ALTITUDE COMPENSATING TRAILER BRAKE SYSTEM
First Claim
1. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
- a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system, and generating a vacuum supply level signal based on a pressure of the vacuum supply;
an ambient pressure sensor generating an ambient pressure signal; and
a controller coupled to the vacuum supply sensor and to the ambient pressure sensor, the controller generating a vacuum pump switch signal based on the vacuum supply level signal and the ambient pressure signal.
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Accused Products
Abstract
The invented apparatus is designed for use with a tow vehicle and trailer combination. The apparatus comprises a controller, a vacuum supply sensor, and a sensor unit used to measure the barometric pressure and/or elevation of the current location of the tow vehicle/trailer combination. Using information from the sensor unit, the controller determines a vacuum pump activation level and/or deactivation level appropriate for the ambient pressure in which the apparatus is operating. By monitoring the signal supplied by the vacuum supply sensor and by operating a vacuum pump switch signal, the controller maintains a supply of vacuum between the activation and deactivation levels. In this manner, the controller can compensate for changes in local conditions so as to operate the vacuum pump in an efficient manner while maintaining an adequate supply of vacuum for operation of the trailer brake system.
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Citations
60 Claims
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1. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system, and generating a vacuum supply level signal based on a pressure of the vacuum supply;
an ambient pressure sensor generating an ambient pressure signal; and
a controller coupled to the vacuum supply sensor and to the ambient pressure sensor, the controller generating a vacuum pump switch signal based on the vacuum supply level signal and the ambient pressure signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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an absolute pressure sensor coupled to sense a vacuum supply of the trailer brake system, and generating an absolute vacuum supply level signal based on an absolute pressure of the vacuum supply; and
a controller coupled to the absolute pressure sensor, and generating a vacuum pump switch signal based on the vacuum supply level signal, the controller being programmed to activate the vacuum pump switch signal from a deactivated state when the vacuum supply signal level is less than or equal to a predetermined activation level, and further programmed to deactivate the vacuum pump switch signal from an activated state when the vacuum supply signal level is greater than or equal to a predetermined deactivation level.
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18. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system, and generating a vacuum supply level signal based on a pressure of the vacuum supply;
a GPS receiver generating a location signal representing a location of the trailer brake system;
a controller coupled to the vacuum supply sensor and to the OPS receiver, the controller generating a vacuum pump switch signal based on the vacuum supply level signal and the location signal. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system, and generating a vacuum supply level signal based on a pressure of the vacuum supply;
an altimeter circuit generating an elevation signal; and
a controller coupled to the vacuum supply sensor and to the altimeter circuit, the controller generating a vacuum pump switch signal based on the vacuum supply level signal and the elevation signal. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. An apparatus for use with brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system, and generating a vacuum supply level signal based on a pressure of the vacuum supply;
at least one switch having at least two different positions and configured to supply a deactivation level selection;
a controller coupled to the vacuum supply sensor and to the switch, the controller generating a vacuum pump switch signal based on the vacuum supply level signal, the controller being programmed to retrieve a deactivation level from its memory based on a position of the switch, and further programmed to deactivate the vacuum pump switch signal from an activated state when the vacuum supply signal level is greater than or equal to the deactivation level retrieved from the memory.
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43. An apparatus for use with driver-operated brake systems of a tow vehicle and a trailer towed by the tow vehicle, the apparatus comprising:
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a vacuum supply sensor coupled to sense a vacuum supply of the trailer brake system used to generate a vacuum control signal based on a brake fluid control signal generated by operation of the tow vehicle brake system by the driver, the vacuum supply sensor generating a vacuum supply level signal based on a pressure of the vacuum supply;
an ambient pressure sensor generating an ambient pressure signal;
a controller coupled to the vacuum sensor and to the ambient pressure sensor, the controller generating a vacuum pump switch signal based on the vacuum supply level signal and the ambient pressure signal; and
a vacuum pump coupled to the controller, and generating vacuum for the supply based on the vacuum pump switch signal. - View Dependent Claims (44)
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45. (cancelled)
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46. A method comprising the steps of:
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a) sensing a pressure level of a vacuum supply;
b) sensing a pressure level of ambient air;
c) determining at least one of an activation level and a deactivation level based on the sensed ambient air pressure;
d) comparing the sensed pressure level of the vacuum supply with the activation level and/or the deactivation level;
e) generating a vacuum pump switch signal based on the comparison in said step (d) f) sensing a brake fluid signal used to operate a brake system of a vehicle towing a trailer; and
g) generating a vacuum control signal with the vacuum supply to operate a trailer brake system, based on the brake fluid signal sensed in said step (f).
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47. (cancelled)
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48. (cancelled)
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49. (cancelled)
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50. (cancelled)
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51. (cancelled)
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52. A method comprising the steps of:
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a) sensing a pressure level of a vacuum supply;
b) determining an elevation of a trailer brake system;
c) determining at least one of an activation level and a deactivation level based on the elevation determined in step (b);
d) comparing the sensed pressure level of the vacuum supply with the activation level and/or the deactivation level; and
e) generating a vacuum pump switch signal based on the comparison in said step (d). - View Dependent Claims (53, 54, 55, 56, 57, 58, 59, 60)
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Specification