New tech may lead to cheaper, greener engines

Scientists have developed a new technology that can reliably and affordably increase the efficiency of internal combustion engines by over 10 per cent.

The system for opening and closing valves could significantly reduce fuel consumption in everything from ocean-going ships to compact cars, researchers said.

"This method has the potential to bring the well-established benefits of a fully variable valve system out of the lab and into production engines because cost and complexity are not issues," said Amir Khajepour, a professor at the University of Waterloo in Canada.

Intake and exhaust valves in internal combustion engines are typically controlled by cam mechanisms that do not allow the timing of their opening and closing to be varied.

The new technology, published in the journal Mechatronics, replaces cams with hydraulic cylinders and rotary hydraulic valves that enable fully variable timing as the speed and torque of an engine change.

This ability to specifically time the opening and closing of valves according to engine operation is a key to increasing fuel efficiency, reducing both costs and greenhouse gas emissions.

"If you think about an ideal solution, it is to make the motion of the valve completely controllable," said Khajepour.

Although other systems to vary valve timing already exist, they are limited to use in experimental engines in laboratories due to their high cost and complexity.

The technology developed and tested at Waterloo is much simpler and far less expensive, paving the way for its use in engines for power generation, mining vehicles, the trucking industry and a host of other applications.