Switching control unit of part time type four-wheel driven car

Abstract

Abstract PURPOSE:To prevent the power steering oil pressure from becoming deficient by switching to a two-wheel drive regardless of an operation to a four-wheel drive side under the condition of an low engine speed when the pressurized oil for power steering is utilized in an oil hydraulic clutch for switching between two and four-wheel drives. CONSTITUTION:A car speed judging circuit 24 and an engine speed judging circuit 28 are provided as the control unit of a valve 21 in a unit controlling the feed of the pressurized oil to an oil hydraulic clutch for switching between two and four-wheel drives by means of a solenoid valve 21. The car speed judging circuit 24 is constituted so that an L output is generated from a comparator 23 when the output from a car speed sensor 35 is zero while the car is at a halt, and the judging circuit 28 is constituted so as to generate an L output when the engine speed based on the output from an ignition coil 25 is equal to or less than a preset value. Then, when the outputs from both circuits 24, 28 are both at an L level, a transistor 30 is turned on, and even if a four-wheel drive judging circuit 34 judges a four-wheel drive, the signal from the circuit 34 is cancelled, thus closing the valve 21 and resulting in a two-wheel drive status.

Inventors

• 👤 Masaaki Ogami
• 👤 正明 大神

Bibliographic Details