Continental develops EV tech for the masses

Continental has dramatically revised its 48-volt mild-hybrid electric-assist system, lifting it from mild-hybrid up to full hybrid status because the system is now capable of powering a vehicle purely with electricity.

The automotive tech giant’s previous mild-hybrid system -- as found in a range of models from brands including Renault – reduced fuel consumption and emissions by helping to accelerate the car using energy recouped under braking, cutting consumption by around 10 per cent.

Now, with a doubled power peak of 30kW, the system’s electric motor/starter/generator can push a car beyond 80km/h without calling on the internal combustion engine – something that previously only more expensive plug-in hybrid vehicles could do.

The giant vehicle components company, best known in Australia for its tyres, claims the improvements have been achieved with little or no extra cost, potentially bringing EV technology to many more car owners.

The performance upgrade for the mild-hybrid system Continental released in 2017 comes without breaking the low-voltage threshold of 60 volts, avoiding the need for the extensive and costly safety requirements that apply to 800-volt hybrid systems currently on the market.

At its recent TechWeek exhibition in Hanover, Continental demonstrated the system fitted to a Ford Focus powered by the Blue Oval’s award-winning turbo-triple petrol engine.

To highlight the advances made, attendees were challenged to drive around a winding and undulating 1.5km track without prompting the internal combustion engine (ICE) to kick in.

They were assisted in this by the inclusion of a detent on the accelerator pedal, beyond which the ICE would fire up.

While no economy numbers were revealed for the prototype, it was clear the system was capable of powering the Focus at normal suburban speeds without the intervention of the ICE.

The system is still being finalised but Continental is indicating it will achieve at least a 20 per cent reduction in fuel consumption and emissions compared to the standard Focus -- double the benefits of its previous mild-hybrid system.

The key to the new system is a motor/generator that produces twice the power output with only a fractional increase in its diameter.

A major factor here is the switch to water-cooling of the motor/generator and another key move was to change the positioning of the motor/generator unit.

While it is still connected to the crankshaft by a drive belt, the whole unit has been moved from the front of the engine to between the engine and the transmission.

This maximises energy recuperation when the vehicle is slowing as it does not have to spin the ICE on its way through to the motor/generator.

Placed between the engine and the transmission, the starter/generator can also be decoupled from the ICE, allowing it to recover more of the car’s kinetic energy under braking.

“Otherwise, there are pumping losses, there are friction losses and you are pumping cold air through the exhaust manifold and you are flooding it with oxygen. That’s horrible,” said Continental engineer Simon Bartsch.

Also assisting in the harvesting of energy is the power electronics unit integrated with the motor. Continental was cagey about a “new technology” that allows the unit to handle significantly higher currents, except to claim it allowed the capture of an extra 10 per cent in recouped energy.

Another positive with the 48-volt hybrid system is that the catalytic converter can be more rapidly heated than with a traditional 12-volt system, reducing the amount of bad emissions that usually happen on start-up.

“It has two heating discs,” Bartsch said. “When you approach the vehicle carrying the key, the lower disc starts to heat up and convection warms the body of the converter.

“When you sit down and push the start button, the upper disc will start heating up and the catalyst will be active. No cold-start problems.”