Why your plug-in car cares where you're going

6 October 2011

Volvo V60 save electricity for later button

One interesting idea Volvo is toying with, ahead of the launch of its V60 plug-in hybrid next year, is an extra set of buttons to let you tell the car whether you’re about to set off on a short, medium or long drive. The duration of an upcoming journey might seem irrelevant for most cars, but for a plug-in hybrid it’s quite an important piece of foreknowledge.

Plug-in hybrids, as well as range-extended electric cars, must juggle two types of energy. There’s cheap, low carbon, slow-to-replace electrical charge fed into the batteries from the mains. And then there’s more expensive, higher carbon but quick-to-replace fuel in the tank. If the goal is to make the best use of the two resources during the journey, to minimise consumption of the dirtier, pricier fuel, it helps a lot to know where you’re going. It helps to know how thinly the electricity needs to be spread.

Vauxhall Ampera charging

Sometimes the driver will want to save all of the electricity up for a particular part of a journey – when you know there will be city streets to traverse at the end of a motorway blast, for example. Volvo’s V60 hybrid and GM’s Volt/Ampera EREV both offer the option to save the battery for later, coupled with a pure-electric mode for summoning up that stored power on command. But for most journeys, the needs won’t be so explicit or so clear cut. It would be helpful for the car to have as much to go on as possible when it comes to metering out its precious stored charge.

“If we know where the driver is going, we can optimise the use of energy,” says Börje Grandin, Volvo’s manager of engine strategy and advanced engineering. “Our models show we can use 20% to 30% less fuel if we know the journey in advance.”

So the question for designers of plug-in cars is, how do we get that information from the driver? How do we know where we are going?

Volvo’s short/medium/long buttons are one obvious idea. Another is to use the satnav. If a driver has plumbed in a particular destination, chances are that’s where the car is headed. But many journeys are more routine, or on roads the driver knows well. In some upcoming plug-in cars, it might be wise to tell the satnav where you’re going even if you don’t need its help in finding your way.

Volvo V60 cutaway showing engine, fuel tank and battery

One other solution is to build some intelligence into the car – some memory of previous trips that will aid it in guessing where it’s going. If it’s a frosty Monday morning at 8am, chances are it’s a commute coming up. A warm summer Sunday afternoon? Somewhat harder to predict but maybe this is going to be a longer drive with some B-road twists.

We already have cars that are better at emergency stops than human feet, better at parking than human judgement, better at knowing which gear to be in, and better at finding their way from A to B. Soon, we’ll have to deal with cars that know where we’re going before we even realise it ourselves.

Like it or not, that’s progress.

1 comment:

Audi Belfast said...

We are exited by the continuing progress of Electric cars but still the technology is a little behind. If you take the scenario of having a 100 mile range electric car and you are either in a cold climate like Canada or like we have seen in the UK this past 2 years the battery will be sapped by using the heaters in the car. Normal oil fuel engines are naturally warm so are great for getting heat in winter but electric cards will drain their batteries fast when trying to heat the car in the cold as we all know to create heat we need lots of electric. something that will have to be considered with electric cards in the future.

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