Fix It

Chevrolet designs, manufactures, and markets the Silverado, a full-sized pick-up truck. The term "Silverado" was first used to describe a trim package on Chevrolet pick-up trucks beginning in 1975. For repair and maintenance of Silverado pick-up trucks, owners need to be able to find the correct parts.

Instructions

1

Go to the Auto Parts Giant website. (See Resources.) Select the "Year," "Make," "Model," "Sub model (if applicable)" and "Engine Size" for your Silverado. Press "Go." Type the part that you are looking for into the "Search" box. Press "Search." Review the results and identify the part you are looking for. The part number appears in the product description.

2

Go to the Napa website. Click "Select a Vehicle" and click the features that match your Silverado truck, such as "Year." Enter the part you are looking for in the "Part Number Search" box. Press "Search." The results display the part number.

3

Launch the Auto Zone web page. Click "Manage My Vehicle" and "Add A Vehicle." Select the details for your Silverado truck and "Look Up Parts." Click on the appropriate category and the specific part to view the part number.

The catalytic converter is part of an automobiles exhaust system. Its function is to convert carbon monoxide and other organic compounds into less environmentally harmful emissions, such as carbon dioxide and water. The catalytic converter helps reduce automotive pollutants and toxic emissions.

History

In the late 1960s, California and other states began requiring the automotive industry to reduce the level of emissions released by cars and trucks. By 1975, the Environmental Protection Agency (EPA) and federal government established stringent regulations for the reduction of emissions. As a result, automotive engineers designed and developed an external converter through which gases would pass and be altered to less harmful products. Today nearly all internal combustion engine vehicles use catalytic converters.

Defining a Catalyst

A catalyst is a substance that allows a chemical reaction to occur at a faster rate or different temperature than it would under normal conditions. In a cars catalytic converter, the surface of the converter (part of the exhaust system) is coated with platinum or rhodium which serves as the catalyst in combination with high heat.

What Happens

Automotive exhaust, which is produced by the internal combustion engine, is a combination of nitrogen, carbon monoxide, organic compounds and water vapor. As the exhaust passes through the catalytic converter, it undergoes a chemical reaction when it comes into contact with the catalyst. The catalyst separates the nitrogen atoms from the oxygen and alters the other organic compounds. The gases are modified into less harmful byproducts and released into the environment.

Location

While the exact location varies by make and model of vehicle, the catalytic converter is mounted with the exhaust system. Typically, it is placed near the vehicles engine between the exhaust manifold and the exhaust pipes where fumes can pass through it before being released into the environment. Heat plates separate the catalytic converter from the exhaust manifold, protecting the vehicles engine from high heat.

Modern automobiles rely on sophisticated computerized engine management systems that include fuel injection, and monitor the air/fuel ratio by means of oxygen sensors in the exhaust system. Thus, oxygen sensors are an integral part of the engine system.

Air/Fuel Ratio

The air/fuel ratio for a gasoline engine has an optimal value of 14.7 to 1. This ratio results in good performance, and also reduces harmful emissions such as carbon monoxide and nitrogen oxides. Oxygen sensors monitor and maintain this critical ratio.

Performance and Emissions

Too much fuel in the air/fuel mix results in a "rich" mixture, and produces excessive unburned hydrocarbon emissions. Too little fuel results in a "lean" mixture, which produces excessive nitrogen oxide emissions. The fuel/air mix changes in response to data from the oxygen sensors, which monitor these emissions to make sure that the mix is neither too rich nor too lean.

Computer Management

A properly functioning engine management system uses fuel injection metering, a computer program and emissions sensors to ensure optimal engine performance, and the lowest possible level of harmful emissions, under a wide variety of operating conditions.