JPH04112956A - Egr device of engine - Google Patents

Abstract

PURPOSE:To suppress the corrosion and abrasion due to an EGR gas by accumulating an exhaust gas in a pressure accumulation means, and by opening a control valve in a period from the time when an exhaust valve is closed to the time when a suction valve is closed, so as to let the exhaust gas blown into a suction side. CONSTITUTION:A part of exhaust gas exhausted through an exhaust pipe 15 is extracted from the exhaust pipe 15 by an extraction pipe 19, and is compressed by a compressor driven through a cam shaft 23, a pulley 24, a belt 22, and a pulley 21, by an engine, and a compressed EGR gas is accumulated in a pressure accumulation chamber 25, and is fed to a common chamber 27. The EGR gas in the common chamber 27 is so controlled as to be fed to a correspondent cylinder when an electromagnetic valve 28 is opened. Namely, the electromagnetic valve 28 correspondent to the time period from the time when an exhaust valve is closed by a computer 32 for inputting the output of a timing sensor 34, to the time when a suction valve is closed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to engine EGR (Exhaust).
Ga5Reclrcu+atron, exhaust gas recirculation)
The present invention relates to an EGR device, and particularly to an EGR device that returns a portion of exhaust gas to the intake side. [Summary of the K invention] Exhaust gas taken out from the exhaust pipe is temporarily stored in a pressure accumulating chamber, and a control valve controlled by a computer allows the exhaust gas to be delivered to the intake side during the period from when the exhaust valve closes until the intake valve closes. By blowing EGR gas into the intake side immediately before combustion, corrosive wear of engine parts is prevented. K. Prior Art As disclosed in, for example, Japanese Unexamined Patent Publication No. 58-10133, EGR has been conventionally used to reduce the amount of nitrogen oxides contained in exhaust gas. Returning a portion of the exhaust gas to the intake side increases the heat capacity of the intake air and reduces the relative concentration of oxygen, thereby slowing combustion. Therefore, the combustion temperature is lowered and the production of nitrogen oxides is suppressed. Problems to be solved by invention K) When EGR is performed to reduce nitrogen oxides, engine parts such as piston rings and cylinder liners will corrode and wear due to sulfates of SO2 and S03 in the exhaust gas. . In other words, if the exhaust gas is circulated and blown into the intake side, the above-mentioned parts will be exposed to components containing sulfur in the exhaust gas for a relatively long period of time, causing unnecessary damage to piston rings, cylinder liners, etc. Wear will be accelerated and the service life will be affected. The present invention has been made in view of these problems, and is an engine EGR system that effectively prevents corrosive wear of engine parts caused by sulfur-containing components in EGR gas.
The purpose of this invention is to provide a GR device.

[Means to solve the problem]

The present invention is an engine that returns part of the exhaust gas to the intake side.
In the GR device, there is a pressure accumulating means for accumulating the pressure of the exhaust gas, and a blowing of the accumulated exhaust gas! The illumination valve is provided with a control valve for controlling the exhaust gas, and the ill valve is opened to blow exhaust gas into the intake side during a period from when the exhaust valve closes to when the intake valve closes. K Effect] Therefore, EGR gas is blown into each cylinder only during the period from when the exhaust valve closes until the intake valve closes, and EGR gas is blown into each cylinder immediately before combustion. Embodiment K FIG. 1 shows an engine equipped with an EGR device according to an embodiment of the present invention, and this engine is composed of, for example, a six-cylinder diesel engine. Intake manifolds 1 are located on both sides of the engine cylinder block 10.
1 and an exhaust manifold 12 are respectively attached. The intake manifold 11 is divided into two parts each having three cylinders, and an intake pipe 13 is connected to the tip end thereof. An air cleaner 14 is connected to the tip side of the intake pipe 13. On the other hand, an exhaust pipe 15 is connected to the exhaust manifold 12, and a muffler 16 is connected to the exhaust pipe 15. An extraction pipe 19 is connected to the exhaust pipe 15. This extraction pipe 19 is connected to a compressor 20. A pulley 21 is attached to the drive shaft of the compressor 20, and a pulley 24 is attached to the rear end of the camshaft 23 via a belt 22.
It is now linked to Also compressor 20
The discharge side of is connected to the pressure accumulation chamber 25. The pressure accumulation chamber 25 is equipped with a relief valve 26. Furthermore, this relief valve 26
The set pressure is, for example, 8 kg/d. The pressure accumulation chamber 25 is connected to the common chamber 27. The common chamber 27 includes a solenoid valve 28 corresponding to each cylinder, and these solenoid valves 2
A blowing pipe 29 is connected to each of the cylinders 8 and 8, and these blowing pipes 29 are used to blow EGR gas into the inlet side of the intake boat of each cylinder. The opening of six electromagnetic valves 28 provided corresponding to each cylinder is controlled by a computer 32. The input side of the computer 32 is connected to a timing sensor 34 that detects the timing of opening and closing of the intake valve and exhaust valve from the rotational position of the disk 33. Furthermore, the computer 32 includes a load sensor 35 and a rotation sensor 3.
6 is connected. In the above configuration, atmospheric air taken in from the air cleaner 14 is introduced into each cylinder of the engine 10 through the intake pipe 13 and the intake manifold 11. Further, exhaust gas generated in each cylinder of the engine 10 is discharged into the atmosphere through an exhaust manifold 12, an exhaust pipe 15, and a muffler 16. A portion of the exhaust gas discharged through the exhaust pipe 15 is extracted from the exhaust pipe 15 by an extraction pipe 19 and is supplied to the compressor 20 . The compressor 20 includes a camshaft 23, a pulley 24, and a belt 22 depending on the engine.
, and pulley 21, and compresses the extracted EGR gas. and compressor 20
The compressed EGR gas is stored in the pressure storage chamber 25. The pressure-accumulated EGR gas is further supplied to the common chamber 27. When the solenoid valve 28 is opened, the EGR gas in the common chamber 27 is supplied to the corresponding cylinder. FIG. 2 shows the timing of R closing of the intake valve and exhaust valve of this engine. Such timing is detected by a timing sensor 34 that detects the rotational position of the disk 33. As shown in FIG. 3, the computer 32 opens the solenoid valve 28 of the corresponding cylinder after the exhaust valve is closed and before the intake valve is closed, and the EGR is applied to the corresponding cylinder only during this period. I'm trying to blow gas into it. As described above, the engine according to this embodiment is a six-cylinder diesel engine in series, and EGR gas is temporarily stored in the pressure accumulating chamber 25 in order to shorten the EGR gas injection period. Then, the solenoid valve 28 is controlled by the computer 32 so that the period during which EGR gas is injected into each cylinder wJ is not the intake valve opening/closing period as in the conventional case, but the period from when the exhaust valve closes to when the intake valve closes. I try to do that. Therefore, just before combustion, E
It is now possible to supply GR gas into the cylinder, and E
The period during which engine parts are exposed to 1lIIli compounds such as S02 and S03, which cause corrosive wear in GR gas, is shortened. Therefore, it is possible to minimize corrosive wear on engine parts such as piston rings and cylinder liners. Further, the computer 32 performs optimum gas reduction and fuel consumption reduction for this engine operating range.

【Effect of the invention】

As described above, the present invention includes a pressure accumulation means for accumulating exhaust gas and a control valve for controlling the blowing of the accumulated exhaust gas, and the period from when the exhaust valve closes to when the intake valve closes. The ilJ III valve is opened to blow exhaust gas into the intake side. Therefore, according to such a configuration, it becomes possible to blow EGR gas into each cylinder immediately before combustion, and it becomes possible to minimize corrosive wear caused by EGR gas.

[Brief explanation of drawings]

FIG. 1 is a plan view of essential parts of an engine equipped with an EGR device according to an embodiment of the present invention, FIG. 2 is a graph showing the W@leap timing of the intake valve and exhaust valve of this engine, and FIG. 3 is an EGR It is a graph showing a gas blowing period. Also, the names of the main parts in the drawings are as shown. 10 ・ 11 ・ 12 ・ 13 ・ 15 ・ 19 ・ 20 ・ 25 ・ 27 ・ 28 ・ 29 ・ 32 ・ 34 ・・Cylinder block・Intake manifold・Exhaust manifold・Intake pipe・Exhaust pipe・Extraction pipe・Compressor・Accumulation chamber・Common chamber, solenoid valve, injection pipe, computer, timing sensor

Claims (1)

[Claims] 1. An EGR device configured to return a portion of exhaust gas to the intake side, comprising: a pressure accumulating means for accumulating the pressure of the exhaust gas; and a control valve for controlling the injection of the accumulated exhaust gas. An EGR device for an engine, characterized in that the control valve is opened during a period from when the exhaust valve closes to when the intake valve closes to blow exhaust gas into the intake side.