposed with respect to the intake pipe such that the exhaust gas supplied to the intake pipe by the exhaust gas recirculation pipe generates a swirling flow in the intake pipe. Exhaust gas recirculation device. 2. The exhaust gas recirculation pipe is open to the intake pipe along a tangent to the cross section of the intake pipe.
An exhaust gas recirculation device for the engine as described in the above.