When you want all-wheel drive but only when you need it
drive system link to the power of a turbo charged engine.
They developed a rally car that used this great grip and power.
But a permanent four wheel drive system uses more energy and wears out more parts.
Dieter Weidemann the head of Audi all wheel drive system talks of the energy efficiencies you could make.
- 80%
For a road car, it would be good to have four wheel drive only when you needed it.
Some old four-wheel drive vehicles had hubs that you could get out of the vehicle and turn the dial and it would disengage the drive to the front wheels. Later this became a switch in the cabin. But this was an all or nothing situation. You had to make a decision and it was a time consuming effort.
Dieter knows that when driving along a road the need for extra grip comes and goes.
- Many situations
Some manufacturer’s developed a “real time” system which automatically engaged all wheel drive when something adverse happened like losing traction on the front wheels.
Audi wanted to be more proactive.
- Make a system
But for it to work the system has to think and react quickly
- 500 milliseconds
Audi have now launched this system in the Q5 and SQ5 models in Australia.
How they predict your needs is not clairvoyance but a clever use of information and a very quick response.
They have 15 algorithms evaluating different operational conditions in your car.
Here’s how one of the algorithms work.
- Press the throttle
They will even take into account the weather, cold weather is more likely to mean wet or icy roads, the frictional resistance of the road, or what sort of driver I am. If I am a dynamic driver they engage the four wheel drive earlier.
But Just how much then is the system operating.
Dieter’s team has developed an ap to show what is happening and how often the system is used.
We drove the car carefully over a dirt road. All wheel drive was engaged 34% of the time.
Then drove down a typical two-lane country road in Australia.
In 111km the car had all wheel drive engaged for 6% of the time. But it has been used on 18 specific occasions. This might be locations of poor grip, tight corners, overtaking
Here is the plot of the road and the times we engaged all wheel drive.
Here are the times when we were in dynamic driving mode. This does not correspond with every four wheel drive engagement because the car is giving intense consideration as to whether we need the extra grip.
Travelling 94% of the time in two wheel drive we have been far more efficient without having to compromise the safety value of having all wheel drive when we needed it.
Originally aired on 8 July 2017. For past programs and individual segments visit www.drivenmedia.com.au
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