Tips and How-to's • Automotive • (1) Comments • Permalink •
It is a bloody cold day in my neck of the woods. At 8:30am the temperature is -23.3C. The wind chill makes it even colder than that.
This is the kind of weather that makes folks want to pre-warm their cars. But, whether you want to warm the engine or the car interior for comfort, it is not a good idea to idle your car. There are a number of reasons why warming your car by idling it is not recommended. Aside from the fact that it is a waste of fuel, pre-warming the car is not actually gentler on the engine, as many people believe.
Most of today's cars use electronic fuel injection. The cars are designed so that the computer tells the fuel injectors to stay open longer when the car engine is cold. This allows more fuel into the engine to help it run cold. When the engine warms up, the injectors let in less fuel.
Letting your car sit and idle for 15 minutes is actually a slower way to bring it up to operating temperature. According to the Canadian Office of Energy Efficiency (OEE), the best way to warm up your engine is to drive it. Even if the outside temperature is -20°C, they recommend that you idle the engine for only 15-30 seconds before you pull out onto the road.
Idling your car in cold weather can actually invite several problems. Richard Backus, editor in chief of Gas Engine magazine explains the following:
"Remember that modern cars are equipped with a multitude of devices to help them run clean, including a catalytic converter (sometimes three of them), a device in the exhaust system that works to burn off unburned hydrocarbons in the exhaust stream. A cold engine emits a far higher percentage of unburned hydrocarbons than a warm engine. Unfortunately, the average catalytic converter can’t process 100 percent of unburned hydrocarbons even in the best of times. Importantly, the catalytic converter needs high exhaust temperatures to work properly. Throw in a cold engine emitting a high percentage of unburned hydrocarbons, repeat several hundred times, and you can end up with what’s called a “plugged” converter. In a nutshell, the converter becomes overwhelmed and literally ceases to function. This won’t happen all at once but over time, the end effect is the same: poor mileage and significantly dirtier exhaust."
The Canadian OEE also adds that what is often forgotten is that "idling warms only the engine – not the wheel bearings, steering, suspension, transmission and tires. These parts also need to be warmed up, and the only way to do that is to drive the vehicle. Until the engine temperature begins to rise, it's a good idea to avoid high speeds and rapid acceleration."
Remember that it is also important to make sure that your car windows are free from snow and frost before you drive away!
I leave you with this from Natural Resources Canada idle-free zone campaign:
"As an individual, you can be instrumental in reducing environmental impacts. If every driver of a light duty vehicle avoided idling by three minutes a day, collectively over the year, we would save 630 million litres of fuel, over 1.4 million tonnes of GHGemissions, and $630 million annually in fuel costs (assuming fuel costs are $1.00/L)."