JPH0618655U - Internal combustion engine intake system - Google Patents

Abstract

(57) [Summary] [Objective] To provide a device in which a mixture with oil is not accumulated when soot is accumulated in the intake port to prevent intake. [Structure] An intake manifold 11 of an internal combustion engine 10 having a plurality of cylinders is divided into a plurality of cylinders and connected to the cylinders.
Is configured so that the blow-by gas B of the closed blow-by gas reducing device is separately introduced into the remaining intake manifold.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to an exhaust system of an internal combustion engine that performs exhaust gas recirculation, that is, EGR, and closed PCV that recirculates unburned gas to the intake system without leaking to the outside in a diesel engine.

[0002]

[Prior art]

 The conventional diesel engine 1 performs EGR of returning the exhaust gas E to the intake manifold 4 through the EGR pipe 3 in order to reduce the nitrogen oxides in the exhaust gas E discharged from the exhaust manifold 2 as shown in FIG. However, there is a closed PCV that returns to the intake manifold 4 by the PCV pipe 5 without releasing the unburned gas leaking from the gap between the piston and the cylinder during operation of the engine, that is, the blow-by gas B to the atmosphere. It has been widely adopted in recent years.

However, since the blow-by gas B contains oil mist, when it is returned to the intake manifold together with the exhaust gas E of EGR in a mixed state, the oil mist and soot in the exhaust gas E are mixed, and as shown in FIG. As illustrated in the cross-sectional view of FIG. 3, the deposit D is formed in the intake manifold 4 or the intake port. This deposit D gradually grows and finally blocks the intake manifold 4, especially the connection part with the cylinder, and also accumulates on the umbrella part of the inlet valve, and as a result, the amount of air in the cylinder decreases. There is a problem in that the air flow in the cylinder is changed, combustion becomes unstable, and engine performance deteriorates.

[0004]

[Problems to be solved by the device]

 The present invention has been made to solve the above-mentioned conventional problems, and provides an intake system for an internal combustion engine that can prevent fluctuations in the rotation of the internal combustion engine 1 without generating deposits in the intake manifold 4. It is intended to be provided.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, an intake system for an internal combustion engine according to the present invention is configured such that an intake manifold of an internal combustion engine having a plurality of cylinders is divided into a plurality of cylinders and connected to the cylinders. The gas is configured so that the blow-by gas of the closed blow-by gas reducing device is separately introduced into the remaining intake manifold.

That is, the intake manifold is divided into a plurality of parts to prevent the intake air from being mixed with each other, and an exhaust gas for exhaust gas recirculation is introduced into a part of the intake manifold and a blow-by gas is introduced into the remaining intake manifold. By doing so, the exhaust gas and the blow-by gas are distributed so as not to be mixed in the intake manifold. Therefore, an intake manifold connected to each cylinder in a branched state is suitable as a place to introduce the exhaust gas and the blow-by gas. The division number of the intake manifold depends on the number of cylinders, but may be divided into two or according to the number of cylinders.

[0007]

[Work]

 According to the intake system of the internal combustion engine having the above-mentioned configuration, the soot in the exhaust gas E and the oil mist in the blow-by gas B do not mix in the same intake manifold 4 to generate a deposit, It is possible to prevent an increase in intake air flow resistance due to deposits.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a portion of an intake manifold 11 of a 4-cylinder diesel engine 10. An EGR pipe 12 is connected to branch manifolds 11b and 11d of the intake manifold 11 via an EGR valve 13, and the remaining branch manifold 11a. And 11d are connected to the PCV pipes 14, respectively.

Exhaust gas E is supplied from the EGR pipe 14 and supplied to the intake branch ports 11b and 11c via the EGR valve 13 and the EGR branch pipe 12a, respectively. The blow-by gas B is supplied to the PCV pipe 14 and is supplied to the intake branch manifolds 11a and 11d via the branch pipe 14a, respectively, and exhausted to the intake air A supplied from the root of the intake manifold 11. Gas E or blow-by gas B is mixed and supplied to each cylinder. In this embodiment, the blow-by gas B is supplied to the first cylinder and the fourth cylinder, and the exhaust gas E is supplied to the second cylinder and the third cylinder, respectively.

Therefore, since the exhaust gas E and the blow-by gas B are not simultaneously supplied to the intake branch manifolds 11a to 11d, the oil mist and the exhaust gas E in the blow-by gas B as shown in FIG. The soot is not mixed and the deposit D as shown in FIG. 5 does not adhere to the inside of the intake manifold 11, and the deposit D accumulates on the umbrella portion of the inlet valve and enters the cylinder. There is no fear that the intake air amount will be reduced and the air flow in the cylinder will change to cause fluctuations in the rotation of the engine 10 and that the engine performance will deteriorate.

In the present invention, since the EGR exhaust gas E is not supplied to all the cylinders, the EGR effect is slightly reduced, but it is excellent in that the engine rotation fluctuation and the performance deterioration can be prevented. FIG. 2 is a plan view of a portion of the intake manifold 11 of the diesel engine 10 according to the second embodiment. The intake manifold 11 has a partition wall 16 formed so as to divide the air A sucked into the root portion into two parts. There is. The intake branch manifolds 11a and 11b are arranged on one side of the partition wall 16, and the intake branch manifolds 11c and 11d are arranged on the other side. A PCV pipe 14 is connected between the intake branch manifolds 11a and 11b, and an EGR pipe 12 is connected between the intake branch ports 11c and 11d. The exhaust gas recirculation effect and blowby gas reduction effect associated with the operation of the engine 10 are the same as those in the embodiment described with reference to FIG.

FIG. 3 is a plan view showing a portion of the intake manifold 11 of the diesel engine 10 of the third embodiment. In this embodiment, the intake manifold 11 is divided into two cylinders, 11e and 11f. An intake pipe 11g is connected to each of the intake manifolds 11e and 11f. Further, a PCV pipe 14 and an EGR pipe 12 are connected to the individual intake manifolds 11e and 11f, respectively. Also in this embodiment, the exhaust gas recirculation effect and the blowby gas reduction effect associated with the operation of the engine 10 are the same as those in the embodiment described with reference to FIG.

[0013]

[Effect of device]

 An intake system for an internal combustion engine according to the present invention divides an intake manifold of an internal combustion engine having a plurality of cylinders into a plurality of cylinders and connects the cylinders to each other. The blow-by gas of the closed blow-by gas returning device is separately introduced into the manifold, and the following effects can be achieved.

Therefore, since soot in the exhaust gas for EGR does not mix with soot in the blow-by gas to generate deposits in the intake manifold, intake is not hindered and engine output It is possible to prevent the decrease of the exhaust gas and the fluctuation of the rotation speed, and further it is possible to prevent the increase of smoke during the exhaust gas.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an intake device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a main part of an intake device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 3 is a plan view showing a main part of an intake device for an internal combustion engine according to a third embodiment of the present invention.

FIG. 4 is a side view schematically showing a conventional internal combustion engine.

5 is a cross-sectional view showing deposits formed in the intake manifold of FIG.

[Explanation of symbols]

10 Diesel Engine 11, 11e, 11f Intake Manifold 12 EGR Pipe 13 EGR Valve 14 P
CV pipe 16 partition wall

Claims (1)

[Scope of utility model registration request] 1. An intake manifold of an internal combustion engine having a plurality of cylinders is divided into a plurality of cylinders and connected to the cylinders, part of the intake manifolds is provided with exhaust gas for exhaust gas recirculation, and the remaining intake manifolds are provided with a closed blow-by gas reducing apparatus. The intake device for an internal combustion engine configured to separately introduce the blow-by gas.