Tire pressure-reduction determining system for wheels of a vehicle
First Claim
1. A tire pressure-reduction determining system for wheels of a vehicle, comprising:
- a driven wheel slip rate calculating means (M1) for calculating driven wheel slip rates (λ
L and λ
R) based on follower wheels speeds (VWNL and VWNR) and driven wheel speeds (VWDL and VWDR);
a driven wheel torque calculating means (M2) for calculating a driven wheel torque (TQDW) based on an engine torque;
a driven wheel slip rate estimating means (M4) for estimating a characteristic variation in driven wheel slip rates (λ
L and λ
R) relative to the driven wheel torque (TQDW) based on the driven wheel slip rates (λ
L and λ
R) and the driven wheel torque (TQDW);
a rotation-number ratio calculating means (M5) for calculating rotation-number ratios (CVWL and CVWR) between follower wheels (WFL and WFR) and driven wheels (WRL and WRR) said driven wheel slip rates (λ
L and λ
R) at the time when the driven wheel torque is zero, from said variation characteristic estimated by said driven wheel slip rate estimating means (M4); and
a tire pressure-reduction determining means for determining a reduction in pressure of tires fitted to the follower wheels (WFL and WFR) and tires fitted to the driven wheel (WRL and WRR) by comparing the rotation-number ratios (CVWL and CVWR) calculated by said rotation-number ratio calculating means (M5) with a predetermined reference value.
1 Assignment
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Accused Products
Abstract
A reduction in pressure in tires fitted to follower wheels and driven wheels is precisely determined irrespective of slipping states of the driven wheels. A driven wheel slip rate calculating means M1 calculates driven wheel slip rates λL and λR. A driven wheel torque calculating means M2 calculates a driven wheel torque TQDW. A driven wheel slip rate estimating means M4 estimates a characteristic of variation in driven wheel slip rates λL and λR relative to the variation in driven wheel torque TQDW using a least squares method. A rotation-number ratio calculating means M5 calculates ratios CVWL and CVWR of the numbers of rotations of the follower wheels to the numbers of rotations of the driven wheels in a state in which the driven wheel torque in a graph of the variation characteristic is equal to zero. A tire pressure-reduction determining means M6 then determines a reduction in pressure from a difference in diameter between the follower wheels and the driven wheels by comparing the rotation-number ratios CVWL and CVWR with a reference value.
23 Citations
4 Claims
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1. A tire pressure-reduction determining system for wheels of a vehicle, comprising:
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a driven wheel slip rate calculating means (M1) for calculating driven wheel slip rates (λ
L and λ
R) based on follower wheels speeds (VWNL and VWNR) and driven wheel speeds (VWDL and VWDR);a driven wheel torque calculating means (M2) for calculating a driven wheel torque (TQDW) based on an engine torque; a driven wheel slip rate estimating means (M4) for estimating a characteristic variation in driven wheel slip rates (λ
L and λ
R) relative to the driven wheel torque (TQDW) based on the driven wheel slip rates (λ
L and λ
R) and the driven wheel torque (TQDW);a rotation-number ratio calculating means (M5) for calculating rotation-number ratios (CVWL and CVWR) between follower wheels (WFL and WFR) and driven wheels (WRL and WRR) said driven wheel slip rates (λ
L and λ
R) at the time when the driven wheel torque is zero, from said variation characteristic estimated by said driven wheel slip rate estimating means (M4); anda tire pressure-reduction determining means for determining a reduction in pressure of tires fitted to the follower wheels (WFL and WFR) and tires fitted to the driven wheel (WRL and WRR) by comparing the rotation-number ratios (CVWL and CVWR) calculated by said rotation-number ratio calculating means (M5) with a predetermined reference value. - View Dependent Claims (2, 3, 4)
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Specification