ME102 Cal Super Mileage Vehicle Engine Spark Optimization

Scott Moura, Dylan Bethel, George Ben Fehlhaber, Brian Harrison, Christian Ueland
December 9, 2005

Mechanical Design (ME 102)
Kourosh Youssefi
UC Berkeley
Our project consists of re-manufacturing the engine and adding a spark-time optimization system for Cal's Super Mileage Vehicle team. The team's goal is to create a gas-powered car that achieves the best possible fuel mileage. We rebuilt the engine according to the competition's rules, which is a Briggs & Stratton single-cylinder 150cc flathead (also called side-valve or L-head) gasoline engine. An overhead cam from the Honda XR-50 mini bike has been adapted for this engine, in which the combustion chamber is centered over the cylinder, as has been standard for the past 50 years. This will increase efficiency and power, and improve combustion characteristics. In addition, the cylinder is sleeve to decrease the displacement to 50cc in an effort to decrease fuel consumption. Even with 1/3 of the displacement of our stock engine, there will be sufficient power to sustain a 15 mph average speed, as required by competition regulations. Other components that are adapted from the Honda 50cc are the piston, connecting rod, crankshaft, and oil pump. These components, with some modifications, provide us with reliability, low friction losses, and the smaller bore and stroke that we desire.