More efficient powertrains cut energy waste

Researchers are working to stem an abundance of wasted energy in car engines, whether driven by gasoline, diesel or electricity. Helping them to optimise the entire development process of the engine are ultramodern test facilities. So far, they have already raised the degree of efficiency by up to 10 per cent in the laboratory.

Trucks, cars and motorcycles are energy-guzzlers. Over 60 per cent of the energy generated in their engines by fuel is lost through the exhaust gas and the coolant. The biggest part of this simply slips off into the environment as heat.

"Beneath our engine hoods, gasoline, diesel and electricity are wasted and unnecessarily pumped into the air through the exhaust system as CO₂," says Dr. Hans-Peter Kollmeier, from the Fraunhofer Institute for Chemical Technology ICT in Karlsruhe. The "new drive systems" project group is probing the causes for this kind of waste. Together with other researchers, it is developing efficient drive concepts for vehicles. In the laboratory, they have already succeeded in increasing the degree of efficiency of car engines by five per cent, and up to 10 per cent for commercial vehicle powertrains.

The scientists have new test facilities available since this summer. "At the Karlsruhe location, we were able to map the entire process of powertrain development: from design to simulation and to testing," says Kollmeier. The researcher's goal is to optimise the technologies of the drivetrain being utilised, so that the fuel savings is optimal. For this purpose, you must know how the individual components interact with each other in reality.

Researchers at a new hot gas test facility are testing the waste heat use systems and turbo-chargers. Their goal is to develop more efficient powertrain concepts for passenger vehicles and trucks.

"With the new testing options, we have come one huge step closer to this goal. Through this effort, we have the opportunity to test the drivetrain as a whole and validate our simulations," says Kollmeier.

The linchpin of this new test infrastructure is an engine and hot gas test stand. There, researchers can analyse engines and their components both mechanically and thermodynamically. A computer controls the systems and simulates realistic application scenarios. For example, the computer can additionally switch on virtual hybrid drives (like electric motors) or systems that use waste heat. The scientists analyse how the vehicle drive acts with regard to fuel consumption and CO₂ emissions.

For this purpose, Kollmeier's team simulated vehicle in terms of type, route or driver methods accordingly. Once sufficient data are gathered, the researchers build prototypes and then gradually substitute the simulation models through real components in the test facility. Step by step, they are thus arriving at the optimal powertrain. In the process, lightweight materials become increasingly important.

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