Patent Publication Number: US-2005131598-A1

Title: Machine sensor with redundant datalogger OEM datalogger

Description:
BACKGROUND OF INVENTION  
      This invention pertains to a machine sensing system that is designed to have an onboard datalogging and post-event time keeping ability. This invention is applicable for a variety of machines; however, for the sake of clarity and simplicity, a vehicle will be used as the example machine. More and more mechanical systems are being controlled by electronic systems. The proliferation of sensors and electronic control systems allow vehicles to monitor and adjust their operation without the intervention of an operator. Most of the electronic systems aboard a modern vehicle have the ability to sense specific parameters, and make adjustments according to predefined algorithms and/or learned algorithms.  
      Along with making adjustments to optimize the operation of the vehicle, these electronic control systems are also designed to detect minor or major faults within the vehicle. One method of classifying faults in a vehicle is to view them as either internal to the electronic control system or external to the electronic control system. The internal faults are generally detected by self-diagnostic systems that run predefined tests to determine if the electronic control system is working correctly. Component and/or subsidiary system sensors generally detect the external faults. Once detected, the fault information is sent to the system controller for processing; a system controller will be referred to as an Electronic Control Unit, (ECU).  
      The ECU is designed to control the vehicle by making decisions based upon feedback from components and sub-systems, monitor vehicle operational conditions and internal and external faults, record operational information and fault conditions, communicate both operational information, and fault information to operators and interface with diagnostic equipment.  
      Today, most vehicles, and other complex machines, are made up of a variety of components and subsidiary systems from different suppliers. These suppliers or Original Equipment Manufacturers, (OEM&#39;s), supply the components and/or subsidiary systems that are then combined to make the vehicle or complex machine. Sometimes the subsidiary systems have a subsidiary electronic control unit, (SECU). These SECU&#39;s control the subsidiary system and also communicate with the ECU so that the entire vehicle operates correctly. One limitation of this system, from the viewpoint of the OEM, is that even though the information is detected by the OEM&#39;s SECU, the recording and communicating of fault conditions is usually handled by the ECU, which is out of their control. This invention relates to the use of a post fault event datalogging system that interfaces with the vehicle&#39;s ECU as well as maintains its own recording and communicating functionality.  
     BRIEF SUMMARY OF THE INVENTION  
      In a complex machine such as a vehicle, the apparatus and control system notifies the machine or vehicle electronic control unit, if present, as well as maintaining a post event timer or counter that is specifically designed to help the component or subsidiary system OEM determine fault detection, failure diagnosis, and time dependant post event actions that are or are not taken by the operator of the machine or vehicle. The information that is kept by the onboard OEM datalogger is designed for their use first, as well as for the vehicle manufacturer.  
      When subsidiary systems fail, it is not always easy to ascertain what component was the initial trigger for a failed system. For example; 
          A large bus develops a transmission fluid leak because the OEM that supplied a fitting manufactured it incorrectly, and this causes the transmission fluid to overheat and crack a tube in the transmission heat exchanger. The cracked tube causes antifreeze to get into the transmission, which immediately begins to breakdown portions of the transmission, which in turn leads to a catastrophic transmission failure. When this transmission is examined, the cause of the transmission failure will most probably be linked to the cracked heat exchanger; therefore, the heat exchanger OEM will be liable for warranty damages even though it was not their component that was the initial cause of the failure.        

      If the heat exchanger OEM had this invention as part of their design, they would not be liable for the damages. If the heat exchanger had a dielectric sensor built into it that was tied into the vehicles ECU through the OEM&#39;s SECU, the aforementioned situation could have been recorded by both the ECU and the onboard redundant datalogger.  
      The heat exchanger sensor would have been monitoring the dielectric constant and temperature of the fluid inside of the exchanger. Air has a dielectric constant of 1, oil between 2 and 4, glycol is 37, and water about 80. Normally the dielectric constant of the transmission oil will slowly increase from 2 to 4 as the temperature increases, (this is dependent upon type of oil and additives). Under normal operating conditions, the heat exchanger SECU would see the small increase in the dielectric constant with an accompanying increase in the temperature during the time that the fluid warmed up, and then both the dielectric constant and temperature would remain constant during operation. In the event of an antifreeze leak, one that was caused by a faulty heat exchanger, the heat exchanger SECU would see would see a sudden abnormally high increase in the dielectric constant inside the exchanger while seeing no significant increase, and possibly even a decrease in temperature. Just a fraction of a percentage of water would cause the dielectric constant to increase past the level of usable hot oil.  
      In the scenario where the transmission fluid level dropped due to a leak elsewhere in the vehicle, which then caused the heat exchanger to crack due to overheated oil, the heat exchanger SECU would see the same small increase in the dielectric constant with an accompanying increase in the temperature during the time that the fluid warmed up. As transmission fluid leaked out of the system the heat exchanger SECU would see an abnormal increase in temperature and an abnormal increase in the dielectric constant due to the oil breaking down as a result of overheating. Once the transmission fluid overheated to the point where it caused the heat exchanger to crack, the SECU would see a sudden increase in the dielectric constant due to the mixing of antifreeze in the transmission fluid. The information provided to the heat exchanger SECU from the dielectric and temperature sensors would provide the heat exchanger OEM with the post event data needed to show that their product was damaged by another faulty system and not the root cause of the transmission failure.  
      As shown in the previous example, this invention provides an OEM with the ability to keep additional information pertinent to their individual component or sub-system as well as providing the ECU, vehicle manufacturer, with the necessary information about the state of the OEM component or sub-system.  
      The current invention can also be used by the vehicle manufacturer to reduce warranty claims due to improper use of their vehicle. This invention is designed to keep a redundant datalogger with a post event counter. Using the aforementioned example, the vehicle manufacturer can state that if their vehicle detects an antifreeze leak, the operator will be notified and then has a set amount of time to shut down the vehicle. Since the system is designed keep up with post event datalogging, the vehicle manufacturer can use this information to determine if the operator heeded the warnings and shut down the vehicle in the proper amount of time so as not to void the warranty. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is view of the main parts of the OEM sub-system electronic control system, OEM SECU.  
       FIG. 2  is a view of how the OEM SECU interfaces with the machine. 
    
    
     DESCRIPTION ON AN EMBODIEMENT OF THE INVENTION  
      Referring to  FIG. 1  and  FIG. 2 , an OEM  5 , which supplies a sub-system  25  to a machine  20  can use a sub-system control unit, OEM SECU, which is shown and generally designated as  10 . The OEM SECU  10  can be placed anywhere on the machine  20  depending upon machine  20  design. The OEM SECU  10  is comprised of at least one sensing means, sensor  50  that is responsible for sensing at least one parameter of a machine component or sub-system, sub-system  25  and relaying that information to the OEM SECU  10  via the sensor interface  30 . The OEM SECU  10  also has counting means, counter  35 , which is used to keep up with post event time and/or time of use data. The OEM SECU  10  also has a processing means, processor  40 , which is used to control the functions of the OEM SECU  10 . The post event information that is sensed from the sensor interface  30  and the counter  35  is stored on the OEM SECU  10  in the memory means, memory  45 .  
      During normal operation of the machine  20 , the machine&#39;s electronic control unit, ECU  55 , is responsible for controlling the functions of machine  20 . The ECU  55  receives information from the OEM SECU  10 , via the ECU interface  65 , and processes it in whatever manner it was designed for. However, when there is a fault with a sub-system  25  that the OEM SECU  10  is responsible for, the OEM SECU  10  begins maintaining time and/or time of use information via the counter  35  and stores that in the memory  45 . The OEM SECU  10  also sends this fault information to the ECU  55  so that it may use the information to continue to control the machine  20  and, if so designed, notify the machine operator  60 . In some cases the OEM SECU  10  may also send information directly to the machine  20 , via the machine interface  70 . Depending upon the design of the machine  20 , the OEM SECU  10  may also directly notify the machine operator  60 , via the operator interface  75 .  
      Once the OEM SECU  10  has detected a fault it counts time and/or time of use via the counter  35 . This post event time and/or time of use information is maintained by the OEM SECU  10  and is stored in the OEM SECU  10 &#39;s memory  45 . When the faulty sub-system  25  that the OEM SECU  10  has been responsible for controlling is analyzed, the OEM  5  connects to the OEM SECU  10  via the OEM interface  80  and retrieves the counter  35  information that has been stored in memory  45 . This information can be used by the OEM  5  to determine if their component was the cause of the machine  20  fault or some other portion of the machine  20  caused the sub-system  25  to fail. This counter  35  information can also be used to verify if the machine operator  60  acted appropriately and in the correct amount of time as mandated by the machine  20  warranty.  
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