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`EP 0 383 593 A2
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`a check symbol and an end of transmission indica-
`tor.
`
`in a feature of this invention a vehicle-mounted
`station includes detecting means for detecting op-
`erating
`conditions
`of
`a
`vehicle,
`transmitting/receiving means for transmitting data
`representative of the detected operating conditions
`to a base station capable of evaluating said data,
`said transmitting/receiving means being adapted to
`receive evaluated signals from the base station and
`to apply signals representative of said evaluated
`signals to a control means adapted to perform at
`least one of vary or display said operating con-
`ditions in dependence upon said received evalu-
`ated signals.
`this invention there is
`In another feature of
`provided a stationary base station adapted to re-
`ceive data from a vehicle mounted station, said
`base station including processing means and stor-
`age means for processing the data received from
`the vehicle mounted station based upon informa-
`tion held in said storage means, the base station
`being
`adapted
`to
`perform at
`least one
`of
`updating/correcting maps carried by a vehicle lo-
`cated processor, vehicle located sensors and injec-
`tors, establish the expected life expectancy of said
`sensors and injectors and further including trans-
`mitting means for transmitting processed data to a
`vehicle.
`Thus, the above mentioned object is principally
`realized by controlling load sharing between com-
`puters. A study of computer control for vehicles
`indicates that data processing is roughly divided
`into data requiring high-speed real-time processing
`and data which may be processed in a compara-
`tively long period. For example, ignition timing con-
`trol and fuel
`injection control are control subjects
`that require processing in synchronism with engine
`rotation so that high-speed processing is required
`in response to high speed engine rotation. On the
`other hand, modification of initial settings because
`of ageing changes such as those in an engine
`transmission and suspension, may be computed
`over a relatively long time cycle. Also, controls
`which haveto be computed with a high accuracy
`take time when processed by a vehicle-mounted
`computer and only increase the load on the com-
`puter.
`Also, with regard to failure diagnosis or failure
`prediction processing when status data is obtained.
`arithmetic processing itself may be separated from
`the
`real-time processing without difficulty. Of
`course, there may be some diagnoses which re-
`quire emergency processing and a feature of this
`invention is to discriminate and act upon abnormal
`conditions that
`require urgent actions and diag-
`noses.
`
`In consideration of the increasing complexity of
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`the control system and the necessity for higher
`speed processing accompanied by the increasing
`r.p.m. of modem engines, this invention carries out
`load sharing between a vehicle-mounted computer
`and a stationary host computer.
`this invention
`More specifically a feature of
`resides in predetermining the processing sharing
`conditions when specific operating conditions of
`the engine or specific conditions of the vehicle-
`mounted computer are detected.
`transmitting in-
`formation to and from the host computer and shar-
`ing the processing.
`The load sharing between the vehicle-mounted
`computer and the stationary host computer
`is
`achieved through the following operations. When
`the operating conditions for the engine are de-
`tected, the subsequent processing thereon is shift-
`ed to the host computer to be shared thereby.
`Thus,
`increases in load on the vehicle-mounted
`computer are prevented.
`The above operating conditions are detected,
`for example, at predetermined distance of travel,
`when cumulative driving time reaches a predeter-
`mined time andlor when a predetermined condition
`is met such as engine stopped or fuel tank low.
`
`Brief Description g the Drawings
`
`The invention will now be described by way of
`example with reference to the accompanying draw-
`ings in which:-
`is an overall block diagram of a
`Figure 1
`system according to the present invention.
`Figure 2 is a block diagram of the vehicle-
`mounted computer.
`when
`occasions
`shows
`Figure
`3
`transmission/reception between the computers is
`performed,
`respectively show a
`Figures 4(A) and (B)
`data signal and a data transmission/reception se-
`quence.
`Figure 5 is a diagram of checking revised
`items for map matching.
`Figure 6 is a diagram of failure diagnosis,
`Figure 7 is a diagram of
`long-term data
`sampling,
`Figure 8 is a flow chart
`,
`revised map,
`Figure 9 is a data transmission flow chart
`when the engine is stopped,
`Figure 10 is a flow chart for revised values,
`
`for preparing a
`
`and
`
`Figure 11 is a series flow chart of transmis-
`sions and receptions.
`In the Figures like reference numerals denote
`like parts.
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`EP 0 383 593 A2
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`Description 9_f Preferred Embodiments
`
`in the drawings, Figure 1 shows one embodi-
`ment of the overall system where information is
`transmitted between a vehicle and a host computer
`located, for example, at a stationary, ground based
`dealership location through a telecommunications
`network.
`
`An engine 2 in the vehicle is connected with a
`vehicle mounted computer 105 including an engine
`controller 3, a transmission 400 controller 4 and
`
`suspension 500 controller 501. In the currently de-
`scribed embodiment only three controllers are
`shown, but usually a number of these types of
`controllers
`are mounted
`on
`the
`vehicle. A
`transmitter-receiver 5 for transmitting and/or receiv-
`ing information to and from the host computer 18 is
`provided within processor 105.
`A telecommunication path 10 which may be
`wired or wireless, e.g. a radio link interconnects the
`vehicle side located processor 105 with a station-
`ary
`host
`computer
`station
`25
`including
`a
`transmitter—receiver 11 on the host computer sta-
`tion side of
`the path. There is provided l/O
`(input/output units)
`for data analysis 12,
`I/O for
`maintenance arithmetic processing 13, I/0 for fail-
`ure analysis computation 14 and l/O for vehicle
`information 15 over a 2-way bus to the transmitter-
`receiver 11 and to the host computer 18. The I/0's
`are also linked to a data base 16 such as a
`memory store. The host computer side apparatus
`may be installed at the vehicle dealership or at a
`vehicle information service center. Although in this
`exemplary embodiment only 4 I/0's are shown.
`other l/0's for many other controllers may exist.
`The host computer 18 may have a capacity of
`several mega bytes. Also, here a radio communica-
`tions link connecting the vehicle side and the host
`side is shown; radio links are preferred as being
`more practical because the vehicle side is normally
`moving. Of course, when occasion demands,
`in-
`formation can be transmitted or received by wire
`communication lines from the host computer to a
`beacon by the roadside for subsequent wireless
`transmission/reception to the vehicle-mounted com-
`puter.
`in some cases the engine controller 3 or
`Also,
`the transmission controller 4 as shown in Figure 1
`has its own built-in processor and carries out re-
`spective processings or a vehicle-mounted proces-
`sor 7 is provided as indicated in broken lines.
`Hereinafter engine controls are described wherein
`a processor for engine control is built in.
`Figure 2 shows the computer 105 on the ve-
`hicle side with the suspension controller 501 omit-
`ted. ROM 21, RAM 22 and CPU 7 are connected
`by a bus line 30 for I/O processing. The bus line
`consists of a data bus, a control bus. and an
`
`address bus.
`Other sequences (of which only two are shown)
`sense the engine operating conditions,
`inter alia,
`the engine cooling water temperature (TWS) 32
`and the air/fuel ratio (028) 34. Battery voltage and
`throttle valve opening and rotation speed also cor-
`respond to operating condition signals, but here
`they are omitted. A multiplexer 36 inputs the op-
`erating condition signals into an A/D conversion
`circuit 38. A register 40 sets A/D converted values.
`An inlet pipe air flow sensor (AFS) 51 has its
`value set in a register 54 after conversion in an A/D
`converter 52. An engine angle sensor
`(AS) 56
`provides reference signals REF and angle position
`signals POS to an angle signal processing circuit
`58. The processed signals are used to control
`synchronizing signals and timing signals.
`Engine operating condition ON/OFF switches
`(SWI-SWi) 59-61 indicate parameters such as start
`engine and engine idle. These signals are input
`into an ON-OFF switch-condition signal-processing
`circuit 60 and are used independently or in com-
`bination with other signals forming logic signals to
`determine controls or controlling methods known
`per se.
`— The CPU 7 carries out computations based on
`the above mentioned operating condition signals in
`accordance with multiple programs stored in ROM
`21 and outputs its computation results into respec-
`tive control circuits through the bus lines 30. Here
`the engine control circuit 3 and the transmission
`control circuit 4 have been shown, but numerous
`other control circuits such as an idle speed control
`circuit and exhaust gas recirculation (EGR) control
`circuit are possible.
`The engine control circuit 3 has a fuel control-
`Ier for controlling air/fuel
`ratios and increases or
`decreases the amount of fuel supplied by control-
`ling an injector 44. 42 is a logic circuit for these
`controls. The transmission controller 4 carries out a
`transmission shift 48 in the transmission 400
`through a logic circuit 46 based on the computation
`results of the driving conditions. A control mode
`register 62 presents timing signals for various con-
`trol outputs.
`transmitting and
`Timing circuit 64-70 control
`receiving operations. For example, circuit 64 out-
`puts a trigger signal
`into the transmitter—receiver
`whenever a predetermined distance is travelled and
`transmits a corresponding engine operating con-
`dition signal through the transmitter—receiver to the
`stationary host computer. A display 90 is used to
`display instructions to the driver.
`Circuit 66 is used to detect an engine stopped
`and to trigger an output signal thereupon. Circuit
`68 is used to detect a low fuel tank condition and
`
`thereupon. Circuit 70 is
`trigger an output signal
`used to check whether predetermined conditions
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`EP0383 593A2
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`are met and when satisfactory, generate a trigger
`output signal. Figure 3 shows symbol
`illustrations
`of these circuits.
`To sum up, circuits 66 to 70 produce signals
`which decide timing to transmit operating condition
`data to the stationary host computer. For example.
`from the circuit 64 which generates a signal when-
`ever a predetermined distance has been travelled,
`it
`is possible to diagnose the operating condition
`per the predetermined travel distance. When only
`condition signals are transmitted,
`the host side
`computer makes a diagnosis based on deviations
`from the previous values or past condition signal
`data and conveys instructions based on its results
`to the vehicle-mounted computer. The vehicle-
`mounted computer gives driver instructions through
`a display or alarm in dependence upon the severity
`or grade of those instructions or modifies process-
`ing programs or sets parameter values.
`Figure 4(A) shows an example of a data array
`and Figure 4(B) shows a data transmitting and
`receiving sequence during data communications
`between the vehicle-mounted computer and the
`stationary, e.g. ground, host computer (here a deal-
`er located computer). A subject vehicle is specified
`by a header and a vehicle number (a number that
`is unique to the vehicle such as the engine number
`or the car body number).
`Figure 5 shows a processing example when
`correction items in the map matching are checked
`(data analysis),
`the transmitter-receiver 11 at the
`dealer side being omitted for clarity. When control-
`ling an engine via a microcomputer, control data is
`computed based on output conditions of each sen-
`sor.
`In addition, a system is used for subsequent
`engine control by responding to various engine
`conditions and by storing control data computed as
`a learning map. Figure 5 shows an example of
`using other control data values after corrections by
`analysing such control data stored in the so-called
`learning map or data to be changed together with
`other engine controls.
`The program processing on the vehicle side is
`assumed in this example to be to check a map
`(step 5a). This satisfies conditions by the circuits
`64 to 70 as described previously and the checking
`program of the map starts. Although this is simply
`called map matching, there is a learning map for
`ignition timing based on the output of a knock
`sensor or a learning map for defining an injection
`pulse width of the fuel
`injector in the fuel/air (O2
`feedback) from an exhaust to an inlet fuel injector,
`i.e. an O2 detector detects if exhaust gas mixture is
`lean or
`rich and sends a pulse in dependence
`thereon to the fuel
`injector. Map revision is de-
`scribed later in detail with reference to Figure 8.
`Now, the flow of the transmission processing at the
`time of map matching is generally explained.
`
`the vehicle-mounted computer
`step 5a,
`In
`checks data in the map by using various methods.
`For example, when data values contained in the
`learning map for defining the injection pulse width
`of the injector using parameters of number of revo-
`Iutions of the engine N and engine load Qa/N
`(where Qa is quantity of air) during 02 feedback
`are analysed, the corresponding map of the output
`of the inlet pipe air flow sensor and the air flow
`quantity is revised by comparing actual data values
`with previous data values and if the comparison
`result exceeds a predetermined value then the
`actual value is used to reset the map, thus effec-
`ting a "learning" process. The injector factor is also
`revised when the injector pulse width of the injector
`is determined in relation to the engine load Qa/N.
`Based on checking of the map, engine control data
`revisions are determined.
`In step 5b. the vehicle-
`mounted computer selects necessary data values
`in the map under check to be used to newly
`correct engine control data or computes data to be
`transmitted to the host computer by processing
`data values stored in the map and stores them in
`RAM as a map. When data to be transmitted is
`determined such is rendered as a trigger signal,
`the map arithmetically processed in the vehicle-
`mounted computer and contained in RAM is trans-
`mitted through the transmitter-receiver 5. The deal-
`er side (host computer). having received this. ex-
`ecutes its program based on received signals.
`In
`step 5c, data signal reception from the vehicle-
`mounted computer is started. However. in step 5d,
`if the dealer-side is already receiving data from
`another vehicle, a wait instruction is issued in step
`5e. When not receiving data from another vehicle.
`the received data is stored in the memory of the
`host computer in step 5f. In step 5g, present mem-
`ory values are compared with past values pre-
`viously transmitted to the host computer.
`In step
`5h. the amount of deterioration in actuators. such
`as injectors, and sensors such as inlet air quantity
`(Qa) sensors, is estimated based on the compared
`results. Next,
`in step 5i, the remaining life is es-
`timated from the deterioration amount.
`In step 5j,
`data transmitted from the vehicle-mounted com-
`puter is computed in accordance with a predeter-
`mined program to determine data to be corrected
`at the vehicle computer.
`In step 5k,
`this data is
`transmitted through the transmitter-receivers
`11
`and 5. When it receives a transmission signal from
`the host computer, the vehicle-mounted computer
`starts the arithmetic processing. When in step 51
`receiving the corrected map transmitted from the
`host computer commences, it is stored in RAM in
`step 5m. In step 5n, the corrected map is re-written
`when the engine restarts after stoppage. In step 5p.
`notification is made to the driver visually, through
`the display or audibly that the map has been re-
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`written. This is an example of notifying the driver
`for caution's sake, because correction items of the
`map may influence whether the vehicle should be
`driven. However, for cases that do not specifically
`require this, notification can be omitted. Also,
`in
`step 5p,
`it is possible to display the deterioration
`amount and remaining life of the injector or sensor.
`Alternatively. re-writing the map at the time of re-
`starting the engine for example and/or shifting to
`the corrected map during travel can be made.
`However, at this time a method to enable a smooth
`transition is preferred. For example, methods as
`follows may be carried out,
`in that, when the de-
`viation before correction is smaller than a predeter-
`mined value, a sequential transition is made and
`when the deviation is larger than the predetermined
`value. its intermediate value (in some cases, plural
`intermediate values) is established and shifted step
`by step to a corrected map.
`in addition, re-writing
`the map may also be carried out in a predeter-
`mined period after the power key switch is turned
`off,
`i.e. power is supplied for a predetermined pe-
`riod after the power key switch is turned off
`to
`enable the map to be re-written or memorised.
`Figure_6 shows an example of a failure diagno-
`sis, the transmitter-receiver 11 again being omitted
`for clarity. The vehicle-mounted computer carries
`out time-sharing computations of the injection pulse
`width and ignition timing by the injector in real
`time. For this, computations for a failure diagnosis
`are made in the intervals of these computations
`and only a basic diagnosis are made. This embodi-
`ment
`is based on the concept of having the
`vehicle-mounted computer make a basic abnormal
`diagnosis and transmit the data to the host com-
`puter. The host computer then makes more ad-
`vanced, comprehensive and appropriate diagnosis
`using data indicative of the condition of other con-
`trol subjects.
`In step 6a, the diagnostic mode starts. This is
`carried out in parallel with the general program and
`for example, is repetitive at predetermined intervals
`of about 60 ms. In step 6b, a decision on whether
`any abnormality exists is made based on the di-
`agnosis results. When no abnormality exists,
`the
`process ends. When an abnormality exists,
`the
`abnormal code is transmitted to the host computer
`on the dealer side through the transmitter-receivers
`5 and 11. The host computer is triggered by the
`transmitted signal and executes a more detailed
`failure diagnosis program. Having received the ab-
`normal code in step 6c, in step 6d, the host oom-
`puter selects comprehensive control data neces-
`sary for failure diagnosis based on the abonormal
`code and asks the vehicle-mounted computer to
`transmit data for decision. Upon receipt of
`the
`request for transmission, the vehicle-mounted com-
`puter transmits the data for decision in step 6e. In
`
`step 6f. the host computer diagnoses comprehen-
`sively the failure using the data for decision trans-
`mitted from the vehicle-mounted computer.
`In this
`case. because the host computer is not carrying
`out
`the real-time arithmetic processing such as
`computation of the injector's injection pulse width.
`if the results of the failure diagnosis in step 6f in
`which an overall diagnosis is possible based on the
`data transmitted from the vehicle-mounted com-
`puter indicate an emergency,
`the host computer
`immediately transmits emergency measures to the
`vehicle-mounted computer.
`If an emergency treat-
`ment is not specifically diagnosed, the host com-
`puter stores the received data in a failure chart in
`step 6i and subsequently transmits countermeas-
`ures to the vehicle-mounted computer in step 6]
`and completes the diagnostic flow in step 61.
`In
`step 6k,
`the vehicle-mounted computer takes ac-
`tions based on the countermeasure signals from
`the host computer and ends the diagnostic mode
`process at step 6m.
`Figure 7 shows an example regarding life pre-
`diction or failure prediction in accordance with data
`collected through sampling over a long period of
`time in which the transmitter/receiver 11 is again
`omitted for clarity. In step 7a, the vehicle-mounted
`computer carries out data sampling at every pre-
`determined interval to detect abnormalities. Detec-
`tion of abnormalities in this case is a very simple
`detection of abnormalities and a high-level failure
`diagnosis is carried out by the host computer.
`In
`step 7b, an existence of abnormalities is confirmed
`and in step 7c,
`the vehicle-mounted computer
`transmits the necessary data including sampling
`values
`to
`the
`host
`computer
`through
`the
`transmitter-receivers 5, 11 and completes the flow
`process.
`if there is no abnormality, the flow pro-
`cess is completed. ln addition, in view of the long-
`term data sampling, high-level failure diagnoses by
`the host computer may be made at every predeter-
`mined distance of travel as shown in Figure 3 or by
`the circuit 64 in Figure 2. Upon receipt of the data
`transmission signal from the vehicle-mounted com-
`puter, the host computer starts the failure diagnosis
`program in step 7d. In step 7e, control data accu-
`mulated in the memory of the host computer is
`analyzed to predict lift expectancy.
`In step 7f, de-
`fective parts are specified from data analysis re-
`sults.
`in step 7g,
`the degree of emergency is
`determined.
`if
`there is an emergency,
`the host
`computer transmits a signal
`to that effect to the
`vehicle-mounted computer through the transmitter-
`receivers 11, 5 in step 71. The host computer
`makes life expectancy predictions based on the
`analysis results and stores the predictions in the
`failure chart at step 7i. At step 7j, countermeasure
`signals are transmitted to the vehicle-mounted
`computer to complete the flow process in step 71.
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`in step 7k, takes
`The vehicle mounted computer,
`action in accordance with the signal
`transmitted
`from the host computer and completes the pro-
`cess.
`
`(1)
`
`invention has shared processing
`this
`Thus.
`where items are divided into those requiring pro-
`cessing by a vehicle-mounted processor and those
`requiring long-term or highly accurate computa-
`tions by a stationary larger computer. Having a
`vehicle-mounted processor execute all process-
`ings, as has been performed in the prior art, only
`makes a vehicle-mounted processor larger in ca-
`pacity and physical size.
`With regard to checking of the matching map
`as well as checking of revision items in the map, as
`performed in steps 5a and 5b of Figure 5, a de-
`tailed explanation will now be made by taking map
`revisions based on the O2 feedback map as an
`example. Although there is a prior application
`(Japanese
`Patent Application No.
`63-283886
`(1988)) by the same applicant as this invention
`regarding 02 feedback and learning based thereon.
`its basic methods and concepts are described as
`follows. The injection time of the injector is deter-
`mined by the equations (1) and (2) below.
`Ti = 'Tp'(Ke+Kt-Ks)‘(1+‘Ki)+Ts
`Tp = K const ‘ Qa/N
`(2)
`where
`Kconst : injector factor
`Tp : basic injection time
`: correction factor for air/fuel ratio
`Ts : delayed injection time of injector due to me-
`chanical and electrical propogation lag
`Ke : steady-state learning factor
`Kt : transient learning factor
`Ki
`: a correction factor
`Ks 2 shift factor
`Qa : sucked air flow amount
`N 2 number of engine revolutions
`That is, a basic fuel injection time Tp is deter-
`mined through a sucked air flow amount of Qa of
`the engine and the rotational speed N from equa-
`tion (2) and the correction factor is changed and
`corrected so that a stoichiometric air/fuel ratio is
`obtained based on the output of the air/fuel
`(O2)
`sensor. Here, the correction factor largely deviates
`from 1.0 because of "ageing" changes in actuators
`such as the injectors and of sensors. Therefore,
`supplementary
`corrections
`are
`performed
`by
`means of the steady-state learning factor Ke and
`the transient learning factor Kt to make the correc-
`tion factor be nearer to 1.0 and determine the fuel
`injection Time Ti.
`.
`Figure 8 shows a flow chart for preparing cor-
`rection maps. In step 8a, the O2 feedback learning
`map is checked to decide whether there are maps
`requiring corrections. Based on the check results, a
`decision is made in step 8b whether there are
`
`the process
`If not,
`maps requiring re-matching.
`ends. ln this embodiment. a Ts map, a Kconst map
`and a Qs table are illustrated as maps requiring re-
`matching. Maps requiring re-matching are specified
`in steps 8c, 8e and 8h and in each of steps 8d, 8t
`and Bi, control data to be transmitted to the host
`computer is selected or computed if necessary and
`is stored in the RAM address of the vehicle-moun-
`ted computer to prepare the maps.
`In step Bj.
`header data of revision items corresponding to the
`map to be corrected is prepared,
`the corrected
`map is read out from RAM to write in the transmis-
`sion area in preparation for transmission to the host
`computer in step 8k and the flow is completed.
`Criteria to decide whether a revision is required
`and specific revision procedures are made in ac-
`cordance with, for example, prior Japanese Patent
`Application No. 63-181794 (1988) of the present
`applicants.
`Figure 9 shows an example of data transmis-
`sion and reception when an engine stops. The
`engine is controlled by a microcomputer by com-
`puting control values to control actuators such as
`the injector based on outputs of each sensor,
`in-
`cluding the inlet air flow and crank angle sensors.
`Each datum may be required for failure diagnosis
`and matching by the host computer. Necessary
`data is taken in and stored in the host computer at
`every ignition key turn OFF.
`In step 9a, a decision is made whether the
`ignition key is turned ON or OFF. When turned ON,
`the engine is running and the flow terminates.
`in
`step 9b, a decision is made whether the engine is
`rotating or not. When rotating.
`the flow ends.
`In
`steps 9c and 9d, a decision is made whether data
`transmission to the host computer is required or
`not.
`In other words, when the previous revision
`request is issued in step 9c and when there are
`revision items of the map to be corrected in step
`9d, a decision is made that data transmission is
`required and operation proceeds to step 9e. Other-
`wise, operation proceeds to step 9i.
`In step 9e, a
`mask setting for transmissionlreception is made to
`prevent interruption, the transmission/reception pro-
`gram is executed in step 9f and the mask is
`cleared
`in
`step
`9h.
`In
`step
`9h.
`transmission/reception is carried out
`through the
`transmitter-receiver 5 if
`transmission/reception is
`possible.
`If transmission/reception is not possible.
`the flow ends. When transmission/reception is
`made, the flow proceeds to step 9i, self-shut off
`‘ and automatically stops the computer after
`the
`elapse of a predetermined time.
`Next, the execution of data matching in step 5j
`of Figure 5 by the host computer will be explained
`by taking Figure 10 as an example.
`Figure 10 is an example of obtaining deviations
`from the previous revision data and for evaluating
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`correction values. In step 10a, a decision is made
`whether the revision is the first or not.
`If
`it is the
`first revision, basic data is stored in step 10c.
`If
`not, the previous data is retrieved.
`In step 10d, a
`correction value is calculated from the map data
`transmitted from the vehicle-mounted computer, re-
`vised (corrected) values in each map are calculated
`in step toe, the calculated values are stored in the
`memory in step 10f and the process completes.
`Figure 11 is an exemplary flow diagram of data
`transmission/reception. The vehicle-mounted com-
`puter starts a flow process at every predetermined
`interval.
`In step 11a, a decision is made whether
`the revision request has been completed or not.
`When completed,
`the flow proceeds to 11g and
`moves to the data return transmission program.
`If
`there is a transmission return request in step 11b.
`necessary data is transmitted to the host computer.
`Next,
`the vehicle-mounted computer awaits until
`the host computer transmits a signal permitting
`transmission.
`in step 111, the host computer re-
`ceives the transmission signal
`from the vehicle-
`mounted computer and at step 11m determines if it
`is
`ready to receive the transmission from the
`vehicle-mounted computer.
`If
`it
`is ready a signal
`permitting transmission is derived in step 11n and
`if it is not ready then a wait instruction is issued in
`step 110. The vehicle-mounted computer transmits
`data in step 11d if it has received a transmission
`permit in step 11c,
`lights up the display lamp in
`step He and applies a revision request flag ON in
`step 11f. If there is no transmission permit, the flow
`process ends. The host computer, which has re-
`ceived data. processes the data in step 11p and
`then,
`if
`the vehicle-mounted computer
`requires
`data return transmission in
`step 11g, decides
`whether return transmission is possible or not
`in
`step 11q. If return transmission is possible, it trans-
`mits back the processed data in step 11r. If it is not
`possible to transmit data back, the host computer
`issues a wait instruction in step 11s and transmits
`back the data in step 11t. The vehicle-mounted
`computer releases the wait condition when a signal
`permitting data return transmission is transmitted in
`step 11h, re-writes the data in step 11i based on
`the data transmission from the host computer in
`step 11t, turns OFF the display lamp in step 11],
`puts OFF the revision request flag in step 11k and
`completes the process.
`Having now fully described the present inven-
`tion it will be realised that processing by a vehicle-
`mounted computer can be transferred to a station-
`ary host computer as the occasion demands and
`real-time vehicle controls are implemented effec-
`tively without
`increasing the workload of
`the
`vehicle-mounted computer.
`
`Claims
`
`1. A method of load sharing processing oper-
`ations between a vehicle mounted station (105, 2,
`400. 500) and a stationary base station (25) includ-
`ing the steps of said vehicle mounted station de-
`tecting operating conditions of the vehicle,
`trans-
`mitting data representative of the detected operat-
`ing conditions to the base station, said base station
`receiving data from the vehicle mounted station.
`processing said data in accordance with data
`stored by said base station, said base station trans-
`mitting processed data to a receiver at said vehicle
`mounted station and control means at said vehicle
`mounted station connected to the vehicle mounted
`receiver and being arranged to perform at least one
`of revising or displaying the vehicle operating con-
`ditions in dependence upon the processed data.
`2. A method as claimed in claim 1 wherein the
`vehicle mounted station detected operating con-
`ditions are performed by a detecting means adapt-
`ed to detect at least one of water temperature (32),
`air/fuel ratio (34) air fuel quantity (Qa), battery volt-
`age,
`throttle valve angle opening (56), engine
`speed (N), transmission gear position (4) and sus-
`pension setting (501).
`3. A method as claimed in claim 1 or 2 wherein
`the vehicle mounted station includes a control
`means adapted to control at
`least one of a fuel
`injector (44), a transmission gear change means
`(400). and a suspension setting actuator (500).
`4. A method as claimed in any preceding claim
`wherein the data transmitted from the vehicle
`mounted station to the base station is performed at
`times of occurrence of predetermined conditions
`including at
`least one of the vehicle covering a
`predetermined distance, detection of the engine
`ceasing rotation and low fuel tank condition.
`5. A method as claimed in any preceding claim
`wherein data transmitted between the vehicle
`mounted station and the base station includes
`header bits, vehicle identification bits, control data
`bits, data array bits, check symbol bits and end of
`transmission bits.
`6. A method as claimed in any preceding claim
`wherein the vehicle mounted station transmits a
`request to transmit to the base station, said base
`station transmits a permission to transmit for the
`vehicle mounted station, said vehicle transmits data
`including header bits, vehicle identification bits,
`control data bits, data array bits and check symbol
`bits, said base station transmits a receipt acknowl-
`edgement and said stationary base station trans-
`mits end of transmission bits.
`7. A method as claimed in any preceding claim
`wherein the vehicle mounted station contains at
`least one map indicative of vehicle operating con-
`ditions including an indication of ageing in at least
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`one of vehicle injectors and sensors, said map
`being transmitted by said ve