Method of cleaning a catalytic converter

Abstract

A method of cleaning an automobile catalytic converter for an automobile engine including introducing a cleaning solution containing sodium hydroxide upstream from the catalytic converter while the automobile engine is running.

Description

FIELD OF THE INVENTION[0001]This invention relates to the art of automotive repair, and particularly to a method of cleaning and / or refurbishing an automobile catalytic converter.BACKGROUND OF THE INVENTION[0002]A catalytic converter is a device used to reduce the toxicity of emissions from an internal combustion engine. Catalytic converters were first widely introduced on U.S. production automobiles for the 1975 model year to comply with tightening EPA regulations on auto exhaust. Catalytic converters are still in wide use today in motor vehicle exhaust systems and are also commonly used on other machines implementing internal combustion gasoline engines including generators, forklifts, mining equipment, trucks, buses, and trains, although catalytic converters can also be implemented with diesel engines. A catalytic converter provides an environment for a chemical reaction wherein toxic combustion by-products are converted to less toxic substances.[0003]The first catalytic converte...

AI Technical Summary

Problems solved by technology

However, until lead was removed from gasoline, the catalytic converter was not an effective device because lead effectively poisons the catalytic converter's catalyst.

Lead was previously used in gasoline to raise octane levels, but was phased out in the 1970s and 1980s due the harmful aspects of lead to people and the environment.

It is not suitable for all applications, however, because of unwanted additional reactions and / or cost.

Cerium, iron, manganese and nickel are also used, although each has its own limitations.

Nickel is not legal for use in the European Union (due to reaction with carbon monoxide).

While copper can be used, its use is illegal in North America due to the formation of dioxin.

However, outside of that band, conversion efficiency falls off very rapidly.

When there is excessive fuel, then the engine is running rich.

Catalytic converters on automobiles can be operationally damaged in two primary ways.

First, catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, encapsulating the catalyst so that it cannot contact and treat the exhaust.

The most notable contaminant is lead, so vehicles equipped with catalytic converters can only be run on unleaded gasoline.

Depending on the contaminant, catalyst poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time.

However, removal of lead deposits in this manner is usually not possible due to lead's high boiling point.

Moreover, this method is inefficient, unreliable and can lead to vehicle engine damage.

The second type of catalytic converter damage is meltdown.

Any condition that causes abnormally high levels of unburned hydrocarbons—raw or partially-burnt fuel—to reach the converter will tend to significantly elevate its temperature, bringing the risk of a meltdown of the substrate and resultant catalytic deactivation and severe exhaust restriction.

This type of failure is generally not repairable.

Catalytic converters, due to their incorporation of precious metals, are expensive, sometimes costing $1000.

However, when a catalytic converter fails, there are no accepted methods of repairing or refurbishing it.

While an ineffective catalytic converter will not generally affect engine performance, it will pollute the environment and cause a vehicle to fail government-mandated emission inspections.

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