FIELD OF INVENTION
This invention relates to a catalyst system employed in automobiles for purification of exhaust gases emitted from the engine of the vehicle upto limit set as per regulatory government requirements.
PRIOR ART
In an automobile and a motor cycle, an exhaust gas purifying apparatus is provided for purifying exhaust gas discharged from them. Several types of the exhaust gas purifying apparatuses such as a thermal reactor type, a lean-burn type and a catalyst type are available.
Among these, the catalyst type exhaust gas purifying apparatus has been widely used. It purifies exhaust gas by using a catalyst noble metal such as Pt (platinum), Rh (rhodium) and Pd (palladium).
Various catalyst systems have been developed to meet the emission norms along with maintaining cost effectiveness of the whole system. Conventionally, catalyst systems comprising of catalysts of substrate (base for noble metals edherence) cell density 400 cpsi have been used in order to meet various Emissions regulation norms. Location of these catalysts have been typically in the exhaust manifold near to converging branches of the ports in order to have temperatures sufficient for quick light-off. However, vehicles are having layout constraints thereby not permitting locations close to manifold. Hence, double catalyst systems are provided in the vehicle under body compensating lower operational temperatures with double the volume and sometimes increased noble metal concentrations.


Conventional practice makes use of single catalyst or tandem catalyst. Catalysts used were 400 or 600 CPSI for single catalyst and 400 CPSI for tandem catalyst.
Thus, conventional systems make use of 400 cpsi substrate catalysts in tandem with increase in noble metal concentrations and cost de-merit or use two separate catalysts of different cell density with de-merit of altogether new manufacturing process to avoid interchangeability of catalyst position which will lead to significant change in exhaust pipe.
However, as mentioned above, methodology of meeting norms in vehicles with constraints of unavailability of space for catalyst to fit in near the manifold is still not clear enough.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a catalyst system employed in automobiles, which overcomes disadvantages associated with the prior art.
Another object of the present invention is to provide a catalyst system employed in automobiles, which reduces cost of loading.
Further object of the present invention is to provide a catalyst system employed in automobiles, which prolongs lifespan of catalyst.
Still another object of the present invention is to provide a catalyst system employed in automobiles, which meets BS4 regulation.


STATEMENT OF INVENTION
According to this invention, there is provided a catalyst system used in automobiles comprising of atleast two catalysts, each of 600 cpsci cell density working in tandem.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawing and wherein:
Fig. 1 shows : catalyst system of the present invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING;
The Present Invention discloses a catalyst system employed in automobiles (as shown in fig. 1). It comprises of two catalysts each of 600 cpsi cell density working in tandem keeping overall size and manufacturing process same.
Following factors are considered for meeting optimum performance, emission norms, durability and cost effectiveness.
• Vehicle calibration to adopt the new tandem catalyst system


• Optimization of Noble metal loading in exhaust system.
With implementation of stricter Emissions norms, catalyst configurations using catalysts of higher cell density 600 cpsi provide higher surface area for catalyst activity and higher conversion rates effectively leading to lower concentrations of precious noble metals such as Pt (platinum), Rh (rhodium) and Pd (palladium).
Salient features of the invention over prior art;
1. Reduction in the cost of loading due to more surface area exposure to exhaust gas.
2. Improvement in durability of catalyst due to smaller size of catalysts.
3. Meets BS4 regulation.
The new system of the Present Invention meets stricter emission norms in vehicles having physical constraints along with other limitations to be considered from commercial point of view like that of lesser cost, minimum or no changes to present configuration/manufacturing process.


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 catalyst system used in automobiles comprising of atleast two catalysts, each of 600 cpsi cell density working in tandem.
2. A catalyst system as claimed in claim 1, wherein the cost of loading is reduced due to more surface area exposure to exhaust gases.
3. A catalyst system as claimed in claim 1 or 2, wherein the durability of catalyst is improved due to smaller size of catalysts.
4. A catalyst system as claimed in any of the preceding claims, wherein the system meets BS4 regulation with no changes to present configuration/manufacturing process.
5. A catalyst system used in automobiles substantially as herein described with reference to the accompanying drawing.