Dyson electric car: new patents show mould-breaking design

DIMENSIONS AND PROPORTIONS

In essence, the patents describe a car that is close to the five-metre length of a standard Range Rover but more than 40cm longer in the wheelbase, at 330cm, with 4-6cm more ground clearance than the Range Rover’s standard 22cm yet at least 25cm less overall height, at around 165cm tall.

The car’s layout allows excellent approach, breakover and departure angles, even in Land Rover terms, although there’s no suggestion that Dyson wants to build a farm vehicle. “It’s just that we can have these things for free,” he said.

This high-floor/low-roof layout is made possible because of the location of the car’s wide, long, thin underfloor battery, and the adoption of saloon-like seating positions for occupants, giving what Dyson described as a “command” driving position.

What's more, the compactness of the (probable) twin electric motors allows a cab-forward layout – assisted by the short nose and raked screen – which allows much of the car’s total length to be used for accommodation. The Dyson patents propose a potential seven-seater (with centre-row and rear-row passengers mounted higher than those in front for good visibility).

A saving of around 10cm on overall width is also possible, said Dyson, because of the lack of a bulky internal combustion engine plus the adoption of narrow-section tyres on big-diameter wheels that need smaller wheel envelopes let into the body. A particular Dyson preoccupation is keeping the new car’s frontal area to a minimum, a major contributor to aerodynamic efficiency.

BODY, SUSPENSION, WHEELS

Dyson confirmed that the car will have an aluminium body, mostly because he and his engineers feel carbonfibre structures haven’t reached the level of maturity they believe the electric project needs. Steel is deemed too heavy.

The patent diagrams suggest a platform-shaped battery mounted beneath the body. Such a battery would need to be encased in an extremely rigid, well-protected structure, which points to the use of a 'skateboard' platform chassis supporting suspension subframes front and rear. Height-adjustable and self-levelling suspension seems likely: Dyson himself pointedd to the pitch-limiting advantages of the very long wheelbase.

The Dyson car is likely to have alloy wheels of a highly unusual 23-24in diameter, running thin tyres of around 45-55 profile. The company is understood already to have a tyre supplier. The inventor said experiments show these wheels have considerably lower rolling resistance than smaller, wider wheels and their greater inertia (often deemed a fault) will help with regenerative brakling.

This unusual wheel/tyre combination also creates less aerodynamic drag, allows relatively low tyre pressures to be used (for good ride comfort), resists aquaplaning on wet roads and requires a smaller wheel envelope, reducing intrusion into the cabin. The tyre can still have an acceptably large footprint because it’s longitudinal, not lateral.

BATTERY AND POWERTRAIN

Dyson’s patent applications contain no powertrain details – beyond a theoretical suggestion that the car could be battery, hydrogen or even petrol-hybrid powered. But Sir James Dyson confirmed that his company is researching two different types of solid-state battery, understood by laymen to be the next big thing after the lithium ion type used almost universally in EVs today.

Dyson’s solid-state battery research is proceeding in four linked global locations, including the UK. It seems a certainty that these advanced batteries (bringing advantages in energy density and lightness) will eventually be used in the Dyson car, although there are unconfirmed suggestions that lithium ion may power the earliest cars.