JP2000034955A - Exhaust circulation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen an EGR allowable area without increasing pumping loss in a supercharger engine. SOLUTION: A rotary valve 16 is attached to an upstream side of a connection part of an EGR circuit 30 and an intake pipe 15. An EGR valve 19 is arranged on an inlet of the EGR circuit 30. The valves 16 and 19 are respectively connected to a control device 25 by an electric circuit. The rotary valve 16 and the EGR valve 19 are controlled based on signals from an operation condition sensor 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exhaust gas circulation device for a supercharged internal combustion engine.

[0002]

2. Description of the Related Art There is known an exhaust gas recirculation device (hereinafter, referred to as an EGR device) for recirculating exhaust gas of an engine to an intake side in order to reduce nitrogen oxides (NOx) contained in the exhaust gas of the engine.

[0003]

However, in a supercharged engine, there is a region where the pressure in the intake pipe exceeds the pressure in the exhaust pipe due to, for example, air supplied by a turbocharger. In such a region, EGR is not sufficient. It is possible. Therefore, when performing EGR in such a region, for example, there is a method of closing the shutter provided in the intake pipe to reduce the pressure in the intake pipe. However, the pumping loss increases due to the negative pressure, and the fresh air amount is reduced. There is a problem of drastic reduction.

[0004] The technique disclosed in Japanese Patent Application Laid-Open No. H8-100662 is disclosed, but does not relate to a supercharged engine and does not relate to the problem of the present application.

Accordingly, an object of the present invention is to provide an EGR device capable of increasing an EGR-capable area / amount without increasing pumping loss in a supercharged engine.

[0006]

According to the present invention, the exhaust gas circulation (EG)
R) In an exhaust circulation device of a supercharged internal combustion engine, a rotary valve is provided upstream of an exhaust passage side outlet of an exhaust circulation circuit, an exhaust circulation valve is provided in an exhaust circulation circuit, and an operating state of the engine is detected. An operation state detection sensor is attached to the engine, and the operation state detection sensor, the rotary valve, and the exhaust gas circulation valve (EGR valve) are connected to a control device that controls the rotary valve and the exhaust gas circulation valve by an electric circuit, respectively.

In carrying out the present invention, the exhaust gas circulation (EG
R) The device, wherein the control device has a first mode in which the rotary valve opening has a phase overlapping with the intake valve opening, and a second mode in which the rotary valve closing has a phase earlier than the intake valve closing.
It is preferable to control the second mode to a third mode in which the exhaust circulation valve closes and the intake valve closes simultaneously.

Here, a shutter, a rotary valve or a poppet valve can be used as the EGR valve.

According to the present invention having such a configuration, the operating condition such as the number of revolutions and the load is detected, and the operating mode is changed in accordance with the operating condition, thereby expanding the EGR-capable region even in the supercharged engine. be able to. Also, EGR
, It is possible to prevent an increase in pumping loss.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a liner 2 is inserted into a cylinder block 1, a piston 3 is slidably inserted into the liner 2, and a piston ring 4 having a reverse number (three in the illustrated example) is inserted into the piston 3. Is attached. An intake valve 7 is attached to the cylinder head 10 via a valve spring 8 and an upper seat 8a, and an exhaust valve 11 is similarly attached via a valve spring 12 and an upper seat 12a. It is configured to be.

The intake pipe 15 is provided with a rotary valve 16.
Is attached to the cylinder head 10 via the The intake pipe 15 is connected to a compressor of a turbocharger 21 attached to an exhaust pipe 20 with an intercooler 17 interposed therebetween, and the compressor is not shown in detail.

An EGR circuit 30 connected to the exhaust pipe 20 via an EGR valve 19 has an EGR cooler 31 interposed and is connected to the intake pipe 15 downstream of the rotary valve 16.

Further, the operation state detection sensor 22 mounted on the engine is connected to a control device 25 via an electric circuit a, the rotary valve 16 is connected to the control device 25 via an electric circuit c, and the EGR valve 19 is connected to the control device 25. Electric circuit b
Is connected to the control device 25 via the. Here, reference numeral 5 denotes a piston pin, and reference numeral 6 denotes a small end of a connecting rod.

The operation will be described below with reference to FIGS. When the operation is started, an operation state such as a rotation speed and a load is detected (step S1). Next, it is determined whether or not it is in the region where the EGR is turned on (step S2). If YES, that is, if it is in the EGR region, the intake stroke control is performed by the rotary valve (step S3), and the EGR valve is operated in synchronization with the intake stroke (step S5, the operation mode of FIG. 3 which is the third mode). C).

If NO in step S2 (if not in the EGR range), it is determined whether or not the vehicle is in a high speed range (step S2).
4). If it is in the high speed range (YES in step S4), the intake stroke control is performed by the rotary valve (step S4).
6. Operation state B) in FIG. 3 which is the second mode B) Return.
If NO in step S4 (if not in the high speed range),
Return to normal operation with EGR off (step S7, operation state A in FIG. 3, which is the first mode) and return.

The relationship between the valve timing (phase) of the intake valve, the exhaust valve, the rotary valve, and the EGR valve and the lift indicates the control mode described above.
In the operation state A) of high load and low rotation, the intake valve opening K is at the same timing as the rotary valve opening R as shown in FIG.
Control is performed so that it operates the same as when there is no rotary valve. Here, reference sign E indicates the exhaust valve opening.

FIG. 5 shows an operation state B of the second mode of high load and high rotation, in which the rotary valve opening R is advanced (to the left in the figure) and the rotary valve 16 is closed even if the intake valve 7 is open ( C), which has the same effect as closing the intake valve early,
The effective opening is an area indicated by A, which is a so-called intake early closing mirror cycle.

FIG. 6 shows an operating state C of the third mode in the entire range of middle and low loads, in which EGR is required.
In the state of the rotary valve opening R shown in FIG. 5 (early closing), the closing timing of the EGR valve opening EG is made the same as the closing timing of the intake valve 7, and the rotary valve 16 is closed and the intake valve 7 is opened. The control is performed such that EGR is performed using the timing D when the downstream of the rotary valve of the intake pipe 15 is at a negative pressure.

In the above embodiment, a shutter is used for the EGR valve. However, a rotary valve or a poppet valve may be used, and the same operation and effect can be obtained.

Therefore, EGR can be effectively performed over a relatively wide area even in a supercharged engine.

[0021]

The present invention is configured as described above,
The EGR-enabled region can be expanded even in a supercharged engine. Further, when performing EGR, it is possible to prevent an increase in pumping loss.

[Brief description of the drawings]

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

FIG. 2 is a flowchart of the control in FIG. 1;

FIG. 3 is a diagram showing an aspect in which an operation state is switched.

FIG. 4 is a diagram illustrating an operation in an operation state A.

FIG. 5 is a diagram illustrating an operation in an operation state B.

FIG. 6 is a diagram illustrating an operation in an operation state C.

[Explanation of symbols]

 7 ... intake valve 8, 12 ... valve spring 9, 13 ... cam 11 ... exhaust valve 15 ... intake pipe 16 ... rotary valve 19 ... EGR valve 20 ... exhaust Pipe 21 Turbocharger 22 Operating condition detection sensor 25 Control device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 13/02 F02D 13/02 H 21/08 301 21/08 301A F-term (Reference) 3G062 AA05 BA06 CA08 DA04 EA10 EB00 ED08 FA23 GA04 GA06 GA21 3G092 AA01 AA17 AA18 AB02 BA01 DC09 DD03 DE11S DG08 EA22 EA25 FA00 FA17 GA18 HA11Z HD07X HE01Z

Claims (2)

[Claims] In an exhaust gas circulation device for an internal combustion engine with a supercharger, a rotary valve is provided upstream of an exhaust passage side outlet of an exhaust gas circulation circuit, and an exhaust gas circulation valve is provided in the exhaust gas circulation circuit to detect an operating state of the engine. An exhaust circulation circuit, wherein an operation state detection sensor is attached to the engine, and the operation state detection sensor, the rotary valve, and the exhaust circulation valve are connected to a control device that controls the rotary valve and the exhaust circulation valve by an electric circuit, respectively. apparatus. 2. The control device according to claim 1, wherein the first mode in which the opening of the rotary valve overlaps the phase of the opening of the intake valve, the second mode in which the closing of the rotary valve is earlier than the closing of the intake valve, and the second mode. 2. The exhaust gas circulation device according to claim 1, wherein the exhaust gas circulation device is controlled to a third mode in which the exhaust gas circulation valve closes and the intake valve closes simultaneously.