Goal - Save $$$, Prevent Pollution : Catalytic Converter

Did you know? Fuel consumption soars in cold weather - sometimes by as much as 50 percent. That means you're spending more - and potentially polluting more - than you do in the summer.

Fuel combustion is also much less efficient in a cold engine, and the air-fuel mixture is richer (i.e., more fuel, less air). The combined effect is a sharp increase in pollutants. To make matters worse, the catalytic converter doesn't work when it is cold. Until the converter warms up, all of the engine's emissions pass through the exhaust untreated.

Fuel consumption and pollution output are much higher in the first minute or two after a cold start than when the engine has achieved normal operating temperatures. One reason is that when your engine starts up, it has to pump oil throughout the block to lubricate moving parts.

In a cold engine, the oil is thick and resists flow, which means the engine has to work harder to overcome internal friction. Thick oil also takes longer to circulate, which allows metal-to-metal contact and increases engine wear.

Engine Warmth

How warm should your vehicle be before you drive it? Hint: The warmth of your interior heater does not directly correspond with your vehicle's readiness to drive. In fact, if you wait to be toasty warm on the inside, you're causing excess pollution on the outside!

"Preheating the catalytic converter is a good way to reduce emissions. The easiest way to preheat the converter is to use electric resistance heaters. Unfortunately, the 12-volt electrical systems on most cars don't provide enough energy or power to heat the catalytic converter fast enough. Most people would not wait several minutes for the catalytic converter to heat up before starting their car. Hybrid cars that have big, high-voltage battery packs can provide enough power to heat up the catalytic converter very quickly."http://auto.howstuffworks.com/catalytic-converter3.htm

Once a vehicle is running, the best way to warm it up is to drive it. Driving cuts warm-up times in half. This will speed up the heating of the catalytic converter which significantly reduces pollutant emissions. With computer-controlled, fuel-injected engines, you need no more than 30 seconds of idling on winter days before driving away. Older cars should only warm for a couple of minutes. Anything more simply wastes fuel and increases emissions.

More than the engine needs to be warmed up - so do the wheel bearings, steering, suspension, transmission and tires, all of which can be done only when the vehicle is moving. Avoid high speeds and rapid acceleration for the first three miles or so. The goal is to bring the whole vehicle up to peak operating temperature as quickly as possible while maximizing fuel economy.

Engine Idling

The catalytic converter - the device that cleans pollutants from the vehicle's exhaust - doesn't function at its peak until it reaches between 750°F and 1000°F. The best way to warm the converter is to drive the vehicle. Idling emits more pollution if the vehicle's catalytic converter isn't working properly. Ask your technician to check the system the next time your car is being serviced.

Ten seconds of idling can use more fuel than turning off the engine and restarting it. If you're stopping for more than 10 seconds - except in traffic - turn off the engine.

In winter conditions, emissions from an idling vehicle are more than double the normal level immediately after a "cold start." A poorly tuned engine uses up to 15 percent more energy when idling than a well-tuned vehicle.

Restarting a car many times has little impact on engine components such as the battery and the starter motor. The wear on parts that restarting the engine causes adds about $10 a year to the cost of driving - money that you'll likely recover several times over in fuel savings.

Excessive idling can be hard on your engine. Because the engine isn't working at peak operating temperature, fuel doesn't undergo complete combustion. This leaves fuel residues that contaminate engine oil and make spark plugs dirty.

If your vehicle has a diesel engine, idling actually lowers the coolant temperature faster than shutting off the engine. In other words, switching off the engine keeps the engine warm longer. http://www.cleanair.utah.gov/winter_driving.htm