VCT control with a direct electromechanical actuator

  • US 5,497,738 A
  • Filed: 05/03/1993
  • Issued: 03/12/1996
  • Est. Priority Date: 09/03/1992
  • Status: Expired due to Term
First Claim
Patent Images

1. An internal combustion engine, comprising:

  • a crankshaft, said crankshaft being rotatable about an axis;

    a camshaft (126), said camshaft being rotatable about a second axis, said camshaft being subject to torque reversals during rotation thereof;

    a vane (160), said vane having first and second circumferentially spaced apart lobes (160a, 160b), said vane being attached to said camshaft, said vane being rotatable with said camshaft and being non-oscillatable with respect to said camshaft;

    a housing (132), said housing being rotatable with said camshaft and being oscillatable with respect to said camshaft, said housing having first and second circumferentially spaced apart recesses (132a, 132b), each of said first and second recesses receiving one of said first and second lobes and permitting oscillating movement of said one of said first and second lobes therein;

    means for transmitting rotary movement from said crankshaft to said housing; and

    ,means for controlling the oscillation of said housing, said control means being reactive to torque reversals in said camshaft for varying the position of said housing relative to said camshaft, said control means comprising;

    a spool valve body (198);

    a spool (200), said spool being reciprocable within said body and having first and second spaced apart lands (200a, 200b), said spool further having a vent to atmosphere (198d);

    a first return line means (194) extending from one of said first recess and said second recess to said spool valve body, one of said first and second lands blocking flow through said first return line means in a first range of positions of said spool within said valve body and permitting flow through said first return line means in a second range of positions of said spool within said valve body;

    a second return line means (196) extending from the other of said first recess and said second recess to said valve body, the other of said first and second lands blocking flow through said second return line means in said second range of positions of said spool within said valve body, permitting flow through said second return line means in a first portion of said first range of positions of said spool within said valve body, and blocking flow through said second return line means in a second portion of said first range of positions of said spool within said valve body;

    an inlet line means (182) extending from said valve body to each of said first recess and said second recess, said inlet line means permitting hydraulic fluid to flow from said valve body to said each of said first recess and said second recess regardless of the position of said spool, said inlet line means having check valve means (184,

         186) for preventing the flow of hydraulic fluid from each of said first recess and said second recess to said valve body;

    means for sensing (207a, 207b) the positions of said crankshaft and said camshaft;

    an engine control unit (208), said engine control unit for receiving information from said sensing means and for calculating a relative phase angle between said crankshaft and said camshaft using said information;

    an electromechanical actuator (201), said electromechanical actuator comprising a variable force solenoid, said variable force solenoid for controlling the position of said spool in response to a signal issued from said engine control unit; and

    ,means for biasing (202) said spool valve, said biasing means for urging said spool valve to a full advance position during periods when said electromechanical actuator is deenergized.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×