Reducing rpm gas engine under increasing suction pressure recip compre
Reducing rpm gas engine under increasing suction pressure recip compre
(OP)
Hi all!
I have problem with Driver – Caterpillar with BHP 810 HP. When the suction pressure is 36 psi, rpm is about max – 1150 -1170, but when the suction pressure starts to increase a bit till 40 – 42 psi, speed starts to reduce and compressor stopped under 50 psi. The discharge pressure doesn’t change. I used Ariel Performance software, and received calc BHP – 512 HP under suction pressure 50 psig. The compressor was designed under suction pressure 60 psig (at this case BHP- 615HP). The output signal from control panel is 100%, and the fuel gas throttle is full opened.
Is this problem can be caused by incorrect adjusted a pressure controller of fuel gas?
Best regards.
I have problem with Driver – Caterpillar with BHP 810 HP. When the suction pressure is 36 psi, rpm is about max – 1150 -1170, but when the suction pressure starts to increase a bit till 40 – 42 psi, speed starts to reduce and compressor stopped under 50 psi. The discharge pressure doesn’t change. I used Ariel Performance software, and received calc BHP – 512 HP under suction pressure 50 psig. The compressor was designed under suction pressure 60 psig (at this case BHP- 615HP). The output signal from control panel is 100%, and the fuel gas throttle is full opened.
Is this problem can be caused by incorrect adjusted a pressure controller of fuel gas?
Best regards.





RE: Reducing rpm gas engine under increasing suction pressure recip compre
if fuel pressure to engine is lower than mfg recommended pressure, then the engine's performance is likely limited or impacted. although i would expect the engine's performance to be impacted regardless of load; unless the fuel pressure is at/above recommended pressure at the lower loads. not only should pressure be at the recommended levels, the pipe should be properly sized to handle the needed capacity (volume) for engine to operate satisfactorily throughout its design range.
double-check the recip comp performance calcs and ensure the data you are using is representative of the actual operating conditions of the compressor.
good luck!
-pmover
RE: Reducing rpm gas engine under increasing suction pressure recip compre
You need to check the engine intake-manifold pressure at each suction pressure to see if the Cat hp calculates out to a number close to the Ariel required hp. If they are very different (more that you would expect from auxilliary loads) then you could easily have other problems (engine valves, etc) that have little to do with the fuel-system.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
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RE: Reducing rpm gas engine under increasing suction pressure recip compre