United States Patent
`
`119;
`
`[11] Patent Number:
`
`4,559,599
`
`Habu et al.
`
`[45] Date of Patent:
`
`Dec. 17, 1985
`
`[54] OPTIMUM SHIFT POSITION INDICATION
`USING SUCCESSIVE TWO-DIMENSIONAL
`DATA MAPS
`
`[75]
`
`Inventors: Nobuo Habu; Kouichi Osawa;
`Yuuichi Kato; Michio Furuhashi;
`Taiyo Kawai; Junichi Saiki; Toshio
`Ito, all of Susono; Tsutomu
`Nakamura, Kariya, all of Japan
`
`[73] Assignees: Nippondenso Co., Ltd., Kariya;
`Toyota Jidosha Kabushiki Kaisha,
`Toyota, both of Japan
`
`[21] Appl. No.: 474,324
`
`[22] Filed:
`
`Mar. 11, 1983
`
`Foreign Application Priority Data
`[30]
`Mar. 18, 1982 [JP]
`Japan .................................. 57-43655
`
`[51]
`
`Int. cu .................... .. B60K 41/18; GO9B 19/16;
`G07C 5/08
`
`[52] U.s. Cl. ............. .; ............... 364/424.1; 340/52 D;
`364/442; 434/71
`[58] Field of Search ............. .. 364/424.1, 442; 434/71,
`340/52 R, 52 D, 52 F
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,150,497 4/1979 Weber ................................... 434/71
`4,198,882 4/1980 Kiencke et al.
`..
`4,294,341 10/1981 Swart ...... ..
`4,320,381
`3/1982 Olivier .... ..
`I 340/52 F
`.... .. 74/866
`4,350,057 9/1982 Kishi et al.
`.. 340/52 F
`..
`4,354,173 10/1982 Kuhn et al.
`4,355,296 10/1982 Drone ............................. .. 340/52 R
`
`.......................... 74/866
`4,411,174 10/1983 Yokoi et al.
`4,428,257
`1/1984 Meyerle et al.
`..
`...... 74/866
`4,438,423
`3/1984
`. 340/52 R
`4,439,158
`3/1984
`4,463,427
`7/1984 Bonnetain et al.
`
`.................. 364/442
`
`FOREIGN PATENT DOCUMENTS
`
`2748227
`3128080
`6235
`2091358
`
`6/1978 Fed. Rep. of Germany .
`2/1983 Fed. Rep. of Germany .
`1/1979 Japan .
`1
`7/1982 United Kingdom ............... . 364/442
`
`Primary Examiner—-Felix D. Gruber
`Attorney, Agent, or Firm--—Cushman, Darby & Cushman
`
`[57]
`
`ABSTRACT
`
`A shift indication apparatus having an engine rotation
`sensor, a throttle valve sensor, and a shift position sen-
`sor, a microcomputer having a ROM and RAM for
`storing data corresponding to the engine speed, throttle
`valve openings, and the shift positions therein, and an
`indicator for indicating preferable shift positions to be
`performed by a driver in which a torque data map and
`a fuel consumption rate data map have stored in the
`ROM for calculating various torque and fuel consump-
`tion rates so as to obtain preferable shift positions relat-
`ing to optimum fuel consumption rate in accordance
`with said data detected. With this construction, it be-
`comes possible for a driver to run his car in accordance
`with the indications of the shift operation on the indica-
`tor so as to enable the economical running of the car to
`be realized.
`-
`
`12 Claims, 4 Drawing Figures
`
`BUS
`
`THROTTLE
`
`VWGoA - Ex. 1004
`
`Volkswagen Group of'America, |nc., Petitioner
`Case No. |PR2015-00276
`1
`
`VWGoA - Ex. 1004
`Volkswagen Group of America, Inc., Petitioner
`Case No. IPR2015-00276
`1
`
`

`
`U.S. Patent Dec. 17,1985
`
`Sheet1of3
`
`4,559,599
`
`BUS
`
`55/7
`L A’;
`_
`
`MICROCOMPUTER
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`
`C ,0 U
`
`I
`
`_
`
`ENG/NE SPEED
`
`SENSOR
`
`2
`
`‘
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`SH/FT POS/7'/ON
`
`SENSOR
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`6
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`20
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`7
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`SENSOR
`
`CONVERTER
`
`W:
`
`THROTTLE
`VA LVE
`
`ENG/NE
`
`2
`
`

`
`U.S. Patent Dec. 17,1985
`
`Sheet2of3
`
`4,559,599.
`
`
`
`
`
`‘9ON/N3:/O3/WW1E:’71lOHH1
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`ENG/NE SPEED
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`Ne (X/Oarpm)
`
`ENG/NE SPEED
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`

`
`1
`
`4,559,599
`
`OPTIMUM SHIFT POSITION INDICATION
`USING SUCCESSIVE TWO-DIMENSIONAL DATA
`MAPS
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates to a shift indication unit
`which can be used for an automotive vehicle having a
`manual
`transmission and for indicating to a driver
`change-speed operations to be performed relating to
`preferable shift position with respect to optimum fuel
`consumption, and a method of performing the optimum
`speed change operation so as to reduce fuel cost.
`2. Description of the Prior Art
`Recently, the situation and circumstances surround-
`ing supply of oils have deteriorated, and various re-
`search and development activities have been made in
`response in an attempt to improve efficient utilization of 20
`energy in each technical field in industry. The situation
`is the same in the autombile industry, where various
`research and development for improving engines to
`have better thermal efficiencies and for pursuing better
`methods for performing effective combustion of fuel for
`vehicles with less fuel consumption rate have been un-
`dertaken. However, there is a problem that unless oper-
`ations including acceleration operation and shift opera-
`tion are included, it is not possible for driving operation
`to sufficiently demonstrate the improved fuel consump-
`tion performance thus reached.
`SUMMARY OF THE INVENTION
`
`It is therefore a main object of the present invention
`to provide a shift indication apparatus which is capable
`of performing optimum running with a good fuel con-
`sumption rate by indicating to a driver preferable shift
`positions for the optimum fuel consumption during the
`running of the automotive vehicle.
`It is another object of the present invention to pro-
`vide a shift indication apparatus having a microcom-
`puter including a speed change instruction indicator and
`a ROM in which predetermined torque and fuel con-
`sumption maps are stored so as to calculate and indicate
`on the indicator preferable shift positions corresponding
`to the optimum fuel consumption rate.
`It is still another object of the present invention to
`provide a speed change operation and indication unit
`having a microcomputer comprising a ROM and a
`RAM into which data corresponding to the‘current
`engine speed and current shift position as well as throt-
`tle valve opening are stored and expected torque and
`fuel consumption rates are calculated from the data read
`from the RAM together with the predetermined maps.
`According to one feature of the present invention, the
`shift indication apparatus is characterized in that the
`unit comprises sensors for detecting the engine speed
`and the opening of a throttle valve, means for calculat-
`ing an expected or assumed fuel consumption rate in
`order to generate the same driving horsepower as that
`in the current car running conditions at a certain shift
`position adjacent to the particular shift position of the
`transmission at that time, means for comparing the cur-
`rent fuel consumption rate with the assumed fuel con-
`sumption rate so as to select a preferable shift position
`with the optimum fuel consumption rate, and means for
`indicating to the driver shift operation instructions to
`the preferable shift position.
`
`2
`These and other objects and advantages of the pres-
`ent invention will become more apparent from the fol-
`lowing detailed description with reference to the ac-‘
`companying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is an overall construction of one embodiment
`of the shift indication apparatus according to the pres-
`ent invention,
`FIG. 2 is one example of the characteristic curves of
`a torque data map stored in the ROM in the microcom-
`puter in FIG. 1 and
`FIG. 3 is one example of the characteristics of a fuel
`consumption data map stored in the ROM in the mi-
`crocomputer in FIG. 1.
`FIG. 4 is a programmed flow chart of the speed
`change operation indicating unit of FIG. 1 for the pur-
`pose of explaining the operation of the unit according to
`the present invention.
`DESCRIPTION OF THE PREFERRED
`' EMBODIMENT
`
`Referring to FIG. 1, the shift indication apparatus
`with a manual transmission according to the present
`invention comprises an engine speed sensor 1 for detect-
`ing the engine speed and for producing pulse signals of
`a frequency proportional to the engine speed, a shift
`position sensor 2 for detecting the shift positions of the
`transmission, a throttle sensor 3 for detecting the open-
`ing degree of the throttle valve by means of, for in-
`stance, a potentiometer, an A/D converter 4 for con-
`verting analog signals from the throttle valve sensor 3
`into digital signals, a microcomputer 5 for performing
`various calculations in accordance with the different
`signals from the sensors, and an indicator 10 for indicat-
`ing the result of the calculations.
`The microcomputer 5 further comprises an input-
`/output port (I/O port) 6, a central processing unit
`(CPU) 7, a read only memory (ROM) 8, and a random
`access memory (RAM) 9. In the microcomputer 5,
`there is provided a bus BUS which communicates the
`I/O port 6 and the CPU 7, ROM 8, and RAM 9.
`The engine speed sensor 1 is mounted in a distributor
`(not shown) and the output of the sensor is connected to
`the input of the I/O port 6 so as to transmit the output
`pulses to the microcomputer 5 through the I/O port 6
`and to store the data corresponding to the engine speed
`into the RAM 9. The output of the shift sensor 2 is‘
`connected to the input of the I/O port 6 so as to trans-
`mit the output signals thereof to the microcomputer 5
`through the I/O port 6 and to store the data from the
`shift sensor 2 into the RAM 9. Similarly, the output of
`the throttle sensor 3 is connected through the A/D
`converter 4 to the input of the I/O port 6 so as to trans-
`mit the output signals thereof to the microcomputer 5
`through the A/D converter 4 and to store the data
`corresponding to the throttle value opening into the
`RAM 9 after converting from the analog signals into the
`digital signals. The input of the indicator 10 is con-
`nected to the output of the I/O port 6 so as to indicate
`each preferable shift position corresponding to the opti-
`mum fuel consumption rate in accordance with various
`parameters calculated.
`_
`The indicator 10 includes a shift-up indicating lamp
`10a and a shift-down indicating lamp 101:.
`The indicator 10 may be assembled by light emiting
`diodes (LED) so as to perform shift-up and shift-down
`indications by up and down directed "arrow marks. Al-
`
`5
`
`

`
`3
`tematively, the indicator 10 may also be replaced with
`other voice combining circuit so as to announce the
`shift operations by voice instead of the indications.
`Before explaining the operation of the apparatus ac-
`cording to the present invention, reference must be 5
`made to the torque data mapshown in FIG. 2 and the
`fuel consumption rate data map shown in FIG. 3. The
`torque data map indicative of torque curves T as shown
`in FIG. 2 has been stored in the ROM 8 in advance. The
`fuel consumption rate data map indicative of equal fuel
`consumption rate curves B as shown in FIG. 3 has been
`also stored in the ROM 8 in advance. In FIG. 2, each
`equal torque curve T was prepared by plotting and
`connecting equal torque points on the graph with re-
`spect to the engine speed vs. throttle valve opening. In
`FIG. 3, each fuel consumption rate curve B was pre-
`pared by plotting and connecting equal fuel consump-
`tion rate points on a graph obtained in advance by ex-
`periment data with respect to the engine speed and the
`torques thus calculated.
`In operation, the microcomputer 5 functions in such a
`manner that
`it determines current
`torque from the
`torque data map stored in the ROM 8 and other_data
`corresponding to the engine speed detected by the sen-
`sor 1 and throttle valve opening detected by the throttle
`sensor 3, determines expected fuel consumption rate
`from the fuel consumption rate data map also stored in
`the ROM 8 and the torque thus determined as well as
`the engine speed, and compares the fuel consumption
`rate thus determined with an assumed fuel consumption
`rate when speed change operation is performed from
`the current shift position to the adjacent shift position in
`accordance with a control program, whereby an in-
`struction signal for changing suitable shift position re-
`lating to optimum fuel consumption rate is generated
`from the microcomputer and it is indicated on the indi-
`cator 10.
`
`The operation of the shift indication apparatus will
`now be made with reference to the control program
`flow chart shown in FIG. 4.
`
`First of all, the engine speed sensor 1 produces pulse
`signals proportional to the engine speed during running
`of the automotive vehicle and transmits these signals to
`the microcomputer 5. In this case, as shown in FIG. 4,
`the operation of a main routine is started at a predeter-
`mined timing, e. g. periodical timing pulses from a timer
`(not shown) and the detection of the engine speed Ne
`from the sensor 1 is carried out and it is stored into the
`RAM 9 at the step 20. Then, the engine speed Ne is read
`from the RAM 9 and it is compared with a predeter-
`mined number N (= 1000 rpm) to determine whether or
`not the Ne exceeds the value 1000 at the step 21. If the
`result of the decision is YES, the next step 22 is exe-
`cuted. That is, in the step 22, the reading in of the open-
`ing of the throttle valve is performed through the throt-
`tle sensor 3 and the A/D converter 4. In the above case,
`if the result of the decision in step 21 is NO, the main
`routine is terminated by determining that the shift oper-
`ation is not necessary and the engine speed Ne is read
`again at the predetermined timing and now the opera-
`tion returns to the step 20.
`In the step 22, the throttle valve opening 0 is detected
`by the throttle sensor 3 and is then stored in the RAM
`9 after conversion from the analog signals into the digi-
`tal signals through A/D converter 4. The next step 23,
`i.e. the torque search step is executed. In this step, the
`torque Te is determined from the torque curves T on the
`torque data map as shown in FIG. 2 and which has been
`
`4,559,599
`
`4
`stored in the ROM 8 in the microcomputer 5, in accor-
`dance with the detected data corresponding to the en-
`gine speed Ne and the throttle valve opening 0. In this
`case, assuming that the engine speed Ne is 3600 rpm and
`the throttle valve opening 0 is 30 degrees, the torque
`value T,-=11 kg-m is determined from the cross point
`on the torque curve T in the torque data map.
`Then in the next step 24, i.e. the torque deterrnination
`step is executed. In this step 24, a decision is made as to
`whether or not the value of the torque Te thus calcu-
`lated in the step 23 is larger than 0.05 kg-m, i.e. the
`vehicle speed is in the middle of speed reduction or it is
`close to the speed reduction. If the result of the decision
`is YES, the next step, fuel consumption search step 25,
`is executed, if the result’ of the the decision is NO, the '
`operation of the main routine terminates. In the step 25,
`the fuel consumption data is read from the equal fuel
`consumption rate curves B on the fuel data map shown
`in FIG. 3 which has been stored in the ROM 8 and fuel
`consumption rate is searched from the calculated torque
`Te and the engine speed Ne.
`‘ Namely, if the shift position is in the fourth speed, as
`the torque T9 is 11 kg-In and the engine speed is 3600
`rpm, the point F4 is obtained on the fuel consumption
`rate curves B in the fuel consumption rate data map.
`Since the point F4 is in the area of the fuel consumption
`rate Be=3OO g/psh to 350 g/psh, the fuel consumption
`rate of the fourth speed is determined as 300 g/psh to
`350 g/psh in this case.
`Then the next horsepower calculation step 26 is exe-
`cuted. In this step 26, the horsepower P is calculated in
`accordance with the following equation.
`
`P=NeX Te/716.2
`
`P=driving power in ps
`where
`Ne=the engine speed in rpm
`Te=torque in kg-m
`In the step 27, the detected data from the shift posi-
`tion sensor 2 is stored in the RAM 9 in the microcom-
`puter 5 through the I/O port 6.
`In the step 28, a neutral position decision is per-
`formed. That is, the decision is made whether or not the
`shift position stored in the step 27 is in the neutral posi-
`tion, i.e. whether or not SP=0 is determined. If it is not
`the neutral in this case, the step 29 for deciding the fifth
`speed is executed. On the other hand, if the result of the
`decision is neutral, the main routine operation is termi-
`nated as it is not necessary to indicate the speed change
`operation.
`In the step 29, since the shift position SP is deter-
`mined as the fifth speed or the upmost shift position, the
`assumed processing for shifting up operations shown in
`the steps 30 through 36 is skipped and now the opera-
`tion moves to the calculating step for the number of
`engine rotations at the time of the shifting down in the
`step 37.
`On the other hand, if the result of the decision in the
`step 29 is such that the shift position SP is not at the fifth
`speed, the next step 30 is executed. In this step 30, the
`engine speed Ng+1 is calculated in the case of one shift-
`up. In this case, the equation for calculating the engine
`speed Ne...1 is as follows;
`
`Ne+1=N._.><gear ratio of shift position SP+1/gear
`ratio of shift position SP
`
`6
`
`

`
`4,559,599
`
`5
`where, each unit indicates: Ne =rpm, Ne+1= rpm, and
`the gear ratio is a physical quantity which one of ordi-
`nary skill understands is dictated by the physical em-
`bodiment of the gears used (and which ratios are stored
`as data for use with a particular embodiment).
`After executing this step, the operation now moves to
`the step 31 for deciding the engine speed Ne+1. In this
`step 31, a decision is made as to whether or not the
`engine speed Ne+1 at the one step shifting up position
`SP +1 is larger than 1000 rpm. In this case, if the result
`of the decision is NO, the processing for the main rou-
`tine is terminated as the shift operation is not necessary.
`However, if the result of the decision is such that the
`engine speed Ne.1.1 is larger than 1000 rpm, the opera-
`tion now moves to the next step 32. In this step 32, the
`calculation of the torque Te... 1 at the one step shifting up
`position SP +1 is performed.
`The calculation of the torque is performed in accor-
`dance with the following equation.
`
`T“. 1 =PX7l6.2/Ne+1
`
`where, each unit indicated
`Te+ 1 '=
`P=ps, and
`Ne+1=rpm.
`And now the operation moves to the next step 33. In
`this step 33,
`the assumed fuel consumption rate is
`searched from the data map stored in the ROM 8 in the
`microcomputer 5. Namely, one cross point is sought
`from the engine speed N.,._1.1 which was calculated in the
`step 30 and the torque Te.1.1 calculated in the step 32 on
`the data map shown in FIG. 4. From the fuel consump-
`tion rate indicated in the equal fuel consumption rate
`curves B surrounding this point in the coordinate posi-
`tions, the assumed fuel consumption rate be.1.1 can be
`found. For instance, assuming that the engine speed
`Ne+1=2800 rpm and the torque Te+1= 12.1 kg-m, the
`cross point F5 can be obtained from the data map and
`this point F5 belongs to the area of the fuel consumption
`rate of 200 g/psh to 250 g/psh in the equal fuel con-
`sumption rate curves B. Accordingly, since the one step
`shifting up position SP +1, i.e. the current shift is the
`fourth speed, the assumed fuel consumption rate be+1
`when shifting up to the fifth speed, becomes 200 g/psh
`to 250 g/psh.
`thus
`The assumed fuel consumption rate be.1.1
`searched (i.e., derived) in step 33 is compared with a
`predetemined value in the next decision step 34. That is,
`the fuel consumption rate be+1 is determined whether
`or not it is larger than 5000 g/psh. In this case, a large
`number such as 60000 g/psh is inputted in the area
`above the full opened torque in FIG. 4. Accordingly, if
`the result of the decision is NO, the assumed fuel con-
`sumption rate be... 1 is compared and is determined in the
`next step 35 as to whether or not it is smaller than the
`current fuel consumption rate be which was searched
`(i.e.,‘derived) in the step 25.
`If the result of the decision is YES, that is, the as-
`sumed fuel consumption rate be.,.1 is smaller than the
`current fuel consumption rate be, the operation now
`moves to the step 43 and the operation for indicating the
`shift-up condition is performed in the step 44 after some
`delay time. Namely, in this step, the speed change oper-
`ation indicating signal is applied to the indicator or ,
`display 10 from the microcomputer 5 through the 1/0
`port 6. As a result, a particular lamp in this case, a shift-
`up indicating lamp in the indicator 10, is illuminated,
`thus indicating to the driver that the speed change from
`
`50
`
`.
`
`6
`current shift position to the one step shifting up position
`SP +1 is preferable. In this case, it is preferable to pro-
`vide some delay time as shown in the step 43 so as to
`prevent the driver from confusion due to intermittent
`illuminations of the lamp of the indicator 10 within a
`short time when the fuel consumption rate is on the
`critical border lines.
`On the other hand, if the result of the decision in the
`step 35 is NO, that is, the assumed fuel consumption rate
`be+1 is larger than the current fuel consumption rate be,
`the operation now moves to the step 36. In this step 36, p
`the decision is made whether or not the current shift
`position SP is the first speed. If the result of the decision
`is YES indicating that the current shift position is the
`first speed, the processing for the main routine is termi-
`nated as no shift-down operation is required, while if
`the result of the decision is NO, the operation now
`moves to the next step 37 for calculating the engine
`speed Ne+1 at the one step shifting down position SP
`-1. In this step, the engine speed Ne.1.1 at the time of
`shifting down from the current shift position SP to the
`one step shifting down position SP _1 is calculated by
`the following equation;
`
`N9. 1 =N,_.>< gear ratio of shift position SP_1/gear
`ratio of shift position SP
`
`where, each unit of each parameter indicates
`Ne _ 1 = rpm
`Ne=rpm.
`From the engine speed Ne_1 calculated here and" the
`driving power which was calculated in the step 26, the
`torque Te_1 is calculated by the following relationship
`in step 38;
`
`Te_1=PX7l6.2/Ne_1
`
`where, each unit of each parameter indicated
`T,_._1=kg-m,
`P=ps,
`Ne— l = rpm-
`The torque thus calculated is compared with a prede-
`termined value such as 0.05 kg-m in the step 45. If the
`result of the decision in step 45 is YES, the operation
`now moves to the fuel consumption rate search step 39,
`where the assumed fuel consumption rate be..1 in the
`one step shifting down position SP_1 is searched from
`the data map in FIG. 3 as in the step 33. Namely, if the
`engine speed Ne_.1 is 4600 rpm and the torque Te_1 is 12 ‘
`kg-m which were calculated in the steps 37 and 38, the
`cross point F3 is determined on the data map in FIG. 4.
`Accordingly, in step 39, from the area of the equal fuel
`consumption rate curve B of 350 g/psh to 400 g/psh on
`which the cross point F 3 is situated, the assumed fuel _
`consumption rate be- 1 is searched to be found in the one
`step shifting down position SP -1.
`With the one step shifting down position SP _1 thus
`obtained, i.e. the current shift position SP being as the
`fourth speed, the assumed fuel consumption rate when
`shifting down to the third speed which is in the shift
`position SP -1 thereunder, becomes 350 g/psh to 400
`g/psh, and then the next step 40 is executed. In this step
`40, the fuel consumption rate be in the current shift
`position SP which was searched in the step 25 is com-
`pared with the assumed fuel consumption rate be..1 .
`Namely, the decision making is performed whether or
`not the assumed fuel consumption rate be_1 is smaller
`
`7
`
`

`
`7
`than the current fuel consumption rate be. If the result
`of the decision is NO which means that the bg.—]
`is
`larger than the be, the processing for the main routine is
`terminated. On the other hand, if the result of the deci-
`sion is YES, meaning that the assumed fuel consump-
`tion rate be_1 is smaller than the current fuel consump-
`tion rate be, the operation moves to the next step 41,
`where some time delay processing is performed, and
`then the operation now moves to the step 42.
`In this step 42, shift-down display is performed.
`Namely in this case, the shift down display instruction
`signal from the microcomputer 5 is applied to the indi-
`cator 10 through the I/O port 6 and the shift-down
`indication lamp in the indicator 10 is illuminated, thus
`indicating to the driver that speed change operation
`' from the current shift position to the one step shifting
`down position SP -1 is preferable.
`In this manner, the operations as indicated in each
`step are repeatedly performed and the assumed fuel
`consumption rate be-+1 in the one step shifting up posi-
`tion and the assumed fuel consumption rate be..1 in the
`one step shifting down position from the current shift
`position are calculated respectively, and each assumed
`fuel consumption rate is compared with the current fuel
`consumption rate be, respectively. In this case, if the
`current fuel consumption rate be is better than the as-
`sumed fuel consumption rate be+1 or the assumed fuel
`consumption rate b3_1, the indicator 10 is not ener-
`gized. However, only when either one of the assumed
`fuel consumption rates above. is better than the current
`fuel consumption rate be, the corresponding shift-up
`lamp or shift-down lamp in the indicator 10 is illumi-
`nated, thus indicating the necessity of the speed change
`operation. As a result, the driver can actually perform
`the speed change operations in accordance with the
`indications so that the optimum speed running of the car
`can be carried out with a preferable shift position in the
`(‘I optimum fuel consumption rate.
`In the preferred embodiment according to the present
`‘" invention described in the foregoing, the range of each
`1 area. indicative of the equal fuel consumption rate
`curves B has been indicated as 50 g/psh. However, if
`the range of each area is defined more narrow or the
`distances between the points is interpolated by calcula-
`tion,
`it
`is possible to indicate more accurate speed
`change operations.
`As stated in the foregoing, in the speed change opera-
`tion and indication system according to the present
`invention, the optimum fuel consumption rate is calcu-
`lated from the data corresponding to the number of
`engine rotation and the throttle valve opening, an as-
`sumed fuel consumption rate is calculated for generat-
`ing the same driving power as that in the current run-
`ning conditions in the shift position adjacent to a partic-
`ular shift position at that time, and the current fuel
`consumption rate is compared with the assumed fuel
`consumption rate, whereby the optimum shift operation
`indications are displayed to the driver.
`With this construction, it is possible for a driver to
`run his car in accordance with the indication of the
`speed change operation on an indicator so as to maintain
`the optimum fuel consumption of the automotive vehi-
`cle, thus enabling the economical running of the car to
`be realized.
`_
`While the invention has been described in its pre-
`ferred embodiments, it is to be understood that various
`changes and modifications may be made within the
`purview of the appended claims without departing from
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`the true scope and spirit of the invention in its broader
`aspects.
`.
`What is claimed is:
`1. An electronically controlled system in an internal
`combustion engine for indicating shift position for a
`manual transmission thereof so as to maintain optimum
`fuel consumption by the engine, comprising:
`first detecting means for detecting current engine
`speed;
`second detecting means for detecting current throttle
`position;
`third detecting means for detecting current shift posi-
`tion;
`first determining means for determining current en-
`_gine torque based on said current, engine speed and
`current throttle position in accordance with a first
`two-dimensional map of engine speed and throttle
`position;
`second determining means for determining current
`fuel consumption rate based on said current engine
`speed and determined current engine torque in
`accordance with a second two-dimensional map of
`engine speed and engine torque, said second map
`including isometric curves representing curves of
`equal fuel consumption rates;
`calculating means for calculating driving force of the
`engine in accordance with current engine speed
`and current engine torque, said calculating means
`further including:
`first comparing means for comparing said current
`fuel consumption rate obtained by said second
`determining means with an assumed one-step-
`transmission upshifted fuel consumption rate
`determined by one-step-transmission upshifted
`engine speed and one-step-transmission upshifted
`engine torque defined by said second map,
`second comparing means for comparing said cur-
`rent fuel consumption rate obtained by said sec-
`ond determining means with an assumed one-
`step-transrnission downshifted fuel consumption
`rate determined by one-step-transmission down-
`shifted engine speed and one-step-transmission
`downshifted engine torque defined by said sec-
`ond map,
`outputting means for outputting a first signal indic-
`ative of one-step upshifting, a second signal in-
`dicative of one-shift downshifting, or a third
`signal indicative of stopping both one-step up-
`shifting and downshifting, respectively, when-
`ever said first comparing means determines said
`assumed fuel consumption rate of one-step up-
`shifting is less than the currently detected fuel
`consumption rate, said second comparing means
`determines said assumed fuel consumption rate
`of one-step downshifting is less than the cur-
`rently detected fuel consumption rate, or both
`values of fuel consumption rate calculated in said
`first and second comparing means are deteniined
`greater than the currently detected fuel con-
`sumption rate; and
`‘ representing means for alternatively representing
`whichever of said three signals are output by said
`outputting means.
`_
`2. A system in claim 1 wherein
`said first comparing means comprises first determina-
`tion means for determining whether the current
`gear position is highest gear or neutral position,
`and for enabling said comparison of said fuel con-
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`sumption rate if the current shift position is not
`determined to be said highest gear or said neutral
`position; and
`said second comparing means comprises second de-
`termination means for determining whether said
`current shift position is first gear, and for enabling
`said comparison of said fuel consumption rate if it is
`determined the current shift position is not said first
`gear.
`3. A system in claim 1 wherein
`said first comparing means comprises first calculating ‘
`means for calculating one-step upshifted assumed
`engine speed obtained from the value of the current
`engine speed, multiplied by a known gear ratio for
`one-step-transmission upshifted, divided by the
`known value for the gear ratio corresponding to
`the current shift position, and for calculating as-
`sumed engine torque obtained from the value of
`current driving force divided by said assumed en-
`gine speed multiplied by a constant;
`said second comparing means comprises second cal-
`culating means for calculating one-step down-
`shifted assumed engine speed obtained from the
`value of the current engine speed, multiplied by a
`known gear ratio for one-step-transmission down-
`shifted, divided by the known value for the gear
`ratio corresponding to the current shift position,
`and for calculating the assumed engine torque ob-
`tained from the value_ of current driving force di-
`vided by said assumed engine speed multiplied by a
`constant.
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`4. A system as in claim 1, wherein said representing
`means makes an indication to keep the shift position
`unchanged whenever said engine speed detected by said
`first detecting means is greater than a predetermined
`value.
`5. A system as in claim 1, further comprising:
`first permitting means for permitting said second
`determining means to determine said fuel consump-
`tion rate whenever the value of said engine torque
`determined by said first determining means is
`greater than a predetermined value; and
`second permitting for permitting said second deter-
`mining means to determine said assumed fuel con-
`sumption rate whenever the value of said assumed
`engine torque calculated by said second comparing
`means is greater than said predetermined value.
`6. A system as in claim 1, wherein said representing
`means represents changes in said first, second and third
`signals, indicative of upshifting, downshifting and keep-
`ing shift position unchanged, respectively, after a prede-
`termined time delay.
`7. A method for indicating shift position for a manual
`transmission associated with an internal combustion
`engine so as to maintain optimum fuel consumption by
`the engine, comprising the steps of:
`detecting the current engine speed;
`detecting the current throttle position;
`detecting the current shift position;
`determining current engine torque based on said cur-
`rent engine speed and current throttle in accor-
`dance with a first two-dimensional map of engine
`speed and throttle position;
`determining current fuel consumption rate based on
`said current engine speed and determined current
`engine torque in accordance with a sec