Committee Chair

Knight, Charles V.

Committee Member

Foster, Edwin P; Jayne, John W.; Jones, Byron M.


Dept. of Mechanical Engineering


College of Arts and Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


For any data acquisition instrumentation, it is essential to have a voltage or current signal output from any transducer that needs to be monitored.Nine OMEGA thermocouples were installed on the Ford engine-Megatech dynamometer system to monitor the temperature of the exhaust gases at different locations and the coolants entering and leaving the dynamometer and the radiator.Those thermocouples have an output signal of O - 55 mv.The TESCOM gas analyzer system measures the concentrations of the different gases present in the exhaust system of the engine and produces an analog output signal (0 - 100 mv) that is used for data acquisition.Two pressure transducers were attached to the Megatech dynamometer's counter clockwise (CCW) torque and clockwise (CW) torque gages to measure the torque output of the engine and the friction torque, respectively.A reproducible signal representing the speed of the engine was obtained from the tachometer generator of the dynamometer. This signal was then reduced, filtered,and calibrated; and a linear relationship (speed vs. output signal) was established and used in the software.A pressure differential sensor was used to determine the amount of air consumed by the engine by measuring the pressure drop across the Meriam laminar flowelement. This signal was also calibrated used an inclined manometer.Output signals from all transducers and the gas analyzers were supplied to three EXP-16 boards according to their ranges. The OMEGA EXP-16 boards are channel multiplexers. They have 16 input channels and one output channel.In addition, each board can output a temperature compensation signal on a separate channel.The output channels from the EXP-16 boards are fed into a Metrabyte DASH-16 data acquisition board installed inside the Dell Computer.The flow rate of the supplementary air supplied to the catalytic converter is controlled using an OMEGA mass flow controller. This controller receives a voltage signal from the computer to determine the flow rate being supplied.Switching of the three solenoid valves that are used to choose the location where the gas sample is taken into the TESSCOM gas analyzer was accomplished through electro-mechanical relays. Those relays are energized by a software addressed digital 1/0 card.A program was written in ASYST to read data from all sensors and perform the necessary calculations related to engine efficiency and emissions. A display screen shows the current status of the whole system. Another program was also written to enable graphics representation of the results.


I wish to thank everyone that contributed to the completion of this project.In particular, I am indebted to Dr. Charles V. Knight, who served as my major advisor,for his guidance and support. I am also indebted to the committee members:Dr. Edwin P. Foster, Dr John W. Jayne, and Professor Byron M. Jones. Their consultation and invaluable advice helped me overcome the difficulties that arose in almost every stage of developing this work.I would also like to thank Mr. Curtis Gossett (mechanical support), Mr. Karl Fletcher (hardware set up), Mr. Ahmed Yasin and Mr. John Sawan (software) for their help.


M. S.; A thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Master of Science.




Internal combustion engines--Design and construction; Testing--Data processing; Automobiles--Motors--Exhaust gas--Testing--Automation


Electro-Mechanical Systems

Document Type

Masters theses




x, 101 leaves



Call Number

LB2369.2 .N687 1990