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Device and method for evaluating low-μ road and power distribution control device for four-wheel drive vehicles

  • US 7,487,028 B2
  • Filed: 05/13/2004
  • Issued: 02/03/2009
  • Est. Priority Date: 05/19/2003
  • Status: Active Grant
First Claim
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1. A low-μ

  • road evaluation device for controlling the distribution of power between the front and rear wheels of a four wheel drive vehicle comprising;

    slip rate calculating means for calculating a slip rate between a wheel of a vehicle and a road surface;

    low-μ

    information magnitude calculating means for calculating a low-μ

    information magnitude associated with a friction coefficient of said road surface, based on both of said slip rate and an acceleration operation magnitude derived from a throttle setting sensor in said vehicle;

    comparison evaluating means for comparing between said calculated low-μ

    information magnitude and a first preset threshold value;

    adding means for adding a value based on said low-μ

    information magnitude to a counter when said comparison evaluating means determines that said low-μ

    information magnitude exceeds said first preset threshold value;

    subtracting means for subtracting a predetermined value from the counter added to by said adding means when said comparison evaluating means determines that said low-μ

    information magnitude does not exceed said first preset threshold value; and

    low-μ

    road evaluating means for determining that there is a low-μ

    road when the counter calculated by said adding means or said subtracting means exceeds a second preset threshold value.

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