Car Care: Stop-start technology explained
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Manufacturers continue to come up with new ingenious ways to improve their vehicles, both to attract new buyers and to meet industry guidelines and best practices.
One example is stop-start technology, which reflects an ongoing shift towards fuel economy and adherence to strict exhaust emission regulations.
Each manufacturer has its own name for it, but the system basically switches off the engine when it’s not needed – like at traffic lights – and quickly starts it again when you want to move. Manufacturers all over the world are incorporating this tech into their vehicles.
This technology isn’t particularly new, with early development reported to have started in the Europe in the 80s by Fiat and Volkswagen.
The system was somewhat rudimentary and never really took off until the mid-90s.
Stop-start technology is commonly found in hybrid vehicles, as their entire premise is centred on being as fuel-efficient as possible.
They’ll often start the driving process electrically and then start the engine once more acceleration is needed.
Won’t just turning the key off do the same thing? Sure, you could just turn the engine off manually to save fuel but, with the engine off, accessories such as radio, wipers and headlights will also switch off.
Then, every time you turn the key back on, you’re causing excessive wear on the ignition, battery and starter motor.
For this technology to work, vehicles have had to undergo a few design changes.
First off, the starter motor has to be more robust so it stays reliable despite being used far more often.
Likewise, the battery must have deep cycle capability that can endure more frequent draws from the starter and keep those accessories running.
You don't want the infotainment, cooling fans, lighting or wipers to shut down each time the engine turns off — and you don't want them to blink when it starts up again.
The crankshaft and bearings also need to have special low-friction coatings to handle the extra loads placed on them during frequent restarts.
There are conditions in which the system will or, more importantly, won’t work.
The vehicle firstly needs to reach operating temperature, the engine then stops when speed reaches zero, there is steady brake pressure and little or no steering wheel angle.
The command to start again is given as the brakes are released or pressure is put on the clutch.
These systems generally won’t work if:
●The vehicle is in reverse
●The bonnet is not locked, driver’s door open, or seatbelt not fastened
●The outside air temperature is too high or too low, or interior climate setting vs ambient temperature difference is too great
●The engine temperature is too low
●The emissions control system is being regenerated (diesel)
●The steering wheel angle exceeds a pre-determined percentage or, in some cases, when a turn signal may be on.
So what are the actual savings?
With the engine switching off when not required, fuel savings of 5-10 per cent are possible.
Vehicle emissions are also reduced by a similar amount, allowing manufacturers to achieve higher emission standards amid strict regulations.
Some vehicles will have a fuel saving display where you can see savings in real time.
It can also tell how many engine starts have been carried out, and advise when the service life of the starter has been reached.