GB2063361A

GB2063361A - Internal combustion engine induction passages

Info

Publication number: GB2063361A
Application number: GB7939001A
Authority: GB
Original assignee: Dowson J H
Current assignee: Dowson J H
Priority date: 1979-11-10
Filing date: 1979-11-10
Publication date: 1981-06-03

Abstract

In an I.C. engine cylinder head, two bores 5 and 6 open into an induction passage near to an intake valve 4 to admit air to the passage while both intake valve 4 and an exhaust valve (not shown) are open to prevent air fuel mixture passing from the induction passage to the exhaust valve. The bores may open directly to the ambient air or be connected to a turbo charger manifold. <IMAGE>

Description

SPECIFICATION Fuel saving internal combustion engine This invention relates to improvements in internal combustion engines and particularly to a means for preventing loss of fuel mixture during purging exhaust gases from the cylinders to such an engine.

In a four stroke internal combustion engine, the sequence power-exhaust-induction-compression- power is wellknown. It is usually the practice to rely on the motion of the piston towards the cylinder head on the return stroke after the powerstroke to purge the exhaust gases from the cylinder. At the same time as the exhaust stroke takes place itis usual for the exhaust and inlet valves to be both open, it being expected that the pressure of the exhaust stroke will prevent fuel leakage. However in practice, it is found that fuel from the inlet mixes with the exhaust gases and is expelled with them through the exhaust port, causing a loss of fuel in the charge inducted into the cylinder, with consequent loss of power.

An object of the invention is to provide a means for avoiding this leakage, without tampering with the valve settings of the cylinder head so that no fuel is wasted by such escapes.

According to the invention, an inlet is provided in the cylinder head for air, the inlet being located to open into the fuel inlet passage within the valve, to create a body of air without fuel in the fuel inlet orifice which will delay fuel mixture admission sufficiently to prevent fuel loss by leakage from the exhaust port during the exhaust stroke.

The body of air can tend to be sucked back towards the fuel outlet manifold which will ensure that no fuel is lost in the exhaust stroke.

The presence of the pocket of air in the fuel inlet orifice is advantageous since it enhances the proportion of oxident in the air fuel mixture, thus helping with the more complete combustion of the fuel.

The air is preferably fed in tangentially to the orifice of the fuel inlet to create turbulence in the orifice, tending to create a vortex which remains stable until the fuel is positively drawn in at the start of the induction stroke.

The air may be fed during the exhaust stroke directly from atmosphere through bores in the cylinder head or from a turbo charger manifold. The port with which the atmosphere pressure of un-boosted directly admitted air is expected to be sufficient for the required purpose, and the overpressure caused by the turbo charger fan if used should be more than sufficient.

The source of air may be turbo charger having as its primary function boosting of the air content of fuel air mixture fed to the cylinder during the induction stroke.

A preferred embodiment and method of the invention will now be described by way of example with reference to the accompanying drawing which is a fragmentary diagrammatic cross-section view of part of the cylinder head of an internal combustion engine modified in accordance with the invention.

As shown, a fuel inlet port 1 is connected by a passage 2 to a fuel manifold (not shown). The port has an orifice zone 3 arranged to open into the interior of a cylinder 4 of an internal combustion engine. The orifice 3 is openable and closable by a mushroom valve 4 controllable by the usual valve cams in accordance with the engine cycle. A pair of air inlet bores 5 and 6, open into the orifice zone 3, one, 5 near the valve 4, and the other 6 near the passage 2. The bores 5 and 6 are of about 2.3 mm, diameter, and open directly to the atmosphere. Alternatively they may communicate with a turbo charger booster manifold.

In use, during the exhaust stroke, the valve 4 is open as is customary. Air is drawn into the orifice zone 3 and the bores 5 and 6 being tangential, a vortex is created in the orifice zone 3 which forms a bubble or body of air in the zone which prevents fuel mixture from entering the cylinder until the start of the induction stroke -- thereby preventing leakage of fuel mixture into the exhaust gases. The air from zone 3 tends in fact to be drawn into the fuel inlet manifold, rather than into the cylinder, forming an extra barrier to fuel leakage. As soon as the induction stroke starts, the vortex collapses, and fuel is positively drawn into the cylinder by the suction created by the movement of the piston.

1. In the cylinder head of an internal combustion engine having at least one cylinder, one or more inlet bores penetrating the cylinder head and opening into the fuel inlet passage adjacent the outlet into the cylinder, to admit air into the passage during the exhaust cycle to prevent leakage of fuel to the exhaust port.

2. The cylinder head of Claim 1, wherein two inlet bores are provided entering an orifice zone of the fuel inlet port tangentially one closely adjacent the orifice and the other near the top of the zone, whereby a vortex can be created by the entrant air.

3. A cylinder head according to claim 1 or 2 wherein the bore or bores open directly to the ambient atmosphere.

4. A cylinder head according to claim 1 or 2 wherein the bore or bores are connected to a turbo charger boost manifold.

5. A cylinder head of an internal combustion engine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

6. A regulable manifold having an idling inlet and a valve inlet regulable by pressure differential emanating from the downstream side from the carburretor throttle edge; in or for an internal combustion engine as claimed in any of the preceding claims.

New claims or amendments to claims filed on 7/7/80 Superseded claims: Claims 1 and 6 New or amended claims:-- Claims 1 and 6

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fuel saving internal combustion engine This invention relates to improvements in internal combustion engines and particularly to a means for preventing loss of fuel mixture during purging exhaust gases from the cylinders to such an engine. In a four stroke internal combustion engine, the sequence power-exhaust-induction-compression- power is wellknown. It is usually the practice to rely on the motion of the piston towards the cylinder head on the return stroke after the powerstroke to purge the exhaust gases from the cylinder. At the same time as the exhaust stroke takes place itis usual for the exhaust and inlet valves to be both open, it being expected that the pressure of the exhaust stroke will prevent fuel leakage. However in practice, it is found that fuel from the inlet mixes with the exhaust gases and is expelled with them through the exhaust port, causing a loss of fuel in the charge inducted into the cylinder, with consequent loss of power. An object of the invention is to provide a means for avoiding this leakage, without tampering with the valve settings of the cylinder head so that no fuel is wasted by such escapes. According to the invention, an inlet is provided in the cylinder head for air, the inlet being located to open into the fuel inlet passage within the valve, to create a body of air without fuel in the fuel inlet orifice which will delay fuel mixture admission sufficiently to prevent fuel loss by leakage from the exhaust port during the exhaust stroke. The body of air can tend to be sucked back towards the fuel outlet manifold which will ensure that no fuel is lost in the exhaust stroke. The presence of the pocket of air in the fuel inlet orifice is advantageous since it enhances the proportion of oxident in the air fuel mixture, thus helping with the more complete combustion of the fuel. The air is preferably fed in tangentially to the orifice of the fuel inlet to create turbulence in the orifice, tending to create a vortex which remains stable until the fuel is positively drawn in at the start of the induction stroke. The air may be fed during the exhaust stroke directly from atmosphere through bores in the cylinder head or from a turbo charger manifold. The port with which the atmosphere pressure of un-boosted directly admitted air is expected to be sufficient for the required purpose, and the overpressure caused by the turbo charger fan if used should be more than sufficient. The source of air may be turbo charger having as its primary function boosting of the air content of fuel air mixture fed to the cylinder during the induction stroke. A preferred embodiment and method of the invention will now be described by way of example with reference to the accompanying drawing which is a fragmentary diagrammatic cross-section view of part of the cylinder head of an internal combustion engine modified in accordance with the invention. As shown, a fuel inlet port 1 is connected by a passage 2 to a fuel manifold (not shown). The port has an orifice zone 3 arranged to open into the interior of a cylinder 4 of an internal combustion engine. The orifice 3 is openable and closable by a mushroom valve 4 controllable by the usual valve cams in accordance with the engine cycle. A pair of air inlet bores 5 and 6, open into the orifice zone 3, one, 5 near the valve 4, and the other 6 near the passage 2. The bores 5 and 6 are of about 2.3 mm, diameter, and open directly to the atmosphere. Alternatively they may communicate with a turbo charger booster manifold. In use, during the exhaust stroke, the valve 4 is open as is customary. Air is drawn into the orifice zone 3 and the bores 5 and 6 being tangential, a vortex is created in the orifice zone 3 which forms a bubble or body of air in the zone which prevents fuel mixture from entering the cylinder until the start of the induction stroke -- thereby preventing leakage of fuel mixture into the exhaust gases. The air from zone 3 tends in fact to be drawn into the fuel inlet manifold, rather than into the cylinder, forming an extra barrier to fuel leakage. As soon as the induction stroke starts, the vortex collapses, and fuel is positively drawn into the cylinder by the suction created by the movement of the piston. CLAIMS

6. A cylinder head according to Claim 4 wherein said manifold has an idling inlet and a valve controlled inlet regulable by pressure differential emanating from the downstream side from the carburretor throttle edge.

1. In the cylinder head of an internal combustion engine having at least one cylinder, one or more inlet bores associated with each cylinder through the cylinder head and opening obliquely into the fuel.inlet passage adjacent the outlet thereof into the respective cylinder, to admit air into the fuel inlet passage during the exhaust cycle to prevent leakage of fuel to the exhaust port.