THE CUBIC CAPACITY OF THE MAHLE DOWNSIZING ENGINE AS A TECHNOLOGY DEMONSTRATOR IS REDUCED BY UP TO 50 % – AND OFFERS BETTER ECONOMIC EFFICIENCY AND ENVIRONMENTAL COMPATIBILITY AT THE SAME POWER OUTPUT.

At last year’s IAA Frankfurt and Tokyo Motor Show, it was the highlight at the MAHLE exhibition stand and since then has frequently made the headlines: the MAHLE downsizing engine technology. The concept engine, which has been developed and built by MAHLE Powertrain, requires up to 50 % less displacement when compared with other engines of similar power. It complies with the Euro V standard and allows up to 30 % reduction in fuel consumption and emissions for a vehicle of 1.6 tonnes kerb weight. The background of the downsizing engine technology: small-volume engines are predominantly operated in the high load range where they have high efficiencies, consume less fuel and emit therefore less CO₂. In addition, they weigh less and their friction values are lower. In downsizing technology, the reduced cubic capacity is combined with turbo charging in order to compensate for the loss in torque and power. This engine concept is therefore regarded as a future-oriented approach for petrol engines to allow compliance with the planned CO₂ limits of 130 g/km.

Shift of the operating point due to downsizing.

The technology demonstrator is equipped with exactly matched components from all MAHLE product lines. This combines engine mechanics with reduced friction and weight with innovative supercharging and optimum combustion. The cylinder head, for instance, is designed with combustion chambers that are optimised in respect of cooling and geometry and feature central direct injection.

The cylinder block with NIKASIL coated cylinders assures high rigidity, low friction and optimum cooling. A special supercharging concept with two-stage turbo charging has been developed to provide high torque and good response characteristics at low engine speeds. An innovative exhaust gas recirculation system allows high recirculation ratios and therefore low exhaust gas temperatures and protection of the turbo charger even at full load.

The integrated and compact intake system is made in a lightweight design. In addition, a friction optimised valve train system is used, which is equipped with roller-type cam followers, build-up camshafts and lightweight valves. Specially developed pistons, piston pins and rings as well as connecting rods and bearings form the so-called Power Cell Unit and their interplay makes it possible to achieve high peak pressures and low friction. Also in the development of the turbocharger – the key technology of the downsizing engine – MAHLE engineers applied their know-how and experience. In future, the further development of this technology will be strongly promoted by MAHLE.

With the concept engine, MAHLE is demonstrating outstanding system expertise and shows that petrol engines show high potentials for fuel savings without power loss – with a technology that offers a favourable cost-benefit ratio. Volume production of the MAHLE downsizing engine is not planned – in future, MAHLE regards itself as a supplier of engine systems and not of complete engines.