How cold weather affects your fuel consumption
xBy Jay Lerue
This time of year in Atlantic Canada, it is not uncommon to see a wide range in temperature variation from one day, or in some cases, even one hour to another. This is a direct result of where we are on the globe, which makes us prone to such drastic and extreme changes in temperature readings. But, have you ever considered exactly how directly this affects your car’s rate of fuel consumption, or how your car’s engine adjusts to maintain optimal performance levels, despite the outside temperature?
To research this topic, I consulted with Bill Isenor, a highly trained and respected technician with Colonial Honda in Halifax. Bill has been at Colonial since 2001 and certainly knows a thing or two about engines. He’s also an avid racing fan, of both cars and high performance motorcycles.
I was amazed at some of the things I learned by consulting with Bill! He pointed out several variables in auto performance, simply by using racing to illustrate his point. Says Bill, “If you want to know how temperature affects performance, all you have to consider is how different a racing engine from a mountainous area, like Denver Colorado and one from a lower altitude, like Arizona would be, as far as parameters are concerned,” says Bill. “The settings and parameters have to be calibrated all the time to compensate for climate and temperature variations.” In a higher altitude, the air is typically cooler and thinner.
Therefore, to optimize the settings, the engines have to be “leaned out,” meaning the fuel use is somewhat restricted, to give the engine a better fuel and air mixture. The polar opposite being the case for racing engines in a lower and typically warmer climate, where the air is more plentiful.
Exactly how this affects the common motorist in Atlantic Canada is in the way your car uses more gas on a colder day than on a warmer one. “Most people don’t have time to consider where the variable lies in their car’s fuel use,” says Bill. “But, the fact remains that on cold winter days, your car is burning a much greater amount of gas than it did on warm spring or summer days,”.
On cold days, your car’s engine requires a much longer “warm up” period. This results in a longer time before your engine reaches a “closed loop” mode, whereupon all your engine’s sensors are working together, to optimize your engine’s performance.
It’s off to the gas pumps we go!
Also, on cold days, the air in our Atlantic Region, is typically damper, meaning more moisture. This moisture influx, affects the way fuel and air condenses. “When the air is colder and damp outside, it grabs more fuel molecules in your engines gas/air mixture,” says Bill. “The end result is that while your car may appear to be running better, your fuel economy suffers considerably in these conditions,” he adds.
In previous engine models from 20 years ago or longer, engines were carbureted and often equipped with a manual pull choke, usually located on the dash panel. The motorist would simply pull the choke outward at the point of ignition. This would essentially restrict the air flow to the engine, adding more fuel and resulting in a faster warm up period.
When the motor was warm enough and running well, the motorist could simply push the choke button back in and drive off. Today’s technology has the modern engine self contained with sensors. These sensors strive to maintain and control your car’s engine parameters and keep them efficient, despite the changes in climate and temperature.
But, for all of their convenience, there still remain some things that the common motorist can do to assist in winter fuel efficiency. According to Bill Isenor, “Installing a block heater will certainly assist in fuel efficiency, because when your oil and anti-freeze are pre-heated, your warm up period is greatly reduced, bringing your sensors up to optimal levels fast.”
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