United States Patent (19)
`Nii
`
`US005650931A
`Patent Number:
`11
`45 Date of Patent:
`
`5,650,931
`Jul. 22, 1997
`
`54 GENERATOR OUTPUT CONTROLLER FOR
`ELECTRIC VEHICLE WITH MOUNTED
`GENERATOR
`
`75 Inventor: Yoshihide Nii, Fuji, Japan
`73) Assignee: Toyota Jidosha Kabushiki Kaisha,
`Toyota, Japan
`
`(21) Appl. No.: 389,810
`22 Filed:
`Feb. 16, 1995
`30
`Foreign Application Priority Data
`Feb. 21, 1994
`JP
`Japan .................................... 6-022371
`(51
`Int. C. m. B60L 11/02
`52 U.S. Cl. .................................... 364/424.026; 318/139;
`180/65.4
`58) Field of Search ..................... 364/423.098, 424.026;
`180/65.1, 65.2, 65.3, 65.4; 318/139; 290/14,
`16, 17
`
`56)
`
`5,176,213
`
`References Cited
`U.S. PATENT DOCUMENTS
`1/1993 Kawai et al. .......................... 180/654
`
`
`
`1/1994 Grabowski et al. ..
`5,280,223
`3.18/39
`5,318,142 6/1994 Bates et al. ......
`180/65.2
`ow
`5,359,308 10/1994 Sun et al......
`o
`180/65.3
`5,461,289 10/1995 Adler et al. ............................. 318/139
`5,492,190 2/1996 Yoshida .................................. 180/65.4
`FOREIGN PATENT DOCUMENTS
`European Pat. Off..
`0556942 8/1993
`Germany.
`3112629 10/1982
`Germany.
`4000678 7/1991
`Germany.
`41 16899 11/1991
`Japan.
`60-74937 4/1985
`Japan.
`62-272803 11/1987
`Japan.
`4-29504 1/1992
`Primary Examiner-Gary Chin
`Attorney, Agent, or Firm-Oliff & Berridge
`57
`ABSTRACT
`An output memory unit 26a stores data for the necessary
`average output of a generator 20 for a pattern obtained from
`the past in-travel-pattern power consumption. Therefore, in
`the case of a travel pattern, the output of the generator 20 is
`set in accordance with the stored data. Moreover, the power
`consumption in the travel pattern is examined to update the
`necessary average output of the generator 20.
`
`14 Claims, 5 Drawing Sheets
`
`
`
`20
`
`18
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`
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`
`
`OUTPUTMEMORY
`UNT
`GENERATOR OUTPUT
`COMPUTING UNIT
`------
`ACCELERATOR
`AND THE LIKE
`
`26
`
`26b
`
`START SWITCH
`STOP SWITCH
`
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`U.S. Patent
`
`Jul. 22, 1997
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`Sheet 1 of 5
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`5,650,931
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`HKO LIWAS L?HVIS
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`
`
`HÕLIMAS dOLS
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`| -61-I
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`
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`JINÍ) . ÅHOWEW I?ld.100
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`EXIT EH10NW,
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`
`HOLVHEITE OOW,
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`92
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`U.S. Patent
`
`Jul. 22, 1997
`
`Sheet 2 of 5
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`5,650,931
`
`START
`
`
`
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`
`
`CONTROL POWER
`GENERATION OUTPUT
`NACCORDANCE WITH
`MOTOR OUTPUT AND
`SOCWALUE,
`
`
`
`
`
`PRESENT
`
`
`
`
`
`CONTROL POWER
`GENERATION OUTPUT
`NACCORDANCE WITH
`MOTOR OUTPUT AND
`SOCWALUE.
`
`
`
`PERFORM OPERATION
`ATAVERAGEOUTPUT
`Xa(KW) UPTO THE
`LAST TIME,
`
`ACCUMULATE
`MOTOR
`
`. OUTPUT.
`
`
`
`
`
`ACCUMULATE
`MOTOR
`OUTPUT.
`
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`S15
`
`S16
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`CALCULATE POWER
`GENERATION OUTPUTX
`NACCORDANCE WITH
`ACCUMULATED MOTOR
`OUTPUT, (EXPRESSION 1)
`
`
`
`
`
`AVERAGE POWER GEN
`ERATION OUTPUT UPTO
`THE LAST TIME AND DETER.
`MINE THENEXTPOWER
`GENERATION OUTPUTXa,
`(EXPRESSION2)
`Fig. 2
`
`
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`U.S. Patent
`
`Jul. 22, 1997
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`sheet 3 of 5
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`5,650,931
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`START
`
`S3
`
`
`
`
`
`MODETRAVEL
`STARTIME WITHN
`PREDETERMINEDTIME
`POWER GENERATION
`POWER GENERATION
`NACCORDANCE WITH
`NACCORDANCE WITH
`MODETRAVEL
`MOTOR OUTPUT AND
`OUTPUT.
`SOCWALUE.
`
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`IS
`TRAVE
`STOPPED?
`
`
`
`Y
`RECORD OUTPUT
`REQUIRED FOR START
`AND STOP,
`
`S36
`TIME ISOUT OF
`PREDETERMINEDTIME OR
`COM
`OUTPUT IS PREDETERMINED
`PARISON WITH
`WALUE ORMORE,
`TRAVELDATAUP
`TO THEN TIME SWITHIN
`PREDETERMINEDTIME AND
`
`
`
`S37
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`COUNTUPAPPEARANCE
`FREQUENCY AS
`PROSPECTIVE MODE
`THOUGHNOT RECORDED
`ASMODETRAVEL
`
`
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`
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`THE MODEAP.
`PEAR"n"TIMES OR
`MORE
`
`RECORD DATA AS
`MODE TRAVEL
`
`OBTAN POWER GEN
`ERATION OUTPUTXa
`NTHE MODE IN
`ACCORDANCE WITH
`EXPRESSIONS 1 to 3,
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`U.S. Patent
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`Jul. 22, 1997
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`Sheet 4 of 5
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`5,650,931
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`S5
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`PERFORM OPERATION
`ATPOWER GENERA.
`TION OUTPUT WITH
`HIGH FREQUENCY,
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`S52
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`OUT OFRANGE
`
`IS
`TRAVEL
`STOPPED?
`
`TRAVEL
`TOPPED?
`
`COMPUTE POWER
`GENERATIONOUTPUT, -S56
`(EXPRESSION 1 TO3)
`IS
`DATAWITH THE
`HIGHEST FREQUENCY COMPARED
`WITH THE PAST POWER GEN
`
`S57
`
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`
`
`
`
`
`
`
`N
`
`DATA WITHN
`PREDETERMINEDTIM
`PRESENT
`
`S58
`COUNT UP APPEAR
`ANCE FREQUENCY
`OF THE DATA.
`
`RECORD THE
`OUTPUT OF THE
`GENERATOR,
`
`
`
`
`
`
`
`
`
`
`
`APPEARANCE
`FREQUENCYLARGER THAN
`THAT OF PASTMOST.
`EQUENT DATA
`
`UPDATE THE NEXT
`POWER GENERATION
`OUTPUT,
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`U.S. Patent
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`Jul. 22, 1997
`
`Sheet 5 of 5
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`5,650,931
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`S71
`
`PERFORM OPERATION
`AT THE PAST
`AVERAGE OUTPUTXa.
`
`
`
`
`
`
`
`
`
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`
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`POWER GENERATION
`INACCORDANCE WITH
`MOTOR OUTPUT AND
`SOCWALUE,
`
`
`
`IS
`TRAVEL
`STOPPED?
`
`
`
`S
`TRAVEL
`STOPPED?
`
`
`
`
`
`
`
`
`
`COMPUTE POWER
`GENERATION OUTPUT,
`(EXPRESSION 1)
`
`UPDATEAVERAGE
`OUTPUTXa NACCOR
`DANCE WITH EXPRES
`SIONS2 AND 3.
`
`S76
`
`S77
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`1.
`GENERATOR OUTPUT CONTROLLER FOR
`ELECTRIC VEHICLE WITH MOUNTED
`GENERATOR
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to a generator output con
`troller for an electric vehicle having a generator mounted in
`addition to a battery.
`2. Description of the Prior Art
`An electric vehicle traveling by driving a motor is already
`known, which is advantageous in view of low environmental
`pollution. However, because the electric vehicle drives the
`motor using electrical power from a mounted battery, the
`maximum travel distance of the vehicle is limited due to the
`capacity of the battery. Particularly, because the weight and
`the size of a battery are limited by the fact that the battery
`is actually mounted on a vehicle, the capacity cannot be
`increased very much, so the maximum travel distance can
`not be increased very much either. Moreover, because it
`takes a longtime to charge the battery, it cannot be expected
`for the state of charge of the battery to recover quickly,
`although gasoline can be fed to a gasoline-fueled vehicle in
`a short time. Therefore, a hybrid vehicle is proposed whose
`maximum travel distance is increased by mounting an
`engine-driven generator on an electric vehicle and it is
`possible to charge a battery using electrical power obtained
`from the generator.
`Because the hybrid vehicle drives an engine, it produces
`exhaust gas. However, because the engine is driven to
`generate electric power, the load fluctuation and the rota
`tional speed fluctuation of the engine are much smaller than
`those for driving a vehicle and therefore harmful compo
`nents in exhaust gas can be greatly decreased.
`35
`Therefore, a travel distance equal to that of a gasoline
`fueled vehicle and a low environmental pollution close to
`that of an electric vehicle can be obtained from the hybrid
`vehicle.
`To minimize harmful components in the exhaust gas of
`this type of hybrid vehicle, it is desirable to drive the engine
`at a constant load and a constant rotational speed so that the
`power generation is kept at a constant value.
`However, the power consumption of an electric vehicle
`depends on the travel conditions. That is, when the electric
`vehicle travels on many upward slopes or repeatedly stops
`and starts because there are many traffic signals, the power
`consumption increases. Therefore, it is disclosed in Japanese
`Patent Application Laid-Open No. SHO-60-7437 (1985)
`(JP-A-60 007 437) that the electric power output of a
`generator is controlled in accordance with the state of charge
`of a battery.
`However, if the generator output is changed as described
`above, the engine output must also be fluctuated. Therefore,
`a problem occurs that harmful components in exhaust gas
`increase. Moreover, a problem occurs that the operation of
`an engine in the above way increases fuel consumption.
`SUMMARY OF THE INVENTION
`It is an object of the present invention to provide a
`generator output controller for an electric vehicle with a
`mounted generator, making it possible to effectively obtain
`a desired amount of power generation
`For example, power generation is properly controlled by
`recognizing a predetermined travel pattern by an instruction
`of the driver or recognizing a travel pattern in accordance
`with the start time of a vehicle.
`
`55
`
`2
`The present invention is a generator output controller for
`a vehicle having a generator mounted in addition to a motor
`driven by a battery, comprising:
`travel-pattern recognition means for recognizing travel
`repeated in accordance with a specific pattern;
`an in-travel-pattern power consumption memory unit for
`storing data for power consumption in a travel pattern;
`and in-travel-pattern power generation control means
`for controlling the output of a generator to a power
`generation equal to the power consumption value in a
`travel pattern read out of the travel-pattern power
`consumption memory unit when the travel pattern is
`recognized by the travel-pattern recognition means.
`According to the present invention, the output of a gen
`erator is set to a generator output equal to the power
`consumption value corresponding to the travel pattern in the
`case of traveling according to a travel pattern. Therefore, it
`is possible to generate optimum electrical power at a con
`stant value by a generator. Thus, it is possible to decrease
`harmful components in the exhaust gas of a generator and
`increase the power consumption of an engine for driving the
`generator. For example, for a regular travel pattern such as
`people commuting using a standard vehicle or taking people
`to and from their offices using a commercial vehicle, it is
`possible to minimize the power generation
`Moreover, it is preferable that the travel-pattern recogni
`tion means includes travel-pattern start input means and
`travel-pattern end input means.
`Thereby, a travel pattern can be securely recognized
`through an input by a driver.
`Furthermore, it is preferable that the travel-pattern rec
`ognition means is provided with:
`in-travel-pattern power consumption detection means for
`detecting the power consumption of a vehicle in a
`travel pattern; and
`update means for updating a target power generation
`stored in the in-travel-pattern power consumption
`memory unit in accordance with the detected in-travel
`pattern power consumption of a vehicle.
`In this case, because the optimum generator output is
`updated in accordance with the travel state after traveling in
`a travel pattern, the accuracy of generator output is improved
`as the travel frequency increases.
`Moreover, it is preferable that the update means averages
`the accumulated in-travel-pattern power consumption
`including a detected in-travel-pattern power consumption
`and updates a target power generation in accordance with the
`calculated average value.
`As described above, it is possible to set the power
`generation in a travel pattern to a proper value by averaging
`the accumulated power consumption when updating a power
`consumption.
`Furthermore, it is preferable that:
`the update means further includes start time detection
`means for detecting the starting time of a vehicle;
`the in-travel-pattern power consumption memory unit
`stores the power consumption in a travel pattern by
`relating it with the start time of the vehicle; and
`the travel-pattern power generation control means con
`trols a generator with the in-travel-pattern power con
`sumption concerned when the starting time of the
`vehicle is for the travel pattern.
`A travel pattern can frequently be determined by the start
`time of a vehicle. Therefore, by recognizing a travel pattern
`by the start time of the vehicle, it is possible to recognize the
`travel pattern and set the power generation of a generator to
`a proper value even if the driver is not conscious of the travel
`pattern.
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`3
`Furthermore, it is preferable that the update means is
`provided with:
`detection means for detecting the power consumption
`under travel;
`duration detection means for detecting the duration of
`travel of a vehicle; and
`travel-pattern recognition means for recognizing a travel
`pattern when a travelling under the same condition is
`repeated a predetermined number of times or more in
`accordance with stored data by storing the starting
`time, power consumption for travel, and duration of
`travel of a vehicle whenever the vehicle travels.
`Thereby, it is possible to accurately obtain the power
`consumption in a travel pattern.
`Moreover, the present invention is a generator output
`controller for an electric vehicle having a generator mounted
`in addition to a motor driven by a battery, comprising:
`power consumption detection means for detecting the
`power consumption under travel whenever a vehicle
`travels;
`zone decision means for deciding which Zone the detected
`power consumption is included in among predeter
`mined power consumption zones;
`respective-zone usage frequency detection means for
`counting the frequency of use in each Zone, and
`power generation control means for controlling a genera
`tor output to a target generator output corresponding to
`a power consumption zone with the highest usage
`frequency in accordance with the result detected by the
`respective-Zone usage frequency detection means.
`Therefore, the degree of power consumption under travel
`is stored for every time of travel, and a power consumption
`appearing with the highest frequency is used for the gen
`erator output at the next time of travel. A travel state having
`a high frequency in the past may also appear in the future.
`Thereby, it is possible to set a preferred power generation.
`Moreover, it is preferable that the generator output con
`troller is provided with:
`state-of-charge detection means for detecting the state of
`charge of a battery; and
`correction means for correcting a generator output so as to
`decrease or increase the generator output in accordance
`with the detected state of charge when the state of
`charge is higher than a predetermined upper limit or
`lower than a predetermined lower limit.
`As described above, because power generation is con
`45
`trolled in accordance with the SOC of a battery when the
`battery SOC goes out of a predetermined range, it is possible
`to prevent the situation where a vehicle cannot travel due to
`an insufficient battery capacity and to prevent electrical
`power from being excessively generated.
`BRIEF DESCRIPTION OF THE DRAWTNGS
`FIG. 1 is a block diagram showing the constitution of an
`embodiment of the present invention;
`FIG. 2 is a flow chart showing operations of the first
`embodiment.
`FIG. 3 is a flow chart showing operations of a second
`embodiment.
`FIG. 4 is a flow chart showing operations of a third
`embodiment.
`FIG. 5 is a flow chart showing operations of a fourth
`embodiment.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`Embodiments of the present invention are described
`below by referring to the accompanying drawings. FIG. 1 is
`
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`a block diagram showing the overall constitution of the
`electric vehicle of this embodiment, in which the torque of
`a motor 10 is transmitted to a tire 12 and thereby a vehicle
`travels. Abattery 16 is connected to the motor 10 through an
`inverter 14, and DC power sent from the battery 16 is
`converted to a desired AC power by the inverter 14 and
`supplied to the motor 10. The motor 10 of this embodiment
`uses a three-phase induction motor.
`A generator 20 is connected to the battery 16 through a
`rectifier 18. The power generated by the generator 20 is
`converted to DC power by the rectifier 18 and used to charge
`the battery 16. The generator 20 is driven by an engine 22.
`In the case of this embodiment, the engine 22 is a gasoline
`engine.
`Moreover, a field (magnetic field) controller 24 is con
`nected to the generator 20, which controls the field current
`of the generator 20 and the generator output.
`Furthermore, a controller 26 is provided which controls
`the switching of the inverter 14, rotational speed of the
`engine 22, and field current generated by the field controller
`24. That is, the controller 26 computes an output torque from
`signals for operating an accelerator and brake, and controls
`the switching of a power transistor in the inverter 14 to
`control the output torque of the motor 10.
`Moreover, in this embodiment, the controller 26 sets the
`field current in the field controller 24 and the rotational
`speed of the engine 22 to desired values. The controller 26
`includes an output memory unit 26a and a generator output
`computing unit 26b.
`Power generation control carried out by the controller 26
`of the first embodiment is described below by referring to
`FIG. 2.
`First, it is decided whether a start switch for designating
`a travel pattern according to this embodiment is ON or OFF
`(S.11). If the switch is OFF, the output of the generator 20 is
`controlled in accordance with the current output of the motor
`10 or the current state of charge (hereafter referred to as
`SOC) of the battery 16 similarly to the case of a normal
`hybrid vehicle because a travel pattern is not designated
`(S12). For example, the generator 20 is operated at a
`constant power generation when SOC ranges between 70
`and 90%, power generation is stopped for an SOC of 90%
`or more, and power generation is increased for an SOC of
`50% or less. Because there is a certain relationship between
`SOC and motor output, it is also possible to use motor output
`instead of SOC. Moreover, it is possible to use any technique
`for the power generation control when under travel.
`However, if the start switch is ON in S11, it is decided
`whether there is the average power consumption up to the
`last travel pattern (S13). If the pattern average value up to
`the last time is not found in S13, the output of the motor 10
`is controlled and power generation is controlled according to
`a motor output or SOC value similarly to the case of the
`above S12 because there is no reference data for power
`generation control. Thus, the output of the motor 10 on this
`occasion is accumulated. In this case, the output X of the
`motor 10 is calculated in accordance with the expression
`"output of motor 10 X=kxtorque commandxmotor
`speed".
`In the above expression, the motor output is kW, torque
`command=Nm, and motor speed is rpm. Therefore, "k" is
`obtained as follows:
`
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`ke2L/60000-1047x10-4.
`Then, it is decided whether the stop switch is turned ON
`(S16). If the switch is OFF, S14 is repeated to repeat travel
`and accumulation of motor output.
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`Thereby, the motor output is accumulated until the stop
`Switch is turned OFF after the start Switch is turned ON.
`Then, the accumulated value is stored in the output memory
`unit 26a as an accumulated motor output for the pattern
`concerned.
`When the average value of power consumption up to the
`last travel pattern is present in S13, the power generation of
`the generator 20 is controlled in accordance with the accu
`mulated motor output up to the last travel pattern (SLY). In
`this control, the controller 26 controls the engine 22 and the
`field controller 24. Then, the output of the motor 10 under
`travel is accumulated (S18). Then, the accumulation of the
`motor output under travel is repeated until the stop switch is
`turned ON (S19).
`When the stop switch is turned ON in S16 or S19, the
`target generator output x is calculated from the accumulated
`motor output X by using the following expression because
`a travel pattern ends.
`a-X/T nB mINV nM
`Where,
`T: Accumulation time,
`mB: Charge/discharge efficiency
`mINV: Inverter efficiency
`mM: Motor efficiency
`The power generation for the time corresponding to the
`motor output (target generator output) is computed in accor
`dance with the above expression. This value is obtained by
`dividing the accumulated output of the motor 10 by the
`travel time and also considering the efficiency, that is, the
`value is obtained by averaging the power consumption of a
`vehicle under a one-time travel pattern. Moreover, by setting
`the generator outputin a travel pattern to "x", the SOC of the
`battery 16 does not change before and after the travel pattern
`if the travel state is the same.
`The average value of motor output in a travel pattern
`travel is calculated by adding the motor output obtained this
`time to the sum of the motor output up to the last time and
`dividing the total value by the number of additions and this
`is used as a new target generator output.
`That is, by assuming the accumulated motor output this
`time as Xn and the accumulated motor output up to the last
`travel pattern as Xin-1, Xn-2, ... , the additional value Xx
`of the target generator output is shown by the following
`expression.
`45
`(2)
`X-Xn+Xn-1-Xin-2, ...
`Therefore, the average value xa which is the new target
`generator output is shown by the following expression.
`... (3)
`Thus, the average value xa serves as the new target
`generator output.
`Then, the new target generator outputxa is stored in the
`output memory unit 26a. In the next travel pattern
`concerned, the output of the generator 20 is controlled so
`that the output comes to the new target generator output.
`As described above, according to this embodiment, a
`driver turns ON the start switch to notify the controller 26 of
`the start of a travel pattern in which the same type of travel
`such as people commuting using a standard vehicle, taking
`of people to and from their offices using a commercial
`vehicle, or delivery, is repeated many times. Then, the
`generator output under a travel pattern until the stop switch
`is turned OFF after the start switch is turned ON is set to the
`target generator output obtained from the accumulated out
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`put of the motor 10 before the last travel pattern. Because a
`travel pattern normally consumes approximately the same
`power, the total power consumption necessary for the travel
`pattern is approximately equal to the electrical power gen
`erated by the generator 20. Therefore, because the generator
`20 is operated without load fluctuation, it is possible to
`decrease harmful components in exhaust gas and improve
`fuel consumption
`Moreover, because the accumulated output of the motor
`10 in the travel pattern at the time is added to the accumu
`lated data and averaged, the target generator output becomes
`more accurate as the travel pattern frequency for the same
`pattern increases.
`When the number of target generator outputs to be aver
`aged increases, more storage area is required. Therefore, it
`is preferable to set an appropriate upper limit (e.g. 10) for the
`number of target generator outputs to be stored. Moreover,
`it is possible to obtain a new generator output by storing the
`storage frequency "n-1" and the average value up to the
`last time, adding a value obtained by dividing the obtained
`target generator output by "n-1” to the average value up to
`the last time, and thereafter multiplying the sum by "n-1/
`n”. Furthermore, it is preferable to set the upper limit of the
`above “n” to, for example, 10.
`The above target generator output is selected so that SOC
`is held before and after travel. However, in the case of a
`travel pattern requiring external charge after travel, it is
`possible to properly set the power generation so that SOC
`comes to almost 0 after the travel pattern within a range in
`which travel is possible. Moreover, it is preferable to set a
`plurality of types of travel pattern so that a pattern can be
`specified by inputting the ID of the pattern when the start
`switch is turned ON.
`The above target generator output "x" corresponds to the
`power consumption due to travel. In the case of the above
`embodiment, the accumulated motor output is stored for
`each travel pattern. However, it is also possible to store a
`target generator output corresponding to the accumulated
`motor output.
`FIG. 3 shows the second embodiment. In the case of this
`embodiment, the starting time and the stopping time of
`travel of a vehicle are stored while the vehicle travels and the
`motor output under travelis accumulated. When a journey at
`the same time and the same accumulated motor output is
`performed many times, a target generator output is stored by
`using the journey as a travel pattern. Thereafter, the travel
`pattern is recognized by the starting time and the output of
`the generator 20 is automatically set to the target generator
`output. Therefore, when the target generator output for each
`pattern is stored as described above, the start time for the
`travel pattern is also stored.
`When travel of a vehicle is prepared by turning ON a
`power switch, the controller 26 decides whether the time is
`the starting time for the stored travel pattern (S31). This
`decision is made not by checking if the time is completely
`equal to the starting time but by checking if the time is
`within a certain range. For example, this decision is made by
`checking if the time is within 30 min before or after the
`stored starting time. If the time is not contain in the range of
`the starting time, power generation is controlled in accor
`dance with the output of the motor 10 or SOC value as usual
`(S32). Then, it is decided whether to stop the travel (S33).
`When it is decided to continue the travel, S32 is restarted and
`repeated until the travel is stopped.
`Meanwhile, when it is within the range of the starting time
`in S31, the travel pattern is performed by setting the output
`of power generator 20 in the stored target generator output
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`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`7
`(S34). Then, it is decided whether to stop the travel (S35).
`When it is decided to continue the travel, S34 is restarted and
`repeated.
`However, if it is decided to stop the travel in S33 or S35,
`the start and stop times in S32 or S34 and the accumulated
`motor output are recorded (S36). Then, the obtained dura
`tion and motor output are compared with the already stored
`duration and motor output (S37). When both the difference
`of duration and the difference of motor output data are kept
`within predetermined values (e.g. 30 min and 1 kWh), it is
`decided whether the pattern appears “n” times or more
`(S38).
`In S38, when the pattern appears “n” times or more, it is
`stored as a travel pattern (S39), a target generator output is
`obtained by the above expressions (1) to (3) (S40), and the
`target generator output is stored together with the starting
`time (S39, S40). When the already-stored travel pattern is
`performed, it is preferable to add the data this time to the
`target generator output and average the data to make the
`average value of motor output more accurate, similarly to
`the above case, and it is also preferable to average start time.
`It is also possible to calculate the standard deviation of
`starting time and change the range in S31 in accordance with
`the standard deviation.
`If the pattern appears less than “n” times in S38, the
`appearance frequency of the pattern is stored as a prospec
`tive mode (S41). That is, the counted value is counted up by
`1 due to the appearance this time.
`According to this embodiment, when a travel with almost
`the same starting time and travel condition (accumulated
`motor output) is performed “n” times (e.g. 5 times) or more,
`the controller automatically regards the travel as a travel
`pattern and stores the starting time at the target generator
`output of the travel pattern. When the driving of a vehicle is
`started at the starting time, a generator output is automati
`cally set to the target generator output.
`Therefore, the driver can set the generator output to a
`desired value without carrying out any operation. However,
`even if the starting time coincides with the stored travel
`pattern, the case may not be a travel pattern. Therefore, it is
`also preferable that a travel pattern is notified to the driver
`at the start by displaying that the travel patternis about to be
`performed and the driver can cancel the travel pattern unless
`it is desired. Moreover, even when there are a plurality of
`patterns, it is possible to automatically select a travel pattern
`in accordance with the starting time.
`Operations of the third embodiment are described below
`by referring to FIG. 4. In the case of this embodiment, the
`power consumption from start to end of travel is always
`accumulated and the generator output corresponding to a
`power consumption with the highest appearance frequency
`among the power consumptions up to the last time is
`assumed as a generator output for future travel.
`When travelis started, a generator output with the highest
`using frequency is selected out of the generator outputs, each
`of which is calculated for each travel stored up to the last
`travel and thereby the generator 20 is operated (S51). It is
`also possible to store the power consumption for each travel
`instead of the generator output. Moreover, it is preferable to
`calculate the usage frequency by sectioning power consump
`tion every 1 kW and countingapower consumption included
`in each section. That is, the frequency is obtained by
`dividing the accumulated power consumption for one-time
`travel by time to obtain the average power consumption and
`counting the average power consumption every predeter
`mined section. Then, an electrical energy corresponding to
`average power consumption with the highest usage fre
`quency is assumed as a target generator output.
`
`45
`
`50
`
`55
`
`65
`
`8
`Then, it is decided whether SOC is kept in a predeter
`mined range (SS2). For example, it is decided whether SOC
`is kept between 70 and 90% (both excluded). When SOC is
`included in the above range, the generator output corre
`sponds to the power consumption under travel. Therefore, it
`is decided whether to stop travel (S53) and S51 is restarted.
`However, unless SOC is included in the above range, it is
`decided that the generator output is not proper. Therefore,
`the output of the generator 20 is set to a power generation
`value corresponding to motor output or SOC(S54). Thereby,
`it is possible to maintain the SOC and continue the travel.
`Then, it is decided whether to stop the travel (S55). Unless
`the travel is stopped, SS4 is restarted to continue the travel.
`However, if the travel is stopped in S53 and S55, the
`power consumption for the travel this time is calculated in
`accordance with the above expressions (1) to (3) and a target
`generator output is computed (S.56) because the travel is
`terminated. Then, it is decided whether the calculated target
`generator output is the data for a generator output with the
`highest frequency (SS7). When the calculated target genera
`tor output has a data value with the highest usage frequency
`among stored data values (or the output is included in the
`range of stored data values), the number of times of appear
`ance of the data value is counted up (S58) and the processing
`is terminated.
`However, unless the target generator output calculated
`this time has a data value with the highest usage frequency
`among stored data values in S57, it is decided whether the
`target generator output is kept in a predetermined range of
`any one of stored target generator outputs (S59). When the
`target generator output is kept in the predetermined range,
`the number of times of appearance of the data value is
`counted up (S60).
`Then, the counted-up result in S60 is compared with the
`appearance frequency of the most-frequent data value (S61).
`When the frequency data calculated this time is maximum,
`the data for the target generator output this time is updated
`to the next-time generator output (S62) and the processing is
`terminated. Unless the frequency data is maximum in S61,
`the processing is immediately terminated. Moreover, unless
`a target generator output included in the predetermined
`range is found in S59, the calculated target generator output
`is directly stored (S63) and the processing is terminated
`Thus, according to this embodiment, the power generation
`of the generator 20 is automatically set to a target generator
`output appearing at a high frequency. Therefore, power
`generation is set to a correct value at a high probability.
`Moreover, because the data for appearance frequency is
`updated each time, data becomes very accurate.
`Furthermore, power generation does not correspond to
`actual power consum