Cooling system for automobiles

Field of the invention

The present invention relates to "Cooling system for automobiles" and more particularly to a catalytic converter cooling mechanism used in internal combustion engines in motor vehicles.

Description of the prior art

Catalytic converters are used in various fields, in promoting reactions, such as reactions for the synthesis of compounds and reactions and cleaning automobile emissions. The catalytic converter stimulates a chemical reaction in which noxious by-products of combustion carbon monoxide, unburned hydrocarbons, and oxides of nitrogen are converted to less-toxic or inert substances such as carbon dioxide, hydrogen, nitrogen and oxygen. When an engine performs at peak efficiency, it will burn all the fuel in the combustion chamber during combustion process. However, most of the engine doesn't perform at peak efficiency at all the operating conditions. During this time, all the fuel doesn't burn and allow excess unburned fuels or hydrocarbons to enter the exhaust system. This constant infusion of unburned fuel due to catalytic converter causes temperature to continuously rise above the designed operating temperature until the core of the catalytic converter actually melts. Furthermore, due to high temperature, the nearby regions, which are joined by welding, also develop cracks and lose its structural integrity. These failures are detrimental to the proper functioning of the engine and the muffler. Furthermore, heat is conducted back in the reverse direction towards engine as the catalytic converter gets overheated. Due to the said reverse heat condition, failure of muffler body is generally observed and engine thermal efficiency also drops.

Hence the main objective of the present invention is elimination of the 'thermal shock' and prevention of transmission of the excess heat from the catalytic converter away to the exterior surfaces for better cooling efficiency.

Brief description of the present invention

Improved cooling mechanism in the catalytic converter is the main aspect of this invention. This invention provides a suitable metal or baffle plate connected across the catalytic converter body to the housing allowing heat conduction to be faster to the exterior surfaces. The baffle plate is placed in such way that is allows to conduct heat in the radial direction and finally to the housing.

In one aspect of the present invention, an additional baffle plate is provided on the catalytic converter body and connected to the housing. For most efficient performance of the catalytic converter, the baffle is placed between 0.3L to 0.7L from the inlet end. Here L is the length of catalytic converter. Two major advantages with this invention are (1) temperature gradient along the catalytic converter surfaces is reduced significantly and (2) significant reduction in reverse conduction of heat is achieved. Thermal failure of the muffler assembly with catalytic converter can be eliminated which was not possible in the prior art.

Brief description of the drawings

The present invention will become more fully understood from the detailed description given herein and the accompanying drawings which are given by way of illustrations only, and thus not limitative of the present invention, and wherein:

Figure 1 illustrates the schematic diagram of engine muffler showing various components as in the prior art.

Figure 2 illustrates one aspect of invention showing the mounting of a baffle plate over the catalytic converter body.

Figure 3 illustrates the effect on temperature with and without baffle plate on the catalytic converter.

Figure 4 illustrates the effect of temperature with and without baffle plate on the catalytic converter pipe.

Detailed description of the present invention

A selected illustrative embodiment of the present invention will be now described with respect to the accompanying figures 1,2,3 and 4. Figure 1 shows the muffler interior used in the prior art. Hot gases from the engine enter the inlet 208; passes through the catalytic converter 207 and then through series of perforated tubes 202 and resonator chambers 201 and finally exit through the outlet 209. The catalytic converter 207 is provided just near the inlet 208 for maximum efficient of the catalytic converter 207. Two baffle plates 204, 205 are provided which essentially divides the muffler into three different chambers. The positions of these mufflers are tuned so that noise can be attenuated as the gases pass through different chambers. The baffle plate 1 204 is put just downstream of the catalytic converter 207. When the catalytic converter core 207 becomes overheated, heat start to conduct in reverse direction i.e. towards inlet 208. Due to differential temperature existing between the catalytic converter 207 and baffle 1 204, thermal distortion happens apart from melting of the core as discussed earlier. Figure 2 describes one aspect of the invention. An additional baffle plate 3 210 is provided just over the catalytic converter body 207 along with the baffle plate 1 204. The baffle plate 3 210 connects catalytic converter tube from one end and muffler housing 203 from other end, just like any other baffle. Baffle 3 210 acts like extended surfaces and conduct heat in radial direction. Due to faster conduction of heat, catalytic converter temperature drops and reverse heat conduction is minimised.

Figure 3 shows variation of temperature over the entire length of the muffler- housing top starting from inlet. It can be seen that with the addition of baffle plate 3, there is a significant increase in the temperature of the housing. This signifies that heat is being conducted through baffle plate 210 to the housing 203 efficiently and results in the drop in temperature of the catalytic converter207, which is demonstrated in the figure 4. Figure 4 shows variation of the temperature along the catalytic converter tube or pipe 206, starting from inlet208. As can be seen, when baffle plate 3 210 was provided, temperature of the catalytic converter tube has dropped substantially due to better heat conduction mechanism.

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.

Claims: We claim:

1. An exhaust muffler comprising an exhaust gas inlet 208, an exhaust gas outlet 209, at least one catalytic converter 207, at least one baffle 204,205 in a housing 203 wherein a suitable metal or baffle plate 210 is connected across the said catalytic converter body 207 to the said housing 203 such that the said baffle 210 is placed between at least 0.2 to 0.8 times of the length of the catalytic converter from the inlet end.

2. The exhaust muffler as claimed in claim 1, wherein the said baffle 210 plate is placed in such way that it conducts heat in the radial direction and finally to the housing 203.

3. A motorcycle having an exhaust muffler as claimed in claim 1.

4. A three-wheeler having an exhaust muffler as claimed in claim 1.