Engine braking Gas Vs Diesel
Just wondering why gas engines have better engine braking than diesel. No real reason, just wondering. With the higher compression of the diesel I would think that diesel would be better but understan...
Forum Discussion
kyle86 wrote:Me Again wrote:
I wonder how the new direct injection gas engines are doing that have no butterfly valve? Audi, BMW and Mini Cooper all have engines in production with DI.
I was under the impression that DI just places the fuel injector in the combustion chamber instead of the intake runner. They should still have a throttle body to let air into the engine. I could be wrong.
Apparently some eliminate the air throttle plate according to Wikipedi anyway:
Wikipedia on GDI wrote:
In addition some engines operate on full air intake. That is, there is no air throttle plate eliminating air throttling losses in some GDI engines, when compared to a conventional fuel-injected or carbureted engine, which greatly improves efficiency, and reduces piston 'pumping losses'. Engine speed is controlled by the engine control unit/engine management system (EMS), which regulates fuel injection function and ignition timing, instead of having a throttle plate that restricts the incoming air supply.
I'm seeing aftermarket replacements for the 3.5L Ecoboost throttle body, complete with butterfly valve, so I guess that engine does have an air throttle plate. http://www.stage3motorsports.com/1822-1-2011-2013-F150-37L-BBK-73MM-Throttle-Body.html, so that should help with engine braking.
