US4749239A — Hydraulic pressure control system for motor vehic…

Claim 1

Independent Claim 240 words

A hydraulic pressure control system for a motor vehicle, comprising: wheel braking means for braking a wheel of said vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching at least between an increasing and a decreasing of said hydraulic pressure applied to said wheel braking means, said braking pressure switching means including a valve with two positions, the hydraulic pressure increasing with the valve in one position and decreasing with the valve in another position; and hydraulic pressure control means for producing a control signal and supplying said control signal to said braking pressure switching means at a predetermined interval to increase and decrease said applied hydraulic pressure, to cause the hydraulic pressure value applied to said wheel braking means to approach a target hydraulic pressure value, said control means including: means for determining a target hydraulic pressure based on system conditions; means for estimating an estimated hydraulic pressure value which is currently being applied to said wheel braking means, and obtaining first and second reference values based on said estimated value; means for comparing said target hydraulic pressure value with said first and second reference values and producing said control signal in accordance with the results of the comparison, including duty cycle control means for setting a duty cycle of said control signal as a duty ratio which is predetermined on the basis of said target hydraulic pressure value and said estimated hydraulic pressure value.

Claim 2

Dependent Claim 240 words

A hydraulic pressure control system for a motor vehicle, comprising: wheel braking means for braking a wheel of said vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching at least between an increasing and a decreasing of said hydraulic pressure applied to said wheel braking means, said braking pressure switching means including a valve with two positions, the hydraulic pressure increasing with the valve in one position and decreasing with the valve in another position; and hydraulic pressure control means for producing a control signal and supplying said control signal to said braking pressure switching means at a predetermined interval to increase and decrease said applied hydraulic pressure, to cause the hydraulic pressure value applied to said wheel braking means to approach a target hydraulic pressure value, said control means including: means for determining a target hydraulic pressure based on system conditions; means for estimating an estimated hydraulic pressure value which is currently being applied to said wheel braking means, and obtaining first and second reference values based on said estimated value; means for comparing said target hydraulic pressure value with said first and second reference values and producing said control signal in accordance with the results of the comparison, including duty cycle control means for setting a duty cycle of said control signal as a duty ratio which is predetermined on the basis of said target hydraulic pressure value and said estimated hydraulic pressure value.

Claim 3

Dependent Claim 39 words

A hydraulic pressure control system as claimed in claim 1, further comprising a rotational speed sensor coupled to said wheel, wherein said target hydraulic pressure value is determined on the basis of a signal from said rotational speed sensor.

Claim 4

Dependent Claim 37 words

A hydraulic pressure control system as claimed in claim 1, wherein said estimating means includes means for estimating said first and second reference values as values at the time of starting of a hydraulic pressure control cycle.

Claim 5

Dependent Claim 42 words

A hydraulic pressure control system as claimed in claim 1, wherein said duty cycle control means includes means for producing said control signal with a duty ratio of 0% when said target hydraulic pressure value is smaller than said first reference value.

Claim 6

Dependent Claim 42 words

A hydraulic pressure control system as claimed in claim 1, wherein said duty cycle control means includes means for producing said control signal with a duty ratio of 100% when said target hydraulic pressure value is greater than said second reference value.

Claim 7

Dependent Claim 202 words

A hydraulic pressure control system for a motor vehicle, comprising: wheel braking means for braking a wheel of said vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching at least between an increasing and a decreasing of said hydraulic pressure applied to said wheel braking means; hydraulic pressure control means for determining, at first predetermined interval, a control signal with a duty ratio to be supplied said braking pressure switching means so that the hydraulic pressure applied to said wheel braking means approaches a target hydraulic pressure value, said control means including means for estimating an estimated hydraulic pressure value to use as said applied hydraulic pressure, and obtaining first and second reference values based on said estimated hydraulic pressure value, means for comparing said target hydraulic pressure value with said first and second reference values and producing said control signal in accordance with the results of the comparison, and means for correcting said duty ratio of said control signal at a second predetermined interval after the duty ratio thereof is determined at said first predetermined interval, the duty ratio being corrected by an amount proportional to the number of times of elapse of said second predetermined interval.

Claim 8

Dependent Claim 202 words

A hydraulic pressure control system for a motor vehicle, comprising: wheel braking means for braking a wheel of said vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching at least between an increasing and a decreasing of said hydraulic pressure applied to said wheel braking means; hydraulic pressure control means for determining, at first predetermined interval, a control signal with a duty ratio to be supplied said braking pressure switching means so that the hydraulic pressure applied to said wheel braking means approaches a target hydraulic pressure value, said control means including means for estimating an estimated hydraulic pressure value to use as said applied hydraulic pressure, and obtaining first and second reference values based on said estimated hydraulic pressure value, means for comparing said target hydraulic pressure value with said first and second reference values and producing said control signal in accordance with the results of the comparison, and means for correcting said duty ratio of said control signal at a second predetermined interval after the duty ratio thereof is determined at said first predetermined interval, the duty ratio being corrected by an amount proportional to the number of times of elapse of said second predetermined interval.

Claim 9

Dependent Claim 30 words

A hydraulic pressure control system as claimed in claim 6, wherein said correcting means corrects the duty ratio by subtracting said amount from a value corresponding to the duty ratio.

Claim 10

Dependent Claim 34 words

A hydraulic pressure control system as claimed in claim 7, wherein said amount is obtained by multiplying the number of the times of elapse of said second predetermined interval by said second predetermined interval.

Claim 11

Dependent Claim 50 words

A hydraulic pressure control system as claimed in claim 1, further comprising means for storing a predetermined map between said estimated hydraulic pressure value, said target hydraulic pressure value and a duty ratio, wherein said control means determines the duty ratio of said control signal in accordance with said map.

Claim 12

Dependent Claim 38 words

A hydraulic pressure control system as claimed in claim 1, wherein the hydraulic pressure is linearly varied on increasing due to the duty ratio, and the hydraulic pressure is curvedly varied on decreasing due to the duty ratio.

Claim 13

Dependent Claim 19 words

A system as in claim 1 wherein said estimated hydraulic pressure value is initially estimated as a predetermined value.

Claim 14

Dependent Claim 67 words

A system as in claim 1 wherein said first reference value is a maximum pressure value indicative of an amount of pressure applied to said wheel braking means during a time of only pressure increasing at said estimated hydraulic pressure, and said second reference value is a minimum pressure value indicative of a pressure applied to said wheel braking means during a time of only pressure decreasing.

Claim 15

Dependent Claim 191 words

A hydraulic pressure control system for a motor vehicle comprising: braking means for braking a wheel of a vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching between an increasing of hydraulic pressure and a decreasing of hydraulic pressure applied to said wheel braking means; and control means for: a. setting a target pressure Py in accordance with system conditions; b. estimating an estimated hydraulic pressure as a predetermined amount at a time of hydraulic pressure control initiation; c. determining, based on said estimated hydraulic pressure, a first reference value indicative of a maximum pressure increase and a second reference value indicative of a maximum pressure decrease; d. comparing said target pressure with said first reference value and said second reference value; e. adjusting said estimated hydraulic pressure Px based on said comparison; f. determining a duty cycle of said braking pressure switching means based on said comparison; g. allowing a predetermined time interval to elapse; and h. repeating said steps (c)-(g) after every said predetermined interval of time elapses to cause said hydraulic pressure applied to said braking means to approach said target hydraulic pressure value.

Claim 16

Dependent Claim 191 words

A hydraulic pressure control system for a motor vehicle comprising: braking means for braking a wheel of a vehicle responsive to an applied hydraulic pressure; braking pressure switching means for switching between an increasing of hydraulic pressure and a decreasing of hydraulic pressure applied to said wheel braking means; and control means for: a. setting a target pressure Py in accordance with system conditions; b. estimating an estimated hydraulic pressure as a predetermined amount at a time of hydraulic pressure control initiation; c. determining, based on said estimated hydraulic pressure, a first reference value indicative of a maximum pressure increase and a second reference value indicative of a maximum pressure decrease; d. comparing said target pressure with said first reference value and said second reference value; e. adjusting said estimated hydraulic pressure Px based on said comparison; f. determining a duty cycle of said braking pressure switching means based on said comparison; g. allowing a predetermined time interval to elapse; and h. repeating said steps (c)-(g) after every said predetermined interval of time elapses to cause said hydraulic pressure applied to said braking means to approach said target hydraulic pressure value.

Claim 17

Dependent Claim 72 words

A system as in claim 13 wherein said first reference value is a maximum pressure value indicative of an amount of pressure applied to said wheel braking means during a time of only pressure increasing at said estimated hydraulic pressure, and said second reference value is a minimum pressure value indicative of a pressure applied to said wheel braking means during a time of only pressure decreasing at said estimated hydraulic pressure.

Claim 18

Independent Claim 174 words

A method for controlling hydraulic pressure for a motor vehicle brake which includes wheel braking means for braking a wheel of the vehicle responsive to an applied hydraulic pressure, and braking pressure switching means for switching between an increasing and a decreasing of the hydraulic pressure applied to the wheel braking means, comprising the steps of: a. setting a target hydraulic pressure P y in accordance with system conditions; b. estimating an estimated hydraulic pressure actually applied to a wheel of the vehicle; c. determining a first reference value indicative of a maximum hydraulic pressure applied to said wheel using said hydraulic pressure Px and a second reference value indicative of a minimum hydraulic pressure applied to said wheel using said hydraulic pressure Px; d. comparing said target hydraulic pressure with said first and second reference values; e. setting a duty cycle of said braking pressure switching means based on said comparison; f. allowing a predetermined time interval to elapse; and g. repeating said steps (c)-(f) after every said predetermined interval of time elapses.

Claim 19

Independent Claim 174 words

A method for controlling hydraulic pressure for a motor vehicle brake which includes wheel braking means for braking a wheel of the vehicle responsive to an applied hydraulic pressure, and braking pressure switching means for switching between an increasing and a decreasing of the hydraulic pressure applied to the wheel braking means, comprising the steps of: a. setting a target hydraulic pressure P y in accordance with system conditions; b. estimating an estimated hydraulic pressure actually applied to a wheel of the vehicle; c. determining a first reference value indicative of a maximum hydraulic pressure applied to said wheel using said hydraulic pressure Px and a second reference value indicative of a minimum hydraulic pressure applied to said wheel using said hydraulic pressure Px; d. comparing said target hydraulic pressure with said first and second reference values; e. setting a duty cycle of said braking pressure switching means based on said comparison; f. allowing a predetermined time interval to elapse; and g. repeating said steps (c)-(f) after every said predetermined interval of time elapses.

Claim 20

Dependent Claim 21 words

A method as in claim 15 comprising the further step of updating said estimated hydraulic pressure Px based on said comparison.

Claim 21

Dependent Claim 20 words

A method as in claim 16 comprising the further step of estimating said estimated hydraulic pressure as a predetermined amount.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-06-07	1991-12-07	1992-06-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-06-07	1995-12-07	1996-06-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-06-07	1999-12-07	2000-06-07	$7700.00	Window Closed / Lapsed

Hydraulic pressure control system for motor vehicles

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