$2.5m DoE funding for MAHLE Powertrain

The US Department of Energy (DOE) has awarded up to $8.4 million

The US Department of Energy (DOE) has awarded up to $8.4 million, spread over the next three to four years, to four projects to improve performance levels of engines and powertrain systems for future vehicles. The projects will focus on developing and testing new cost-efficient technologies for engines and powertrain systems which will remove the technical barriers for broad commercial use of advanced engine technologies in the mass market.

MAHLE Powertrain LLC, will receive $2.5 million to develop a next-generation combined ignition/turbo-charging concept known as 'Turbulent Jet Ignition'. TJI facilitates the implementation of ultra lean-burn technology to gasoline engines, improving their efficiency and reducing the formation of pollutants such as nitrogen oxide.

The intent behind the DOE's effort is to ensure that automakers receive support from the government to focus on innovations to meet the latest emissions standards for passenger and commercial vehicles. In August this year, US president Barack Obama announced the first-ever fuel economy regulation for medium- and heavy-duty commercial vehicles, including semis, garbage trucks, buses, and three-quarter-tonne pick-ups and vans. In addition, Obama has announced mileage and emission standards suggestions for passenger and light trucks. The new standards would increase fuel economy to 54.5mpg fleet average by 2025--62mpg for cars and 44mpg for light trucks.


MAHLE Powertrain introduces Turbulent Jet Ignition



Specialists at MAHLE Powertrain have recently been developing a novel combustion system concept which offers significant fuel economy benefits without the need for expensive engine hardware.

MAHLE Powertrain’s Turbulent Jet Ignition (TJI) utilises a spark-initiated pre-chamber combustion process in an otherwise conventional gasoline engine to achieve fuel economy improvements of up 20% Engine-out NOx emissions are also virtually reduced to zero levels, negating the need for lean NOx after-treatment.

Existing jet ignition systems involve the creation of hot gas jets from a pre-chamber which are then introduced into the cylinder where they rapidly induce ignition of the main in-cylinder charge. MAHLE’s TJI system is characterised by auxiliary pre-chamber fuelling, small orifices connecting the main and pre-chamber combustion cavities and a very small pre-chamber volume. The smaller orifice size causes turbulence in the hot gas jets which then penetrate deeper into the main combustion chamber and cause a distributed ignition effect. This process then allows extension of knock limits and increased compression ratios (up to 14:1) combined with lower combustion temperatures and reduced throttling / pumping losses to achieve thermal efficiencies in the region of 45%.

MAHLE’s TJI unit replaces the conventional spark plug and can utilise the original PFI or DI fuel system in both naturally aspirated and turbocharged engines. The conventional engine control system can be retained and the system can be operated on readily available, commercial fuels. Strong synergies exist when coupling turbulent jet ignition with engine downsizing at both high and low engine loads through the use of modern variable valvetrain systems.

The ultra-high efficiency achievable with Turbulent Jet Ignition and the simplicity of the mechanical hardware and controls systems also offers unique opportunities to hybrid and range extender vehicle applications.