Fuel Pump Compatibility 4

[arotester]

Hello everyone,

We are converting a Kirloskar diesel engine into CRDI and i wanted to know which HP pump will be compatible and driven by engine itself?

 

[PJGD]

I would take a close look at the Delphi Unit Pump Common Rail (UPCRS) system made by Delphi TVS and shown here:

http://delphitvs.com/product_brochure2.aspx

PJGD

 

[arotester]

I looked at the system and i think that is a two cylinder rail,so is it possible to make it work for single cylinder?
Also,How can i give drive to the HP pump from the engine?

Thank you,
Ashish.

 

[BrianPetersen]

When you're trying to make two things work together that were never meant to, it's up to YOU to design that!

Timing belt ... chain ... shaft and gears ... direct coupling ... it's up to YOU to design it!

 

[PJGD]

The Delphi pump is driven off the camshaft of the existing engine similar to but not the same as the Kirloskar engine. A different cam profile (a lower velocity) will be required relative to the Kirloskar pump cam. You can use the 2-cylinder rail; just block off the extra outlet. Talk to the TVS engineering people in Chennai.

PJGD

 

[tbuelna]

Just out of curiosity, why do you want to spend huge amounts of money and effort to fit a sophisticated electronic common rail injection system to a low-cost, low-performance, single cylinder, 7HP utility engine? The digital CRI would provide little improvement, and the cost of adding the digital CRI system would likely increase the total cost of this engine by a factor of 2 to 3.

Installing a high-pressure CRI system on a single cylinder engine presents some challenges. Controlling the pump output and accurately regulating fuel rail pressure are very difficult with the flow conditions in a 7HP single cylinder engine.

 

[arotester]

Actually i am trying to make engine test setup for academic purpose and I am also using a programmable diesel ECU for it .
Can you explain why it would be hard to maintain the rail pressure in this engine?

 

[tbuelna]

Common rail diesel injection systems use very high rail pressures. And having a very small fuel rail volume combined with a single injector makes it hard to regulate the fuel pump output to meet demand.

 

[arotester]

what are possible solutions to that?

 

[tbuelna]

You will also need to redesign the injector nozzle to match your engine's combustion chamber shape and flow requirements. A CRI nozzle designed for a cylinder making 30hp is not suitable for one making 7hp.

 

[arotester]

hello everyone,

I have one more question, the HP pump being cam driven in a crdi system then does the pump provide fuel to rail instantaneously after injection to maintain the rail pressure or it is independent of injection.I mean how the pressure in rail is maintained after injection as diesel being incompressible?

 

[BrianPetersen]

At the pressures involved, diesel fuel can no longer be considered compressible, nor can the steel fuel lines be considered inflexible.

On many normal applications (4 or 6 cylinder engine), the piston-pump delivery strokes are synchronized with the crank/camshaft so that a delivery stroke is occurring during the time that an injector would be expected to open (i.e. through each TDC). Obviously the delivery volume is not co-ordinated, but doing that allows (at least theoretically) less rail pressure fluctuation, because "in" and "out" are happening more-or-less together, even if not absolutely synchronized.

I suspect that you are in for a whole lot of trouble with this project, as others have been suggesting. Most modern diesel injection components are designed for automotive, and those are more-or-less 500cc and 30-ish horsepower per cylinder, or more. What's your objective?

 

[arotester]

I am converting a Kirloskar single cyl. engine to crdi .
Actually I am not in any trouble with this project.
I am actually testing a pump and injector of bosch for their discharge at different pressure .I think this project can be done.

 

[BrianPetersen]

... the question is, WHY are you doing that.

What do you hope to gain from this exercise?

 

[arotester]

we are making a test setup so that we can make it available to the students for experiments.