Since the outset of the reciprocating piston engine era, engine designers have recognized the need for systems that provide infinitely variable valve (IVV) action including open/close timing, duration and lift. While a limited degree of IVV has been achieved with mechanical systems, the development of ideal infinitely variable systems has been difficult.
A promising IVV system, however, is being advancd at Valeo SA, a France based producer of automotive components and integrated systems. The Valeo IVV system referred to as â€œcamlessâ€ employs computer control of electromagnetically actuated engine valves replacing conventional cam actuation and phasers.. Energy consumption of the â€œcamlessâ€ system for a typical moderate size 4-cylinde car is said by Valeo to be under 250 watts at 3000 rpm.
Valeo reports that its â€œcamlessâ€ system applied to gasoline engines is cost competitive vs. diesels and that 20% reduction in both fuel use and emissions have been demonstrated When combined with other Valeo systems such as low consumption A/C compressor, beltless engine accessory drive, thermal management , dual clutch transmission and micro hybrid, 40% overall fuel economy gain is feasible according to the firm.
Valeo claims that 80% of the gain from its valve system can be obtained at reduced cost by application only to intake valves. . Its use on 3-cylinder engines could be very economic for small cars . For comparison, VW has begun marketing a 3-cylinder 1.4L diesel car with claimed 72 mpg fuel economy. A`gasoline version with â€œcamlessâ€ valves at equal thermal efficiency might be about 63.mpg; well below the EU target of 130 g/km CO2. While emotionally unsettling for many US car buyers , 3 cylinder cars driven by AI performed well and demonstrated good smoothness due to their balance shafts. For a given total displacement, 3 cylinders in place of 4 are inherently more efficient due to reduced thermal and friction losses. . .
AI recently sought an interview with Valeo valve system engineering personnel but was turned down by the firm’s public relations representative who said customer relations at this time did not permit discussion that might indicate commercialization status. Valeo is a member of the Southwest Research Institite consortium development of the HEDGE system high efficiency dilute gasoline engine to which Ford has reportedly given high priority status. Ford CEO, Fred Mulally; credited with successful business turnaround performance at Boeing by adopting dynamic new aircraft technology and a high degree of outsourcing, is being closely monitored by auto industry analysts for bold moves. Ford’s position on camless valve systems is not known. .
About the author: Bob Brooks is a member of the Society of Automotive Engineers and long time automotive technology journalist specializing in powertrains and fuels.