CRDI engine at different fuel pressure

[arotester]

Hi,

I want to change the fuel pressure of CRDI engine and check the performance of it,how can i do it (is there any pressure valve that i can adjust)?​

 

[BrianPetersen]

Modern diesel engine with common-rail injection? A lot of them have the rail pressure electronically controlled and monitored.

Very easy to blow things up by not knowing precisely what you are doing with such systems, though.

 

[arotester]

I am talking about changing the rail pressure from 900 bar to 1600 bar which is within the crdi limits ,so i wanted to know both methods i.e. electronically as well as mechanically.

 

[BrianPetersen]

It will really help if you specify exactly which engine that you want to do this to, which manufacturer the fuel system is (Bosch? Denso? Siemens? Something else?), which series/generation the fuel system is, what type of injectors it has (solenoid? piezo?), type of fuel pump, type of engine control hardware and software (Bosch EDC15? EDC16? EDC17? something else?), etc. They are not all the same and right now, the rest of us are flying blind in the absence of any information whatsoever!

Nearly doubling the rail pressure, without making hardware changes, does not sound like a good thing to be doing. If the rail pressure was 900 bar in the original engine design, it is likely older-generation hardware that was not designed for higher pressure.

Do you know if the rail pressure is electronically regulated? If it is, you just have to change the setting in the ECU. But it is highly likely that such a large change is beyond the range of the original sensor and actuation hardware.

 

[ivymike]

I have been watching this thread quietly wondering things like "what system" and "how does he know what the limits are" ... but now I have a more fundamental question:
- Assuming you can dial up the pressure, what do you hope to gain? Lower particulate emissions?

If you're hoping for more power, wouldn't it be easier to change to injectors with larger orifices, and/or change injection timing+duration? I just can't see loading up the geartrain and the high pressure fuel system with a huge pressure increase as a viable option for "performance" (power) gains alone.

 

[Lou Scannon]

If you've seen what the pressure and heat release vs crank angle curves look like on modern emissions compliant common rail diesel engines look like, you'd know that a large scope for power increase would be moving the combustion phasing to earlier in the expansion stroke. Of course you would need the tuning tools and really need to know what you're doing to do this without inviting a catastrophic mechanical failure. Of course, NOx would be through the roof if you did this. The engine out exhaust would be significantly cooler, which could throw a wrench into any aftertreatment systems.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

 

[tbuelna]

900bar to 1600bar? It will be very difficult to recalibrate both the injector and fuel pump controls to work at this significantly higher rail pressure. The nozzle of a DI injector designed to operate at 900bar will not likely work well at 1600bar. It will likely have difficulty accurately metering fuel at 1600bar under part load conditions. The nozzle orifices sized for 900bar will also likely produce a fuel jet that over-penetrates at 1600bar, and impinges on the chamber surfaces causing over heating.

 

[arotester]

Actually i am doing a project on crdi engine(maruti swift crdi engine with 1248cc) and i would like to make changes to the engine accordingly. Also, is it possible to change injection pressure from BDM100 flasher to the ecu.
I am ready to select the injector and pump for the high pressures.

thank you for your comments