GB2031999A

GB2031999A - Air induction manifold for an internal combustion engine

Info

Publication number: GB2031999A
Application number: GB7933599A
Authority: GB
Original assignee: IFA MOTORENWERKE
Current assignee: IFA MOTORENWERKE
Priority date: 1978-10-02
Filing date: 1979-09-27
Publication date: 1980-04-30
Also published as: FR2438167A1; IT7950397A0; SE7908110L; DD143940A1; DE2928590A1

Abstract

In the induction manifold (4), (5) a regulating member (7) having openings (8) is located upstream of a rifled inlet channel (6) and in one position, Fig. 2 (not shown), does not obstruct the openings (9) of manifold branches (5), but in a second position, Fig. 3, covers a major part of each opening (9). The second position is used during and immediately after starting a turbo-charged diesel engine to reduce rotation of the air entering the cylinders. Intermediate settings of the regulating member (7) are possible and may be set manually or automatically in response to an engine operating condition. The regulating member (7) can be a flat slide, a rotary slide or pivotable about an axis external to the branches of the manifold. <IMAGE>

Description

SPECIFICATION A manifold The present invention relates to an air induction manifold for an internal combustion engine such as one provided with exhaust gas turbo-charging and air charge cooling.

Rotating air motion in engine cylinders, which is needed for the attainment of optimum operational values in diesel engines with direct injection and produced by appropriately constructed inlet ducts, acts disadvantageously on the starting behaviour of these intemarcombustion engines, particularly at low temperatures. For the reduction of air rotation up to complete freedom from twist, there are the most diverse devices arranged near to or far from the valves. The latter are as a rule simpler to realise and comprise pivotable control members which are disposed in the inlet duct, cover over nearly the entire cross-section and which after starting of the engine receive a nearly ineffective position.

Such a proposal is described in DD-PS 46 906. Disposed at about the start of the rifling inlet duct is a disc, which is pivotable through 900, has a functional setting in which it nearly fills the duct cross-section, and which at the edge has recesses which are matched to the flow conditions in the rifling duct. This partial air passage then effects the twist reduction. After starting the disc is pivoted through 900 so that it offers minimum resistance to the fresh air.

Nevertheless, the control member also in this position impairs the generation of twist and thus the engine operation. Moreover, the spacing between the disc circumference and the duct wall must be nearly zero for the attainment of a clear reduction in twist To meet this requirement, is either very expensive or even impossible in the frequently complicated or asymmetrical duct cross-sections. In multi-cylinder engines, an expensive actuating mechanism is provided in addition in order to be able to set centrally the control members connected with one another through coupling elements. Finally, the sealing of the bore, leading outwardly on each cylinder unit, for the pivot spigots of the control member requires appropriate measures.

According to the present invention there is provided an air induction manifold for an internal combustion engine, comprising means to impart a twist to air induced through the manifold an air flow control member comprising a plurality of openings each associated with a respective branch of the manifold and each having a crosssection at least correspond to the flow crosssection of the respectively associated branch, the control member being selectively displaceable between a first position thereof at which each opening exposes inlet means of a respective branch of the manifold and a second position at which the control member covers at least a major portion of each inlet means.

The control member may comprise a flat side.

The control member may comprise a rotary slide.

The control member may be pivotable about an axis disposed extemally of the branches of the manifold and preferably extending longitudinally of the engine.

Before starting the internal combustion engine, the control member is brought into a setting, in which its wall conceals the largest part of the passage cross-section of the cylinder branchings.

A remaining passage opening may be localized in such a manner that fresh air is substantially withdrawn from the influence of the subsequent rifling inlet duct and passes to the combustion space re-inforced in peripheral regions of the inlet valve gap, which lead to the variation of the original speed profile optimum for the twist generation. The arrangement of the passage opening may be adapted specifically to each type of inlet duct and as a rule to be determined or to be optimized experimentally. After taking the internal combustion engine into operation, the control member may be brought into another position, in which its opening are disposed in congruent agreement with the flow cross-section of the cylinder branchings. It can for reasons of production by necessary to execute the openings somewhat larger than the flow cross-section.

Also, the openings are also feasible as one-sidedly open recess (e.g. comb slide).

For the optimisation of certain operational states, for example idling after starting, an application of the control member is possible at any time and also in intermediate positions particularly to make possible a reduction of the cold smoke and of the irritants in the exhaust gas.

An embodiment of the present invention will now be more particularly described by way of example and with reference to the accompanying drawing, in which: Fig. 1 shows a cross-section through an engine hood disposed on a cylinder head, Fig. 2 shows a longitudinal section through Fig.

1 in the direction ofthe arrows and illustrating a regulating member in an ineffective position, and Fig. 3 shows a longitudinal section through Fig.

1 illustrating the regulating member in an operative setting.

Referring to the drawing, Fig. 1 shows an engine hood 2 sitting on a cylinder head 1. The hood comprises a chamber 3 for covering operational groups, for example of the valve gear.

The engine hood 2 has a main duct 4, which extends in the longitudinal direction of the engine and from which cylinder branches 5 lead to rifling inlet ducts 6 arranged in the cylinder head 1. The main duct 4 and the cylinder branches 5 form a fresh air duct. A guide slot for a flat slide 7, which acts as a longitudinaliy displaceable control member for the fresh air supply, is disposed in the upper and lower walls of the engine hood 2 in the transition region between main pipe 4 and the cylinder branches 5.

It is evident from Fig. 2 that the flat side 7 possesses openings 8, which in their illustrated left-hand end setting are disposed so as to conform with the flow cross-sections 9 of the cylinder branches 5.

To exclude any negative influences, for example from dimensional deviations caused by production, the openings 8 are somewhat larger than the flow cross-sections 9 would require.

The right-hand end setting, illustrated in Fig. 3, of the flat slide 7, which by comparison with Fig. 2 is displaced by the actuating element 10 up to the abutment 11 bearing against the closure member 12, has the consequence that the flow crosssections 9 are largely covered by the flat slide 7.

The remaining residual openings 13 effect in the rifling inlet ducts an air current which in consequence of their course is largely withdrawn from a formation of twist or detunes the flow component entailed by twist so far that freedom from twist almost prevails during the suction stroke.

Apart from both the described end settings, any desired intermediate settings of the flat slide 7 are possible, which permit a differentiated twist regulation in a manual manner through known mechanisms (e.g. a rope pull) as well as automatically (e.g. in dependence on certain operational magnitudes).

An advantage of the above described embodiment is that a unitary control member is provided which, apart from the opening provided for the twist-free air sully, on the one hand completely covers over the fresh air duct and on the other hand during normal engine operation is absolutely removed from the fresh air duct and, if need be, permits intermediate settings for the influencing of certain operational states.

Claims

1. An air induction manifold for an internal combustion engine, comprising means to impart a twist to air induced through the manifold and an air flow control member comprising a plurality of openings each associated with a respective branch of the manifold and each having a crosssection at least corresponding to the flow crosssection of the respectively associated branch, the control member being selectively displaceable between a first position thereof at which each opening exposes inlet means of a respective branch of the manifold and a second position at which the control member covers at least a major portion of each inlet means.

2. A manifold as claimed in claim 1 ,wherein the control member comprises a flat slide.

3. A manifold as claimed in claim 1, wherein the control member comprises a rotary slide.

4. A manifold as claimed in claim 1, wherein the control member is pivotable about an axis disposed externally of the branches of the manifoid.

5. A manifold as claimed in any one of the preceding claims, comprising control member displacing means responsive to operational parameters of an engine when the manifold is mounted thereto.

6. A manifold substantially as hereinbefore described with reference to the accompanying drawings.