EQUIPMENT SERVICE VEHICLE HAVING
ON-BOARD DIAGNOSTIC SYSTEM
CROSS-REFERENCE TO RELATED
This application is a continuation of U.S. Ser. No. 09/500, 506, filed Feb. 9, 2000, now U.S. Pat. No. 6,553,290, issued Apr. 22, 2003, hereby incorporated by reference.
FIELD OF THE INVENTION 10
This invention relates to diagnostic systems for equipment service vehicles. In particular, this invention relates to an on-board diagnostic system for equipment service vehicles.
DESCRIPTION OF RELATED ART
Modern vehicles have become increasingly complex and difficult to maintain. In order to enable more efficient vehicle maintenance, it is desirable to be able to accurately diagnose 20 malfunctioning subsystems, such as engine systems, transmission systems, and so on, as well as specific vehicle components. When a malfunction is not properly diagnosed, the result is typically that parts which are fully operational are repaired or replaced, that parts which are repairable are 25 replaced, and/or that parts which are not fully operational are not repaired or replaced. Accurate diagnoses therefore allow more efficient vehicle maintenance by avoiding unnecessary repairs and replacements, and by enabling necessary repairs and replacements to be made. 30
It is known to provide electronic diagnostic systems to aid in the accurate diagnoses of vehicle malfunctions. Government Report No. CR-82-588-003, entitled "STE/ICE-R Design Guide For Vehicle Diagnostic Connector Assemblies," February 1988, describes a diagnostic system used in 35 connection with military vehicles. According to the approach described in this document, a military vehicle is provided with numerous sensors that are located throughout the vehicle and each of which obtains information pertaining to the health and operation of a subsystem of the vehicle. The sen- 40 sors are used to measure typical parameters of interest such as engine RPM, engine temperature, fuel pressure, and so on. The sensors are connected by way of vehicle wiring to a common connector assembly. Diagnostic equipment provided at a maintenance depot is then capable of connecting to 45 the various sensors by way of the connector assembly. At the maintenance depot, the diagnostic equipment can be utilized to perform tests on the vehicle to aid pinpointing the source of vehicle system malfunction.
In this arrangement, the sensors that are used by the diag- 50 nostic system are used exclusively by the diagnostic equipment at the maintenance depot, and not by other systems during normal operation of the vehicle. Additionally, in this arrangement, the connector assembly defines a hardwired analog interface between the sensors and the diagnostic 55 equipment, and the diagnostic equipment expects signals appearing at given pins of the connector assembly to have predefined signal characteristics that are unique to the sensor utilized.
This approach suffers several disadvantages. First, this 60 approach is expensive to implement because it requires numerous sensors above and beyond those required for normal operation of the vehicle. Additionally, the required sensors typically have unique signal characteristics that are specifically matched to the diagnostic equipment, and therefore 65 the sensors are specialty items that are more expensive and not commonly available.
Second, this approach results in a diagnostic system with an unduly limited capability to accurately diagnose system faults. The capabilities of the diagnostic system are limited by the fact that the diagnostic system only utilizes information that is available from the diagnostic system sensors and not from other sources of information available on-board the vehicle. Therefore, the number of different types of information that can be obtained is limited to the number of diagnostic system sensors utilized. Further, because the sensors that are utilized tend to be specialty items as previously noted, they often do not incorporate the latest advances in sensor technology that provide performance/durability improvements over earlier sensor technologies. This further limits the accuracy of the diagnostic system as compared to that which could otherwise be achieved.
Finally, this approach is unduly cumbersome to utilize. As previously noted, the diagnostic equipment is provided at a maintenance depot and not on-board the vehicle. Therefore, in order to have a vehicle malfunction diagnosed, the vehicle must be brought to the maintenance depot. This requirement is inconvenient and limits the potential for field servicing of vehicles to minimize the amount of time that the vehicle is out of service for maintenance reasons.
SUMMARY OF THE INVENTION
According to a first preferred embodiment, an equipment service vehicle comprises a network communication link, a plurality of vehicle subsystems, a test control module, and an operator interface. Each vehicle subsystem comprises a mechanical system and an electronic control system that controls the mechanical system. Each respective electronic control system is connected to the network communication link and transmits information pertaining to the health and operation of the mechanical system on the network communication link. The test control module is mounted on board the vehicle and is coupled to the plurality of vehicle subsystems by way of the network communication link. The test control module is programmed to acquire at least some of the information pertaining to the health and operation of the mechanical system. The operator interface is mounted on board the vehicle and is coupled to the test control module. The operator interface comprises a display that displays a menu of test options to an operator and an input device that receives an operator input indicative of a menu selection made by the operator. The menu selection indicates a test selected by the operator. At least some of the information pertaining to the health and operation of the mechanical system, including results of the test, are displayed to the operator.
According to a second preferred embodiment, a method of diagnosing a fault on an equipment service vehicle is provided. The method comprises displaying a plurality of test options to an operator using an operator interface that is mounted on the vehicle. The method also comprises receiving an operator input using the operator interface, the input being indicative of a selection made by the operator and indicating a test selected by the operator. The method also comprises performing the selected test on the vehicle in response to the operator input, including communicating information pertaining to the health and operation of a vehicle subsystem from a control system for the vehicle subsystem to the operator interface by way of a network communication link. The method also comprises transmitting information pertaining to health and operation of a vehicle subsystem from an electronic control system for the subsystem to the operator inter