JPS635106A - Exhaust pipe for multi-cylinder engine of motorcycle - Google Patents

Abstract

PURPOSE:To prevent exhaust gas from blowing back from a posterior pipe, so as to check torque-down in a middle-speed range, by connecting an inner pipe which is connected with the rear end of a collecting pipe of alterior pipes, to the inner circumferential side of the front end part of the posterior pipe of an exhaust pipe, at a space on this inner circumferential side. CONSTITUTION:The rear end parts of plural anterior pipes 1 which correspond with cylinders respectively, are connected to a collecting pipe 2, and the front end of the tapered front end part 7 of an inner pipe 6 is connected to the outlet port 4 of the collecting pipe 2. Then, the inner pipe 6 and a posterior pipe 5 are connected with each other, as forming a cylindrical space 8 between the outer circumferential side of the inner pipe 6 and the inner circumferential side of the front end part of the posterior pipe 5. In this way, as the blowing speed and pressure of exhaust gas are increased in the inner pipe, and this exhaust gas blows into the posterior pipe, it is seldom that inside of the anterior pipe accepts the blown-back gas from the posterior pipe, and consequently, torque-down at the beginning of a middle-speed range can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exhaust pipe conveniently attached to a high cycle multi-cylinder engine of a motorcycle.

[Conventional technology]

Conventionally, an exhaust pipe for a motorcycle multi-cylinder engine for a motorcycle m[, as shown in Figure 3, for example, connects the rear end of a plurality of pipes /l, /l corresponding to each cylinder of the engine to a collecting pipe. It was connected to the single rear tube/3 via l.

[Problem that the invention seeks to solve]

Therefore, when the exhaust pipe described in item h is attached to an engine (when the engine moves from a low-speed rotation range to a medium-speed rotation range, that is, an initial Nitorque trough occurs in the medium-speed rotation range, This obstructs the smooth rotation of the engine, causing inconvenience in driving the vehicle.

It is thought that the decrease in torque is caused by the pulsation of exhaust gas generated in the rear pipe 13 of the exhaust pipe affecting the front 'W//, /I as a blowback phenomenon, and further reaching the exhaust pulp portion of the engine.

Therefore, the invention was designed to make it difficult for the 10,000 pipes to receive the blowback of the rear pipe ηλ due to the pulsation of exhaust gas.
The present invention aims to provide an exhaust pipe for a multi-cylinder engine of a motorcycle that can prevent the occurrence of a torque valley at the beginning of the engine's medium speed rotation range.

[Means for solving problems]

That is, the exhaust gC pipe of the present invention can be used for each type of engine.
In an exhaust pipe in which the rear end of the four-way pipe corresponding to the number of summers is connected to a single rear pipe via a collecting pipe, a gap is provided on the inner side of the front end of the rear pipe, and This is characterized in that the inner vias connected to the rear end are R1-j7'j.

[For production]

With such an exhaust pipe, when the front end of each front pipe is connected to the exhaust port of the corresponding cylinder of the engine, the exhaust gas flows from each four-way pipe to the collecting pipe, inner pipe, and rear pipe to the outside. However, at this time, due to the throttling effect of the inner pipe placed inside the front end of the rear pipe, the exhaust gas increases the flow velocity and internal pressure in the inner pipe and is ejected into the rear pipe, so that the inside of the front pipe becomes exhausted. It is difficult to be affected by changes in the internal pressure of the rear tube due to the pulsation of the gun, and is in a state where it is difficult to receive blowback from the upper portion of the rear tube η. In addition, the gap formed between the outer circumferential side of the inner via and the inner circumferential side of the front end of the rear tube prevents some of the blowback from the rear tubes 711 and the like, so that the air flow from the rear tube h to the front seven tubes is prevented. There are conditions aK that further enhance the blowback prevention effect.

〔Example〕

Next, the embodiment shown in FIGS. 1 and 2 will be explained. Since the exhaust pipe of the example is one for a double-cylinder engine,
Connect the rear ends of the four front pipes corresponding to the number of cylinders of the engine to the front and lower left inlets 3 to 3 of the collecting pipe 2, respectively, and The rear end of the inner vibro 1 is connected to a small rear tube SK, and the inner vibro 1 is installed concentrically within the front end of the rear tube J, and the four tapered ends 7 of the inner vibro 0 are connected to each other. The front end is connected to the outlet t of the collecting pipe, and a cylindrical gap r is formed between the outer circumferential side of the inner vibro and the inner circumferential side of the front end of the rear tube 5.

In such an unusual exhaust pipe, the front pipe /-, /
7r17; J! When connected to the exhaust port of the engine, the exhaust gas from the engine 9 is discharged to the outside from each of the front pipes 7 to 1 through the collecting pipe 2, the inner vibro, and the rear pipe S. t<Eve 6
Due to the constriction effect, the exhaust gas increases the flow velocity and internal pressure in the inner vibro and is ejected into the rear pipe j. Therefore, the influence of the internal pressure change in the rear pipe 5 due to the pulsation of exhaust gas is reduced by the front pipe / ~L is difficult to catch, and there is a DK in which it is difficult to catch the blowback of the rear tube 5, and there is a protruding ring Ir formed by the outer circumferential side of the inner vibro and the inner circumferential side of the bottom end of the inner vibro.
is intended to catch a part of the blowback from the rear pipes Wjβ1, etc., thereby further enhancing the effect of preventing blowback from the rear pipes jρ to the circumferential pipes.

〔Effect of the invention〕

In this way, in the uninvented exhaust pipe, when in use, the exhaust gas increases the flow velocity and force in the inner pipe 1 and flows into the rear pipe, so the inside of the front pipe is difficult to receive blowback from the rear pipe, and the inside of the front pipe is difficult to receive blowback from the rear pipe. The blowback from the outer circumference of the inner pipe and the rear pipe can be alleviated, which prevents the engine from developing torque at the beginning of the mid-speed rotation range, and from the low speed range to the medium speed range and high speed range. Engine performance can be improved.

[Brief explanation of the drawing]

Fig. 1 is a converted plan view of the non-inventive example, Fig. 2 is an enlarged 121 side view with a part cut out, and Fig. 3 is an enlarged side view with a part cut out of the conventional product compared to Fig. 2. It is. /...front pipe, 2...collecting pipe, 3...inlet, μ・
··Exit.

Claims (1)

[Claims] In an exhaust pipe in which the rear ends of a plurality of front pipes corresponding to each cylinder of an engine are connected to a single rear end via a collecting pipe, a gap is provided on the inner peripheral side of the front end of the rear pipe, and the collecting pipe is An exhaust pipe for a multi-cylinder engine of a motorcycle, characterized by having an inner pipe connected to the rear end.