Simply put, I don't need anyone explaining the legalities of catalytic converters. I have asked this question a couple of times and folks keep saying the same things about EPA and passing inspection etc etc... Also it is not for the engine on a car, it is on a truck mount carpet cleaner called a Legend and manufactured by Prochem. The catalytic converter is inside of a cylinder measuring roughly 2 feet long and around 10 inches in diameter. Inside is a coil of stainless steel tubing that heats up from the incoming exhaust diverted from a Kohler 2 cylinder gasoline engine's exhaust pipe. There is a mechanical 'flap' controlled by linkage hooked to a thermostat. This controls how hot the water will be for the water used to spray the floor, furniture etc. My ultimate question that no one is able to answer is simple. WILL the heat exchanger heat the coiled inner tubing with the water running through it ENOUGH to work, or is the catalytic converter needed? Please no legal eagles, Thanks
Since the converter adds heat to the system, it likely that with the catalytic converter removed, there will not be sufficient temperature to provide all the heat needed. There might be sufficient heat at lower loads but not at maximum demand. The only way to know would be to have the design information including temperatures and flow rates.
The catalytic converter is probably using heat from the engine exhaust to react exhaust gases over an internal catalyst bead or mesh bed, and these reactions are slightly endothermic, generally (meaning the reaction is a net cooling, not a further heating, of exhaust gases). So, the lack of a catalytic converter might not make much difference in the temperature of the spray water, unless the converter also slows the flow rate of the exhaust gases enough to facilitate heat exchange. But that is more a plumbing issue, than a chemistry problem. It's just that if the hot exhaust gases exit the chamber too quickly, because their flow is undamped with the catalytic converter removed, the net heat exchange rate might go down, as the hot gases carry heat energy along with them as they exit the exchanger, instead of giving it up to the coil, as they might better at lower velocities. Flow turbulence has a lot to do with this, so it's not easy to give an answer just from theory. I'd suspect a fair amount of testing went into the original design, to get the best combined rates of emission drop and heat exchange with the total design. Removing part of it, without other compensation, might not work in the way you imagine, for subtle reasons. Over time, the effectiveness of the exchanger could also be further compromised by the deposition of raw exhaust gas deposits (mainly carbon), that are now trapped or reacted by the catalytic converter. Another problem I'd be wary about is the effect of hot exhaust gas on the flapper valve and other equipment around the exchanger, as without the catalytic converter, these might become much warmer in use.
Could it affect your mpg's...yes. It could take it from whatever you are getting now down to zero...permanently. The heat shield does exactly what the name implies. It shields everything around it from the intense heat of the catalytic converter. If it was the lower shield that was removed, this is of less concern unless you park on the grass or on something else that may catch fire and burn eventually catching the car on fire. If it was the upper shield that was removed, you run the risk of the residual heat from the cat heating up the floorboard and catching the carpet on fire. Heat wrapping the cat would be a good idea if you can't get the shield reinstalled.
What I don't understand is the design of this thing. Is the only use for the engine to heat water, and that is only via a heat exchanger inside the catalytic converter? You are lucky if you get 1% effeciency! Why not heat the water in the radiator? 30% of the energy loss in an engine is there. Or heat water via the muffler, a lot of heat is lost there. But best would be some sort of heater running from the rotary output of the engine itself. Or even better, just burn the gasoline under a boiler/water heater.
The catalytic converter can generate heat so that is probably why the water flows past it. There should still be enough heat in the exhaust to heat the water. I doubt that the heat produced by the converter is high compared to the engine exhaust itself. It should only convert a relatively small amount of incompletely burned hydrocarbons.
