Hydraulic control system for vehicle

A hydraulic control system for a vehicle, comprising:

• an engine;
• an oil pump that is driven by the engine to generate hydraulic pressure;
• a clutch device that is brought into engagement to enable power transmission between the engine and drive wheels by delivering a pressurized fluid thereto, and brought into disengagement to interrupt the power transmission between the engine and the drive wheels by discharging the fluid therefrom;
• an accumulator that stores the fluid delivered to the clutch device;
• wherein the hydraulic control system is configured to:
• control the hydraulic pressure established by the oil pump or the accumulator serving as a hydraulic source that is delivered and discharged to/from the clutch device,
• stop the engine while bringing the clutch device into disengagement upon satisfaction of a predetermined stopping condition, and
• restart the engine while bringing the clutch device into engagement upon satisfaction of a predetermined restarting condition;
• and
• the hydraulic control system comprising a hydraulic circuit configured to increase flow rate of the fluid flowing between the hydraulic source and the clutch device when the engine is stopped, in comparison with that of the case in which the engine is activated;
• wherein the hydraulic circuit comprises:
• a diametrically smaller passage to deliver the fluid from the hydraulic source to the clutch device and to discharge the fluid from the clutch device on which a first orifice is formed;
• a diametrically larger passage to deliver the fluid from the hydraulic source to the clutch device and to discharge the fluid from the clutch device on which a second orifice that is diametrically larger than the first orifice is formed;
• and
• a change valve to close the diametrically larger passage when the engine is activated while establishing a communication between the hydraulic source and the clutch device through the diametrically smaller passage, and to close the diametrically smaller passage when the engine is stopped while establishing a communication between the hydraulic source and the clutch device through the diametrically larger passage.