Performance and Emission Analysis of a Non-Conventional Gasoline Engine

A new engine design concept, characterized by a singlecylinder-double piston and a cycloid crank rotor insteadof the conventional crankshaft has been developedrecently by Gul & Co Development AB, Sweden. Therotor (crank disc) is equipped with an oval groove in theshape of a sinusoidal cycloid according to the expressionY=S(-Sin(2)/(2)) where S is the piston stroke and varies from 0 to 1. Inside the oval groove a ball rolls/slides in order to transfer force from the piston to therotor. Such a rotor contains groove surfaces for the valvemovement control as well. Each turn of the rotorcorresponds to four strokes for both the pistons. Thus, afull 4-stroke engine cycle is developed for a single nonconventionalcrankshaft revolution.Having the extra freedom to select an optimal pistonmovement, the new design is believed to have thepotential to provide low emissions, low noise levels andlower fuel consumption. Therefore, it has been subjectedto an engine thermodynamics simulation, to provide aninsight to engine performance.Simulation results and preliminary laboratory tests haveshown that the optimized cycloid crank rotor, whichfurther intensifies the reduction of the piston speed closeto both dead centers, gives better conditions for thecombustion processes, and thus a higher efficiency.Since the single cylinder-double piston with cycloid crankrotor displays better performance and reduced sizecompared to conventional combustion engines, it isbelieved that this new patented Swedish engine willcompete with conventional engines in lawn movers, chainsaws, outboard motors and other engines in similarsmall-scaled equipment