Diesel Engine Testing Questions
Diesel Engine Testing Questions
(OP)
I am doing some real world testing using a 7.3liter TD (Ford/International) with the intent of gathering information to perform some exhaust CFD modeling.
Any exhaust experts have any advice as to best way to measure flow? I plan in placing numerous temp and static pressure taps along the system. Since it is a diesel can I use the intake mass flow and correct for temperature, how do I correct for the boost? Is a pitot tube best approach? Any way to accurately get the flow ?
Any exhaust experts have any advice as to best way to measure flow? I plan in placing numerous temp and static pressure taps along the system. Since it is a diesel can I use the intake mass flow and correct for temperature, how do I correct for the boost? Is a pitot tube best approach? Any way to accurately get the flow ?





RE: Diesel Engine Testing Questions
(intake mass flow + fuel mass flow = exhaust mass flow).
The turbo just increases mass flow beyond what a NA engine would flow, but measuring the intake mass flow takes care of that.
Mike Halloran
Pembroke Pines, FL, USA
RE: Diesel Engine Testing Questions
RE: Diesel Engine Testing Questions
don't forget that you "leak" up to about 2% of your mass flow out the crankcase ventilation system (if it's not recycled into the intake)
RE: Diesel Engine Testing Questions
RE: Diesel Engine Testing Questions
RE: Diesel Engine Testing Questions
Diesel exhaust flows present a very complex flow condition to model dynamically, since the temperatures, pressures, velocities, gas compositions, etc. can vary widely at any given instance, at any given point in the exhaust system.
Real time dynamic pressure data can be collected using a water cooled piezo pressure transducer with a high enough sampling rate.
As others noted, exhaust mass flow is simply intake air mass flow plus injected fuel mass flow. Diesel engines don't require intake air mass flow sensors, since they don't need to run at stoichiometric AF ratios. If you need mass air flow data, most dynos have intake airflow measuring equipment available.
Hope that helps.
Terry