New engine technology claimed to solve the problem of low speed 'turbo lag' in diesel engines has been developed by a subsidiary of Bosch GmbH.

Erphi Electronic has developed a controlled two-stage turbo charging for diesel engines that is said to eradicate turbo lag at low speed.

The charging system consists of two connected turbo chargers of different sizes. The smaller high-pressure charger responds at low engine speeds and is supplemented at medium speed by the larger low-pressure charger.

Control software switches the smaller charger off at high speed and the larger charger kicks in and completely takes over the air compression. This strategy delivers a regular high torque curve. Turbo lag is eliminated and the diesel engine delivers more power and economy providing car manufacturers with the option of practical engine downsizing.

In this type of downsizing, smaller but equally powerful engines with the Erphi two-stage charging system can be used instead of conventional turbocharged engines. The company has built a pilot vehicle that confirms the potential of this innovative charging system.

The vehicle's specific values are 82 kW output and 210 Nm of torque per litre of piston swept volume, power that would not have been possible only a year ago.