Ben, I guess you are trying to make some point.  The diesel truck with jake brakes indeed has engine braking.  So far as I know, that is pretty much all diesel tractors for over the road hauling.  Without the jake brakes, it effectively lacks engine braking.  How is your little logic lesson applicable?  mcneely

---- Ben <syncro@GMAIL.COM> wrote:
> If all ducks waddle and Donald waddles, does that immediately making him a duck? What if Donald's pants have an uneven stitch which makes him walk in an even gait causing him to waddle? Does that mean his pants made him into a duck or just to appear like he is?
>
>
> Quack!
>
> BenT
> sent from my electronic duck & cover
>
> On Sep 14, 2013, at 12:42 PM, Dave Mcneely <mcneely4@COX.NET> wrote:
>
> > http://en.wikipedia.org/wiki/Compression_release_engine_brake
> >
> > If Wikipedia is an acceptable source, then this sounds authoritative to me.  So, seems that a diesel engine has little or no engine braking capacity in its raw form, because it gives it up as the pistons move to compress the air previously entrained, creating a spring effect.  The engine does brake the vehicle, but then it accelerates it, obviating the braking effect.
> >
> > What jake brakes (more generically termed engine brakes or compression brakes) do is release the air before compression, preventing the accelerator effect, thus conserving the engine braking.
> >
> > So, diesel trucks do indeed have engine braking.
> >
> > mcneely
> >

--
David McNeely