fang ice performance testing

8/6/2019 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
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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

fang ice performance testing

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