Honda reveals details of dual-clutch hybrid powertrain for small cars

The latest addition to Honda’s new Earth Dreams Technology powertrain family features a newly developed 1.5-litre four-cylinder Atkinson cycle petrol engine, a seven-speed dual-clutch automatic transmission with a built-in high-output electric motor, and a lithium-ion battery.

Honda says the powertrain delivers faster and more linear acceleration than its existing hybrid models, and eclipses the efficiency of conventional hybrids by more than 30 per cent.

The hybrid system disengages the clutches from the engine at start-up, at low to medium vehicle speeds and during deceleration to facilitate zero-emission electric-only driving – enhancing efficiency and boosting the vehicle’s range.

Honda says the lightweight one-motor hybrid system has been optimised for small vehicles, with the Honda Civic and CR-Z seeming the most obvious beneficiaries of the future technology.

The one-motor hybrid system will complement Honda’s new two-motor hybrid powertrain designed for mid-sized vehicles and its three-motor all-wheel-drive system that has been optimised for larger vehicles and sports cars.

The two-motor system will debut in the Honda Accord Plug-In (pictured top), which goes on sale in North America in January 2013. The hybrid's powertrain incorporates a petrol engine, two electric motors, a continuously variable transmission (CVT) and a lithium-ion battery to deliver a driving range in excess of 800km.

The three-motor system, destined for the all-new Honda NSX sports car and the next-generation Honda Legend, will pair a front-mounted 3.5-litre direct-injection V6 with two electric motors on the rear axle and a newly developed seven-speed dual-clutch transmission with an in-built motor.

With independent motors controlling the left and right rear wheels, positive torque can be applied to the outside wheel and negative torque applied to the inside wheel to make independent control of the torque distribution possible without relying on engine output.

Honda’s new-generation hybrid powertrains will be introduced to its global vehicle showroom throughout the rest of the decade.