Stop/start systems are now a common feature in new cars. Sometimes referred to as mild hybrids, start/stop, idle stop and go and all other manner of similar terms. They help save fuel and reduce air pollution by seamlessly switching off the engine when the car comes to a standstill and restarting it again when the driver dips the clutch.
Such systems allow motorists stuck in traffic jams, waiting at lights etc, to easily save fuel which is so often wasted in urban driving conditions. Research suggests that a stop/start system will save around 5-10 per cent in fuel consumption with the savings greater in urban environments.
How do they work?
Some motorists may not use their stop/start if they are in the habit of staying in gear when they come to a standstill. Stop/start systems only work when a car stops and the driver puts the car in neutral and lifts off the clutch. Initially installed on manual models, they are now increasingly featured on automatics too. Here the car switches off the engine when the it comes to a halt, and stays put for at least a couple of seconds, without the driver needing to switch from D to N.
Why should I choose a stop-start car?
It is not just the driver’s pocket that can feel the benefit of start/stop, such systems are also useful for reducing inner-city air pollution. They are becoming so popular that even the most hardy, fuel-hungry sports cars now sometimes feature them. Take the Ferrari California for one.
What’s really great about a stop/start system is just how easy it is to use. Manually switching off the engine disturbs the car auxiliary systems and causes an unnecessarily delay in restarting. A stop/start system is smooth and leaves your radio, lights, air con etc settings untouched and quickly restarts the engine when you are ready to move again.
People often worry about the additional strain that repeated starting and stopping places on the engine and starter motor, but stop-start car come with more robust starters and batteries to cope. 
Some people have complained that they find stop-start systems annoying, but it is often just a case of getting use to it, it quickly becomes normal.
Adding a stop/start system to a car is often how carmakers shave off those extra few grammes of CO2 which might otherwise push a vehicle into a different tax bracket, meaning you would incur more tax as well as suffer higher fuel consumption.
How the market is growing
According to recent estimates from Pike Research (see story), 41million vehicles are expected to feature stop-start systems by 2020: a near ten-fold increase compared to 2012.
Oddly while full hybrids are proving more popular in the US, stop-start systems are more popular in Europe. This is expected to change however, as Americans become increasingly interested in reducing fuel consumption and new CAFE standards create a greater incentive for carmakers to introduce the systems. Globally stop-start cars are already outselling hybrid vehicles with the gap expected to increase to a 16 to one ratio by 2017.
Cars with stop/start systems in the UK
Carmakers including Volkswagen, smart, Toyota, Ford, Citroen, Kia Vauxhall, Nissan, Volvo and Audi are just some of the names which currently sell cars with this fuel saving tech.
Everything from small city cars like the smart fortwo MHD (micro-hybrid drive) to big vehicles like the Land Rover Freelander are available with stop/start systems. Usually, they are included with the most eco-friendly cars in each model range, so watch out for eco sub-brand names such as Bluemotion (Volkswagen) and ecoFLEX (Vauxhall) for clues that such a system is already in your car.
Some of the best start/stop available include the aforementioned smart fortwo, Ford Focus EcoBoost, Kia Rio Idle Stop and Go (ISG), Audi A3 1.6 TDI Sport stop-start and the Nissan Qashqai 1.6 dCi Start Stop to name a few.
Faye has been writing about cars and environmental issues since 2007. A suspected eco-warrior working on the corporate inside, Faye mainly likes the weird, quirky vehicles that show a distinct environmental advantage. Her ideal car has enough room to fit a bale of hay in the boot. When not working, she likes nothing better than to head out on her bicycle and explore the countryside.
Vidar
I find the start/stop-system quite useless. When I drivethe engine stops for less than 3 seconds when it stops automatically. Often the engine has to start in less than one second. This will cause slower acceleration and more strain on the battery and the starter. The reason why the system has been so popular, is merely that the EU-cycle which is used for CO2-rating favour the system. In real life I suppose that the consumption actually may be increased because of the start/stop-system (more need for charging).
May 16, 2013
Vidar
I find the start/stop-system quite useless. When I drivethe engine stops for less than 3 seconds when it stops automatically. Often the engine has to start in less than one second. This will cause slower acceleration and more strain on the battery and the starter. The reason why the system has been so popular, is merely that the EU-cycle which is used for CO2-rating favour the system. In real life I suppose that the consumption actually may be increased because of the start/stop-system (more need for charging).
May 16, 2013