[eXquisite Inception]

Are Gas Engines Now More Efficient Than Diesel?
By Rex Roy

The diesel engine has always been the most efficient internal combustion engine available, but thanks to new technology, the gas engine is quickly catching up.

When it comes to traversing great distances at highway speeds, the diesel engine's higher compression ratios and lean-burn combustion provide an efficiency that no gas engine can currently match—at least not without a major assist from an expensive hybrid system. Over the diesel's operating range, the average thermodynamic efficiency—how much work the engine produces from the fuel—is in the mid 30 percent range, at least 15 percent better than a gas engine. Not even close, right?

The reality is that this lead is shrinking. As emissions regulations stiffen, diesels are slowly losing their edge; the same pricey after-treatment systems that scrub diesel exhausts also happen to crimp efficiency. Meanwhile, gas engines continue to improve.

"There is certainly a convergence in efficiency levels between gasoline and diesel engines," says Uwe Grebe, GM's director of global advanced engineering. "While diesels will always maintain a slight advantage, the gap will nearly close in as little as 10 years."

Over the past decade, once-exotic efficiency-enhancing hardware such as variable camshaft timing, direct fuel injection and turbochargers have become commonplace on spark-ignited engines. Certainly, these technologies aren't new, but incremental improvements in electronics and materials have pulled them into the mainstream. And there's more on the way, like lean-burn combustion and homogeneous charge compression ignition (HCCI), a gas-combustion technology that blurs the line between gas and diesel engine cycles. Ricardo is working on a turbocharged engine that uses E85, a lofty compression ratio and high boost levels to achieve diesel-like efficiency. Rod Beazley, Ricardo's VP of spark-ignited engines, boasts that "our ethanol-boosted concept engine achieves thermal efficiency in the low 40 percent range."

But don't expect the diesel engine to lie down and play dead. "We'll continue to see incremental improvements in diesel efficiency," says Marc Trahan, Audi's North American director of quality and technology. "It won't be as large as going from sequential port fuel injection to direct injection, but there are still more gains to be made." Trahan says these smaller gains will come from hardware such as variable valve timing and independent cylinder combustion control, as well as improved after-treatment systems.

Moreover, there are other factors in play. As GM's Grebe points out, diesel fuel contains about 14 percent more energy by volume than gasoline. This gives compression-ignition engines a significant edge in fuel economy, as opposed to thermal efficiency. Of course, everything will change if and when spark-ignited engines switch to more energy-dense fuels. This race is far from over.

 

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I'm standing on the edge of me.

[AYAZ]

i think yes gas engine are more reliable and the most plus point of gas engine is that it reduce pollution .

 

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ALLAH FARMATA HAI :
AEY BANDEY JO HUA
WO ACHA HUA .
JO HORAHA HAI ACHA HO RAHA HAI.
JO HOGA WO BHI ACHA HOGA.
TERA KIYA GAIYA JO TU ROTA HAI
TU KIA LAYA JO TU NE KHO DIYA.
JO LIYA YAHIN (DUNYA) SEI LIYA
JO DIYA YAHIN (DUNYA) PE DIYA
JO AAJ TERA HAI PEHLAY KISI AUR KA THA
AUR KAL KISI AUR KA HOGA.
TABDEELI KAINAAT KA MAMOOL HAI
BAS TU WO JAMA KAR JO TU SATH LEI KAR JANEY WALA HAI
YANI NAIK AMAAL.

[Morash]

Well Jo Rex Roy Ne Kaha Hay Ye To Theek Hay , I Do Agree!

But Pakistan Ki Gas Quality To Bohat Down Hay ..

I Think Yahan To Diesel Or Petrol He Filhaal Efficient Hay!

 

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➳ bE driveN wiTh puRpOse, Be r313n71355 in your alιgnмenт;
with excellence.
pAy n0 mInd to the ∂ιsιмραssισηε∂ เ๓ק๏tєภt ђคtєгร ♬

☣

.. нoolιgan ☠

[eXquisite Inception]

Originally Posted by Morash

Well Jo Rex Roy Ne Kaha Hay Ye To Theek Hay , I Do Agree!

But Pakistan Ki Gas Quality To Bohat Down Hay ..

I Think Yahan To Diesel Or Petrol He Filhaal Efficient Hay!

America main Gas ---> Patrol ko kahthay hain ...so Article Patrol and Diesel kii baat keer raha haay

 

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I'm standing on the edge of me.

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Last edited by eXquisite Inception; 10-11-2011 at 02:39 AM..

[eXquisite Inception]

Originally Posted by AYAZ

i think yes gas engine are more reliable and the most plus point of gas engine is that it reduce pollution .

Gas (Patrol) Engine kii hii baat keer rahay hain naa app?

 

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I'm standing on the edge of me.