Project/Customer Specifications

Mixing

Team Tank-Up's job was to create many design improvements over the previous mixing methods used for the Alcohol/Water Fuel Vehicle (AWV). To date mixing has been done entirely by hand. The alcohol and water volumes were calculated to achieve an approximate 70 - 30% concentration of ethanol in the fuel based on a 55-gallon source supply of ethanol. With this accomplished, the fuel pump was removed from the vehicle and used to deliver each component amount to a seperate 55-gallon drum at approximately 1 Gpm. This method was extremely time intensive, and the verification of the concentration was almost non-exsistent (beside the volume measurement).

The above photos show the front and back views of
the AWV's engine. One thing that is interesting
to note is the lack of a distributor.

Objective

Team Tank-Ups objective for this project was to devise an accurate means of mixing and delivering a user set concentration of ethanol and water to be used as an alternative fuel. Or put simply, "mix the fuel accurately and reliably". This fueling station needed to be able to test and verify the accuracy of the mixture before it was dispensed to the vehicle. Additionally, our fueling station must have the capability to test and verify the concentration of an exsisting batch of fuel. Finally the fueling station should posses the power to improve the delivery time to the vehicle considerably.

Design Components

In order to create these improvements, Team Tank-Up attempted to address the issues in the following manner.

Source Delivery

The Source delivery/mixing system implements the use of Little Giant 5-MD-SC centrifigual, magnetic drive, pumps purchased from MSC. The SC series pump are designed to handle semi-corrosive chemicals through the use of glass filled Ryton wetted parts. These pumps are designed to deliver a max psi of appx 11.9 (gage) and 14 Gpm while pushing 9 feet of head. They also have the capability to protect themselves from thermal wear via an internal thermostat switch.

Little Giant, 5-MD-SC seriew pumps used for mixing transfer. The pump head was seperated from the motor which was encased in a pressurized enclosure to provide a "clean air" enviorment in which to operate. The enclosure experiences approximately 2.5 complete air changes per second.

Flow Rate Controll

Probably of the most importance to the success of our project was the means by which we controled the flow rate of the delivery in order to ensure the proper volume percentage of the mixture. To perform this task WA Kates model FM38 adjustable flow rate controllers were chosen. These flow controllers are designed to operate over a minimum of 8-psi differential pressure, and can be adjusted over a wide range of flow levels.

The WA Kates flow rate controllers operate on a 10-turn mechanical potentiometer, which in turn controls the level of an internal, spring loaded needle valve. This configuration allows a wide range of flow levels to be set.

Concentration Verification

Finally, the verification of the fuels concentration was performed by a PR-111 inline process refractometer distributed by the AFAB corporation. The PR-111 undervent an in-house calibration to perform in % ethanol concentration before distribution. This component was placed inline in a mixing chamber recirculation loop in order to effectivley eliminated the effects of ambient light and foreign materials ensuring an accurate measurement.

The PR-111 is shown with an LCD output display. This was removed after further calibration due to the non-linear output properties of the refractive index of ethanol. In the end a manually linearized output display was created to work with the analogue output display.

Team Tank-Up Background Concept Evolution Concept Verification