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See How Start Stop Technology Works

posted on Oct 16 2009 by Kyle McWilton

See How Start Stop Technology Works

No one likes traffic jams. Not only to they waste your time, but as you sit there, idle, your car also wastes fuel and money. Until now. I'm sure you'll be aware of Start/stop technology. It should be no surprise seeing as Audi alone have reportedly pumped 4million into promoting this fuel saving technology.

Basically, when you come to a stop, the engine stops and as you go to move off, the engine restarts. But how does it work There are essentially three main parts involved in an idle-stop system: the gasoline engine, an electric starter/generator and a battery. The transfer of energy works in that order, both forwards and backwards -- it just depends on what state the car is in.

When the car's engine is on and you're decelerating, stop-start systems use regenerative braking, where rotational energy from the wheels turns the electric generator and creates electricity (see our post on brake regeneration here for more info). The generator sends electricity to the battery where it can be stored for later use. When the car comes to a stop and the driver selects neutral gear and releases the clutch pedal, the generator shuts off the gasoline engine.

Depressing the clutch pedal and selecting a gear tells the engine to start once again by taking the stored energy from the battery and running it through an electric starter. With an electric starter, the restart process happens in just over two thirds of a second. Normally, the system is inactive during the warm-up phase of the engine, so that the engine oil becomes warmer and the exhaust gas cleaning systems reach their operating temperature faster. And according to Audi, with their start-stop models, the driver can also switch off the start-stop system at any time by pressing a button.

So now when you're sitting in that traffic jam, you don't have to worry about wasting fuel. And when driving around town your car will be saving fuel at every traffic light, pedestrian crossing and roundabout. Mazda claim to be able to give you an extra 10% in fuel savings with their Smart Idle Stop System (SISS). Here's what Mazda said in their press release, "Where Conventional idling stop systems restart a vehicle's engine with an electric motor using exactly the same process as when the engine is started normally.

Mazda's SISS, on the other hand, restarts the engine through combustion. Mazda's system initiates engine restart by injecting fuel directly into the cylinder while the engine is stopped, and igniting it to generate downward piston force. In order to restart the engine by combustion, the pistons must be stopped at exactly the correct position to create the right balance of air volume in each cylinder.

The Smart Idle Stop System provides precise control over the piston positions during engine shutdown to accomplish this. The SISS indexes each cylinder and initiates fuel injection before the engine begins to rotate. This enables the engine to be restarted in just 0.35 seconds, roughly half the time of a conventional electric motor idling stop system." Regardless of how it's achieved, you'll agree, start-stop technology is a great way of making your new car more eco-friendly. Head over to our car leasing website to see what deals you can get on a car deals  will save you more fuel.