|The Mahle downsized engine concept. Click to enlarge.|
Mahle, an automotive supplier headquartered in Stuttgart, Germany, showed a new 1.2-liter engine downsizing concept as a technology demonstrator at the Frankfurt Motor Show. Mahle presented the unit in two different supercharging models (single and double).
In its variant with double supercharging, the 3-cylinder power unit developed by Mahle Powertrain achieves 120 kW, or 163 hp/liter. By cutting the displacement in half compared to a 2.5-liter displacement engine commonly used to power a mid-range car, fuel consumption is lowered by more than 20%.
A further advantage of downsizing is that small-displacement engines are operated mainly in upper load ranges, where the engine’s efficiency is higher.
In addition to the charging technology, the engine uses forged pistons, two overhead composite camshafts, four valves per cylinder, direct injection, air-water charge cooling, exhaust gas recirculation cooling, injector tip cooling, dual camshaft adjustment, and cooled lightweight valves. Another technological highlight is the fully integrated intake module, which accommodates the oil mist separator, air filter, noise damping, and exhaust gas recirculation.
To consistently minimize fuel consumption, frictional loss was also drastically reduced. The engine concept, for example, uses DLC-coated (DiamondLikeCarbon) piston pins, cylinder running surfaces coated with NIKASIL, and PVD coated (Physical Vapor Deposition) piston rings.
|Mahle exhaust gas turbocharger.|
New exhaust gas turbochargers. Mahle will begin series production of a line of exhaust gas turbochargers for gasoline and diesel engines in 2010. Mahle is presently developing wastegate exhaust gas turbochargers in the engine power class up to 200 kW for gasoline engines and Variable Flow Turbine (VFT) turbochargers for diesel engines with a maximum engine power up to 150 kW.
|Mahle SLV-R EGR valve.|
New EGR. Mahle is also introducing a new EGR technology based on a rotating fast-switching charge air valve (SLV-R). In this system, an electromagnetic valve with rotating flap movement is positioned in the fresh air line upstream of the EGR inlet point. By briefly closing the valve, a temporary vacuum is generated on the charge air side, which creates the necessary pressure gradient for exhaust gas recirculation. An advantage over conventional EGR valves is that the charge air valve is installed in the fresh air path and is consequently not directly exposed to the recirculated exhaust gas. This minimizes thermal stress as well as pollution of the valve. In addition, the continuously rotating movement of the flap ensures simple control and a long service life.