Nissan unveils new Dual Injector System to boost efficiency
Posted Jul 14th 2009 6:01PM by Jeremy Korzeniewski
Nissan Dual Injector System - Click above for high-res image gallery
We've said it before and we'll say it again – the internal combustion engine has a lot of life left in it. While we fully expect electric cars to make an impact in time, the reality is that the ICE's reign as sales leader won't be coming to an end for at least the next several years, possibly with a little assistance from biofuels. With that in mind, even mild efficiency improvements are always welcome to Otto's good old four-stroke engine.
Nissan believes its new Dual Injector System will offer a fuel mileage increase of roughly four percent, a small but important improvement. While larger displacement powerplants will be blessed with direct injection, small-bore motors will get the Dual Injector System. The Japanese automaker says the technology, which splits the fuel squirting duties through twin intake ports, reduces the diameter of fuel droplets by a substantial 60%, thereby improving vaporization.
Besides the obvious benefit of improved efficiency, Nissan claims its Dual Injector System costs 60% less than comparable direct injection technology. Plus, the system allows for a 50% reduction in the amount of rare precious metals in the catalytic converter. Check out the press release after the break for all the techy details.
PRESS RELEASE:
Nissan Introduces New Dual Injector System for Improved Fuel Efficiency in Small-Displacement Engines
TOKYO (July 14) - Nissan Motor Co., Ltd. today 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*1, 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. Nissan will introduce the new system in production vehicles starting early in fiscal 2010.
While most current gasoline engines utilize 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%, 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 4%*2 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% compared to direct-injection engines of similar displacement.
The new Dual Injector 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% in combination with the ultralow-rare-metal catalysts that were introduced in 2008.
"We consider it important to further improve the fuel efficiency of gasoline engines as demand for gasoline and other internal-combustion systems continues to increase around the world," said Shuichi Nishimura, Corporate Vice President, Nissan Powertrain Engineering Division. "By widely applying the Dual Injector system on small-displacement engines, we hope to help reduce CO2 emissions and conserve rare metals."
Nissan has been addressing a wide range of actions under "Blue Citizenship," which represents the company's desire to protect the blue planet and to be a corporate citizen that can live symbiotically with people and society. These efforts range from such global issues as the environmental protection to contribution to communities, promoting diversity and making personal mobility available to as many people as possible. Nissan continues promoting the "Nissan Green Program 2010," based on the "Blue Citizenship" spirit by introducing effective technologies, products and services into the market.
*1: Mass production passenger cars (Nissan's research).
*2: Compared with Nissan gasoline-powered engines in the same class.
Reader Comments (Page 1 of 3)
BoneHeadOtto 6:12PM (7/14/2009)
I hope this is correct but from the cutaway the injectors are in the intake not in the cylinder. I wonder if there is any loss of efficiency to due to location. Also are the droplets smaller compared to normal injectors or compared to direct injectiors. I know that with DI the high fuel pressure cools the cylinder allowing for higher compression ratios. With this tech that would not be the case. But if they have gains in efficiency then great!
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fooznugget 6:54PM (7/14/2009)
injectors are usually in the intake. I think you may have misread the article. This is supposed to be a cheaper alternative to direct injection.
BoneHeadOtto 10:19PM (7/14/2009)
I read somewhere that direct injection fuel injectors were actually in the combustion chamber like a diesel. Actually looked it up on wikipedia and DI does occur in the combustion chamber
"..directly into the combustion chamber of each cylinder, as opposed to conventional multi-point fuel injection that happens in the intake tract"
So what i was saying is that if it is a cheaper alternative to DI it may not achieve the same gains without the injectors in the combustion chamber.
Shamdiddly 9:45AM (7/15/2009)
Let's not forget, D.I. gets you added benefits by moving around injection timing since you're no longer tied to valve timing as in PFI.
One thing people fail to realize is that in a PFI system, fuel is sprayed directly onto the back of a hot intake valve, where vaporization is damn near optimal. i.e. I'll believe the 4% increase in fuel economy when I see the numbers. If you read closely, AUTOBLOG goofs up, writing that Nissan claims the 4% is due to these injectors - but further reading uncovers they are banking on variable exhaust valve timing for the 4%. (which is not too believable either - variable intake and exhaust vale timing together will net about 4% over a similar displacement non-VVT engine)
As for reducing precious metals in the catalysts - this may be a function of the better atomization during a cold start when there are not hot intake valves to aid in vaporization. The benefit is most likely reduced engine-out emissions during EPA testing. Again, I'm skeptical; with SULEV/PZEV emissions standards measuring exhaust constituents in MILLIGRAMS per mile, you cannot thrift much precious metal out of the converters.
I'll wait see better data - this is mostly smoke and mirrors - and PR.
ij70 6:12PM (7/14/2009)
Awesome.
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tgriffith 6:15PM (7/14/2009)
Nissan's playing two angles at once... this new advancement of the combustion engine, and an all-out gamble on electrics... is that smart?
http://www.cargurus.com/blog/2009/07/06/nissans-ev-gamble-could-fail/
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zamafir 6:56PM (7/14/2009)
of course it's smart, what are you talking about? Did GM halt all engine advancements when they started production on the Volt? Did VW halt all diesel work when they began working on a warm fuel cell. What major automaker do you know of that takes such an on and off approach to drive train development. I've never heard of such a thing.
Jared 10:45PM (7/14/2009)
The phrase "Don't put all your eggs in one basket" comes to mind.
jv2k 7:23AM (7/15/2009)
Is it smart to invest in new gasoline engines? Are you an idiot or something?
Rocketboy 11:11AM (7/15/2009)
jv.. +1 for avatar alone.
Visnick 6:34PM (7/14/2009)
Sweeet! twice the injectors to replace
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Aki 6:48PM (7/14/2009)
Because you totally know the cost to replace this, as well as its longevity.
EB 7:02PM (7/14/2009)
It says the system costs 60% less. Besides, it looks like it's a single injector split into two.
SimbaDogg 7:33PM (7/14/2009)
besides what the last two have said...how often have you had to replace injectors on any modern vehicles?
Franz 7:48PM (7/14/2009)
The only time I've ever had to replace the injectors on any car I've owned is when my quest for more boost dictated bigger ones.
A.N.E. 6:35PM (7/14/2009)
Why not triple?
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IK 6:49PM (7/14/2009)
dang, we need engineers like you at GM
give us a call
Dru 7:01PM (7/14/2009)
Because an uneven number of injectors would be odd
Matt 7:11PM (7/14/2009)
...Because it goes to 11? ...
MikeW 9:05AM (7/15/2009)
Well, Nissan could use two small injectors really close to the intake valves, and one large injector way up the intake.
But that would probably require two fuel rails.
and the size of the intake droplet in the intake port really doesn't matter, the size of the droplet in the cylinder matters-that was Nissan's big point about VVeL.
http://www.nissan-global.com/EN/TECHNOLOGY/INTRODUCTION/DETAILS/VVEL/