Date of Award
Master of Science (MS)
The Paslode Cordless XP Framing Nailer is a combustion-powered nail gun that operates using a fuel blend of a propylene and 1-butene. This tool is designed to drive nails using a piston driven by a combustion reaction. The current fuel blend is able to fire approximately 1200 shots per fuel cartridge and match the energy output of pneumatic, corded nailers on the market. This thesis is written with the intent to gain a better understanding of the operation of the tool and how its performance varies when the fuel source is altered. A bizonal combustion model was created to simulate the operation of the tool. The model predicts the unburned gas temperature, burned gas temperature, piston displacement, compression pressure due to the rapid travel of the piston, and combustion pressure. The model predicts the importance of two key factors when selecting a fuel – the laminar flame speed and the energy density of the fuel. To validate the model, an experimental test stand and redesigned combustion chamber were developed. The test stand provided clean, repeatable results for both liquid and gaseous fuels. The fuels tested were 1-butene (gas), propane (gas), propyne (gas), heptane (liquid), and iso-octane (liquid). The current fuel blend was used as a benchmark to compare the fuels. The fuels that performed best, using the metric of boundary work done on the piston, were those that had higher lower heating values. However, the fuels with higher energy density provided more volumetric efficiency. Flame speed was shown to positively affect the peak chamber pressure but should be considered as a secondary metric for optimizing tool performance. This thesis characterizes the performance of the tool using several fuels. Based on these results, an ideal fuel for the XP Framing Nailer would be a fuel blend that would have a high volumetric energy density.