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Old 09-28-2016, 03:34 PM   #665
Leiffi
 
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Name: Leiffi
Title: Too Much Time
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Join Date: Jan 2013
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Posts: 1,381
Quote:
Originally Posted by tall boy View Post
I got some data from a EGR+SCR XPI engine telling me 2200Bar from around 1400Rpm but the thing is you need to load up the engine to get to this load mapping as fast acceleration will give only 1500Bar trying to maintain temp in the system as I also have this data that confirms this.

Hmm that way to retarded injection for making power. If we set 1400 rail pressure end of injection will be 20 ATDC max and if we set fuel pressure on target we end up 11 ATDC so knowing the OE NON EGR engine runs about half power of what we make and assuming the injector is more than half the size we use you need a bit more than only g/stroke to work out end of injection also depend on the amount of injections used that is.

As for looking on what parts to use it can only be done by looking a the engine serial number verifying it has the same piston and injector used. We put great effort in making a low CR piston that work well with the injectors we used. On the race truck we use from 2014 onwards we still have 12.7l EGR+SCR Euro 5 pistons and 730Hp V8 injectors and they make a lot more smoke than what we use today on the rally engines. These V8 XPI injectors are about 38% smaller on fuel volume on what we use today so it’s not like slam in a bigger injector and a miracle will happen. It will tell you in a smelly way that I will need a total different set-up on parameters and the biggest chance is fuel rail pressure and these engine likes to have it short and fast on fuel injection. We know form truck racing the piston dome makes all the difference on making power with less smoke. A good example is the Mercedes from Norbert Kiss making a load of progress as for getting the engine parts needed.
I just wonder how these engines can still be so fuel efficient ? Scania knows something we dont.

When is big holes and high pressure causing too strong fuel penetration which makes fuel air mixing worse ?
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