We can all pick up bad habits driving. But, like Dr Karl, it seems some of us are guilty of a bad habit before we've even pulled out from the curb!
I've had a lot of fun teaching the Junior Members of my Family how to drive the Family Chariot. But along the way, I realised that something I had done for a long time was actually wrong. Previously, I tried to be "kind" to my car's engine by giving it a nice long idle before I pulled away from the kerb. But when I went looking, I found that long idle was actually harming the engine, and the environment, and my wallet.
The powertrain of a car is the mechanical stuff that makes it go. The power starts at the engine, goes through the gearbox and finishes at the driving wheels. Les Ryder, the chief powertrain engineer from Ford, USA, said in the January 2007 issue of Popular Mechanics, "Engines run best at their design temperature". In other words, Mr. Ryder is telling us that engines run most cleanly and efficiently somewhere between 85°C and 95°C. Idling is not the best or quickest way to warm up your engine. Gentle driving is.
The Canadian Office of Energy Efficiency agrees that 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. You need even less idling time at the temperatures we usually experience in Australia.
Idling an engine is bad in so many ways. The fuel is not completely burnt, so it condenses in drops on the cylinder walls. This leads to both extra wear of the cylinder walls (because the fuel washes the lubricating oil off the walls), and unburnt fuel flowing down the walls and contaminating the oil in the sump. Idling also drops the temperature of the spark plugs, leading to dirty plugs, which can worsen your fuel consumption by some five per cent.
You might have noticed a vapour coming out of the exhaust of some cars in the early morning. That vapour is not the oil vapour of a worn engine, but the normal water vapour from a cold engine. So the longer you idle the engine, the longer it will take to warm up, and so more water droplets will be deposited inside your exhaust system – making it rust sooner.
A long time of idling means that the engine will produce a lot more unwanted pollutants. For example, modern cars have catalytic converters. When they get to their normal operating temperature (400-800°C, which is a lot hotter than the engine), they convert nasty pollutants into much less nasty chemicals. And you guessed it, the quickest way for catalytic converters to get to their normal operating temperature is by driving, not idling. The longer the time that you idle your engine, the longer that your catalytic converter is too cold to do its job.
Canada has started a national campaign to reduce unnecessary idling of engines. There are similar regional campaigns in Japan and the UK, and in the USA, 13 states have now passed laws regulating idling of engines. The ski resort town of Aspen, in Colorado, has passed laws making it illegal for car engines to idle for more than five minutes.
People are now talking about the benefits of switching off your engine in traffic, if you are going to be stopped for more than 10 seconds. But this is exactly opposite to the Remote Start function, available in some US cars, which lets you start the engine from some 60 metres away. The advantage is that you walk out of your house into a nice warm car. The disadvantage is that in 10 minutes of idling, you burn about half-a-litre of fuel.
The Canadian Office of Energy Efficiency crunched the numbers for the hypothetical situation of each Canadian driver idling their engine for 5 minutes fewer each day. Over a year, that reduced idling would save Canadian drivers C$646 million, and stop 1.6 million tonnes of greenhouse gases from escaping into the atmosphere.
When you idle a car, you get zero miles per gallon, lots of pollution, and a hole in your wallet.
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