FIELD OF INVENTION
This invention relates to a dust cap for CNG Filler Valve inside the engine room. This invention relates in particular to dust cap used in NGV Type CNG Vehicles wherein the filler valve is inside the Engine Room.
PRIOR ART
In CNG Vehicles two types of filler valves are used:
a) NGV Type (Stainless-Steel Filler Valve)
b) NZS Type (Brass Filler Valve)
Dust Cap is generally used in CNG vehicles to prevent the filler valve from getting contaminated by dust, dirt, etc. Inside the engine room, temperatures are very high. In case of dust cap of metal, it is difficult for operator to open it because of high surface temperature. Also, the manufacturing cost is high. If dust cap of resin had been provided, there would have been chances of the dust cap to operate with extra effort. This causes difficulty while opening and closing with filler valve due to different coefficient of expansions for 'Steel' and 'Resin'. Thus, the required functionality would not have been achieved.
Generally in the known vehicles, either the filler valve is located on the side body where a plastic or a metallic cap is provided. Also, no gripping is provided onto the holding area for ease of opening and closing. Even if it is provided in the engine room, no arrangement of cap with different material is made in order to provide ease to the end user.


Reference may be made to Fig.l (a) wherein plastic dust cap requires more force during opening and closing. Further, reference may be made to fig. 1 (b) which is associated with disadvantages of burrs and non-smooth opening and closing as no gripping portion is provided in case the cap is made of Aluminium.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which protects the filler valve from dust, dirt etc.
Another object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which prevents the filler valve from falling inside the engine room, which would be difficult for user to pick up due to high temperature.
Further object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which can withstand temperatures inside the Engine Room.
Another object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which can be used in engine room without affecting the function.
Still another object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room having ease of opening and closing along with visual marking.


Yet another object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room provided with a tether to avoid the Dust Cap from falling inside the Engine Room.
Yet further object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room provided with metal insert so that it properly sticks to the resin part & resin part can withstand the load of metallic insert.
A further object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which is cost effective and efficient.
A still further object of the present invention is to provide a dust cap for CNG Filler Valve inside the engine room, which is light in weight.
STATEMENT OF INVENTION
According to this invention there is provided a dust cap for CNG filler valve inside the engine room wherein contact material with said micro-switch is a metal for withstanding high contact pressure and the holding area is non metallic in which said dust cap is provided with a tether.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:


Fig. 1 is the comparative view of different types of dust caps used in NGV vehicles.
a) Type 1 shows plastic type of dust cap.
b) Type 2 shows metallic type of dust cap.
c) Type 3 shows combination of resin and metal.
Fig. 2 shows isometric view of the dust cap indicating several child parts.
Fig. 3 shows cut section of the dust cap which explains the mating parts
and clearances therewith.
Fig. 4 is the exploded view of the dust cap showing each of the child part
in detail.
Fig. 5 is the front view of the dust cap wherein the gripping provided on
the holding area.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS;
The present invention discloses a dust cap comprising of a combination of materials, which are chosen such that, the contact material with filler valve is steel and the material at the holding area is Resin wherein said dust cap is provided with a tether. Reference may be made to the accompanying drawings.
The above provision ensures a problem free opening and closing of the dust cap inside the engine room.
For ease of the end user, an 'Open-Close' mark is provided onto the cap and also gripping is provided on the holding area for comfortable opening and closing. Knurling is carried out on metallic insert in contact with


filler valve in such a way that, it properly holds the resin material. Further, said tether prevents the dust cap from falling inside the engine room by holding the same. During fuel filling, dust cap can hang with the Tether and can also be closed afterwards. The clearances of tether with the mating part (dust cap) are kept in such a way that, a smooth rotation is obtained.
Features of the present invention
1. Arrangement of different materials such that it can be used in engine room (high temperature zone) without affecting the function.
2. Ease of opening and closing along with visual marking.,
3. Tether to avoid the Dust Cap from falling inside the Engine Room.
4. Provision of metal insert so that it properly sticks to the resin part & resin part can withstand the load of metallic insert.
Advantageous features
1. Cost Reduction: Instead of a single metallic insert, two different inserts are used. This results in material reduction. Hence, weight & cost reduction.
2. For ease of operation, gripping is provided.
3. Material is chosen to withstand the temperatures inside the Engine Room.
4. No chance of falling of the Dust Cap inside the Engine Room.


It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

WE CLAIM:
1. A dust cap for CNG filler valve inside the engine room wherein contact material with said micro-switch is a metal for withstanding high contact pressure and the holding area is non metallic in which said dust cap is provided with a tether.
2. A dust cap as claimed in claim 1, comprising of a metallic insert provided with knurling in contact with filler valve.
3. A dust cap for CNG Filler Valve inside the engine room substantially as herein described with reference to the accompanying drawings.