Abstract:
A device, for controlling a vehicle-occupant restraining device in a vehicle having a trailer, includes an arrangement for controlling the vehicle-occupant restraining device as a function of at least one signal of the trailer.

Description:
BACKGROUND INFORMATION 
   It is known from German Patent No. DE 697 07 148 T2 to calculate the load transfer ratio and the height of the center of gravity for a vehicle trailer system to consequently display the probability of a vehicle rollover to the vehicle driver. The vehicle driver may then use this information to operate the vehicle more safely, thereby reducing the occurrence of rollover accidents. 
   A disadvantage in this case is that the rollover probability is only displayed and not automatically further processed and provided to other systems in the vehicle. 
   An object of the present invention is to further refine the device such that a signal from the trailer is automatically further processed in a safety system. 
   SUMMARY OF THE INVENTION 
   The device of the present invention for controlling restraining means in a vehicle having a trailer has the advantage that information regarding the trailer is included in the deployment decision for the restraining means. As a result, the increased total mass of the vehicle/trailer combination in a crash and the increased risk of a rollover accident are able to be taken into consideration in the deployment decision for the restraining means or the rollover bar. This allows improved passenger protection. 
   It is particularly advantageous that the signal which takes the trailer into consideration in the deployment algorithm for the restraining means only indicates the presence of the trailer. As a result, the deployment algorithm is able to use worst case scenario analysis to take the influence of the trailer into consideration, for example. The presence of the trailer may be generated, for example, via a circuit which may be coupled to an electrical trailer coupling. Vehicles having a trailer coupling have a turn indicator light in the driver&#39;s field of vision which blinks only once when the turn indicator is operated and there is no electrical load at the electrical coupling for the trailer and which blinks during the entire operation of the turn indicator when there is an electrical load. In a very simple variation, this signal is used to deduce an increased vehicle load. 
   However, since the signal may indicate an illuminated trailer as well as an illuminated bicycle rack, additional information is needed for clarification. This additional information is transmitted from the trailer to the towing vehicle. An electrical connector or another communication connection between the vehicle and the trailer may be used for this purpose. This signal may also indicate only the presence of the trailer or additional special information regarding weight and driving condition. Information about weight and driving condition may include, for example, the curb weight as the minimum weight, the total weight, the load distribution, or information regarding oscillatory movements. The total weight and the load distribution may be determined via pressure or weight sensors at one, two, or more axles of the trailer or via a pressure sensor between the coupling head of the towing vehicle and the coupling jaw of the trailer. The oscillatory movements may be determined, for example, via friction sensors between the coupling head of the towing vehicle and the friction elements in the coupling jaw of the trailer. This information provided by the trailer may be transmitted via the electrical coupling to the towing vehicle and provided to the control unit of the restraining means, such as airbags or seatbelt tensioners, the control unit of the rollover bar, and other systems for increasing occupant safety, such as the seat control unit or the reversible seatbelt tensioners. 
   In the case of increased oscillatory movements of the trailer, this information makes it possible, for example, to sensitize the deployment decision for the rollover bar or to operate the reversible seatbelt tensioner to bring the driver and front passenger to an optimum sitting position and to warn the driver of the increased danger. This warning is a haptic warning in this case. In addition, the increased mass and consequently reduced braking effect of the towing vehicle are able to be taken into consideration in the deployment decision for the restraint and safety systems. Moreover, the knowledge of the increased mass may be used to better predict the impact speed via precrash signals. All this information is used as input data in the control unit of the restraint and safety systems. This control unit has at least one processor on which an algorithm is executed and which makes the deployment or activation decision for the restraint and safety systems. Therefore, within this total system, additional information from the trailer is made available to the control unit in the towing vehicle to render possible a more sensitive, precise, and robust deployment decision for the safety and restraint systems and to warn the driver of an increased swerving hazard. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a block diagram of the device of the present invention. 
       FIG. 2  shows a sensor system for oscillatory movement. 
       FIG. 3  shows a further block diagram of the device of the present invention. 
   

   DETAILED DESCRIPTION 
   In current systems, the deployment decision for the restraining means in a vehicle, e.g., airbags or seatbelt tensioners, is based on information from acceleration sensors or precrash sensors. 
   The present invention provides including the trailer load directly in the triggering decision, thereby resulting in more precise deployment of the restraining means and the rollover bar. The trailer load results in a lower maximum deceleration of the vehicle/trailer combination so that trailer load information may be used as a correction value when predicting the impact speed during the evaluation of precrash signals. Moreover, the increased mass may be used in the evaluation of the acceleration signals measured, for example, by the upfront sensors or the central acceleration sensor. A vehicle/trailer combination is also more susceptible to swerving and is therefore at a greater risk of a rollover accident. As a result, the trailer information in particular should be taken into consideration when detecting a rollover occurrence. 
     FIG. 1  shows a block diagram of the device of the present invention for controlling restraining means in a vehicle having a trailer. A restraining means control unit  6  has a processor  7 , on which an algorithm  8  is calculated. This algorithm  8  is used for controlling restraining means  9 - 12  and uses sensor signals for controlling restraining means  9 - 12 . These sensor signals are supplied to control unit  6 . However, control unit  6  also has its own acceleration sensors and in some cases rotation-rate sensors for determining the plausibility of and identifying crash or rollover occurrences. Control unit  6  receives turn indicator information  1  via a first data input from an electronic circuit which indicates whether a trailer is present. Control unit  6  receives information regarding the vehicle dynamics of the trailer from a sensor via a second data input. This may be a sensor  2  for swerving movements of the trailer, for example. In particular, this sensor may be a friction sensor situated at the coupling for recording the swerving movements of the trailer. Via a third data input, control unit  6  receives information regarding the curb weight of the trailer from a weight sensor  3  or a memory situated on the trailer. Control unit  6  receives information regarding the load on the axles and the coupling of the trailer via a fourth data input  4 . This may also be taken into consideration in activating the restraining means since the load distribution influences a rollover occurrence and the vehicle dynamics of the towing vehicle. Control unit  6  is connected via a fifth data input to a precrash sensor system  5  to obtain environment information. This is important for controlling restraining means in particular. Processor  7  controls restraining means, such as airbags  9 , seatbelt tensioners  10 , seat adjustment  11 , or a rollover bar  12 , as a function of these sensor signals. 
     FIG. 2  shows a sensor system for detecting oscillatory movements of the trailer. A coupling head  21  has friction sensors  25 ,  26 , and  27 , while a coupling jaw  20 , which belongs to the trailer, has friction elements designated by reference numerals,  22 ,  23 , and  24  in this instance. Friction elements  22 ,  23 , and  24  are to counteract oscillatory movements of the trailer. 
     FIG. 3  shows a further block diagram of the device of the present invention. An airbag control unit  35  having a circuit  34  connected to its data input is located in vehicle  30 . Control unit  35  is connected via a data input/output and a data connection to a trailer  31  and an interface  36 . This allows data exchange between the trailer and vehicle  30 . In this context, information may be transmitted from the sensors in trailer  31 , such as the weight sensors for determining the load distribution, or a memory  37 , in which data, such as the curb weight of trailer  31 , is stored, to control unit  35  so that control unit  35  takes this sensor data into consideration when calculating the deployment algorithm for the restraining means. Control unit  35  receives the information from circuit  34  as to whether trailer  31  is coupled to vehicle  30  via coupling head  32  and coupling jaw  33 . Additional sensors may be situated in trailer  31  and deliver information to control unit  35  for consideration in the triggering algorithm.