JPS63106324A - Exhauster for v-type multicylinder engine - Google Patents

Abstract

PURPOSE:To produce resonance positively with an exhaust system well as to improve the exhaust efficiency of exhaust gas, by setting each suction stroke between respective cylinders at both sides so as not to adjoin each other, and having symmetrical collecting exhaust passages interconnected at the upstream side of a centralized part. CONSTITUTION:An engine body 1 has symmetrical bank parts 2L and 2R formed in a V-type with each other, and in each bank part, there are provided with each three of cylinders 3L and 3R. And, each of collecting exhaust passages 22L and 22R is independently connected to each of exhaust ports 5L and 5R of these bank parts, and these passages are converged on one supply-exhaust passage 24 at the position one-sided to the right exhaust port 5R. In this constitution, these collecting exhaust a passages 22L and 22R are connected to each other at the upstream side of a centralized part 25 via a resonating interconnecting passage 26. And, firing order of each cylinder should be set so as to be alternately performed at these symmetrical cylinders 3L and 3R. With this constitution, resonance is produced positively in an exhaust system, and the exhaust efficiency of exhaust gas is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust system for a V-type multi-cylinder engine.

(Prior art) In order to improve engine output, many engines use the dynamic effect of intake air to perform supercharging. There is resonance supercharging. In this resonance supercharging, multiple cylinders are divided into a first cylinder group and a second cylinder group so that their ignition order is not adjacent to each other during the intake stroke, or in the case of a gasoline engine, and each cylinder in the first cylinder group The first collecting section is communicated with through a branch pipe, and each cylinder of the second cylinder group is communicated with the second collecting section via a branch pipe. The two collecting parts are brought together at a common collecting part via independent resonance tubes. With such a configuration, the air column within the resonance pipe is vibrated due to pressure waves generated by the periodic opening and closing of the intake boat, and this vibration is propagated to (the intake port of) each cylinder. Then, when this vibration causes resonance, the amplitude of the pressure vibration becomes maximum, and large supercharging, that is, resonance supercharging is performed. In such resonance supercharging, the longer the length of the resonance tube, the lower the rotation range where resonance occurs.

On the other hand, in a V-type multi-cylinder engine in which a pair of left and right bank portions each having a plurality of cylinders are arranged in a V-shape, the exhaust path thereof is generally configured as follows. That is, exhaust gas from each cylinder in the left bank section is temporarily collected in the left collective exhaust passage via a branch exhaust passage, and similarly, exhaust gas from each cylinder in the right bank part is also collected in the right collective exhaust passage, and then finally Specifically, the left and right collective exhaust passages are further gathered together and guided into a single common exhaust passage. The collecting portion that collects the left and right collecting exhaust passages is located toward one of the left and right bank portions in order to avoid large components surrounding the engine, such as a transmission.

(Problem to be Solved by the Invention) By the way, in order to improve the output of an engine, it goes without saying that more air can be filled into the cylinder, but it is also important to consider how efficiently exhaust gas can be discharged from the cylinder. It is important to scavenge the air.

The present invention was made in consideration of the above-mentioned circumstances, and
It is an object of the present invention to provide an exhaust system for a V-type multi-cylinder engine that utilizes a resonance phenomenon in an exhaust system to more effectively discharge exhaust gas and improve engine output.

(Means and operations for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration. That is, each cylinder has a plurality of cylinders, and
A pair of left and right bank portions forming a shape, a left side collective exhaust passage in which exhaust gas from each cylinder is collected in the left side bank part, and a right side collective exhaust passage in which exhaust gas from each cylinder is collected in the right side bank part; In a V-type multi-cylinder engine in which the left and right collective exhaust passages are gathered at a position offset to either one of the left and right bank portions, the intake stroke between the plurality of cylinders in the left bank portion and the right side The intake strokes between the plurality of cylinders in the bank portion are set so that they are not adjacent to each other.

A resonance communication passage is provided for communicating the left and right collective exhaust passages with each other on the upstream side of the collective part.

With such a configuration, a large resonance phenomenon can be obtained using the resonance communication passage in a practical rotation range, and the exhaust gas discharge efficiency can be greatly improved. That is, while resonant supercharging utilizes resonance due to positive pressure waves generated in the intake system, the present invention utilizes resonance due to negative pressure waves generated in the exhaust system.

(Example) Examples of the present invention will be described below based on the attached drawings.

In FIG. 1, the engine body l has left and right bank portions 2L and 2R that form a V-shape.
R is for V-type six cylinders each having three cylinders 3L or 3R. These six cylinders 3 are set so that the ignition order is alternated between the left cylinder 3L and the right cylinder 3R. That is, the three cylinders 3L in the left bank portion 2L form one group of cylinders whose intake strokes are not adjacent to each other, and the three cylinders 3R in the right bank portion 2H form the other group of cylinders whose intake strokes are not adjacent to each other. It consists of

The intake ports 4L and 4R in each cylinder 3L and 3R are each opened into the V bank central space V, while the exhaust ports 5L and 5R are each opened on the opposite side of this central space V, so that they are of the so-called cross-flow type. It is said that

The intake passage 6 has one common intake passage 7 and two collective intake passages 8L and 8R branched from the downstream end thereof,
Each of the collective intake passages 8L, 8R extends within the bank central space V so as to be substantially parallel to a crank shaft (not shown). Intake bows 4L in the left bank portion 2L are individually and independently connected to the left intake passage 8L via short branched intake passages 9L. Similarly, for the right intake passage 8R, a short branch intake passage 9
The intake ports 4R of the right bank portion 2R are individually and independently connected to each other via R. A branch portion where the common intake passage 7 branches into left and right collective intake passages 8L and 8R is a first pressure inversion portion IO for resonance having a relatively large volume.

Further, downstream of this first pressure inversion part 1O, a second pressure inversion part 11 for resonance is formed which communicates the left and right collective intake passages 8L and 8R, and here the communication between the two collective intake passages 8L and 8R is formed. An on-off valve 12 for shutting off is arranged.

Further, downstream of the second pressure inversion section 12, throttle valves 13L and 13R are disposed in each of the collective intake passages 8L and 8R, and are interlocked so as to have the same opening degree.

In FIG. 1, reference numeral 14 indicates an air cleaner, and reference numeral 15 indicates an air flow meter, and fuel is supplied from fuel injection valves disposed in each of the branch intake passages 9L and 9R, although not shown. Further, in the embodiment, the collective intake passages 8L and 8R downstream of the second pressure reversal point 11 are configured as straight pipes without a surge tank in the middle so that pressure vibrations due to resonance are not attenuated as much as possible.

On the other hand, the exhaust passage 21 has two collective exhaust passages 22L on the left and right.
and 22R. This left collective exhaust passage 22L is connected to the branch exhaust passage 23L.

They are individually and independently connected to each exhaust port (5L) of the left bank portion 2L. Similarly, the right collective exhaust passage 22R,
They are individually and independently connected to each exhaust port 5R of the right bank portion 2H via a branch exhaust passage 23R. After the re-gathering exhaust passages 22L and 22R are gathered at a position offset to the right side bank portion 2R, they are connected to one common exhaust passage 24. This is an indication. In addition, the recollection exhaust passage 22
L and 22R are connected via a resonance communication path 26 on the upstream side of the gathering portion 25. The positions of the connection parts 30L and 30R of the resonance communication passage 26 with respect to the recollection exhaust passages 22L and 22H are such that the lengths from the branch exhaust passages 23L or 23H to the collection parts 27L or 28R are equal to each other. There is. A resonance reaction force reversal section 28 having a relatively large volume is formed exactly in the middle of such a resonance communication path 26 .

Note that 29 in FIG. 1 is a silencer disposed in the common intake passage 24.

In the above configuration, in the intake system, the second pressure inversion section 10 or the on-off valve 12 is opened.
Filling efficiency is improved by resonance supercharging using the pressure inversion section 11. Resonant supercharging using the first pressure inverting section IO is set to reach a peak when the engine speed is Nl in FIG. 2, and resonant supercharging using the second pressure inverting section 11 is It is set so that it reaches its peak when the engine speed is N2 in FIG. 2, which is greater than N1. Of course, the engine speed when opening the on-off valve 12 is based on the torque curve T1 obtained during resonance supercharging using the first pressure inversion section 10 and the resonance supercharging using the second pressure inversion section 11. It is assumed that the rotation speed is NO at which the obtained torque curve T2 intersects.

On the other hand, in the exhaust system, resonance using the resonance communication path 26 improves exhaust gas exhaust efficiency. That is, the negative pressure waves generated when the exhaust ports 5L and 5R are opened and closed vibrate the air column in the resonance communication passage 26, and this vibration becomes extremely large due to resonance, and a large negative pressure wave is generated when the exhaust ports 5L and 5R are opened and closed. 5L and 5R, and a strong suction action of the exhaust gas is performed. Resonance using this resonance communication passage 26 is performed when the engine rotation speed is N as shown in FIG.
It is set to peak at point E. In other words, the torque curve T3 is created by using the resonance communication passage 26 to change the torque valley portion due to resonance supercharging.
It should be filled in with That is, as a whole, as the engine speed increases, a torque curve is obtained that extends from torque curve T1 through T3 to T2.

In the above embodiment, a case has been described in which the peak of torque obtained by utilizing the resonance of the exhaust system fills the valley of torque obtained by setting the intake system.
Depending on the specifications of the engine, the setting of the intake system may be configured to further increase the peak of torque obtained.Of course, the present invention can also be applied to diesel engines. It's something you get.

(Effects of the Invention) As is clear from the above description, the present invention actively generates resonance in the exhaust system to increase the efficiency of exhaust gas discharge, making it possible to significantly improve engine output. can.

In addition, in the present invention, the above-mentioned output improvement can be obtained by effectively utilizing the structure of the exhaust system that is generally adopted in type 3 multi-cylinder engines and providing a communication passage for resonance. It can be easily implemented.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a graph schematically showing the effects of the present invention. 1: Engine body 2L, 2R: Bank section 3L, 3R: cylinder 5L, 5R: Exhaust port 22L, 22R: Collective exhaust passage 23L, 23R: Branch exhaust passage 24: Common exhaust passage 25: Gathering area 26: Resonance communication path 27L, 27R: Gathering section 28: Pressure reversal section

Claims (1)

[Claims] (1) A pair of left and right bank sections each having a plurality of cylinders and forming a V-shape, a left side collective exhaust passage in which exhaust gas from each cylinder is collected in the left bank section, and a left bank section in which exhaust gas from each cylinder is collected in the right bank section; a right side collective exhaust passage where exhaust gases of the left side are collected, and the left and right side collective exhaust passages are gathered at a position offset to either one of the left and right bank portions, The intake strokes between the plurality of cylinders in the bank section and the intake strokes between the plurality of cylinders in the right bank section are set so that they are not adjacent to each other, and the left and right collective exhaust passages are arranged upstream of the collective section. An exhaust system for a V-type multi-cylinder engine, comprising: a resonance communication path that communicates with the side.