b) The accelerator : This pedal has two functions : - To alter the position of the butterflies (or the strangler-flap on injection models). - To operate the hydraulic selector (which is connected by a cable to the butterfly spindles).: The length of time in each gear increases the more the pedal is depressed and consequently the more rapid is the acceleration of the vehicle (the engine tums at higher speeds). When the pedal is fully depressed this time is at a maximum. However, if the speed of the vehicle permits, a lower gear may be engaged.