GB2213875A

GB2213875A - I.C. engine intake manifold air inlet valves

Info

Publication number: GB2213875A
Application number: GB8829648A
Authority: GB
Inventors: David Lawrence Nolan
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-01-14
Filing date: 1988-12-20
Publication date: 1989-08-23
Also published as: GB8829648D0; GB8800853D0

Abstract

A manifold chamber 2 has a one-way air inlet valve 3. The spring force is adjustable by screwing the cap 19 along the body 4 and is locked by a nut 1 and the valve opens at a vacuum between 40 and 750 mm of mercury. The valve body may be mounted in an adaptor (18, Fig 4) located in a brake servo vacuum line. <IMAGE>

Description

An Air Control System This invention relates to an air control system and more particularly to a valve controlled air intake system for a spark ignition internal combustion engine.

In known inlet manifolds for spark ignition engines the inlet manifold acts as a resevoir and distribution system for air which subsequently enters the cylinders of the engine. The amount of air entering the manifold is controlled either directly or indirectly by a valve known as a throttle. The air entering the manifold may or may not be mixed with a combustible mixture of fuel depending on the method of fuel mixing used by the engine be it a carburettor, single point or multi point fuel injector or port fuel injection or a combination of more than one of these. There are occasions during the normal operation of the engine when there is an element of wastage of the fuel supplied to the engine. During all operation of the engine the products of combustion of the fuel and air are emitted to the atmosphere.These products of combustion may include but not be limited to carbon dioxide, carbon monoxide, hydrocarbons, and nitrogen oxides as well as unreacted nitrogen. Their emission into the atmosphere may cause pollution of the atmosphere to the detriment of flora and fauna.

An aim of the present invention is to reduce fuel consumption and the emission of noxious products of combustion into the atmosphere.

According to the present invention there is provided an air control system for an inlet manifold, comprising an inlet chamber and distribution system for the air or an air and fuel mixture to be admitted to the cylinders of a spark ignition internal combustion engine and a one-way inlet valve connecting the inlet chamber directly or indirectly with the ambient atmosphere to supply air to the inlet manifold.

Advantageously the valve includes a spring loaded ball valve having a volume of between 20% and 80% of the volume of a passage housing the ball and spring.

Conveniently, the volume of the ball is between 40% and 50% of the volume of the passage.

Preferably, the one-way inlet valve has a through passage with a constriction to provide a venturi action on a fluid passing therethrough.

In a modified construction a plurality of one-way inlet valves are connected between the inlet manifold and the ambient atmosphere.

The spring loaded ball valve preferably has a constant spring loading when installed to allow the valve to open when there is a pressure difference across it of between 40mm and 700mm of mercury where the prefered range is betweem 300mm and 670mm of mercury.

As an alternative construction the or each valve has a lockable adjustment means to permit the adjustment of the spring load on the ball valve.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective view of an air control system according to the invention: Figure 2 is an exploded perspective view of the valve shown on Figure 1: Figure 3 is an axial cross section of the valve shown in Figure 2.

Figure 4 is a side view of the adaptor positioned between the manifold and the vacuum assist system.

Referring now to the drawings in detail the air control system illustrated comprises an intake manifold 1 which when fitted to a cylinder head forms a chamber 2 and a system of tubes to supply the air to be used by the engine to the cylinders of said engine (not shown). The intake manifold 1 may or may not contain a combustible fuel/air mixture for burning in the engine depending on the method of fuel/air mixing employed by the engine. Fitted into the intake manifold 1 between the throttle valve and the inlet valves is a one-way air inlet valve generally indicated at 3. It may also be fitted by way of an adaptor 18, in a tube connected directly to the intake manifold, such as the brake servo 'vacuum' line as shown at 15.

The one-way inlet valve comprises a tubular body with two internal connecting passages. The body 4 is provided with an external screw threaded portion 7 at one end by which the body is screwed into the wall of the manifold 1 or into some device which allows it to be adapted to fit into an existing tube such as the brake servo 'vacuum' line or a tube fitted to the intake manifold specifically to accept the fitting of the air control valve. The other end of the body has an external screw thread 8 which screws into the end of cap 9 of the valve which is provided with a central aperture 10. This central aperture connects the chamber 2 with the ambient atmosphere via the passages 5 and 6 and is closed by a ball valve 11 urged to its closed position by a spring 12 contacting the ball valve 11 at one end and seating on a shoulder 13 formed in the tubular body 4.The dimensions of the passage 6 should be larger than that of the ball valve so that air admitted to the intake manifold when the ball valve is forced off its seat may have ready access to the connection passage 6/5. In practice the projected area of the ball should be between 20% and 80% of the area of the pasage with between 40% and 50% being the prefered range. The dimensions of the ball and its seat should be such that the aperture 10 may be closed but the restriction to the flow of air caused by the ball when the latter is forced off its seat provides a mimimum restriction. By way of example, a lOmm diameter ball would be suitable for an aperture 10 of 9mm diameter.These dimensions have been found to be suitable for a system for application to engines of up to 2 litre swept volume though they may together be increased or decreased to vary the size of the air control system which may be used singly or in plurality to suit the size of the engine to which the system is applied and any restrictions of space in, on or around the engine. The aperture 10 has a filter 16 to filter any particles of dust entering the engine.

When installed the spring applies a pressure to the ball valve such that air will be allowed to pass from the ambient atmosphere into the intake manifold when the difference in pressure between that of the ambient atmosphere and the intake manifold is in the range 40mm to 700mm of mercury where the prefered range is between 300mm and 670mm of mercury.

The valve is adjusted such that it is just closed when the engine is operating at its normal idle speed. Under these circumstances the depression in the intake manifold is high but not at its maximum. When the throttle of the engine is opened to obtain more power from the engine the intake manifold depression temporarily increases and the valve will open momentarily but close again as the manifold depression decreases. After the initial opening the valve will close and remain closed until the pressure difference across the ball valve exceeds the preset value whereupon the valve will permit the flow of air into the intake manifold.The manifold vacuum will exceed its idle value when the throttle as in its normally closed position and either the inertia of the vehicle or the inertia of rotation of the engine or a combination of both will tend to cause the engine to continue to rotate at a speed higher than that set as the idle speed. Under these circumstances the ball valve will be forced off its seat and the valve will admit air into the intake manifold. This will have the effect of reducing the internal friction of the engine and ensuring that any fuel, particularly excess fuel which might be drawn into the engine under these conditions, is more completely burned and hence the system will reduce the fuel consumption of the engine and the vehicle to which it is fitted and reduce the emission of potentially harmful exhaust gas emissions.

The manifold may be provided with a plurality of air control valves 14 such number being used to provide sufficient air to enter the intake manifold.

Tests using the air control system, according to the invention, have produced fuel savings of up to thirty percent when a vehicle fitted with an engine using the air control system according to the invention is driven in a typical manner on the road, and have produced reductions in carbon monoxide emissions of in excess of fifteen percent without any loss of power or performance. It is believed that fuel savings in excess of this are possible depending on the method of driving and road conditions.

In a modified construction the air control valve has a lockable adjustment means in the form of a nut 17 to enable the spring load to be varied to be compatible with the particular engine to which the air control system is fitted.

The setting of the air control system is achieved by moving the cap 9 with respect to the body 4 to vary the spring load and thus the pressure difference at which the valve will allow the passage of fluid. The correct setting is achieved when the valve just remains closed when the throttle is at its normally closed position and the engine is at its idle speed with the engine producing no power other than that required to overcome its own internal friction and to drive ancilliaries which may include but not be limited to the oil pump, coolant pump, electricity generation system, power steering pump and air conditioning pump. When correctly set the nut 17 is locked against the cap 9.

It will be understood that the air control system, according to the invention, could be used in internal combustion engines incorporating turbocharging or other similar boosting devices.

Claims

1. An air control system for an inlet manifold comprising an inlet chamber and distribution system for the air or an air and fuel mixture to be admitted to the cylinders of a spark ignition internal combustion engine and a one-way inlet valve connecting the inlet chamber directly or indirectly with the ambient atmosphere to supply air to the inlet manifold.

2. An air control system as claimed in claim 1 wherein the valve includes a spring loaded ball valve having a volume of between 20% and 80% of the volume of a passage housing the ball and spring.

3. An air control system as claimed in claim 1 or 2 wherein the volume of the ball is between 40% and 50% of the volume of the passage.

4. An air control system as claimed in claim 1, 2 or 3, wherein the one-way inlet valve has a through passage with a constriction to provide a venturi action on a fluid passing therethrough.

5. An air control system as claimed in any preceding claim, wherein the spring loading pressure is between 40mm of mercury and 750mm of mercury.

6. An air control system as claimed in claim 5, wherein the spring loading pressure is between 300mm of mercury and 670mm of mercury.

7. An air control system as claimed in any preceding claim, wherein a plurality of one-way inlet valves are connected between the inlet chamber and the ambient atmosphere.

8. An air control system as claimed in any preceding claim, wherein the or each one-way inlet valve has lockable adjustment means to permit adjustment of the spring pressure.

9. An air control system as claimed in claim 8, wherein the lockable adjustment means is a screw-threaded nut.

10. An air control system as claimed in any preceding claim1 wherein the or each one-way valve has an external screw thread for screwing into a screw-threaded hole formed in the inlet chamber wall.

11. An air control system as claimed in any of clai 1 to 10 wherein the or each one-way valve is formed integrally with the inlet chamber.

12. A one-way inlet valve when fitted to an inlet chamber of a spark ignition internal combusion engine, wherein the valve comprises a screw-threaded valve body with a screw threaded closure cap having a central aperture communicating with a passage pasing through the body, the aperture being closed by a spring loaded closure member.

13. An air control system for an inlet manifold, substantially as hereinbefore described with reference to the accompanying drawings.