I’m old enough to remember when it was ‘cool’ to own a 5-speed gearbox when everyone else had four, but now if you really want to impress the neighbour’s kids you’ll need at least eight – preferably nine.
At least that’s what Land Rover are banking on with the new ZF 9HP transmission – the world’s first 9-speed automatic.
Land Rover were chosen as lead partner on the 9HP, which it will demonstrate at next week’s Geneva Motor Show. The transmission was specifically designed for transverse applications and weighs 7.5kg less than the outgoing 6-speed transmission used in the Range Rover Evoque.
Despite the extra three gear ratios it’s only 6mm longer and features a number of packaging innovations including two patented dog clutches replacing the conventional clutch packs.
The obvious concern with such a multitude of gear ratios is for the gearbox to forever be hunting between gears, but Land Rover say this is not a problem. The adaptive shifting system matches the driver’s mood in seconds, sharpening up during brisk driving and slipping into a more relaxed (i.e. less eager to change) mode just as quickly.
The gearbox resists upshifts depending on longitudinal acceleration, throttle position and when it senses cornering and also measures the rate of throttle-release – anticipating further requests by the driver when a sudden response is called for.
The 9-speed box suits the Evoque’s Terrain Response system, with its lowest ratio far lower than the 6-speed box – designed for off-road use, towing and climbing steep gradients.
The 9HP’s extremely fast gear changes are described by ZF as being “below the threshold of perception” and while the current 6-speed box is limited to sequential shifts the 9-speed has a ‘skip-shift’ function which responds more intuitively under rapid deceleration.
Land Rover say a higher top gear reduces fuel consumption and noise while improving comfort at speed, and overall offers another layer of performance, refinement and efficiency.
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