Antonio Cuquerella: "It is a fashionable green technology that helps to sell more [road] cars" © Sutton Images Enlarge

HRT engineer Antonio Cuquerella believes Kinetic Energy Recovery Systems (KERS) are "inefficient" and returning to Formula One in 2011 for marketing reasons.

The technology, which recovers energy otherwise lost under braking and turns it into a power boost, first ran in 2009 before it was dropped by the teams in 2010 to cut costs. Both HRT and Virgin are not expected to run KERS in 2011 due to cost reasons, while F1's frontrunners are committed to the system.

Cuquerella, who previously worked for BMW in F1, questioned the logic behind the return of KERS while speaking at a technical university in Valencia.

"It is a fashionable green technology that helps to sell more [road] cars," he is quoted by Spain's motor21.com. "It's inefficient but the large manufacturers want it to sell their cars."

Cuquerella added: "A lot of the manufacturers want KERS as a tool of their marketing departments to justify their investments in Formula One."

He also addressed his boss Colin Kolles' controversial statement that it was HRT's inexperienced drivers that held the team back in 2010.

"It is true that we were disadvantaged compared to having a driver like Trulli, but there is no doubt that the car was slow as well," he conceded.