Lighter valves to render cams redundant

The introduction of more fuel-efficient ‘camless’ engines could be made easier thanks to a joint European and Chinese project to develop lightweight valves.

Under the Livalves (Lightweight valves for high-efficiency engines) project, researchers at automotive supplier TRW Germany, Birmingham University and the Chinese Institute of Metal Research (IMR) have developed valves from titanium aluminium (TiAI) alloys.

Klaus Gebauer, director of global research and product development at TRW Germany, said the heavy steel valves currently used to take in fuel and remove exhaust gases from engine cylinders need a considerable amount of force to move. Reducing the weight of valves would remove the need for the rotating cams used to move them.

‘With this feature we could see advanced valve actuation systems like electromagnetic actuators,’ he said.

Such systems would cut the number of moving parts that cause friction and allow car makers to tune valve timing according to engine speed and load, improving fuel efficiency and reducing emissions. The technology could also increase available torque.

Camless systems could cut fuel consumption, carbon dioxide emissions and engine noise by up to 10 per cent, the researchers claim.

The TiAI valves were developed jointly by Birmingham University’s Interdisciplinary Research Centre in Materials Processing and the IMR in China. In a process developed at the IMR, the molten TiAI alloys are superheated and centrifugally cast, ie a mould is rotated at high speed as the molten metal is poured in. This reduces the material’s porosity.

During testing the valves performed well and showed almost no wear. The team now plans to take the development work further, according to Gebauer. ‘We still have a small issue with the product cost so we are currently focusing on raw material and recycling issues,’ he said.

On the web