Through the Road Parallel Hybrid

A “through the road” parallel hybrid demonstrator vehicle has been created by installing in-wheel motors to the rear axle of a standard gasoline powered C-segment car. The powerful, independently controlled, electric motors work in combination with the standard front wheel drive configuration.

The aim of this project was to improve both the performance and the fuel economy of the vehicle through the addition of the hybrid system. The hybrid configuration adopted also provides the vehicle with all-wheel drive (AWD) capability.

The in-wheel motors, which also incorporate the disc brake and associated power electronics, provided an innovative solution to the packaging challenge in cars of this size by utilizing the available space within, and around, the wheels.

The in-wheel motors also brought performance and handling advantages as they have a large flat-torque response and the delivery of tractive effort is instant and seamless. This in turn sharpened up the feel of the vehicle by improving the response to driver torque demand.

The vehicle easily achieved its performance targets with the benchmark 0-100 km/h acceleration time being reduced from 13.9 to <7.0 seconds and its top speed increased by more than 10%. Even more significantly, the NEDC fuel economy was reduced from 6.4 to 1.7 l/100km and the CO2 emissions from 149 to <40 g/km. The AWD capability of the dual drivetrain system also enhanced the dynamic behavior of the vehicle in both high and low grip road conditions.

This convincing demo vehicle clearly illustrates the functional and packaging advantages of high torque in-wheel motors and the complimentary benefits of their integration into parallel hybrid architecture. It also demonstrates the benefits offered by using reconfigurable controller architecture. The VCU, developed by MAHLE Powertrain, is powerful enough to interact with multiple separate CAN buses simultaneously and provides an ideal platform for the development of demonstrator and niche volume vehicle fleets.

Through the Road Parallel Hybrid Demonstrator Vehicle [PDF; 1043 KB]