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Hydraulic control system for hybrid vehicle

  • US 5,415,603 A
  • Filed: 03/25/1993
  • Issued: 05/16/1995
  • Est. Priority Date: 04/01/1992
  • Status: Expired due to Fees
First Claim
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1. A hydraulic system for a hybrid vehicle, combining an internal-combustion engine and an electric motor together for selective use, wherein power of the internal-combustion engine and that of the electric motor are transmitted to a differential gear unit with drive axles through a hydraulic power transmission and an input clutch device, said hydraulic system comprising:

  • a hydraulic oil pump for supplying hydraulic oil to a line pressure hydraulic path;

    a primary regulator valve having at least a line pressure port and a converter pressure port, said line pressure port connecting with said hydraulic pump and with the line pressure hydraulic path and said converter pressure port connecting with a secondary pressure hydraulic path, the extent of opening of said ports being variably controlled;

    a control valve having at least a first port which receives hydraulic oil pressure from the secondary pressure hydraulic path and a second port and means for switching said control valve between an engine cruising mode position wherein said first and second ports are in communication and an electric motor cruising mode position wherein there is no communication between said first and second ports;

    motor cooling means, including a cooling oil path, for supplying said hydraulic oil to the electric motor;

    lubricating means, including a lubricating oil path, for supplying said hydraulic oil to lubricate mechanical parts in the transmission; and

    an electrical control unit including a drive mode decision device for selecting one of an engine cruising mode in which the vehicle is moved by the engine and an electric motor cruising mode in which the vehicle is moved by the electric motor, said primary regulator valve, in the engine cruising mode, controlling the pressure in the line pressure hydraulic path and in the secondary pressure hydraulic path to said control valve and the hydraulic power transmission and, in the electric motor cruising mode, directing most of the hydraulic oil from said hydraulic oil pump to said motor cooling means with said control valve positioned to prevent communication between said first and second ports.

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