Automotive manufacturer Mayflower this week unveiled a technical breakthrough which, it claims, promises dramatic improvements in fuel economy and emission performance in internal combustion engines.
The technology used in the E3 Variable Motion Engine, which allows the compression ratio and cylinder capacity to be changed while running, can be applied to engines of all sizes and would not require fundamental changes in engine production plants, it said.
Chief executive John Simpson said the system would bring about ‘a new generation of engines with groundbreaking performance and economy’ with the potential to prolong the life of the internal combustion engine until cleaner fuel cell technology is fully commercialised.
The idea is the brainchild of Dr Joe Ehrlich, who has been involved in developing racing engines since the 1940s. His idea was introduced to Mayflower through business associate Sir Jack Brabham.
A joint venture owned 33% by Mayflower and the rest by Brabham, Ehrlich and other investors has been formed to exploit the technology. Mayflower has been granted worldwide patents. It plans to license the system and is in talks with major car makers.
Mayflower has invested £6m for its 33% stake and has the option to increase this within five years to 51%. Simpson said that with a global market for 160 million engines a year, the project represented ‘minimal risk capital for potentially enormous profit’.
The key is a pivoted lever arm between the piston connecting rod and crankshaft, which allows precise control of piston motion. This arm imparts an elliptical path to the motion of the connecting rod big end bearing, with the effect of slowing down the piston at the top of its stroke. This leads to better combustion, increased power and improved economy.
The lever arm is pivoted at the side of the engine block. Moving the pivot point vertically changes the compression ratio; moving it horizontally increases or decreases the piston stroke and hence the capacity of the engine.
At the top of its stroke the piston is offset slightly from the crankshaft rather than directly above it, so that it is in a better position to develop torque at the onset of combustion, leading to smoother and quieter running.
Various systems – including Saab’s radical SVC variable compression ratio engine and BMW’s Valvetronic variable valve lift system – are being developed by car makers in an effort to meet increasingly stringent emission requirements.
Mike Bryant, chief executive subsidiary Mayflower Engines, said the E3 system had the advantage of simplicity – only one component is added to the engine itself and a radical redesign of the cylinder block is not needed. A control system, which would use hydraulic or electronic actuators under control of the engine management system, could be sited remotely from the engine itself.
Tests were conducted on a single cylinder engine, varying the compression ratio from 9:1 to 15:1 and capacity from 260 to 300cc.
Bryant said that results suggested that improvements of 40% in fuel economy and 50% in emissions could readily be achieved if combined with supercharging or turbocharging to extract maximum performance from a smaller engine. The E3 technology allows a high compression ratio for maximum economy at low engine loads and a lower ratio at high loads, allowing supercharging or turbocharging for more power while preventing knocking.
Mayflower will leave the big car makers to decide how to use the technology, which could be on the market within three to five years, depending on the speed of development programmes.
Initial applications may vary just the compression ratio and not the cubic capacity, since this alone produces many of the potential advantages, said Bryant.