ELECTRIC VACUUM PUMP CONTROL UNIT

摘要

PROBLEM TO BE SOLVED: To make it possible to ensure that a vacuum pump stops operating even when a vehicle is present in a location at a low atmospheric temperature.SOLUTION: A pump ECU starts actuating a vacuum pump when a booster negative pressure ΔP is not higher than a pump-actuation start threshold ΔPstart (S11 to S13). The pump ECU calculates a negative-pressure increase gradient ΔP' that represents the increase gradient of the booster negative pressure ΔP, and stops actuating the vacuum pump when the negative-pressure increase gradient ΔP' is not greater than a stop gradient threshold ΔP'stop (S14 to S17).SELECTED DRAWING: Figure 2