GB2369652A

GB2369652A - I.c engine intake manifold

Info

Publication number: GB2369652A
Application number: GB0029112A
Authority: GB
Inventors: Rik Osmond Alewijnse
Original assignee: Lotus Cars Ltd
Current assignee: Lotus Cars Ltd
Priority date: 2000-11-29
Filing date: 2000-11-29
Publication date: 2002-06-05
Also published as: GB0029112D0

Abstract

The invention provides an intake manifold comprising an elongate plenum chamber (1), a plenum entry pipe (2) connected to the chamber (1), and a plurality of runners (5) extending from the chamber (1), the runners (5) being spaced in the direction of elongation of the plenum chamber. When viewed along the direction of elongation of the plenum chamber (1), at least one runner (5) curves across the plenum entry pipe (2). A throttle valve (4) is provided in the plenum entry pipe (2) and is positioned such that when viewed along the direction of elongation of the plenum chamber (1), the throttle valve (4) is on the same side of the at least one runner (5) as the plenum chamber (1). The invention allows the runners to be less curved for a given package space and runner length.

Description

INTAKE MANIFOLD This invention relates to an intake manifold for an internal combustion engine.

An intake manifold for an in-line petrol engine usually comprises a plenum chamber fed with air from a plenum entry pipe under the control of a throttle valve, and a runner for each cylinder in the engine extends from the plenum chamber. There is normally one runner per cylinder head, although there may also be two runners if there are two inlet valves for each cylinder. Usually the runners are curved by an amount which is dictated be the space available for the engine, for example under a car bonnet.

For improved engine performance, it is desirable for the runners to be as straight as possible so that there is very little resistance to the flow of air from the plenum chamber to the cylinders.

Furthermore, flow resistance will be less if the flow is substantially laminar rather than turbulent, which condition is only achieved when the runners are substantially straight. Such a design is provided by a log plenum as is well known in the art.

However, in order that the intake manifold fits within a given space, the runners have been made curved.

Such a design is known as a scroll type inlet manifold and is shown in Fig. 1. The scroll type intake manifold comprises a plenum chamber 1 through which air enters along a plenum entry pipe which extends upwardly from the top of plenum chamber 1. Flow into the plenum chamber is controlled at the throttle body 3 which is provided with a throttle valve 4. A plurality of runners 5 (only one of which is shown in Fig. 1, but which are spaced along the length of the

plenum chamber 1 in a direction into and out of the plane of the paper in Fig. 1) extend from the side of the plenum chamber 1. The throttle body 3 is above the runners 5 to allow space for a mechanical linkage to the throttle valve 4. The runners 5 pass beneath the throttle body 3 so as to avoid taking up too much space perpendicular to the plane of the paper as shown in Fig. 1. The runners thus have a relatively small radius of curvature. This design therefore suffers from the problems of high air flow resistance and turbulent flow referred to above.

According to the present invention there is provided an intake manifold comprising an elongate plenum chamber, a plenum entry pipe connected to the chamber, and a plurality of runners extending from the'chamber, the runners being spaced in the direction of elongation of the plenum chamber, wherein, when viewed along the direction of elongation of the plenum chamber, at least one runner curves across the plenum entry pipe; and wherein a throttle valve is provided in the plenum entry pipe and is positioned such that when viewed along the direction of elongation of the plenum chamber, the throttle valve is on the same side of the at least one runner as the plenum chamber.

As the at least one runner passes'above'the throttle valve, it can have a greater radius of curvature than

if it was required to pass'beneath'the throttle valve. As compared to the prior art manifolds, the invention allows the runners to be less curved for a given package space and runner length. Thus, the invention provides the air flow advantages of a log plenum and the compactness of a scroll type intake manifold.

The invention can provide an advantage when any of the

runners provides the at least one runner. However, preferably the runners adjacent to the plenum entry pipe are configured according to the definition of the at least one runner as these are the runners which would have to be displaced in some other way to avoid them interfering with the throttle body. The most convenient arrangement is obtained when all of the runners are configured according to the definition of the at least one runner.

The plenum entry pipe may enter the plenum chamber through a part of the chamber which is arranged, in use, to face generally laterally as is known in the art. However, preferably the plenum entry pipe is connected to a face of the chamber which, in use, is a generally laterally facing side and the runners extend from a face of the chamber which, in use, is a generally upwardly facing side. With this orientation, the angle through which the runners must be curved is reduced thereby improving the flow through the runners.

The throttle valve is preferably electronically actuated as this requires less space than a mechanical linkage if the throttle valve is mechanically actuated.

A specific embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a sectional front elevation of a known scroll type intake manifold; Figure 2 is a sectional front elevation of an intake manifold according to the present invention ; and Figure 3 is a sectional side elevation of the intake manifold of Figure 2.

The present invention is applicable as intake manifold for any internal combustion engine such as a multi cylinder fuel injection engine. The fuel injection may be direct or indirect.

The manifold of the present invention as shown in Figs. 2 and 3 contains all of the same components as the intake manifold described with reference to Fig.

1, but these are connected together in a different configuration. Thus, the intake comprises a plenum chamber 1 which is fed with air via a plenum entry pipe 2. The throttle body 3 is provided in the plenum entry pipe 2 and has throttle valve 4 of conventional design. A plurality of runners 5 extend from the plenum chamber 1 and are connected, in use, to the cylinder head. As shown in Fig. 3, the illustrated manifold comprises four runners 5, positioned two on either side of the plenum entry pipe 2. The manifold may be of a two-piece construction joined at joint 6 within the plenum chamber.

As can be seen in Fig. 2, the plenum entry pipe 2 is positioned to one side of the plenum chamber 1 and has a generally 900 bend 2A at its bottom end. This bend leads into the bottom of one side 1A of the plenum chamber 1. The runners 5 extend from the top face of the plenum chamber 1 and are curved with a generally constant radius of curvature through an angle. of approximately 1000 to terminate on the opposite side of the plenum entry pipe 2 from the plenum chamber 1.

The throttle body 3 is positioned within the plenum entry pipe 2 beneath the runners 5.

Claims

CLAIMS : 1. An intake manifold comprising an elongate plenum chamber, a plenum entry pipe connected to the chamber, and a plurality of runners extending from the chamber, the runners being spaced in the direction of elongation of the plenum chamber, wherein, when viewed along the direction of elongation of the plenum chamber, at least one runner curves across the plenum entry pipe; and wherein a throttle valve is provided in the plenum entry pipe and is positioned such that when viewed along the direction of elongation of the plenum chamber, the throttle valve is on the same side of the at least one runner as the plenum chamber.
2. An intake manifold according to claim 1, wherein the runners adjacent to the plenum entry pipe are configured according to the definition of the-at least one runner.
3. An intake manifold according to claim 2, wherein all of the runners are configured according to the definition of the at least one runner.
4. An intake according to any one of the preceding claims, wherein the plenum entry pipe is connected to a face of the chamber which, in use, is a generally laterally facing side and the runners extend from a face of the chamber which, in use, is a generally upwardly facing side.
5. An intake manifold according to any one of the preceding claims, wherein the throttle valve is electronically actuated.
6. An intake manifold substantially as described

with reference to the accompanying drawings.