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Nissan Motor Co has announced the development of a 'dual injector' system designed to improve fuel efficiency in small-displacement gasoline engines.
The new fuel delivery system, the first of its kind in the world, uses an injector for each port rather than one per cylinder - speeding up fuel vaporisation, reducing the amount of unburned fuel and reducing hydrocarbon emissions. Nissan will introduce the new system in production vehicles starting early in fiscal 2010.
"Nissan is constantly researching a wide range of technologies which will offer consumers improved fuel economy and cleaner exhaust emissions in the future," said Monal Zeidan, general manager, marketing and corporate communications at Nissan Middle East. "This 'dual injector' engine technology is just one example of the many innovative solutions the company is currently exploring.
"Since no one can fully anticipate customer preferences, we decided to invest in a portfolio of transitional technologies to make sure we meet all our customer demands," he added.
While most current petrol engines utilise one injector per cylinder (furnishing fuel to two intake ports), the new Nissan 'dual injector' system doubles the number of injectors per cylinder. This reduces the diameter of the fuel droplets by about 60 per cent, resulting in smoother, more stable combustion.
The system also adds continuous valve timing control on the exhaust side to conventional intake-side control, improving heat efficiency, reducing pumping losses and raising fuel efficiency by up to four per cent in sync with the dual injectors.
While similar in theory to 'direct-injection' systems, which also inject fuel directly into cylinders, such direct injection systems are difficult to use on small-displacement engines because they require a high-pressure pump that complicates system design, making component layout less cost-efficient.
In contrast, the Nissan 'dual injector' system is lighter and structurally simpler because it furnishes fuel at normal pressures, reducing cost by about 60 per cent compared to direct-injection engines of similar displacement.
The new system also uses half the amount of rare metals in the catalyser while maintaining the efficiency of the catalytic conversion system. That number could potentially be reduced to 75 per cent in combination with the ultralow-rare-metal catalysts that were introduced in 2008.
