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Dual Injector

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The new Nissan Dual Injector system doubles the number of injectors per cylinder. This reduces the diameter of the fuel droplets, resulting in smoother, more stable combustion. The system also adds Continuously Variable valve Timing Control (CVTC) on the exhaust side to conventional intake-side control, improving heat efficiency, reducing pumping losses and raising fuel efficiency by up to 4%* in sync with the Dual Injector. The new Dual Injector system also uses half the amount of rare metals in the catalyzer by reducing the amount of unburned fuel (hydrocarbon emissions).
Nissan will introduce the new system in production vehicles starting early in fiscal 2010.

* Compared with Nissan gasoline-powered engines in the same class

System Configuration

To improve combustion stability, one of the famous approach is reducing fuel droplet diameter. While the Dual Injector system uses 2 narrower injectors per cylinder and mounts close to intake valve, the injector can have smaller nozzle holes and wide spray cone angle. Thus the Dual Injector system realize smaller fuel droplet and contribute improving combustion stability.
Dual Injector
Dual Injector
Conventional Injector
Conventional Injector

Higher fuel efficiency with Dual Injector and CVTC

Atkinson-cycle design*1 and EGR*2 help improve fuel efficiency, but neither achieves really stable combustion because of the lower compression and temperatures of the Atkinson cycle and the refeeding of unburned exhaust gas in the combustion chamber with EGR. To make the most of these technologies, Nissan brought in Dual Injector and CVTC to boost fuel efficiency.

*1: Atkinson-cycle internal-combustion designs allow more expansion than compression to improve heat efficiency.
*2: EGR: Exhaust Gas Recirculation

At idle
By significantly delaying the compression process by closing the intake valve later, the compression load is reduced (Atkinson cycle).
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In normal operation
By overlapping the open cycles of intake and exhaust valves, exhaust gases are recirculated into the cylinder (EGR), so pumping loss is reduced.
dual_injector_05.gif
 

NISSAN TECHNOLOGY MAGAZINE