We have been testing two diesel engines with various blends of bio-based fuels. One is a 10 HP Briggs and Stratton diesel engine and the other is a two stroke model made by Two Stroke International. The main problem with the bio-based fuels are that they tend to be more viscous than the petroleum based fuels. This tends to clog up the injection jets on the engines. It also tends to inhibit homogeneous combustion which, in turn, results in lower efficiency than that generated using petroleum based fuels.
The plot below shows the power output of the test engine as measured by dynamometer tests performed by Cadet Joseph Prinzinger. As can be seen in these plots, the power output drops continuously as the percentage of canola oil is increased. This is due primarily to the reasons noted above.
The plot at the bottom of the page shows the results of a computer model for the pressure in the combustion chamber as a function of the cylinder volume (i.e. crankshaft angle).
We are in the process of generating measured pressure vs. volume data which will be matched to the computer model shown below by nonlinear regression. This will allow us to determine parameters such as cylinder wall temperature, heat transfer coefficient, and the rate of combustion of the fuel.