EN0751 Interdisciplinary Engineering Project Shell Eco Marathon

Appendix 38: Cobra 4s Engine Cost

Appendix 39: Net Power and Torque for Engine Comparison Table

GX35 GXH50

Power curves further justify the use of a GXH50 engine over the GX35 as a conservative choice for this year’s SEM.

Appendix 40: Engine Test 1

Wooden engine mount produced in house to ensure safe testing of engine. Directly bolted onto wooden mount in order to satisfy university safety regulations. First test completed with unmodified engine as pictured above. Petrol tested then with an 80:20 mix of Ethanol.

The flywheel produced in house is fitted to the crankshaft and the electric starter motor mounted to the side of the engine. Exhaust pipe was moved to accommodate this and the fuel tank moved with the aid of a new bracket also produced in house. Switch secured to wooden mount and spinning parts covered to ensure safety standards were maintained (above: left and right respectively).

Appendix 43: Engine Comparison

A variety of engines were researched until a Honda engine was chosen due to it meeting the power requirement for the project, while the size and fuel efficiency compared well to other Engines.

With the exact layout of the track (slope angles etc.) released after engine needed to be selected it was agreed that a conservative approach would need to be adopted as the exact weight of the vehicle is still not yet known.

Three engines were shortlisted for comparison between a Honda GXH50, GX35, and a Cobra 4s before a final decision was made.

[Fig. 1: Engine Comparison]