Fang ICE Performance Testing
Transcript of Fang ICE Performance Testing
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Internal Combustion Engines
MAE 408
Engine Performance and Testing
Dr. Peter B. Corson, 3171 Broughton Hall
Slides courtesy of Dr. Tiegang Fang
Mechanical and Aerospace Engineering Department
North Carolina State University
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Three characteristics curves showing the brake torque, brakepower, and brake specific fuel consumption
Engine Full Load Performance
Intermittent
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Example Full Load Performance
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Example Full Load Performance
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Added contours of constant BSFC and constant power to theload-speed graph
Load is commonly denoted by torque or BMEP
Engine Performance Maps
Constant powercurves
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These help to describe the effect of load-speed variations
Engine Performance Maps contd
There is oneload-speedcombination with
BSFC reaching aminimum
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Finding the engine work in the region of low BSFC and highefficiency
Optimizing Engine Performance
For constantspeed, BSFCdecreases withincreasing load(due to mechanical
efficiency loss) andthen increases upto the full loadconditions (due toover fueling withpoor combustion)
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Optimizing Engine Performance contd
For constant load,BSFC decreaseswith increasing
speed (due to heatloss) and thenincreases up to themaximum speedconditions (due tofriction loss)
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Optimizing Engine Performance contd
The optimum efficiency curve can only be achieved by using theContinuously Variable Transmission (CVT) technique
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Map Example
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Map Example: Engine Torque vs. Throttle
0%
20%
30%
40%
50%
60%
70%80%90%
100%
Car Load
Curve
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Engine Testing
Parameters to be measured:1. Power (brake, indicated)2. Torque3. Speed4. Fuel consumption5. Air consumption
6. In-cylinder pressure for combustion analysis7. Other parameters such as pressures, temperatures, etc.
Specific equipment is required for different parameters
Engine Test Cell Control Room
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Power, Torque, and Speed Measurement contd
Eddy current dyno
Electric Dynos (AC and DC)
AC electric dynos are newer and response faster.
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Fuel Consumption Measurement
Measurement includes two types: Mass or Volume
Volume measured using rotameter: Float in a tapered tube Reading affected by viscosity and temperature of fuel
Volume measured using turbine flow meter
Volume measured by positive displacement flow meters:
Advantage: independent of viscosity
Rotameter Turbine flowmeter Positive displacement
flow meters
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Fuel Consumption Measurement contd
Mass: steady state batch flow measurement with scale and
beaker Mass: Coriolis flow measurement
Fluid passes through a vibrating tube, causing the tube totwist; the amount of twisting is proportional to the massflow
Coriolis mass flow meter
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Air Consumption Measurement
Most common: calibrated orifice or nozzle
Pressure drop across orifice or nozzle increases with flow rate Pressure differential measured with pressure transducer
Normally calibrated by manufacturer under controlled conditions
Orifice or nozzle cause slight air restriction
http://images.google.com/imgres?imgurl=http://me.queensu.ca/people/sellens/teaching/airflow/Orifice.jpg&imgrefurl=http://me.queensu.ca/people/sellens/teaching/airflow/commonFeatures.php&h=1332&w=972&sz=131&hl=en&start=19&um=1&tbnid=h9ZT4M68DSgXIM:&tbnh=150&tbnw=109&prev=/images?q=orifice+plate&start=18&ndsp=18&svnum=10&um=1&hl=en&rlz=1T4DMUS_enUS214US217&sa=N -
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Engine Combustion Data Acquisition
Pressure-volume conditions in combustion chamber easily
measured Two-channel shaft encoder (synchronize the timing)
Top Dead Center (TDC) pulse Crank angle pulses at
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Engine Test Facility
Typical engine test facility