A frame has a continuous upper surface with a pair of side-by-side elongate openings for receiving foot pedals. The catalyst comprises a substrate over which a hydrocarbons adsorbing material layer is formed as a lower layer to absorb hydrocarbons contained in exhaust gas. Each time differential value is calculated from the pair of each calculated moving average values, by least squares approximation. The base defines an assembly hole therethrough. The brushes are arranged such that commutation times are distributed as uniformly as possible in order to reduce current ripple when using a wave winding and a number of brushes which is less than a number of poles in the electrical machine. The transistor also comprises a source region, which is formed in the tub on a first side of the gate region, and a drain region, which is arranged in the second half of the active area, on a second side of the gate region.