Fuel Additive Validation Study
The University of Michigan
Department of Mechanical Engineering
To evaluate the validity of GTA's claims, a CFR engine was used. In order to get a reliable baseline, the engine was completely rebuilt. Unfortunately the Yanmar diesel engine was not ready, so no data of how the additive effects diesel performance could be evaluated. The Horiba gas analyzer was not interfacing with the computer at the time of testing, so no emissions tests could be performed. However, we do hope to be able to take emissions data in the not to distant future. We were able to attain peak cycle pressure, brake specific fuel consumption, spark advance allowed before knock, and maximum brake torque.
87 octane ~ For our baseline testing Sunoco 87 octane unleaded fuel was used. This fuel also served as the base fuel to which the additives were mixed.
Viscon control - 0% polymer and 50% oil and 50% Exxsol solvent.
Viscon oil - 1.0-% polymer in Exxsol solvent.
Viscon pib - 1.0% polymer in 87 octane gasoline
All of the additives and the fuel were combined with a mixing ratio of 2-fl. oz. of Viscon to 10 gallons of gasoline.
Record all ambient conditions before each run.
Place the desired fuel to be tested in the fuel cart.
Ran engine long enough to reach steady state operating conditions.
Set MBT timing.
Make sure fuel height is set correctly on carburetor-
Acquire P-V data using the Lab View software.
Acquire fuel consumption rate from the fuel cart.
Acquire max. Brake torque from the dyno controller.
Run the engine completely out of gas to clear the lines of fuel.
Change fuel types and perform test procedure again.
All pressure vs. volume data and pressure vs. crank angle data is given in the appendix. The results of our testing are summarized in the tables below. The first table is a summary of our findings of the effect on peak cycle pressure with the addition of the various additives. The second table shows the effect on brake torque. The third gives the relationship between brake specific fuel consumption time and fuel type. Lastly, the fourth graph characterizes the spark advance needed for the onset of knock for each of the different fuels.
Peak Pressure Results
Fuel Type Peak Pressure (k PA)
87 octane 1633
Viscon control 1671
Viscon pib 1695
Viscon oil 1745
Brake Torque Results
Fuel Type Max. Brae Torque (ft-LB)
87 octane 14.4
Viscon control 15
Viscon PB 15
Viscon oil 15.5
Brake Specific Fuel Consumption (g/kW*h)
Fuel Type BSFC (g/kW*h)
87 octane 442.49
Viscon control 425.43
Viscon PB 439.63
Viscon oil 426.82
Spark Advance Needed for the Start of Knock
Fuel Type Spark Advance (degrees BTC)
87 octane 6
Viscon control 7
Viscon PB 10
Viscon oil 8
In conclusion, our test results show that with the addition of the polymer to the fuel the peak cycle pressure and maximum brake torque both increase. The addition of the additive to the fuel caused a desirable decrease in BSFC.
The results obtained for the maximum amount of spark advance tolerable before the onset of knock suggest that the additive increases the octane rating. It was hard to get exact values for spark advance at the onset of knock because the knock was being detected by ear. So, although these measurements were not the most precise, it was very clear that the fuel containing the Viscon PB had a higher octane rating.
The results seem to show promise, we recommend further investigations be made to this fuel additive when all of the equipment is up and working.
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