Internal-combustion engines – Valve – Valve head cooperates with manifold
Patent
1990-05-08
1991-07-23
Kamen, Noah P.
Internal-combustion engines
Valve
Valve head cooperates with manifold
123193M, F01L 300
Patent
active
050334247
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an internal combustion engine having dual tract induction, that is to say two tracts leading to each intake valve of the engine.
2. Disclosure Information
In racing engines not intended for road vehicles, the intake ports have been inclined as near as possible to the valve axis. This makes better use of the skirt area of the valve opening and facilitates a ram effect to maximise the intake charge. However, this is not practicable in a commercial engine as the height of the engine is restricted and one is obliged to bend the intake port to permit sensible packaging. This bending distorts the flow conditions and introduces an asymmetry causing the flow to cross the valve stem which introduces turbulence and reduces the usage of the available skirt area.
GB-971,211 provides two intake tracts leading to each inlet valve from above with the aim of restoring symmetry and improving the breathing so as to improve top end performance. Other known designs (see GB-728,487) have two intake tracts, one opening on to the side of the engine in the conventional manner and the other on to the top surface of the engine. A further prior art proposal has been to provide tracts from each side of the engine leading to the same intake port.
With tracts entering the cylinder head from both sides of the engine, the performance improvement obtained was found disappointing and development was discontinued. In the case of engines with one or more tracts opening on to the top of the cylinder head, a complex design of inlet manifold is required to straddle the valve train. Furthermore, the engine needs to be fuel injected as the problems caused by the wet manifold of a carburetted engine would be difficult to overcome on account of the complex manifold design.
In further known proposals, for example GB-1,179,087, U.S. Pat. No. 4,550,699, U.S. Pat. Nos. 4,174,686 and GB-1,567,812, two inlet tracts have been used with the intention of creating swirl in the intake charge. The above patents include proposals for angling the tracts tangentially relative to the valve skirt and for introducing different amounts of air through the two tracts in order to promote swirl. The present invention, on the other hand, is not concerned with promoting swirl and on the contrary takes steps to avoid such swirl.
According to the present invention, there is provided an internal combustion engine including a cylinder head, intake poppet valves and intake tracts controlled by said valves and leading from a side face of the cylinder head to the engine cylinders, there being two tracts leading to each intake valve, characterised in that the tracts are dimensioned and shaped for substantially equal air flow under all engine operating conditions so as to supply air uniformly to the perimeter of the valve skirt without introducing swirl into the intake charge, the tracts being formed of outer sections which extend substantially parallel to the base of the head and which open separately on to the said side face of the engine and inner sections which lie in a plane containing the axis of the valve and disposed symmetrically within the latter plane about the axis of the valve, the inner sections of the tracts remaining symmetrical about the valve axis for a sufficient length to ensure that the major component of the velocity of the intake charge is directed along the valve axis.
In the prior art in which the purpose of the separate porting was to promote swirl, it was possible for the ports to open onto the side of the engine. However, it was never suggested in the prior art to employ side entry porting in arrangements where laminar air flow was to be maintained as such a port geometry appears to negate the purpose of the design, namely to maintain symmetry and equal air flow around the entire valve skirt perimeter. The present invention is predicated on the realisation that by the use of side entry, an engine with non-swirl twin porting can be packaged to fit under the bonnet of a
REFERENCES:
patent: 2669984 (1954-02-01), Marchal et al.
patent: 2804862 (1957-09-01), Nedwidek
Drouillard Jerome R.
Ford Motor Company
Kamen Noah P.
Sadler Clifford L.
LandOfFree
Dual tract induction does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dual tract induction, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dual tract induction will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-426021