Abstract:
In a vehicular electronic control apparatus of which the manufacturing process is finished under a condition such that at least a portion of control data is not specified, while permitting control data that corresponds to a specific specification to be set afterwards, and which includes self-diagnosing means and an associated means for transmitting a diagnosis result of the self-diagnosing means to the outside, a technical measure is provided in which a diagnosis result of self-diagnosis indicating an occurrence of any abnormality due to such a reason that the control data corresponding to the specific specification has not yet been set, is prevented from being transmitted to the outside.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a vehicular electronic control apparatus with at least a portion of control data therefor remaining unspecified when the process for manufacturing thereof is finished, and permitting control data corresponding to a specific specification to be specified at a later stage. Further, the invention relates to a method for setting a control specification for the vehicular electronic control apparatus. 
         [0003]    2. Description of the Related Art Japanese Laid-open (Kokai) Patent Application Publication H04 (1992)-092734 discloses a vehicular electronic control apparatus in which a plurality of control specifications are previously stored, and one of the control specifications is selected to execute the control. 
         [0004]    Japanese Laid-open (Kokai) Patent Application Publication No. H08 (1996)-237772 discloses a technique in which a plurality of electronic control devices mounted on a vehicle mutually diagnose failures, and if a first electronic control device which sends data is failed, a second electronic control device which receives the data carries out control by using a default value. 
         [0005]    In the case of a vehicular electronic control apparatus of which the manufacture is finished in a state where at least a portion of control data is unspecified during the production of the electronic control apparatus, so that information of a specification is taken therein afterwards from an outside to determine the control specification, if the power is turned ON to carry out taking-in of the specification information, a normal control operation is not yet carried out because the control specification is not determined. 
         [0006]    Hence, when the electronic control apparatus includes a self-diagnosing means and an associated means for transmitting the result of self-diagnosis done by the self-diagnosing means to the outside, since the normal control operation does not take place, the self-diagnosing means will determine that a condition is abnormal due to its self-diagnosis operation, and such an abnormality determination result will necessarily be outputted by the associated transmitting means to the outside. 
         [0007]    Nevertheless, under a condition such that the control specification has not yet established, determination of occurrence of any abnormal state should not be made by the self-diagnosis operation, and therefore if any abnormality determination result is outputted to the outside, an unfavorable problem may occur such that an erroneous result of the self-diagnosis is stored and unnecessary control operation may start, based on the erroneous result of the diagnosis. 
       SUMMARY OF THE INVENTION 
       [0008]    Therefore, it is an object of the present invention to positively avoid a case where either any erroneous result of diagnosis is stored or else unnecessary control operation is carried out based on such an erroneous result of diagnosis under a condition that a vehicular electronic control apparatus has not yet been supplied with information for specifying a control specification. 
         [0009]    To achieve the above object, according to the present invention, in a vehicular electronic control apparatus which is finished in the manufacturing process thereof under a condition such that at least a portion of control data is not specified during production of the electronic control apparatus while permitting control data that correspond to a specific specification to be set afterward, and which includes self-diagnosing means and an associated means for transmitting a diagnosis result obtained by the self-diagnosing means to an outside, a novel technique is provided in which a diagnosis result indicating an occurrence of any abnormality due to a reason that the control data corresponding to the specific specification has not yet been set, is prevented from being transmitted to the outside. 
         [0010]    The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a diagram showing a vehicular control system according to an embodiment of the present invention; 
           [0012]      FIG. 2  is a flowchart showing a process of selecting control data according to the embodiment of the invention; and 
           [0013]      FIG. 3  is a flowchart showing a process before specification is specified according to the embodiment of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]      FIG. 1  shows a vehicular electronic control apparatus according to an embodiment of the present invention. 
         [0015]    An engine (internal combustion engine)  102  is mounted in an automobile  101  shown in  FIG. 1 . Power taken out from engine  102  is input to a transfer  104  through an automatic transmission  103 , and the power is distributed to front and rear axles by transfer  104 . 
         [0016]    Transfer  104  is a device which varies a distribution of power to the front and rear axles by an electronic control hydraulic multiple disk clutch. 
         [0017]    Transfer  104  is controlled by an electronic control unit (TF-ECU, hereinafter)  105  for controlling the transfer. 
         [0018]    TF-ECU  105  includes a microcomputer  105   a , an input circuit  105   b , a communication circuit  105   c , a drive circuit  105   d  and an external memory  105   e.    
         [0019]    In microcomputer  105   a , a ROM (mask ROM)  105   f  is incorporated. A plurality of control data sets (a control program, a control constant and the like) which correspond to a plurality of specifications of a vehicle are previously stored in ROM  105   f.    
         [0020]    The vehicular specifications include presence or absence of an antilock brake system (ABS, hereinafter), difference between an automatic transmission (AT) and a manual transmission (MT), and difference in output characteristics of engine  102 . 
         [0021]    Since requirement of the power distribution characteristics is varied depending upon the difference in specification, control data suitable for a case where there is the ABS and AT is used, control data suitable for a case where there is no ABS and MT is used, and the like are previously stored in ROM  105   f.    
         [0022]    Information indicating which control data set out of the plurality of control data sets is actually used, in other words, information indicating that the subject vehicle corresponds to which specification, is written into external memory  105   e  after TF-ECU  105  is mounted in the vehicle in the factory and the specification is specified. 
         [0023]    Microcomputer  105   a  selects control data corresponding to information written into external memory  105   e , and executes the control using the selected control data, thereby controlling the power distribution in transfer  104 . 
         [0024]    Specifically, control data is selected based on the information written in external memory  105   e  as shown in a flowchart in  FIG. 2 . 
         [0025]    Following a turning ON of power, initializing processing is carried out (step S 11 ) and then, specification information written in external memory  105   e  is read (step S 12 ). 
         [0026]    When the specification information is read, control data corresponding to the read specification information is read from control data sets which are previously stored in ROM  105   f  on a specification-by-specification basis, and the read control data is copied in a RAM (step S 13 ), and control is executed using the control data which is copied in the RAM (step S 14 ). 
         [0027]    The memory in which the specification information is written may be an electrically rewritable memory, and may be flash ROM incorporated in microcomputer  105   a.    
         [0028]    As described above, a plurality of control data sets corresponding to the plurality of specifications are previously stored and control data which is to be actually executed in accordance with a specification of a subject vehicle is selected. Therefore, as compared with a case in which different TF-ECUs  106  are prepared for a plurality of different specifications and a TF-ECU  105  to be mounted is selected for the subject vehicle, it is possible to reduce the manufacturing costs of TF-ECU  105  and to make it easy to manage parts. 
         [0029]    Input circuit  105   b  is provided for reading, into microcomputer  105   a , a signal of a 4WD change over switch  106 , and a signal from a sensor which detects a state (oil temperature, operation pressure, line pressure and the like) of transfer  104 . 
         [0030]    4WD change-over switch  106  is a switch through which a driver freely selects any one of a 2WD mode, an AUTO mode and a LOCK mode. 
         [0031]    The 2WD mode is a mode fixed to rear wheels driving, the AUTO mode is a mode for automatically adjusting power distribution to front wheels in accordance with slip of the rear wheels from 0% to 50% (rear-wheels-drive to four-wheels-drive), and the LOCK mode is a mode fixed to a direct-coupled four-wheels-drive (power distribution of 50:50). 
         [0032]    Drive circuit  105   d  outputs a drive signal to a solenoid which controls operation pressure applied to the electronic control hydraulic multiple disk clutch of transfer  104  and to a transfer motor which drives an oil sub-pump of transfer  104 , and outputs a drive signal to an indicator lamp  107  (warning means) provided on an instrument panel or the like of the vehicle. 
         [0033]    In addition to TF-ECU  105 , the following units are provided in the vehicle of the present embodiment, i.e., an engine-controlling electronic control unit  110  (ENG-ECU, hereinafter) for controlling engine  102 , an AT-controlling electronic control unit (AT-ECU, hereinafter)  111  for controlling automatic transmission  103 , and an ABS-controlling electronic control unit (ABS-ECU, hereinafter)  112  for controlling the ABS. 
         [0034]    ENG-ECU  110  controls a fuel injection amount and a fuel injection timing of a fuel injection valve provided in engine  102 , and controls ignition timing by an ignition plug provided in engine  102 . 
         [0035]    AT-ECU  111  controls a shift solenoid, thereby controlling a gear shifting operation in automatic transmission  103 . 
         [0036]    ABS-ECU  112  controls the operation pressure of a brake to prevent wheels from locking at the time of braking. 
         [0037]    Each of ENG-ECU  110 , AT-ECU  111  and ABS-ECU  112 , as well as TF-ECU  105 , includes a microcomputer. 
         [0038]    The four electronic control units, i.e., TF-ECU  105 , ENG-ECU  110 , AT-ECU  111  and ABS-ECU  112  are connected to each other through a network  115 . These electronic control units conduct communication with each other through network  115 , and commoditize information and mutually diagnose failure from the communication information. 
         [0039]    Data for specifying a specification is written into external memory  105   e  of TF-ECU  105  through a vehicle plant equipment  120  connected to network  115 . 
         [0040]    Vehicle plant equipment  120  obtains specification information of a subject vehicle by reading an identification label, for example, attached to the vehicle, and instructs microcomputer  105   a  of TF-ECU  105  to write the specification information into external memory  105   e.    
         [0041]    The specification information is written into external memory  105   e  of TF-ECU  105  after all of the electronic control units including TF-ECU  105  are mounted in the vehicle and power is turned ON in the entire control system. 
         [0042]    However, at the instant when the power is turned ON, data for specifying a specification has not yet been written in external memory  105   e  and thus, TF-ECU  105  can not execute control of transfer  104 . 
         [0043]    When no control operation is executed by TF-ECU  105 , normal communication processing is not conducted among electronic control units  110 ,  111  and  112  or TF-ECU  106  does not output a signal indicative of an implementation state of control to network  115 . Then, other electronic control units  110 ,  111  and  112  determine the control abnormality in TF-ECU  105 , and store the determination result. When TF-ECU  105  has a self-diagnosis function, it might diagnose that TF-ECU  105  is failed because the control is not executed. 
         [0044]    However, in the above case, the reason why the control of TF-ECU  105  is not executed is that data for specifying a specification is not written, and thus, TF-ECU  105  is not actually failed. However, when other electronic control units  110 ,  111  and  112  determine that TF-ECU  105  is failed and/or when the self-diagnosis of TF-ECU  105  determines a failure thereof, an erroneous diagnosis results may be stored. 
         [0045]    Hence, in this embodiment, processing in TF-ECU  106  is carried out as shown in a flowchart in  FIG. 3  to avoid the erroneous failure determination in a state where data for specifying a specification is not written in external memory  105   e.    
         [0046]    The flowchart in  FIG. 3  is executed when power is turned ON for the entire system, and the initializing processing is executed in step S 101 . 
         [0047]    In step S 102 , it is determined whether there is writing request of specification information from vehicle plant equipment  120 . 
         [0048]    If there is the writing request of specification information from vehicle plant equipment  120 , the procedure is advanced to step S 103 , and designated specification information is written in external memory  105   e.    
         [0049]    When there is no writing request of specification information from vehicle plant equipment  120 , the procedure is advanced to step S 104  bypassing step S 103 . 
         [0050]    In step S 104 , it is determined whether external memory  105   e  is in an initial state, in other words, whether it is in a state where specification information is not written (i.e., a state where date for specifying specification is left to be still unset). 
         [0051]    When external memory  105   e  is not in the initial state and the specification information is written, the procedure is advanced to step S 106 , and specification information written in external memory  105   e  is read. 
         [0052]    In next step S 106 , it is determined whether external memory  105   e  is in its normal state, based on a read data. 
         [0053]    When the specification information is normally read and it is determined that external memory  105   e  is in the normal state, the procedure is advanced to step S 107 , control data corresponding to the specification information is read from ROM  105   f  and copied in the RAM, and the control of transfer  104  is executed based on the control data stored in the RAM. 
         [0054]    If it is determined in step S 104  that external memory  105   e  is in the initial state and the specification information is not written, the procedure is advanced to step S 109  from step S 104 . 
         [0055]    In the vehicle factory, after TF-ECU  105  is mounted on the vehicle, and until power is turned ON to write the specification information in external memory  105   e  and the writing operation is actually completed, the procedure is advanced to step S 109  from step S 104 . 
         [0056]    In step S 109 , driving output with respect to transfer  104  is fixed to an OFF state, normal output similar to that carried out when control is executed is carried out to network  115 , indicator lamp  107  is lit and the self-diagnosis processing is stopped. 
         [0057]    Examples of the signal which is output to other electronic control units  110 ,  111  and  112  via network  115  from TF-ECU  105  include a fixed time communication signal, a return message, a signal indicative of a result of self-diagnosis, and control data. 
         [0058]    In step S 109 , the same contents as those output when the control is execute are output as the fixed time communication signal and the return message. Further, a signal indicating that a result of the self-diagnosis is normal is output, and a default value is output as the control data. 
         [0059]    A message that specification information is not written is sent to other electronic control units  110 ,  111  and  112  from TF-ECU  105  through network  115 , and other electronic control units  110 ,  111  and  112  which have received the message that specification information is not written do not request TF-ECU  105  to control transfer  104 . 
         [0060]    If the driving output to transfer  104  is fixed to the OFF state, transfer  104  is fixed to a rear wheels driving state. 
         [0061]    Since the same output as that carried out when the control is normally executed is carried out for network  115 , even if TF-ECU  105  does not carry out the normal control operation, it is possible to avoid a case in which other electronic control units  110 ,  111  and  112  determine that TF-ECU  105  is failed (control abnormality). 
         [0062]    A state where normal control of the transfer is not executed because specification information is not written in TF-ECU  105  is not a control abnormality. Therefore, if other electronic control units  110 ,  111  and  112  determine the abnormality of TF-ECU  105  and store this information, it is necessary to clear the memory of the failure history prior to shipment from the vehicle factory. 
         [0063]    However, if it is possible to avoid the case in which electronic control units  110 ,  111  and  112  determine the failure as described above, labor for clearing the memory of the failure history can be reduced, and further the operability can be improved. 
         [0064]    Further, since indicator lamp  107  is lit, an operator in the vehicle factory can easily confirm that the writing operation of the specification information is not completed, and it is possible to prevent the writing leakage and writing failure of specification information. 
         [0065]    When indicator lamp  107  is lit because specification information is not written in TF-ECU  106 , the procedure waits until the writing operation in step S 103  is completed, and then indicator lamp  107  is turned off. 
         [0066]    Since the self-diagnosis processing in TF-ECU  105  is stopped, it is possible to avoid a state in which control can not be executed because the writing operation of specification information is not completed to be self diagnosed as failure. 
         [0067]    In this manner, it is possible to avoid a state in which control can not be executed because the writing operation of specification information is not completed to be self diagnosed as abnormality and this result of diagnosis to be output to other electronic control units  110 ,  111  and  112 . Further, it is possible to prevent an erroneous self-diagnosis result from being stored, and it is possible to eliminate the clearing processing of the result of self-diagnosis processing. 
         [0068]    If it is determined that external memory  105   e  is failed in step S 106 , the procedure is advanced to step S 108  and a failure determination result of external memory  105   e  is stored, and then, the procedure is advanced to step S 109 . 
         [0069]    In this case also, the driving output with respect to transfer  104  is fixed to the OFF state, and transfer  104  is fixed to the rear wheels driving state. 
         [0070]    The same normal output as that executed when the control of the transfer is executed is carried out with respect to network  115 . Therefore, the control of the transfer is stopped due to the failure of external memory  105   e , and it is possible to prevent other electronic control units  110 ,  111  and  112  from determining the failure (control abnormality) of TF-ECU  105 . 
         [0071]    By the lighting of indicator lamp  107 , it is possible to easily recognize a state in which specification information is not written, and a state in which specification information can not be read and transfer  104  can not be controlled normally. 
         [0072]    When indicator lamp  107  is lit because it is determined that external memory  105   e  is failed, indicator lamp  107  is turned off when it becomes possible to read specification information from external memory  105   e.    
         [0073]    In a vehicle factory or a maintenance factory, it is possible to distinguish whether specification information is not written or specification information can not be read due to failure of external memory  105   e  based on the memory of the failure history in external memory  10   e.    
         [0074]    Therefore, in the vehicle factory or the maintenance factory, TF-ECU  105  or external memory  105   e  is reliably replaced by a new one so that specification information can be written or read and then, the specification information is again written so that the transfer can normally be controlled. 
         [0075]    When external memory  105   e  is failed during usage by a user and thus specification information can not be read and transfer  104  is fixed to the rear wheels driving state, a user is informed of a fact that transfer  104  is fixed to the rear wheels driving state by means of lighting of indicator lamp  107 . Therefore, it is possible to avoid a case in which a user misunderstands that distribution control of driving force is normally carried out and the user drives, and it is possible to urge the user to carry out maintenance early. 
         [0076]    In the embodiment, TF-ECU  105  commonly uses the plurality of specifications depending on specification as the specification-by-specification electronic control unit, but any of other electronic control units  110 ,  111  and  112  can be used as the specification-by-specification electronic control unit. 
         [0077]    Alternatively, some of the plurality of electronic control units may be used as the specification-by-specification electronic control units. 
         [0078]    The electronic control unit connected to network  115  is not limited to TF-ECU  105 , ENG-ECU  110 , AT-ECU  111  and ABS-ECU  112 , an electronic control unit which controls a driving operation of a fuel pump, and an electronic control unit which controls display of a meter provided on an instrument panel may be included, and such an electronic control unit can be used as the specification-by-specification electronic control unit. 
         [0079]    In this embodiment, indicator lamp  107  is used as the warning means for informing a user of be fact that specification information is not written in external memory  105   e  or the fact that external memory  105   e  is failed. Alternatively, a buzzer, a voice guide, an operation lamp provided on a case of the electronic control unit, or a display on a diagnosis tool screen can be used as the warning means. 
         [0080]    When specification information is extinguished even if the external memory  105   e  is in a normal state after the specification information is written in the external memory  105   e , it is preferable that the other electronic control units are informed of this abnormal condition to allow them to determine abnormality and store an abnormality determination result. 
         [0081]    It is possible to write, in external memory  105   e , control data corresponding to a specific specification from vehicle plant equipment  120 , to copy the control data written in external memory  105   e  in the RAM, and to execute the control using the control data copied in the RAM. In this case also, in a state where control data corresponding to the specific specification is not written in external memory  105   e , if the same procedure as that in step S 109  is carried out, the same effect can be obtained. 
         [0082]    The entire contents of Japanese Patent Application No. 2006-299530, filed Nov. 2, 2006 are incorporated herein by reference. 
         [0083]    While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. 
         [0084]    Furthermore, the foregoing description of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.