Broken Secrets

Idling a Cold Engine Is GOOD For The Environment

December 14, 2009 at 12:53 am Chad Upton 2 comments

You may notice when you start a cold vehicle, its exhaust is visible at first and disappears after a few minutes. Here’s why.

Technically, modern vehicles do not require much warm up time before you can drive them; advanced lubricants and materials allow the vehicles to be driven shortly after a cold weather start. Of course, you may want to warm your car for your comfort and surprisingly, to reduce emissions.

This is not intuitive, unless you understand the emission control systems on modern vehicles.

The first system is called Exhaust Gas Recirculation, and it’s probably obvious from the name: it routes exhaust gases back into the engine. The vehicle computer system monitors and controls this process to lower the amount of Nitrogen Oxides, precursors to smog and acid rain, that are created in the engine and then expelled from the tailpipe. Depending on your vehicle, this system will not operate in certain conditions, for example: low engine temperatures.

Vehicles also have a component in their exhaust system that converts various pollutants into less harmful gases with various catalysts. That conversion occurs in the catalytic converter, and that chemical reaction doesn’t happen when the catalytic converter is cold.

According to WP, some catalytic converters can take up to thirty-minutes to reach ideal operating temperature. That isn’t to suggest you should wait that long before driving your car — there are countermeasures in many cars that make it effective long before that.

When your car is at idle, it uses less gas and releases less pollution than when you are driving it. Getting your emission system to an effective point before driving it helps reduce overall emissions. For my car, it take about 3-5 minutes before the exhaust is invisible and that’s about how long it takes to clear the snow anyway. It’s not an exact science and it varies by car and by temperature.

BrokenSecrets.com

Sources:  WP, WP, WP, EPA, GM

Photo: steveyb (Creative Commons)

Entry filed under: Automotive, Be Efficient, Be Green, Despite Popular Belief, ProTips. Tags: acid, auto, automobile, Automotive, car, emissions, environment, green, idle, pollution, rain, reduce, smog, warm.