Cleaning system for vehicles and cleaning method for same

A vehicle cleaning system that removes foreign matter from a subject of a vehicle, the vehicle cleaning system comprising:

• a drive pump;
• an ejection nozzle that sprays fluid supplied from the drive pump against the subject;
• and
• a valve device located between the drive pump and the ejection nozzle, wherein:
• the valve device includes
• a housing,
• an intake passage positioned in the valve device at a portion located toward the drive pump to draw in the fluid,
• a discharge passage positioned in the valve device at a portion located toward the ejection nozzle,
• an auxiliary mechanism, and
• an urging spring that urges the valve body in a direction closing the intake passage;
• the auxiliary mechanism includes a diaphragm that partitions the housing into a valve chamber through which the fluid flows and a back pressure chamber at a side opposite to the valve chamber;
• the diaphragm includes a valve having a valve body configured to close the intake passage, the valve being configured to accumulate pressure so that pressure of the fluid supplied to the intake passage from the drive pump becomes higher than a discharge pressure of the drive pump;
• the auxiliary mechanism is configured to
• generate leakage of the fluid from the intake passage during the pressure accumulation to accumulate pressure with the leakage at a leaked side,
• open the valve body based on two pressures accumulated in the intake passage and the leaked side,
• output the fluid, which is pressure-accumulated in the intake passage, to the discharge passage by opening the valve body, and
• close the valve body as the fluid is output to the discharge passage to allow for re-accumulation of the pressure in the intake passage;
• the diaphragm includes
• a first pressurized section having a first area and pressurized by the fluid supplied from the drive pump in a state in which the intake passage is closed, and
• a second pressurized section located around the valve body and having a second area, the second pressurized section being pressurized at a leaked side by the fluid leaked from the intake passage in a state in which the intake passage is closed;
• and
• the diaphragm is configured to open against an urging force of the urging spring when the first and second pressurized sections are pressurized and close when the fluid is output to the discharge passage as a result of the opening.