FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
PROVISIONAL SPECIFICATION
(SEE SECTION 10; RULE 13)
"REED VALVE FOR GASEOUS FUEL DIRECT INJECTION (Dl) ENGINE"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C, SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION DESCRIBES THE NATURE OF THE
INVENTION

FIELD OF INVENTION:
The present invention is related to reed valve used in internal combustion engines. More particularly the present invention is related to reed valve that directs gaseous fuel towards the spark plug in two stroke spark ignition engine wherein the fuel is injected very close to the spark plug inside the combustion chamber of an engine.
BACKGROUND OF THE PRESENT INVENTION:
Two stroke gasoline engines have dominated the two wheeler market till the 80s. Two stroke engines have advantages over 4 stroke engines in specific power, cost, simplicity, low friction, etc. At the same time they have major drawback of excessive hydrocarbon emissions because of short circuiting of fuel into the exhaust during the scavenging process. This was a major impediment in meeting exhaust emission norms. To overcome this, there have been attempts to introduce gasoline into the combustion chamber under pressure, either directly or along with compressed air mixture after or near about the time of exhaust port closing. In this manner, fuel short circuiting is dramatically reduced. To generate the required injection pressure, there is a need for either a fuel pump or an air compressor. Where either Compressed Natural Gas (CNG) or Liquefied Petroleum Gas (LPG) or Propane or any other gaseous fuel was used in a 2 stroke engine, the fuel has mostly been introduced into the combustion chamber through the transfer ports, thus participating in the scavenging process and while doing so escaping partly into the exhaust port without burning. Where direct injection was tried out, the injectors were exposed to the combustion gases and resulted in poor service life of injectors. To overcome this drawback, the invention described herein is proposed.
Also, the existing reed valves are used to allow inlet air into the crankcase and hence have to be sized adequately to handle large volume of gas. The construction of such a reed valve typically has an aluminium body with rubber

coated surfaces against which the spring steel leaves seal. The temperatures to which this reed valve is subjected to, is below 100 deg.C and the pressures are near atmospheric. Rubber sealing surface is provided to make the reed valve near leak proof.
OBJECTIVES OF THE PRESENT INVENTION:
The main objective of the present invention is to provide reed valve assembly that directs any gaseous fuel under pressure towards the spark plug.
Another objective of the present invention is to provide reed valve assembly that protects the injector from combustion chamber pressure thereby resulting in better combustion stability and increased injector life.
Another objective of the present invention is to provide reed valve assembly that shields the injector from high temperatures of the combustion chamber, thus prolonging the life of the injector.
Still another objective of the present invention is to provide reed valve assembly that achieves a stratified charge inside the combustion chamber to support a stable combustion.
ADVANTAGES OF THE PRESENT INVENTION:
• The reed valve assembly delivers simplicity in its construction for repair, service and maintenance.
• It is compact, user friendly and versatile in nature for use in 2-wheeler, 3-wheeler, stationary engines in industrial applications.
• It is a low cost and light weight solution for directing the gaseous fuel.
• The invention as disclosed herein can be applied to single cylinder or multi-cylinder engines.

BRIEF DESCRIPTION OF THE FIGURES:
Further objectives and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein,
Figure 1 (a) and (b) shows location of reed valve assembly in the fuel injection system inside the cylinder head of an engine.
Figure 2 (a) and (b) shows reed valve assembly in accordance with the present invention.
Figure 3 shows the reed valve of the present invention wherein the strips on the reed valve are removed.
Figure 4 shows the leaves/strips of the reed valve of the present invention.
Figure 5 shows cross sectional view of reed valve with flow direction orifices.
DETAILED DESCRIPTION OF THE PRESENT INVENTION:
Referring to figure 1, gaseous fuel injection system (1) comprises of two main components namely gas injector (2) and reed valve (3). This fuel injection assembly (1) is placed in the cylinder head (4) of an engine. The injector (2) is used to inject the gaseous fuel under pressure inside the combustion chamber whereas reed valve (3) is used to direct the fuel flow towards the spark plug (5) inside the combustion chamber. The spark plug (5) is mounted on the top of the combustion chamber (4) parallel to the bore axis. The fuel injector (2) is mounted on the cylinder head (4) in such way that it makes the angle of about 98 degrees with the spark plug (5). The injector has a supply pressure of about 9 bar and is clamped axially by a locking plate.

The reed valve (3) of the present invention is placed between the injector (2) and the combustion chamber in the cylinder head (4) of an engine. The reed valve assembly is threaded into position from inside the combustion chamber of the cylinder head using a square key on the head of the reed valve body. Referring to figure 2, reed valve (3) comprises of head (6), shank (7) and leaves/strips (9). The head (6) and shank (7) are the integrated single part made of stainless steel or any other material which can withstand the high temperatures inside the combustion chamber. The head (6) of the reed valve (3) has at least four slanting surfaces (8) converging at the top center point. Each slanting surface has gas outlet orifice (10) as shown in figure 3 thus enabling the reed valve (3) to direct the gaseous fuel flow in four directions at 90 degrees with each other. Each of the slanting surfaces is provided with leaf or strip (9) to cover the gas outlet orifice (10). The leaf / strip,(9) is an add-on kind of covering component and is made of spring steel or any other material having high tensile strength. Each strip has a projection (11) on its lower inner side as shown in figure 4 that snap fits with the groove (12) provided on the lower surface of the head (6) as shown in figure 4 thus tightly resting on slanting surface (8) of the head (6) of the reed valve (3). If the gaseous fuel flow is desired only in one direction, the respective leaf/strip (9) is removed.
The profile / geometry of the proposed reed valve (3) of this invention, particularly the shape, it's location in the fuel injection system and material of construction, is configured to prevent the hot (upwards of 400 deg. C) combustion gases under high pressure (upwards of 60 bar) from going past it and thus protecting the gas injector on the other side. Minor back leakages can be tolerated and hence the spring steel leaf (9) directly rests against the steel body (8) of the reed valve (3) thus eliminating the need for a rubber surface. The size of the reed valve is small enough to fit into the combustion chamber area of the cylinder head (4) and yet is big enough to allow the gas flow quantities required for combustion within the small time slot available for this. The quantity of gas per stroke is typically one 20th of the cylinder cubic capacity.

Such an inventive reed valve (3) allows us to use a regular gas injector used in manifold injection application. In conventional direct gas injection, the injectors are of the outward opening type and are therefore more expensive (high temperature withstanding capability), noisy (sealing is against a metallic seat) and prone to deterioration as the valve seat is exposed to soot in the combustion chamber. The proposed reed valve allows the use of a cheaper and silent injector which is less prone to deterioration. In addition, it protects the injector from combustion chamber pressure, resulting in better combustion stability and increased injector life; shields the injector from high temperatures of the combustion chamber, thus prolonging the life of the injector; and directs the gas plume towards the spark plug so as to achieve a stratified charge, which supports a stable combustion.
The inventive reed valve as disclosed herein can also be implemented in the engine specially made for stationary applications such as gensets, pump sets, etc.
It should be understood that the present invention is not to be limited by the exact details of the illustrated embodiment. However, it is to be taken as the preferred example of the invention and that various changes may be resorted to by a person skilled in the art without departing from the spirit of the invention. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.