Claims:We Claim:
1. A supercharger for an engine, comprising at least:
a housing (200) accommodating at least one rotor (202) and at least one cover plate (204); characterized in that
inner surface of said housing (200), said rotor (202) and said cover plate (204) are coated with corrosion resistant coating.

2. The supercharger of claim 1, wherein said coating is at least one of nickel-phosphor coating and hard anodizing.
, Description:Field of the invention
[0001] This invention relates to the field of superchargers.

Background of the invention.
[0002] Supercharger for one cylinder diesel engines used in passenger vehicles, three wheelers and four wheelers have to meet the future emission legislations like Bharat Stage VI. One key component for this is exhaust gas recirculation (EGR). In these engines, the exhaust gas is recirculated through the low pressure side of the supercharger. This means the supercharger components should resist the corrosive nature of diesel exhaust gases. Hence there is a need for coating components of supercharger that are exposed to exhaust.
[0003] Prior art patent application US 20080292486 discloses a rotary blower rotor includes a rotor body having a corrosion-resistant coating covering the rotor body. An abradable coating covers at least a portion of the corrosion-resistant coating for providing an essentially zero operating clearance for increasing a volumetric efficiency of the rotary blower. A rotary blower including a rotor with a corrosion-resistant coating is also provided.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:
[0005] FIG. 1 illustrates a housing for a supercharger;
[0006] FIG. 2 illustrates a rotor for a supercharger; and
[0007] FIG. 3 illustrates a cover plate for a supercharger.

Detailed description of the embodiments
[0008] FIG. 1 illustrates a housing for a supercharger. The supercharger comprises at least a housing 200 accommodating at least one rotor 202 and at least one cover plate 204. The inner surface of the housing 200, the rotor 202 and the cover plate 204 are coated with corrosion resistant coating..
[0009] FIG. 2 illustrates a rotor for a supercharger. The lobes of the rotor are coated with the corrosion resistant coating. As the lobes rotate, the air sucked in between the lobes and gets compressed. The exhaust gas is recirculated through the low pressure side of the supercharger. Since this exhaust comprises particles, these particles may corrode the lobes of the rotor. The corrosion resistant coating on the lobes of the rotor prevent the rotor from particles present in the exhaust.
[0010] FIG. 3 illustrates a cover plate for a supercharger. The cover plate encloses the housing of the supercharger on end and supports the rotor at another end. The pair of cover plate, along with the housing form 200 a single unit. The cover plate (204) is coated with corrosion resistant coating.
[0011] During working of the supercharger, the exhaust from the engine reaches the inlet of the supercharger. This exhaust contain particles which are capable of corroding the components of the supercharger. Hence in order to prevent corrosion to the components of the supercharger, the inner surface of the housing 200, the rotor 202 and the cover plate 204 are coated with corrosion resistant coating. The coating may be nickel-phosphor coating or hard anodizing. The thickness of coating may be around 15 – 30 microns. The Nickel Phosphorous alloy has good, natural corrosion and chemical resistance.
[0012] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of type of coating employed. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.