TURN YOUR mind from cars to ships. T h e g r e a t n e w cruise liner Queen Victoria, weighing over 90,000 tons, is electrically propelled. And, no, she doesn’t have a long wire, plugged into the harbour. Nor are there battery-charging points at frequent intervals out in the ocean. The power comes from engines burning diesel or heavy oil — and what engines! There are four V16s, each with capacity of 1,125 litres. Each engine develops 15,500 bhp while cruising at a leisurely 514 rpm — this is roughly the tickover speed for most car engines. But the fact that this form of power can drive this great ship shows the versatility of electricity.
The twin 17ft-diameter propellors are each mounted on a huge pod, which takes the incoming 11,000-volt supply and reduces it to 2,000 volts. The propellors are mounted ahead of the pods, so they are running in relatively undisturbed water and the pods can be revolved through 360 degrees. This eliminates heavy propellor shafts, as well as the need for a rudder with its inevitable drag. Steerage is by turning the pods and by control of propellor speed and the pitch of the blades.
Further advantages of electricity are quietness, lack of vibration and high torque at low revs, as well as efficiency — all of which are also needed for cars.
At the Paris Show earlier this month, Michelin launched the “active wheel”. I thought April Fool’s Day had come early when I read that the active wheel would do away with gearbox, transmission and suspension; but then I learned that electric motors, springs and brakes would all be incorporated in the wheel. There could be four motors, one in each wheel, giving fourwheel drive, or two motors for a car with front-wheel drive. I don’t think we will see this in production for a while, but again it shows the versatility of electric power.
Also revealed at Paris was Audi’s concept study for a Sportback five-door capable of CO output as low as 92 g/km. This would be off the government’s scale, meaning no annual car tax to be paid, even up to 2011. It would have a 1.4-litre petrol engine driving the front wheels and developing 150 bhp, backed up by a 27 bhp electric motor adding substantial torque to the wheels when accelerating.
The car would also have automatic stop/start to save fuel at halts and regenerative braking, which would put charge back into the lithium-ion batteries on slowing down or braking. Audi doesn’t tell us when such a car might go into production, but it all helps demonstrate the possibilities of electricity.
Like the Queen Victoria, hybrid cars need a source of power to produce the electricity, which will usually mean a diesel- or petrol-burning engine, as in the Lexus and the Honda Civic hybrids. But General Motors plans to bring into production, possibly next year, its all-electric car, the Volt. It is claimed to offer a top speed of 100 mph, but the range limitation of 40 miles is the big problem. And how the Volt will be heated in winter. Will it have an oil- or petrol-burning heater?
Some manufacturers are researching the use of hydrogen for cars, but the drawbacks are the need for storage under pressure at ultra-low temperatures and the consumption of electricity to produce the hydrogen in the first place. These are all questions on which sizeable funds are being expended.
Great developments are on the way and the only certainty is that electricity will play an increasingly important part in the car of the future. How unfortunate that we are now being told electricity may also be in short supply, even for domestic and industrial use, without the added burden of powering transport.
Michelin’s ‘active wheel’