Low noise,vibration and harshness solutions for in-line three-cylinder range extender and hybrid electric vehicles

Consideration of internal combustion engine formats suitable for hybrid or range extender electric vehicles usually focuses on selecting a power plant, which is as compact as possible to meet the demands and constraints of the installation. In-line three-cylinder engines often provide an attractive solution for such vehicles. This article presents a low emission two-stroke engine of in-line three-cylinder format and draws a comparison with an equivalent four-stroke engine. The particular focus of the analysis is on strategies for minimization of noise, vibration and harshness with significant reduction in piston lateral force compared with the four-stroke unit. The design also considers a balance shaft arrangement to further assist with noise, vibration and harshness reduction. The presented arrangement demonstrates an integrated induction control/balance shaft arrangement, which erodes the usual cost penalties typical of balance shaft consideration in three-cylinder engines.