Conventional internal combustion engines waste about 10 percent of their potential power through “pumping losses” caused by the throttle plate that regulates and restricts airflow into cylinders. In 2001, BMW’s Valvetronic system reduced those losses using electronically controlled intake valves. But the BMW system is complex and expensive. Now Fiat’s MultiAir engines will deliver a similar edge in fuel consumption and carbon-dioxide emissions with a simpler, more affordable design that makes minute adjustments to the intake valve. The system is inexpensive enough that it will soon power millions of cars from Fiat and its partner, Chrysler. MultiAir rolls out with the Fiat 500, which comes to the U.S. early next year.