An electric motor ensures that extra fresh air is available whenever the engine needs it (image: MTU)
Agility and efficiency: Those are the watchwords for MTU’s turbocharger development, its director of development, turbocharging and fluid systems, Johannes Kech, told The Motorship.
For projects where high agility is needed, MTU can now consider using its new electrically assisted turbocharger, which has successfully passed its field tests, Dr Kech said. This was announced in 2018 as a solution to the frustration of ‘turbo-lag’, which occurs at low speeds because there is not enough exhaust to drive the turbocharger.
MTU’s solution uses an electric motor to support the turbocharger using technology licensed from G+L innotec and it appears that its development is on track or even ahead of that 2018 announcement: at that time, it predicted a market debut for its first engines with electrically-assisted turbocharging in 2021.
Meanwhile, it is focusing development efforts on increasing turbocharger efficiency by developing individual solutions for specific engines. In a way, this is returning to its historical roots, which date back 45 years to when the first MTU engine (series 396) was fitted with an in-house ZR turbocharger, Dr Kech recalled.
At that time, turbocharger systems were matched to an engine’s specific requirements, he said, an approach that gave way some years ago to a modular system that could be used across engine platforms.
But now “trends in engine development demand more and more specific turbocharging systems that need individual solutions,” he said. “They impose various requirements such as efficiency, compressor pressure ratio and map width, power-to-weight ratio and acceleration capability.” In response, MTU is supplementing its modular approach by applying “modern design methods to cope with the broad set of requirements imposed by [each] engine application,” he explained.
In particular, MTU uses “fully automated, multidisciplinary optimisation methods for wheels, flow guiding systems and bends,” which shortens design cycles and minimises development efforts, he said. It also delivers high efficiency and high pressure ratios and the approach is now being applied to gas engines for stationary applications “to ensure highest efficiencies and a minimum of CO2 emissions,” he said.