Abstract:
A method of logging faults in an electronic controlled internal combustion engine that passes any fault readings through a debounce logic to determine whether the fault indication is real.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims priority to U.S. Provisional Application Ser. No. 60/877,928 filed on Dec. 29, 2006, the contents of which are incorporated herein in their entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method of logging faults in memory in an electronic controlled internal combustion engine having an electronic control unit with memory. 
   The present invention further relates to a method of filtering data signals through a debounce logic to filter erroneous fault signals. 
   2. Description of Related Art 
   Young U.S. Pat. No. 6,157,671 discloses a circuit for digitally monitoring a duty cycle of a pulse width modulated signal. The circuit includes s counter portion, a digital filter, and a data storage device. The counter portion is connectable to receive the pulse width modulated signal and is operable to monitor the pulse width modulated signal for a predetermined time period during which account value is established. The digital filter is connected to receive the count value established by the counter portion and is also connected to receive a stored count value from the storage device, the digital filter being operable to establish a filtered count value based upon the count value and the stored count value input thereto. The storage device is connected to receive the filtered count value established by the digital filter. Multiple pwm signals may also be monitored by including multiple counters, multiple storages devices, and one or more multiplexers. 
   Downs U.S. Pat. No. 6,492,818 discloses an apparatus for determining component fault conditions associated with a capacitive discharge ignition system for an internal combustion engines and includes a number of AC coupling circuits connected to a spark detection circuit, wherein the combination is responsive to a corresponding number of primary coil voltage signals to produce digital pulses indicative of recorded spark events from various secondary coils in the respective primary coils of the ignition system. A number of level shifting circuits are also included and provide a pulse width circuit with a corresponding number of level-shifted primary coil voltage signals. A pulse width circuit is responsive to the number of level-shifted primary coil voltage signals to produce appropriate digital pulses time d to match the non-zero voltage times of the various primary coil voltage signals. A voltage processing circuit is responsive to the digital signals produced by the spark detection circuit and the pulse width circuit to determine spark breakdown voltage, shorted ignition coils, worn ignition plugs, shorted ignition plugs, ignition control module faults and external arcing conditions. These faults are communicated to a service technician via a display and/or by logging such faults in memory. 
   Kendrick et al. U.S. Pat. No. 6,810,366 discloses apparatuses and methods for filtering a signal. A first processing device receives a first control signal and a first feedback signal and transmits a first error signal as a function of those signals. A second processing device receives the first error signal and transmits a second control signal as a function of the first error signal, a deadband, and a gain factor. A third processing device receives the second control signal and the first feedback signal and transmits an output signal as a function of those signals. A fourth processing device receives the out signal and transmits the first feedback signal as a function of the output signal to the first processing device and the third processing device, the first feedback signal being substantially equal to the output signal delayed by a first predetermined duration of time. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a method of logging faults in an electronic controlled internal combustion engine having an electronic control unit with memory. The electronic control unit may comprise a motor control module in electronic communication with at least one sensor to provide data signals including vehicle operating conditions, and a Common Powertrain Controller in electronic communication with the Motor Control Module. Both the Motor Control Module and the Common Powertrain Controller may be equipped with a fault code memory manager for logging faults. The method includes the steps of;
         sensing engine operating condition and transmitting a data signal indicative of said engine operating conditions to said electronic control unit;   filtering said data signals from said sensor through a debounce logic; said logic comprising a timer to measure time duration of an error in said data signal; a recovery time for any deactivation of an error and a healing time for an inactive fault self deletion; and   logging any faults after debounce filtering in a fault control module and activating any alerts indicating said faults.
 
The motor control module faults monitoring units are updated once per second, and the Common Powertrain Controller includes monitoring units that may be evaluated up to 10 times per second. When a fault is logged, the engine may reduce at least one of engine torque or engine speed.
       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic representation of an internal combustion engine, an electronic controller, and various systems; 
       FIG. 2  is a is a schematic representation of an electronic controller depicting some of the internal organization; 
       FIG. 3  is a schematic representation of a Fault Code Memory Module resident in a Common Powertrain Controller as described in  FIG. 2 . 
       FIG. 4  is a schematic representation of the software flow chart of one method according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings where like numerals depict like structures and particularly to  FIG. 1 , there is schematically represented a diagrammatic view illustrating a compression-ignition internal combustion engine system  10  incorporating various features according to the present invention is shown. The engine  12  may be implemented in a wide variety of applications including on-highway trucks, construction equipment, marine vessels, stationary generators, pumping stations, and the like. The engine  12  generally includes a plurality of cylinders disposed below a corresponding cover, indicated generally by reference numeral  14 . 
   In a preferred embodiment, the engine  12  is a multi-cylinder compression ignition internal combustion engine, such as a 3, 4, 6, 8, 12, 16, or 24 cylinder diesel engine. However, the engine  12  may be implemented having any appropriate number of cylinders  14 , the cylinders having any appropriate displacement and compression ratio to meet the design criteria of a particular application. Moreover, the present invention is not limited to a particular type of engine or fuel. The present invention may be implemented in connection with any appropriate engine (e.g., Otto cycle, Rankin cycle, Miller cycle, etc.) using an appropriate fuel to meet the design criteria of a particular application. 
   A controller  16  preferably comprises a programmable microprocessor  18  in communication with (i.e., coupled to) various computer readable storage media  20  via at least one data and control bus  22 . The computer readable storage media  20  may include any of a number of devices such as read only memory (ROM)  24 , random access memory (RAM)  26 , and non-volatile (keep-alive) random access memory (NVRAM)  28 . 
   The various types of computer-readable storage media  20  generally provide short-term and long-term storage of data (e.g., at least one lookup table, LUT, at least one operation control routine, at least one mathematical model for EGR control, etc.) used by the controller  16  to control the engine  10 . The computer-readable storage media  20  may be implemented by any of a number of known physical devices capable of storing data representing instructions executable by the microprocessor  18 . Such devices may include PROM, EPROM, EEPROM, flash memory, and the like in addition to various magnetic, optical, and combination media capable of temporary and permanent data storage. 
   The computer-readable storage media  20  may include data representing program instructions (e.g., software), calibrations, routines, steps, methods, blocks, operations, operating variables, and the like used in connection with associated hardware to control the various systems and subsystems of the engine  10 , and the vehicle. The computer readable storage media  20  generally have instructions stored thereon that may be executable by the controller  16  to control the internal combustion engine  10 . The program instructions may direct the controller  16  to control the various systems and subsystems of the vehicle where the engine  12  is implemented, with the instructions being executed by microprocessor  20 , and optionally, instructions may also be executed by any number of logic units  28 . The input ports  30  may receive signals from the various engine and vehicle systems, including sensors and switches generally designated at  32 , and the controller  16  may generate signals (e.g., the signals ACT and ADJ) at output ports  34 . The output signals are generally presented (or transmitted) to the various vehicle components. 
   A data, diagnostics, and programming interface  36  may also be selectively connected to the controller  32  via a bus and connector  38  to exchange various information therebetween. The interface  36  may be used to change values within the computer readable storage media  20 , such as configuration settings, calibration variables, and the like. 
   As used throughout the description of the present invention, at least one selectable (i.e., programmable, predetermined, modifiable, etc.) constant, limit, set of calibration instructions, calibration values (i.e., threshold, level, interval, value, amount, duration, etc.) or range of values may be selected by any of a number of individuals (i.e., users, operators, owners, drivers, etc.) via a programming device, such as the device  36  selectively connected via an appropriate plug or connector  38  to the controller  16 . 
   Rather than being primarily controlled by software, the selectable or programmable constant and limit (or range) values may also be provided by an appropriate hardware circuit having various switches, dials, and the like. Alternatively, the selectable or programmable limit and range may also be changed using a combination of software and hardware without departing from the spirit of the present invention. However, the at least one selectable value or range may be predetermined and/or modified by any appropriate apparatus and method to meet the design criteria of a particular application. Any appropriate number and type of sensors, indicators, actuators, etc. may be implemented to meet the design criteria of a particular application. 
   In at least one mode of operation, the controller  16  may receive signals from the various vehicle sensors and switches, and execute control logic embedded in hardware and software to control the engine  12 , various engine and vehicle systems  32 , and the like. In one example, the controller  16  is implemented as at least one implementation of a DDEC controller available from Detroit Diesel Corporation, Detroit, Mich. Various other features of the DDEC controller are described in detail in a number of different U.S. patents assigned to Detroit Diesel Corporation. However, the present invention may be implemented in connection with any appropriate controller to meet the design criteria of a particular application. 
   Control logic may be implemented in hardware, firmware, software, or combinations thereof. Further, control logic may be executed by the controller  16 , in addition to and by any of the various systems and subsystems of the vehicle or other installation where the controller  16  is implemented. Yet further, although in a preferred embodiment, the controller  16  includes the microprocessor  20 , any of a number of known programming and processing techniques, algorithms, steps, bocks, processes, routines, strategies and the like may be implemented to control the engine  12 , and the various engine and vehicle components  32 . Further, the engine controller  16  may receive information in a variety of ways. For example, engine  12  systems information may be received over a data link, at a digital input, or at a sensor input of the engine controller  16 . 
     FIG. 2  is a schematic representation of the controller  16  of the present invention. The controller has a Motor Control Module  40  and a Common Powertrain Controller  42 . Each of the Common Powertrain Controller and the Motor Control Module has memory for storage and retrieval of operating software and faults. The Motor Control Module and the Common Powertrain Controller communicate with each other via the Engine Controller Area Network (ECAN)  44 . It is contemplated that any electronic communication between the Motor Control Module (MCM) and the Common Powertrain Controller is acceptable to communicate static faults stored in either, so that each has the most current version of the faults in the other module at any time. The Common Powertrain Controller communicates with the vehicle systems such as lamps and gauges  46 , instrument cluster  48 , and tool/instrument  50 . The CPC 2  communicates with the instrument cluster and the tool/instrument via an SAE data link J 1939  and J  1587 , ( 52  and  54 , respectively). CPC 2  outputs  56  are communicated to the lamps and gauges, and the CPC 2  communicates with the diagnostic tool  36  over a UDS/CPC 2  link  58 . The CPC 2  further acts as a gateway for the MCM to communicate with the diagnostic tool  36  over a UDS link/MCM  60  through the MCM gateway  62  in the CPC 2 . The MCM communicates to the gateway via a UDS CPC/MCM tuunel  64  and from there, communication is possible with the diagnostic tool. 
     FIG. 3  is a schematic representation of the fault code memory manager resident in the CPC 2 . A similar Fault Code Memory Manager Module may be resident in the MCM. The fault code memory manager tracks and stores faults in memory that are received by each MPU  18  (as seen in  FIG. 1 ) and a system that the MPU is monitoring. Those skilled in the art will recognize that while only one MPU is schematically presented in  FIG. 1 , it is understood that multiple MPUs may be present, each MPU monitoring a different system of the vehicle or engine, such as EGR, Engine Speed, Engine Torque, Engine coolant temperature, Engine Boost Pressure, Engine Percent Load, Vehicle Speed as well as other engine operating systems and parameters. 
   The Fault Code Manager Administrator Module  65  interfaces to the individual features  66  through an interface  68  to evaluate conditions and periodically provide status of each individual fault condition. These fault conditions are indicated by fault condition status flags, and are then processed and debounced in the Fault Code Module  70  internal logic based upon a configurable set or other rules. Once the faults are logged, they are kept and maintained in memory in a fault table which can then sent out on all communication links through the communications link  72  to the modules such as the CPC  2 , or the MCM, or both, designated as  76 . This communication may be over J 1587/11939 SAE data links, or the ECAN, or a UDS link. Additional interfaces back to features and LOR module allows the engine system behavior to change depending on the active faults. The FCM system component may include any number of monitoring units (MU) and preferably, the CPC 2  Fault Control Module contains approximately 200 CPC 2  defined MUs and any number of monitoring units (MU) in the MCM, and preferably approximately 500 MCM defined MUs. The faults are debounced prior to being transmitted to ensure that each fault is indicative of current operating conditions, and not an error or an anomaly. The MCM debounced faults are updated once per second via the EeAN, and the CPC 2  MUs are internally evaluated 10 times per second. 
   The system has a range of fault logging and handling capabilities, including at least one of Fault Identification, such as Monitoring Unit Identifier internally unique Fault Identifier, KWP path/type, Universal Diagnostic Service Identification, SPN (J1939 ID)/FMI, Flash code (lamp blink code) and fault name/description via a UDS tool, Environmental Conditions such as specified feature sponsor, exclusion conditions, Fault Debounce Timer types, such as none, or ramp/rest or integrating, debounce timers, such as debounce time (fault activation) recovery time (fault deactivation) healing time (inactive fault self deletion) lamp control for each MU, such as a buzzer, SEL, CEL, MIL, and Engine control, such as torque reduction and engine protection shutdown protection. 
   Low priority faults are not sent to the lamps over the communications links. Normally, these low priority faults are used in internal control logic but should not necessarily be shown to the vehicle operator. Preferably, lamp control on the dash board is handled separately and defined individually on per fault/per lamp basis. Preferably the system contemplates the following Communications Visibility Semaphore: Active Fault SENT, Inactive Fault Sent results in fault visibility for a majority of faults. Active Fault NOT SENT, Inactive Fault SENT results in fault which do not illuminate the lamps. Active Fault SENT, Inactive Fault NOT SENT results in no fault defined at the moment. Active Faults NOT SENT, Inactive Faults NOT SENT results in full invisibility of Faults, indicative of none for the moment. 
   The architecture of the present invention provides a snapshot of data record that includes, but is not limited to seconds active counter, seconds inactive counter, First Occurrence Date/Time Stamp (1 second), First Occurrence Engine Hour Stamp (1 second), Last Occurrence Date/Time Stamp (1 second) Last Occurrence Engine Hour Stamp (1 second) Engine and Vehicle Data, including engine RPM, engine torque, engine coolant temperature, engine boost pressure, engine percent load, vehicle speed, and number of SEO events. The present invention further indicates communications link failures, Fault code memory MCM link failure faults, Non volatile storage rated failures, such as checksum faults, Engine data Faults based upon the MCM warning level information, including oil level, oil pressure, coolant temperature, input/output related faults, such as analog inputs such as shorted or open circuit detection (both ground and battery), digital outputs such as open circuit, short to battery, short to ground, and rationality faults, such as the diesel particulate filer switch, and remote Power Take Off request switch. 
     FIG. 4  is a schematic representation of a software flowchart of one method  78  according to the present invention. Step  80  is sensing engine operating conditions and transmitting data signals indicative of the engine operating conditions to the Electronic Control Unit. In this regard, it is noted that, as set forth above, many different engine operating parameter may be sensed and those signals transmitted to the ECU. Step  82  is filtering the data signals through a debounce logic. The debounce logic begins at step  84  by determining whether a fault reading persists beyond a predetermined period of time. If no, step  86  is deactivate the fault code flag. If yes, step  88  is determining whether the fault persists beyond a predetermined recovery time. If not, the software loops back to step  86 . If yes, step  90  is logging the fault in the Fault Code Memory Manager. An alert may also be activated upon storage of the fault in memory. 
   While one aspect of the invention has been described, it is understood that the words used are words of description, and not words of limitation. Many variations and modifications are possible without departing from the scope and spirit of the invention as set forth in the appended claims.