Multiple-stage collision avoidance braking system and method

Abstract

An apparatus and method for automatic actuation and control of an air braking system on a commercial vehicle, under a warning of collision conditions, has multiple stages of operation, which supplements the normal brake pedal activation and control of the air brake operation under the driver's foot control. Automatic actuation has two stages: (1) impending collision automatic activation and control for 1.4 second closure; and (2) imminent collision automatic activation and control for 0.9 seconds closure. A determination of closure occurring in excess of 1.6 seconds, turns off the warning, and also deactivates the automatic activation and control. A modification to a standard air brake system structure enables the addition of the automatic activation and control stages. When an impending collision signal is received, an activation component operates valves to pressurize the rear brakes to 40 psi. When the air pressure at the rear brakes rises to 20 psi, other valves pressurize the front brakes. This first stage automatic operation stops or slows the vehicle with 40 psi on the rear brakes and 20 psi on the front brakes. When an imminent collision signal is received, the activation component opens valves to pressurize the rear brakes to 120 psi. Once the air pressure at the rear brakes rises to 20 psi, the front brakes are also pressurized. This second stage automatic operation stops the vehicle with 120 psi on the rear brakes and 80 psi on the front brakes, unless restricted to a lower pressure by the brake system manufacturer. The driver can deactivate the automatic braking functions by stepping on the brake pedal or by operating the vehicle turn signals.

What is claimed: 
     
         1 . A method of automatic braking, collision avoidance for vehicle air brake systems, including the steps of:
 detecting an impending collision condition;   pressurizing the rear brakes with a source pressure of about 40 psi when said impending collision condition is detected;   pressurizing the front brakes when the pressure at the rear brakes has risen to about 20 psi; and   maintaining an air pressure of 40 psi at the rear brakes and 20 psi at the front brakes to slow or stop the vehicle.   
     
     
         2 . The method of collision avoidance of  claim 1 , including the steps of:
 detecting an imminent collision condition;   pressurizing the rear brakes with a source pressure of about 120 psi when said imminent collision condition is detected;   begin pressurizing the front brakes when the pressure at the rear brakes has risen to about 20 psi; and   maintaining an air pressure of about 120 psi at the rear brakes and about 80 psi at the front brakes to slow or stop the vehicle.   
     
     
         3 . The method of collision avoidance of  claim 1 , including the steps of:
 detecting an imminent collision condition;   pressurizing the rear brakes to a pressure of about 80 psi when said imminent collision condition is detected;   begin pressurizing the front brakes when the pressure at the rear brakes has risen to about 20 psi; and   maintaining an air pressure of about 80 psi at the rear brakes and about 60 psi at the front brakes to slow or stop the vehicle.   
     
     
         4 . The method of collision avoidance of  claim 1 , including releasing said brake pressure and returning brake operation entirely to the driver when a non-collision condition is detected. 
     
     
         5 . The method of collision avoidance of  claim 1 , wherein said impending collision is determined to occur in about 1.4 seconds. 
     
     
         6 . The method of collision avoidance of  claim 2 , wherein said imminent collision is determined to occur in about 0.9 seconds. 
     
     
         7 . The method of collision avoidance of  claim 4 , wherein said non-collision condition is determined by a closure of greater than 1.6 seconds. 
     
     
         8 . The method of collision avoidance of  claim 1 , including maintaining a front air pressure reservoir at 120 psi, and a rear air pressure reservoir at 120 psi, and pressurizing said rear brakes from said rear reservoir, and pressurizing said front brakes from said front reservoir. 
     
     
         9 . The method of collision avoidance of  claim 2 , including maintaining a front air pressure reservoir at 120 psi, and a rear air pressure reservoir at 120 psi, wherein said pressurizing of said rear brakes is from said rear reservoir, and said pressurizing of said front brakes is from said front reservoir. 
     
     
         10 . The method of collision avoidance of  claim 8 , wherein the step of pressurizing the rear brakes includes opening at least one valve between said rear air pressure reservoir and said rear service brakes with an air control pressure of 120 psi, and opening at least one valve between said front air pressure reservoir and said front service brakes with an air control pressure of 120 psi. 
     
     
         11 . The method of collision avoidance of  claim 8 , wherein the step of pressurizing the rear brakes includes opening at least one valve between said rear air pressure reservoir and said rear service brakes with an air control pressure of 120 psi, and opening at least one valve between said front air pressure reservoir and said front service brakes with an air control pressure of 120 psi. 
     
     
         12 . An automatic braking collision avoidance system, for a commercial vehicle air brake system, having a front brake circuit and a rear brake circuit, comprising:
 a collision warning device providing a signal representing closure time with a foregoing vehicle or object, including an impending collision warning signal and an imminent collision warning signal;   a rear air pressure reservoir, and a front air pressure reservoir, where the pressure in said rear and front reservoirs is each maintained at the same pressure;   an actuation apparatus element being electrically connected to said collision warning device for reacting to an impending collision warning signal and to an imminent collision warning signal;   at least one connection element in a pneumatic pressure line between said rear air pressure reservoir and said rear service brake circuit, wherein said connection element operates as a valve;   at least one connection element in a pneumatic pressure line between said front air pressure reservoir and said front service brake circuit, wherein said connection element operates as a valve;   wherein when an impending collision warning signal is detected, said actuation apparatus first controls said rear air service brake pressure to pressurize said rear brake circuit such that when said rear brake pressure reaches a first threshold, said actuation apparatus controls said front air service brake pressure to pressurize said front brakes;   wherein when the pressure at said rear brakes and the pressure at said front brakes each reach its predetermined target pressure, further pressure increases are ceased and the target pressures are maintained.   
     
     
         13 . The automatic braking collision avoidance system of  claim 12 , wherein when an imminent collision warning signal is detected, said actuation apparatus first controls said rear air service brake pressure to pressurize said rear brake circuit at a target pressure of said rear air reservoir pressure, wherein when said rear brake pressure reaches a first threshold, said actuation apparatus controls said front air service brake pressure to pressurize said front brakes to a target pressure of less than said rear brake target pressure, wherein when said rear brake pressure and said front brake pressure each reach the predetermined ultimate target pressures, further air pressure increases are ceased, and the ultimate target pressures are maintained. 
     
     
         14 . The automatic braking collision avoidance system of  claim 12 , wherein the first threshold pressure at said rear brakes is about 20 psi, and wherein the predetermined target pressure at which said air pressure increases are ceased is at about 40 psi for said rear brakes, and at about 20 psi for said front brakes. 
     
     
         15 . The automatic braking collision avoidance system of  claim 13 , wherein said rear air pressure reservoir and said front air pressure reservoir are each at about 120 psi, and wherein the rear brake pressure threshold for activating said front brake pressure is about 20 psi, and wherein the predetermined ultimate target pressure at said rear brake circuit is 120 psi and at said front brake circuit is about 80 psi. 
     
     
         16 . The automatic braking collision avoidance system of  claim 12  wherein said valve action between said rear air pressure reservoir and said rear service brake circuit is controlled with a high pressure pneumatic signal from said actuation apparatus, which pneumatic control signal passes through a delayed operation gate pneumatically connected to a rear brake control valve, the operation of said delayed operation gate being controlled by a separate pneumatic control signal form said actuation apparatus. 
     
     
         17 . The automatic braking collision avoidance system of  claim 12  wherein said actuation apparatus element is an electronic solenoid operated two stage valve. 
     
     
         18 . The automatic braking collision avoidance system of  claim 13 , wherein said actuation apparatus element is an electronic solenoid operated two stage valve. 
     
     
         19 . The automatic braking collision avoidance system of  claim 18 , also including a quick release crack valve connected to the front brakes, a front brake control valve pneumatically powering said crack valve. 
     
     
         20 . A method of automatic braking, collision avoidance for vehicle air brake systems, including the steps of:
 receiving a collision indication signal;   pressurizing the rear brakes with a first higher pressure when said collision indication signal is detected;   pressurizing the front brakes when the pressure at the rear brakes has risen to a first threshold value which is less than said first higher pressure, said pressurizing maintaining a pressure differential between a higher rear brake pressure and a lower front brake pressure; and   maintaining an higher air pressure of at the rear brakes and a lower air pressure at the front brakes at said pressure differential, to slow or stop the vehicle.