"Pressure pulses" refer to sudden changes in pressure that occur in a short period of time. It can be a temporary increase or decrease in the force or intensity of pressure. Full definition
The concept employs two Schaeffler technologies to enable engine stop - start systems: a latching valve, which is controlled by pressure pulses; and a wrap spring one - way clutch for permanently connecting a starter to the housing of the torque converter. (greencarcongress.com)
A shockwave is a mechanical pressure pulse. (csiro.au)