Tokyo, Japan – Nissan Motor Company has announced the development of a dual injector system designed to improve fuel efficiency in small-displacement gasoline engines, which it will introduce in production vehicles starting early in fiscal year 2010.
The company said that the system, the first of its kind in the world, uses an injector for each port, rather than one per cylinder, speeding up fuel vaporization, reducing the amount of unburned fuel, and reducing hydrocarbon emissions.
While most current gasoline engines use one injector per cylinder, providing fuel to two intake ports, the new Nissan system doubles the number of injectors per cylinder. This reduces the diameter of the fuel droplets by about 60 per cent, resulting in smoother and 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.
Nissan said that while the system is 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 increases cost. In contrast, the Nissan system is lighter and structurally simpler because it furnishes fuel at normal pressures, reducing cost by about 60 per cent when compared to direct injection engines of similar displacement.
The new system also uses half the amount of rare metals in the catalyzer, while maintaining the efficiency of the catalytic conversion system. That number could potentially be reduced to 75 per cent in combination with the ultra-low rare metal catalysts that Nissan introduced in 2008.