Abstract:
A trailer brake controller  10  for use in a passenger vehicle  12  is provided, including a control element  11  positioned within the passenger vehicle  12 , a vehicle speed input  16  and a vehicle brake pressure input  14  providing speed and brake pressure data to the control element  11 , and a trailer brake output  18  sending a signal to the trailer in response to the vehicle speed input  16  and the vehicle brake pressure input  14.

Description:
BACKGROUND OF INVENTION 
   The present invention relates generally to a passenger vehicle brake controller and more particularly to a passenger vehicle trailer brake controller. 
   The design of passenger vehicles is often driven by a variety of factors. Two prevalent features are often the need for increased utility and the need for increased safety. Consumer convenience also can play a significant role. One area in which all such design factors must be considered is often a passenger vehicle&#39;s ability to transport objects. Passenger vehicle transport capabilities is an important design aspect of modern vehicles. The ability to haul objects and equipment is often as important as the vehicle&#39;s ability to transport additional passengers. Solutions aimed at increasing a vehicle&#39;s hauling capabilities must not only be directed at improving the vehicle&#39;s utility but must also be directed towards improving a vehicle&#39;s safety and performance while accomplishing this task. One traditional approach towards improving a vehicle&#39;s transport capabilities has been through the addition of a trailer attached to the vehicle. Trailers allow for a wide range of items to be transported by a vehicle, often without impacting transport capabilities of the vehicle&#39;s passenger compartment. 
   When a trailer&#39;s size and transport weight capabilities remain small in relation to the towing vehicle, impact on the towing vehicle&#39;s performance and safety is minimized. When the size and weight capacity, however, are increased, it is known that the trailer can impact the performance of the towing vehicle. Many states, in fact, impose restrictions on trailer design based on towing capacity. One such restriction requires the use of an independent braking controller to actuate the trailer&#39;s brakes. This allows the trailer&#39;s brakes to provide independent braking power to facilitate stopping of the vehicle/trailer combination. 
   A wide variety of trailer brake controllers are well known in the prior art. These controllers are commonly sold through after-market channels independent of the passenger vehicle. These after-market trailer brake controllers must therefore be designed to accommodate a wide variety of towing vehicles and trailer assemblies. Thus, the specific braking characteristics of a given passenger vehicle, a given trailer, or a given passenger vehicle/trailer combination are often not designed into these after-market brake controllers. In addition, intercommunication between the vehicle braking system and the trailer braking system is often minimal. Due to the wide variety of passenger vehicles capable of towing trailers, the simplistic approaches towards trailer brake controlling are often undesirable. In addition, these prior art approaches often leave the determination of a suitable brake controller to the vehicle consumer or after-market technician rather than relying on the preferable knowledge of the vehicle designers to determine suitability. It would, therefore, be highly desirable to have a trailer brake controller integrated into the passenger vehicle prior to the vehicle&#39;s sale such that proper braking performance could be predetermined and advanced braking procedures could be implemented. 
   Commercial truck/rig designs have long realized the benefit of integrating trailer brake control with the semi-cab braking. The mere proportions and travel weight of commercial cab/trailers dictates that the trailers must play a significant role in braking. In addition, significant development has been achieved in the interaction between cab and trailer braking in these commercial embodiments. Yet, despite over two decades of popularity for large passenger vehicles such as SUV&#39;s, minivans, vans, and pickup trucks, the developments within the commercial sector have not always translated into approved passenger vehicle/trailer braking. 
   One significant difference between commercial and passenger vehicle braking systems is that commercial systems often utilize the trailer as the primary braking component of the vehicle. In passenger systems, however, the passenger vehicle itself usually remains the primary braking component. Despite this fact, it is still highly desirable to have an improved coordination between trailer and co-vehicle braking systems within the passenger vehicle design. It would further be highly desirable to utilize concepts developed for commercial trucking scenarios, and adopt and adjust them to better suit passenger vehicle towing scenarios. 
   SUMMARY OF INVENTION 
   It is, therefore, an object of the present invention to provide a passenger vehicle braking system with an integrated trailer brake controller. It is a further object of the present invention to provide a passenger vehicle braking system with improved cooperation between vehicle and trailer braking. 
   In accordance with the objects of the present invention, a trailer brake controller is provided. The trailer brake controller is incorporated into the braking equipment of a passenger vehicle in order to provide a braking command signal to a trailer towed by the passenger vehicle. The trailer brake controller includes a controller element having a vehicle speed input and a vehicle brake pressure input. The trailer brake controller tailors the command signal to accommodate different vehicle speed inputs and vehicle brake pressure inputs. 
   Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a block diagram of an embodiment of a trailer brake controller in accordance with the present invention; 
       FIG. 2  is an illustration of an automotive dash assembly illustrating an embodiment of communication elements intended for use with the present invention; and 
       FIG. 3  is a detail of the communication elements illustrated in  FIG. 2 , the communication elements are intended for use with a trailer brake controller in accordance with the present invention. 
   

   DETAILED DESCRIPTION 
   Referring now to  FIG. 1 , which is an illustration of a trailer brake controller  10  in accordance with the present invention. The trailer brake controller  10  is intended for integration into a passenger vehicle braking system. It is further intended that the trailer brake controller  10  be designed, assembled, and sold with the passenger vehicle such that its control characteristics can be properly set by the vehicle manufacturer for a specific passenger vehicle. Additionally, by integrating the trailer brake controller  10  into the passenger vehicle through manufacture, assembly and distribution, control and display features for the trailer brake controller  10  may be professionally integrated into the passenger vehicle  12  design. Thus, appearance, performance, safety, and customer convenience may be improved. 
   The trailer brake controller  10  utilizes control element  11 , such as a microprocessor, having a brake pressure input  14  and a vehicle speed input  16 , in order to adjust the trailer brake output  18 . It is contemplated that the inputs from the brake pressure and vehicle speed  14 ,  16  may be utilized to adjust trailer brake output  18  in a variety of fashions. For example, when the brake pressure input  14  experiences general ramp-up in brake pressure, a similar gradual ramp-up may be applied to the trailer brake output  18 . When a sudden market increase in brake pressure input  14  is experienced, however, a step function may be applied to the trailer brake output  18  or to quickly and efficiently apply braking pressure to the trailer. In addition, the vehicle speed input  16  may be used to adjust the trailer brake output  18  such that as the speed of the vehicle increases, the level of gain of the trailer brake output  18  may be increased. Although a fairly straightforward braking algorithm has been thus described, it should be understood that a variety of trailer brake outputs  18  may be applied in response to a given brake pressure input  14  and vehicle speed input  16 . One advantage of the present invention is that the relationship of the trailer brake output  18  to the brake pressure input  14  and vehicle speed input  16  may be adjusted for the particular vehicle  12  in which the trailer brake controller  10  is mounted. 
   It is contemplated that the brake pressure input  14  and the vehicle speed input  16  may be supplied by a variety of contacts with the vehicle  12 . In one embodiment, however, it is contemplated that the brake pressure input  14  and the vehicle speed input  16  are supplied through a communication between the vehicle antilock brake system  22  and control element  11 . It is known that modern antilock brake systems often contain sensors that provide vehicle speed, vehicle acceleration, and vehicle deceleration. By placing the ABS system in communication with the control element  11 , the vehicle speed input  16  may be easily provided. In addition, the acceleration information from the ABS system  22  can be utilized to determine a brake pressure input  14 . Finally, an ABS activation input  23  may be utilized to communicate to the control element  11  when the ABS braking system  22  has been activated. This can allow the trailer brake controller  10  to tailor the trailer brake output  18  such that the trailer brakes work in cooperation with the vehicle ABS system  22 . It should be understood that although the ABS system  22  may be utilized to supply both the brake pressure input  14  and the vehicle speed input  16 , in alternate embodiments, the brake pressure input  14  may be supplied through a variety of known devices or sensors such as vehicle master cylinder sensor  24 . Again, although specific embodiments have been described that provide a brake pressure input  14  and a vehicle speed input  16 , a variety of methods of obtaining these inputs would be obvious to one skilled in the art. 
   It is intended that the trailer brake output  18  be capable of controlling a plurality of trailer brakes. Although a variety of trailer brake outputs  18  are contemplated by the present invention, one embodiment contemplates the trailer brake output  18  taking the form of an electrical output. In addition, the trailer brake controller  10  may include a variety of additional components to increase its functionality and performance. A brake indicator lamp output  26  may be used in conjunction with the trailer brake output  18  to improve the safety and performance of the trailer brake controller  10 . Similarly, a diagnostic input/output  28  may be included such that the trailer brake controller  10  may communicate with a trailer system  30  to verify the proper operation and functionality of the trailer  30 . This diagnostic input  28  not only allows the trailer brake controller  10  to inform a vehicle operator of improper connections, but may also be utilized to help inform the vehicle operator of damage or improper operation of the trailer&#39;s braking system. Power supplies  34 , ignition run/start inputs  36 , grounds  37 , and spare inputs  38  and outputs  40  may be utilized to provide basic functionality, concepts well known in the art. 
   It is further contemplated that the trailer brake controller  10  may further provide communication between the control element  11  and the owner/operator. Although this communication can take on a variety of forms, in one embodiment it is contemplated to take the form of a display  42 , a user control input  44  (such as a gain input control) and an override switch  46 . These communication elements  48  can be adapted and complimented to provide a range of communication and control to the owner/operator. Similarly, although these communication elements  48  may be positioned in numerous locations, one embodiment mounts them to the vehicle dash  50  (see  FIGS. 2 and 3 ). By equipping the vehicle with such a control system during design and manufacture, the appearance of the communication elements  48  can be significantly improved and thereby increase customer satisfaction. The display  42  can include a gain display  52  and a signal strength display  54 . The signal strength display  54  allows the owner operator to visualize the trailer brake output  18  signal and adjust the gain input control  44  to suit individual preferences. The override switch  46  can be operated by the owner/operator to apply the trailer brakes independently of the vehicle without braking. It is further contemplated that the display  42  may be utilized to communicate to the owner any improper connections or diagnostic faults determined by the control element  11 . This can serve to increase the safety and awareness of the owner by properly apprising them of the status of their trailer&#39;s operation. 
   It should be understood that it is contemplated that the trailer brake controller  10  may include a variety of additional inputs, outputs, and components in addition to those already described. Similarly, if an communication elements  48  are utilized, it is contemplated that they may include a wide variety of displays and control elements such that the owners/operators control and/or understanding of the trailer brake operation is improved. The fully integrated nature of the trailer brake controller  10  allows for close interaction with other vehicle components consistently and thereby allows the trailer brake output  18  to be closely tailored to the braking response of the vehicle  12 . 
   While particular embodiments of the invention have been shown and described, numerous variations and alternative embodiments will occur to those skilled in the arm. Accordingly, it is intended that the invention be limited only in terms of the appended claims.