Honda's new hybrid - sporty & clean?Comment on this story
Honda has announced a new lightweight, compact single-motor hybrid system for small cars, which it calls the Sports Hybrid Intelligent Dual Clutch Drive system - and no, Cyril we're not going to give it an acronym.
It's the third in a series of new-generation hybrid systems Honda has labelled Earth Dreams Technology, following the Sport Hybrid Intelligent Multi Mode Drive for mid-sized vehicles and the Sport Hybrid Super Handling - All Wheel Drive for sports cars.
The new system is intended to provide comparable fuel consumption to current models such as the CR-Z, but with better acceleration. It combines a newly-developed, 1.5-litre, four-cylinder Atkinson cycle petrol engine with a high-output electric motor where a normal clutch would be and a seven-speed duel clutch transmission.
It uses the clutches to completely disengage the engine during start-up and gentle cruising, drawing power from a lithium-ion battery, engages all the clutches under hard acceleration so that both petrol and electric motors contribute to performance - and then disengages both clutches again on the overrun to use every last bit of momentum to poke a few more amps back into the battery.
So much so, that is claiming a 30 percent improvement in efficiency compared to a conventional hybrid set-up.
TWO-MOTOR SPORT HYBRID
This, says Honda, is the world's most efficient two-motor hybrid system for mid-sized cars, combining the best features of hybrids, plug-ins and extended-range electric vehicles.
It has a new two-litre Atkinson-cycle petrol engine developed specially for hybrids, an electrically-operated constantly variable transmission hooked up to two electric motors, and a lock-up clutch.
The system seamlessly switches between three driving modes depending on speed, accelerator position and battery charge level.
At low to medium speeds around town it will operate, as long is it can, as a pure electric vehicle - and it can be plugged in to a charging station when parked to make the most of that mode.
If the battery runs flat while driving the car doesn't stop, the engine starts up to charge the batteries, while still using the the two electric motors to drive the front wheels. In this mode, the car thus operates as an extended-range EV.
For high-speed cruising, however, the engine is connected directly to the front axle by a lock-up clutch, with no power lost in either transmission or in generating power to drive the electric motors.
It may sound like science fiction, but this system will actually reach showrooms in the United States in January 2013, in the North American version of the new Accord.
THREE MOTORS TO DRIVE FOUR WHEELS
Hondas doesn't actually say so but the indications are that this is the drive-train that will be used in the new NSX sports coupé, already 'leaked' in the Iron Man movies.
Honda claims that this combination of 3.5-litre V6 petrol power and three electric motors will deliver acceleration comparable to a V8, on the fuel consumption of a four-cylinder engine.
We'll take that under advisement until we've driven one.
The big direct-injection V6 is front-mounted, driving the front wheels via a seven-speed, dual-clutch transmission with a built-in electric motor. There's also an electric motor permanently hooked up to each rear wheel.
Under hard acceleration, of course, everything gets hooked up for maximum voomah; that we expected.
Fling this car into a corner, however, and only the outside rear wheel is powered up. The inside wheel produces 'negative torque' by being switched over as a generator, pushing a few amps back into the batteries and slowing that wheel, allowing accurate control of over and understeer without using the brakes.