Search Results

Moto GP engines have since the year 2012 4 cylinders in V or inline layout for a total capacity of up to 1,000cc. With pneumatic valve spring but wet sump, and with the maximum bore limited to 81mm, the maximum speed these engines may have is about 18,000 rpm, with power outputs 250-260 HP. The paper presents the design of a 65 degree V4 Moto GP engine further optimizing the pneumatic poppet valve design, as well as a novel rotary valve design. The rotary valve permits up to extremely sharp opening or closing and very large gas exchange areas. The two engines are then modeled by using a 1D engine & gas dynamics simulation software package to assess the potentials of the solution. The improved design produces much larger power densities than the version of the engines with traditional poppet valves revving at higher speeds.

The present paper is an introduction to a novel rotary valve engine design addressing the major downfalls of past rotary valves applications while permitting the typical advantages of the rotary valves. Advantages of the solution are the nearly optimal gas exchange, mixture formation, ignition and combustion evolution thanks to the large gas exchange areas from the two horizontal valves per engine cylinder, the good shape of the combustion chamber, the opportunity to place a direct fuel injector and a spark or jet ignition device at the centre of the chamber. The novel engine design also permits higher speed of rotation not having reciprocating poppet valves and the reduced friction losses of the rotating only distribution. This translates in better volumetric efficiencies, combustion rates and brake mean effective pressures for improved power density and fuel efficiency. Additional advantages are the reduced weight and the better packaging.