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Re: back fire to gas engine

back fire is always the common problems of some gas engines, sometimes its directly the fuel(like quality or density or wet or dry), sometimes the flpas like throttle or bypass..

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Re: back fire to gas engine

Hello,

     Sounds like you have solved your problem.  Just FYI, the G3500E products use a compressor bypass rather than a wastegate.  This bypass serves a similar function to the wastegate (disposing of exhaust energy that is not required for compression of the fresh charge), but it does so by bypassing some of the already compressed charge around the turbocharger compressor, rather than bypassing exhaust flow around the turbine.  The two main advantages of this approach are that it is faster than a wastegate (i.e. you don't have to wait for the turbine to spin up or down) and it is cooler than a wastegate and can thus easily use an electronic rather than mechanical actuator.  The 'backfire' condition you describe sounds like compressor surge to me.  In this case the compressor pressure ratio exceeds the allowable value and the compressor pressure ratio drops very rapidly.  This can be caused by ambient conditions (low ambient temp or high altitude) or by faulty throttle or bypass hardware.  Hope your throttle swap has fixed the problem.

 

hiltnerj

Contributor

Re: back fire to gas engine

 Hello all,

 

After a lot of ckecks the problem was the opperation of throttle actuator. I exchange throttles from one engine to an other and the problem transported with the throttle. Finally i bought a new throttle and the engine is working fine. Thank you all!

 

George

Everything goes electric
Regular Contributor

Re: back fire to gas engine

[ Edited ]

Hi,

 

Few Inputs from my experience

 

01. If you have data looging facility in CCM than data log for individual cylinder detonation and ignition angle. It will nullify doubt for any individual cyl. head's perfomance.

 

02.In my G3520C I have put my head in wall to resolve load hunting problem and in process replaced and repaired Raptor valve,throttle and so many things but at the end i found that it was due to Electricla harness malfunction proble. Usually I do not see anything wrong with Raptor valve.

 

03. If you are repetadelly getting this problem than batter to check Turbochager also.

 

04. Does it trips with any repeted fault code.

 

05. One more point hope your exhaust line have drain point also.

Message Edited by drkosamia on 03-27-2009 11:25 AM
Contributor

Re: back fire to gas engine

Hello,

 

Engine G3516E has not a mechanical waste gate. There is an electronic by pass valve that does the same operation (i think). After all the test that i made i believe the problem caused by the bad operation of the raptor valve. Even if it seems to operate well something is not correct. Today i will try to change it and i will post the result later. 

 

If somebody wants to add some comment or ideas about the problem i would be really gladfull to read.

 

Thank you

 

Have a nice day 

Everything goes electric
Contributor

Re: back fire to gas engine

I had seven G3516A with mechanical waste gate valves (pressure operated type).  They suffered occasionally from diaphragm holes and vibration related issues, i.e. screws working there way loose.  I also had the odd one fail with under 10k hrs.  I replaced them every 26k hrs regardless.

 

When faulty they could make the engine very unstable randomly which often resulted in a consequential shut down due to detonation.  Your data looks ok except for the boost pressure which seems about 60 kPa high.  This could of course be normal for this spec engine as I haven't looked up the data sheet for this spec.  Is it similar to the others?

 

Good luck!

Contributor

Re: back fire to gas engine

Hello,

 

Can you please write some details about the condition of your problem? Do you have the same engine set? After how many hours of operation the engine had the problem? My engine has only 5600 hours. I will check the waste gate and i will post the results.

 

Thank you

 

 

Everything goes electric
Contributor

Re: back fire to gas engine

Hi, Have you checked the waste gate?  I have had very similar experience when a waste gate was begining to fall apart.
Contributor

Re: back fire to gas engine

Hello,

 

I have just printed all the parametes from the diagnostic tool.

 

Engine Speed 1500 RPM
Generator Total Real Power 1590,523 kW
Engine Load Factor 99 %
Actual Engine Ignition Timing 30,0 Deg
Detonation Level (1) #
Actual Oxygen 0,00 %
Inlet Manifold Air Pressure (abs) 383,5 kPa
Inlet Air Temperature 56 Deg C
Engine Oil Temperature 88 Deg C
Engine Coolant Temperature 89 Deg C

 

G3516: EPG-Standard (GAS00172)
Engine Oil Pressure 519 kPa
Unfiltered Engine Oil Pressure 579 kPa
Oil Filter Differential Pressure 56 kPa
Engine Coolant Pressure (abs) 184 kPa
Engine Coolant Pump Pressure Status OK
Hydrax Pressure Switch Status Unavailable
Engine Oil Temperature 88 Deg C
Engine Coolant Temperature 89 Deg C
Engine Oil to Coolant Differential Temperature -1 Deg C

 

G3516: EPG-Standard (GAS00172)
Engine Mode Switch Auto
Initiate Contact Status Engine Run
Auxiliary Driven Equipment Status Ready
Emergency Stop Engine Run
Pre-Lube Switch Ready
Pre-Lube Relay De-energized
Starter Motor Relay De-energized
Fuel Control Relay Energized

 

G3516: EPG-Standard (GAS00172)
Requested Detonation Derate Percentage 0,0 %
Run Relay Energized
Genset Fault Relay De-energized
Crank Terminate Relay Energized
Crank Terminate Speed 250 RPM
Remaining Cooldown Time 0 Sec
Engine Cooldown Duration 0 min
Engine Control Alarm Status Off

 

G3516: EPG-Standard (GAS00172)
Engine Speed 1501 RPM
Desired Engine Speed 1594 RPM
Throttle Actuator Position Command 63,66 %
Engine Speed Status Rated
Grid Status On
Governor Type Setting Droop
Engine Speed Droop 6,0 %
Battery Voltage 26 Volts

 

G3516: EPG-Standard (GAS00172)
Air Flow 6147,2 Nm3/h
Actual Air to Fuel Ratio 15,8
Gas Fuel Flow 389 Nm3/h
Fuel Valve Position 66 %
Fuel Pressure (abs) 111 kPa
Fuel Valve Differential Pressure 10 kPa
Fuel Temperature 18 Deg C
Gas Specific Gravity 0,610
Fuel Quality 35,9 MJ/nm3

 

G3516: EPG-Standard (GAS00172)
Oxygen Sensor Status Off
Desired Oxygen at Full Load 8,00 %
Desired Oxygen 0,00 %
Actual Oxygen 0,00 %
Fuel Correction Factor 102 %
Oxygen Feedback Enabled Status Enabled

 

ITSM
# 1 Exhaust Port Temp 569 Deg C
# 3 Exhaust Port Temp 569 Deg C
# 5 Exhaust Port Temp 578 Deg C
# 7 Exhaust Port Temp 574 Deg C
# 9 Exhaust Port Temp 556 Deg C
#11 Exhaust Port Temp 560 Deg C
#13 Exhaust Port Temp 571 Deg C
#15 Exhaust Port Temp 566 Deg C
#17 Exhaust Port Temp Unavailable Deg C
#19 Exhaust Port Temp Unavailable Deg C

 

ITSM
# 2 Exhaust Port Temp 575 Deg C
# 4 Exhaust Port Temp 568 Deg C
# 6 Exhaust Port Temp 573 Deg C
# 8 Exhaust Port Temp 573 Deg C
#10 Exhaust Port Temp 575 Deg C
#12 Exhaust Port Temp 578 Deg C
#14 Exhaust Port Temp 580 Deg C
#16 Exhaust Port Temp 575 Deg C
#18 Exhaust Port Temp Unavailable Deg C
#20 Exhaust Port Temp Unavailable Deg C

 

ITSM
Right Bank Turbine Inlet Temp 598 Deg C
Right Bank Turbine Outlet Temp 432 Deg C
Left Bank Turbine Inlet Temp 611 Deg C
Left Bank Turbine Outlet Temp 430 Deg C

 

I have never inspect the exhaust system, after the engine there is a catalyst system. The temperatures and the presure before and after the catalyst are ok.

 

I don know if these data can help. Please let me know.

 

Have a nice day

Everything goes electric
Regular Contributor

Re: back fire to gas engine

Can you give us some more info. Fuel type, exhaust  and intake temps, amount of boost your getting. Have you inspected exhaust system? A collapsed silencer will affect operation. What about turbos?