Method of controlling a transmission of a vehicle in two different modes according to requirements for power and economy

A method of controlling a transmission of a vehicle selectively either in a first mode of operation in such a manner that the transmission is shifted among a plurality of speed stages according to a first shift pattern, or in a second mode of operation in such a manner that the transmission is shifted among those speed stages which lacks at least one intermediate speed stage in the above-mentioned plurality of speed stages according to a second shift pattern, according selection between the above two modes of operation. On-off controlling of a lockup clutch is also changed in two modes according to the selection between the two modes of speed stage shifting, when it is incorporated in the transmission.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to transmissions for vehicles, and more 
particularly to a method of controlling a transmission of a vehicle in two 
different modes according to requirements for the quality of control from 
the view point of power performance and economical performance of the 
vehicle. 
2. Discussion of Prior Art 
A transmission for a vehicle generally comprises a gear mechanism and 
selective engaging means such as friction clutches or one way clutches 
which selectivity rotationally connect two mutually rotational members in 
said gear mechanism and friction brakes or one way brakes which 
selectively brake a rotational member in said gear mechanism relative to a 
casing structure thereof, and provides selected one of a plurality of 
speed stages according to the engagement and disengagement of those 
engaging means. In an automatic transmission in which the engagement and 
disengagement of the engaging means are automatically controlled by a 
control means according to operational conditions of the vehicle, in 
acceleration of the vehicle from stoppage the transmission first provides 
1st speed stage and is gradually successively shifted up to higher speed 
stages such as 2nd, 3rd, 4th and 5th speed stages generally according to 
the balance between vehicle road speed and throttle opening. It is already 
well known to apply a restriction to the automatic shifting of the 
transmission according to the balance between vehicle road speed and 
throttle opening in order to temporarily modify the performance of the 
automatic transmission so as to increase the power quality of the vehicle 
or to ensure better engine braking, by restricting upshifting to the 4th 
or the 5th speed stage, by shifting a speed shift lever shiftable by hand 
among D, S and L shift positions. However, in the conventional automatic 
transmissions for vehicles, regardless of such temporary restrictions to 
the shifting up of the gear transmission to the 4th speed stage or the 4th 
and 5th speed stages, the upshifting and the downshifting of the 
transmission are always performed through all intermediate speed stage or 
stages. However, when the vehicle is operated in a relatively moderate 
manner with no great demand for power quality under such a condition that 
not much load is carried by the vehicle, no great acceleration is 
required, the vehicle is operated in a region of no high altitude, the 
engine is operating with all of its cylinders, the engine is sufficiently 
warmed up, battery is in good charged condition, or the vehicle which 
incorporates a two wheel/four wheel drive changing over system is operated 
in two wheel drive mode, it would be possible to operate the vehicle in 
sufficiently good condition by shifting the transmission up to a higher 
speed stage directly from the start speed stage or a lower speed stage 
without passing through an intermediate speed stage so that the vehicle is 
more often operated at a higher speed stage with a smaller reduction gear 
ratio and therefore at a lower rotational speed of the engine thereby 
saving consumption of fuel. 
SUMMARY OF THE INVENTION 
It is therefore the primary object of the present invention to provide a 
method of controlling a transmission of a vehicle, said transmission 
comprising a gear mechanism for providing a first plurality of speed 
stages, the method being characterized in that said gear mechanism is 
shifted among said first plurality of speed stages according to a first 
shift pattern and among a second plurality of shift speed stages which 
lack at least one intermediate speed stage in said first plurality of 
speed stages according a second shift pattern according to selection 
between first and second modes of operation, respectively. The 
intermediate speed stage to be omitted in the operation of the 
transmission according to said second shift pattern may preferably be a 
second speed stage. When the gear mechanism is adapted to provide up to 
the 5th speed stage or a higher speed stage, said intermediate speed stage 
may be a 2nd speed stage and a 4th speed stage. Since the operation of the 
vehicle under the control of the transmission according to said second 
shift pattern will save consumption of fuel, this shift pattern for the 
transmission may be called an economical shift pattern, by contrast to 
said first shift pattern in which all speed stages are used, which may be 
called, in contrast, as a power shift pattern. 
When the first and second shift patterns are expressed in a diagram having 
an abscissa coordinate for vehicle road speed and an ordinate coordinate 
for throttle opening, the spacing between each two adjacent speed stage 
shift lines along the abscissa in the second shift pattern is 
substantially the same as that in the first shift pattern, with the 
interval between a speed stage shift line for upshifting from the lowest 
speed stage to an adjacently higher speed stage and a speed stage shift 
line for upshifting to the highest speed stage from an adjacently lower 
speed stage in said second shift pattern being substantially smaller than 
that in said first shift pattern by an amount corresponding to the 
reduction of the number of the speed shift lines. 
As supported by the above-mentioned basic concept of the present invention, 
another object of the present invention is to set out said first and 
second shift patterns in such a manner that, when said first and second 
shift patterns are expressed in a diagram by a coordinate of an abscissa 
for vehicle road speed and an ordinate for throttle opening, speed shift 
lines in said second shift pattern are totally generally biased toward 
smaller vehicle road speed side than the corresponding speed shift lines 
in said first shift pattern. By this arrangement, the vehicle operation 
according to said second shift pattern will become even more economical by 
a synergistic interrelation of the omission of an intermediate speed stage 
and the general shifting of the speed shift lines toward smaller vehicle 
road speed side than those in the conventional operation of the 
transmission. Alternatively, said second shift pattern may be so set out 
that it is substantially the same as said first shift pattern except that 
a speed shift line between a speed stage adjacent said intermediate speed 
stage on lower speed side thereof and said intermediate speed stage in 
said first shift pattern is converted into a speed shift line in said 
second shift pattern between said speed stage adjacent said intermediate 
speed stage on lower speed side thereof and a speed stage adjacent said 
intermediate speed stage on higher speed side thereof in said first shift 
pattern, and that a speed shift line between said intermediate speed shift 
stage and said speed stage adjacent said intermediate speed stage on 
higher speed side thereof in said first shift pattern is omitted in said 
second shift pattern. 
As a further modification, the control of a transmission may be adapted to 
follow said second shift pattern when and only when throttle opening is 
smaller than a predetermined medium opening. 
When a lockup clutch is incorporated in the transmission, the lockup clutch 
may desirably be controlled with regard to engagement and disengagement 
thereof in relation with the selection between said first and second shift 
patterns in order to cooperate with the control of the gear mechanism to 
place preference on power quality or economical quality of the vehicle. In 
accordance with this principle, on-off switching lines for the lockup 
clutch to be combined with said second shift pattern may desirably be 
biased toward smaller vehicle speed side than the corresponding on-off 
switching lines combined with said first shift pattern. 
When the gear mechanism of a transmission controlled according to the 
method of the present invention comprises a first gear mechanism which 
provides two speed stages and a second gear mechanism which provides three 
speed stages, said first and second gear mechanisms being connected in 
series to one another, said gear mechanism providing a 1st speed stage 
when said first gear mechanism is in a lower speed stage thereof and said 
second gear mechanism is in a low speed stage thereof, a 2nd speed stage 
when said first gear mechanism is in a higher speed stage thereof and said 
2nd gear mechanism is in said low speed stage thereof, a 3rd speed stage 
when said first gear mechanism is in said lower speed stage thereof and 
said second gear mechanism is in an intermediate speed stage thereof, a 
4th speed stage when said first gear mechanism is in said lower speed 
stage thereof and said second gear mechanism is in a high speed stage 
thereof, and a 5th speed stage when said first gear mechanism is in said 
higher speed stage thereof and said second gear mechanism is in said high 
speed stage thereof, said intermediate speed stage of said transmission 
may preferably be said 2nd speed stage. 
When the gear mechanism of a transmission controlled according to the 
method of the present invention comprises a first gear mechanism which 
provides two speed stages and a second gear mechanism which provides three 
speed stages, said first and second gear mechanisms being connected in 
series to one another, said gear mechanism providing a 1st speed stage 
when said first gear mechanism is in a lower speed stage thereof and said 
second gear mechanism is in a low speed stage thereof, a 2nd speed stage 
when said first gear mechanism is in a higher speed stage thereof and said 
second gear mechanism is in said low speed stage thereof, a 3rd speed 
stage when said first gear mechanism is in said lower speed stage thereof 
and said second gear mechanism is in an intermediate speed stage thereof, 
a 4th speed stage when said first gear mechanism is in said higher speed 
stage thereof and said second gear mechanism is in said intermediate speed 
stage thereof, a 5th speed stage when said first gear mechanism is in said 
lower speed stage thereof and said second gear mechanism is in a high 
speed stage thereof, and a 6th speed stage when said first gear mechanism 
is in said higher speed stage thereof and said second gear mechanism is in 
said high speed stage thereof, said intermediate speed stages of said 
transmission may be said 2nd speed stage and said 4th speed stage. 
As described above, the selection of said second shift pattern which 
provides more economical advantage with preference placed thereon rather 
than placing preference on power quality of the vehicle should preferably 
be prohibited under some operating conditions of the vehicle. Such 
conditions may be selected from such conditions that load carried by the 
vehicle is equal to or larger than a predetermined weight value, a two 
wheel/four wheel drive mode switching over system is switched over to a 
four wheel drive mode, rate of increase of throttle opening on time base 
is equal to or larger than a predetermined value, altitude at which the 
vehicle is operated in equal to or larger than a predetermined height 
value, engine of the vehicle is operated in partial cylinder operation 
mode, engine temperature is equal to or lower than a predetermined warmed 
up temperature value, and battery charge condition is equal to or worse 
than a predetermined good condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described with reference to the preferred 
embodiment thereof, and with reference to the figures. Referring to FIG. 
1, a transmission designated by reference numeral 1 is shown as being 
powered by an internal combustion engine 100 via a shaft 101, and as 
transmitting output rotational power to a shaft 8 which, via a two 
wheel/four wheel drive changing over device 35 which is changed over 
between a two wheel drive mode and a four wheel drive mode by a hand lever 
36, transmits rotational power to a shaft 37 for driving rear wheels and a 
shaft 38 for driving front wheels. However, this two wheel/four wheel 
drive changing over device may be omitted according to a manner of 
embodying the present invention. 
The transmission 1 comprises a fluid torque converter assembly 2 and a gear 
transmission mechanism 7. The fluid torque converter assembly 2 is 
supplied with rotational power via the power output shaft 101 of the 
engine 100 and outputs rotational power to a shaft 9 which functions as a 
power output shaft for the fluid torque converter assembly 2 and also as a 
power input shaft for the gear transmission mechanism 7. 
The fluid torque converter assembly 2 is of a per se conventional three 
elements single stage type which comprises a pump impeller 3 rotationally 
connected to the power output shaft 101 of the engine 1, a turbine member 
4 rotationally connected to the power output shaft 9, and a stator member 
5 mounted via a one way clutch 5a to the casing of the fluid torque 
converter assembly 2, and further incorporates a lockup clutch 6 which 
selectively directly connects the pump impeller 3 and the turbine member 
4. 
The gear transmission mechanism 7 comprises an auxiliary gear transmission 
mechanism 10 and a main gear transmission mechanism 11. The auxiliary gear 
transmission mechanism 10 is supplied with rotational power via the power 
output shaft 9 of the fluid torque converter assembly 2 and outputs 
rotational power via a shaft 102 which functions as a power output shaft 
for the auxiliary gear transmission mechanism 10 and also as a power input 
shaft for the main gear transmission mechanism 11, and transmits 
rotational power therebetween. 
The auxiliary gear transmission mechanism 10 is of the same general type as 
the overdrive device typically included in a conventional type of four 
speed automatic transmission with overdrive, and comprises a first 
planetary gear mechanism 103 which comprises a sun gear 12, a coaxially 
provided ring gear 13, and a carrier 15 which rotatably supports a 
plurality of planetary pinions 14 which are meshed with the sun gear 12 
and the ring gear 13. The carrier 15 is rotationally connected to the 
power input shaft 9, and the ring gear 13 is rotationally connected to the 
power output shaft 102. A one way clutch F0 16 is provided for always 
rotationally connecting the carrier 15 to the sun gear 12 with respect to 
mutual rotation therebetween in one rotational direction only; a clutch C0 
17 is provided for selectively rotationally connecting the carrier 15 to 
the sun gear 12 with respect to mutual rotation therebetween in both 
rotational directions; and a brake B0 18 is provided for selectively 
rotationally connecting the sun gear 12 to the casing of the auxiliary 
gear transmission mechanism 10 with respect to mutual rotation 
therebetween in both rotational directions. By selective engagement and 
disengagement of clutch C0 and brake B0, the auxiliay gear transmission 
mechanism 10 can be controlled to provide either of two gearing ratios or 
rotational speed stages between its power input shaft 9 and its power 
output shaft 102, in a manner which will be clear to one of ordinally 
skill in the art. 
The main gear transmission mechanism 11 comprises second and third 
planetary gear mechanisms 104 and 105 which are arranged on the outside of 
a hollow intermediate shaft 19 which is coaxially fitted over the 
aforementioned power output shaft 8 of the main gear transmission 
mechanism 11. The second planetary gear mechanism 104 comprises a sun gear 
20, a coaxially provided ring gear 22, and a carrier 26 which rotatably 
supports a plurality of planetary pinions 24 which are meshed with the sun 
gear 20 and the ring gear 22. The sun gear 20 is fixed on the left end in 
the figure of the intermediate shaft 19, and the carrier 26 is 
rotationally connected to the power output shaft 8. A clutch C1 28 is 
provided for selectively rotationally connecting the ring gear 22 to the 
power output shaft 102 of the auxiliary gear transmission mechanism 11, 
which may be also taken as a power input shaft of the main gear 
transmission mechanism 11, with respect to mutual rotation therebetween in 
both rotational directions. A clutch C2 29 is provided for selectively 
rotationally connecting said power input shaft 102 to the sun gear 20 and 
to the intermediate shaft 19 with respect to mutual relation therebetween 
in both rotational directions. 
The third planetary gear mechanism 105 comprises a sun gear 21, a coaxially 
provided ring gear 23, and a carrier 27 which rotatably supports a 
plurality of planetary pinions 25 which are meshed with the sun gear 21 
and the ring gear 23. The sun gear 21 is fixed on the right end in the 
figure of the intermediate shaft 19. The ring gear 23 is rotationally 
connected to the power output shaft 8. A brake B1 30 is provided for 
selectively rotationally connected the intermediate shaft 19 to the casing 
of the main gear transmission mechanism 11 with respect to mutual rotation 
therebetween in both rotational directions. A brake B2 31 is provided for 
selectively rotationally connecting the carrier 27 to said casing of the 
main gear transmission mechanism 11 with respect to mutual rotation 
therebetween in both rotational directions. A one way clutch F1 32 is 
provided for always rotationally connecting said carrier 27 to said casing 
of the main gear transmission mechanism 11 with respect to mutual rotation 
therebetween in one rotational direction only. By selective engagement and 
disengagement of clutches C1 and C2 and of brakes B1 and B2, the main gear 
transmission mechanism 11 can be controlled to provide any one of three 
forward gearing ratios or rotational speed stages and a reverse stage 
between its power input shaft 102 and its power output shaft 8, in a 
manner which will be clear to one of ordinally skill in the art. 
The gear transmission mechanism 7 as a whole, as a combination of the 
auxiliary gear transmission mechanism 10 and the gear transmission 
mechanism 11, can be controlled, according to selective engagement and 
disengagement of the three clutches and of the three brakes, to provide 
any one of the maximum six forward gearing ratios or rotational speed 
stages including an overdrive speed stage and one reverse stage between 
its power input shaft 9 and its power output shaft 8. In the Table shown 
at the end of the description under the present subtitle, there is shown 
an embodiment of such selective combinations which, however, is selected 
to provide five forward gearing ratios or speed stages, in detail to give 
all shift schedules available by selection of "P", "R", "N", "D", "S" and 
"L" ranges. In the Table, an "O" in the column relating to a clutch or a 
brake indicates that the clutch or the brake is engaged, while an "X" 
relating to a clutch or a brake indicates that the clutch or the brake is 
disengaged; and an "O" in the column relating to a one way clutch 
indicates that the one way clutch is engaged so as to transmit rotational 
power when the engine 100 is powering the driven wheels of the vehicle via 
the automatic transmission system 1, while an "F" relating to a one way 
clutch indicates that the one way clutch is free wheeling or disengaged. 
In the embodiment shown in the Table, when the automatic transmission 1 is 
being operated in the drive or "D" range, all five of its forward speed 
stages are available to be utilized, according to vehicle operational 
conditions as will be explained later; when the automatic transmission 1 
is being operated in the second or "S" range, no upshifting to the 4th or 
the 5th stage is ever performed, and only the 1st through the 3rd speed 
stages are available to be utilized; and when the automatic transmission 1 
is being operated in the low or "L" range, no upshifting to the 2nd, the 
3rd, the 4th, or the 5th speed stage is ever performed in normal 
operation, and only the 1st speed stage is available to be utilized, 
provided that the 2nd speed stage or even the 3rd speed stage is performed 
as an intermediate stage in a manually forced downshifting from a higher 
speed stage to the 1st speed stage in order to avoid too high speed 
rotation of the engine. In general, each of the clutches and the brakes 
and the lockup clutch incorporated in the fluid torque converter is 
constructed as a hydraulically operated clutch or brake and is selectively 
engaged and disengaged by its hydraulic actuator system according to 
selective supply of hydraulic fluid pressure thereto. 
With regard to the skeleton transmission diagram in FIG. 1 and the schedule 
of engagement and disengagement of the clutches and brakes shown in the 
Table, it will be noted that the auxiliary gear transmission mechanism 10 
provides its directly connected stage when brake B0 is released and clutch 
C0 is engaged, while it provides its speed increasing stage when brake B0 
is engaged and clutch C0 is released. 
In the main transmission mechanism 11, when clutch C1 and clutch C2 are 
both engaged, it provides its high speed stage which is a directly 
connected speed stage, and in this condition of the main gear transmission 
mechanism 11 the auxiliary gear transmission mechanism is allowed to 
switch between its directly connected speed stage and its overdrive speed 
stage so as to provide the 4th speed stage and the 5th speed stage, 
respectively. When clutch C1 and brake B1 are engaged, the main gear 
transmission mechanism 11 provides its medium speed stage, and in this 
condition of the main transmission mechanism 11 the auxiliary gear 
transmission mechanism 10 is maintained in its directly connected stage so 
as to provide the 3rd speed stage. When clutch C1 only is engaged, and 
also with one way clutch F1 automatically being engaged, the main gear 
transmission mechanism 11 provides its low speed stage, and in this 
condition of the main gear transmission mechanism 11 the auxiliary gear 
transmission mechanism 10 is allowed to switch between its directly 
connected speed stage and its overdrive speed stage so as to provide the 
1st speed stage and the 2nd speed stage, respectivey. In the 2nd speed 
stage in the "S" range and in the 2nd and the 1st speed stage in the "L" 
range, brake B2 is also engaged in order to connect the carrier 27 to the 
casing of the main gear transmission mechanism 11 with respect to mutual 
rotation therebetween in both rotational directions. As a design example, 
the reduction gear ratios of the low, intermediate and high speed stages 
of the main gear transmission 11 may be 2.826, 1.532 and 1.000, 
respectively, while the reduction gear ratio of the auxiliary gear 
transmission mechanism 10 may be 0.705. In this case, the reduction gear 
ratio of the 2nd speed stage is equal to 1.992. In FIG. 2, there is shown 
a relationship between the driving force and the vehicle road speed, for 
each of the various speed stages of the gear transmission mechanism 7, 
when the reduction gear ratios are exemplarily as mentioned above. In this 
figure, the ideal relationship is shown by a double dotted line, and it 
will be clear that by switching over the forward speed stage of the 
transmission mechanism 7 between these five speed stages as appropriate it 
is possible closely to approximate this ideal characteristic. 
FIG. 3 is a schematic block diagram of the control system including various 
possible aspects of control which may be totally or partially applied to 
the control of the transmission according to the present invention. In 
this figure, reference numeral 40 denotes the hydraulic portion of the 
control device, while 60 is a microcomputer. The hydraulic control device 
40 comprises a hydraulic fluid (oil) pump 41 which picks up hydraulic 
fluid from a sump (not shown) and supplies it under pressure to a solenoid 
type line pressure regulation valve 42 which selectively bleeds off some 
of said pressurized hydraulic fluid back to the sump so as to produce a 
line pressure at its output side which is regulated according to the 
current operational conditions of the vehicle and the engine such as 
described hereinbelow by the duty ratio of an electrical pulse signal 
supplied to a solenoid incorporated in said valve 42 being varied by the 
microcomputer 60. An electrically controlled hydraulic fluid pressure 
control valve of this type is per se well known in the art. This line 
pressure its supplied to other components of the control system shown in 
FIG. 3. 
The control system further comprises: a manual shift valve 44 which is 
manually operated by the driver of the vehicle to select any optional 
shift position among "P", "R", "N", "D", "S" and "L" ranges; a lockup 
clutch control valve 45 which controls selective supply of actuaing 
hydraulic fluid pressure to the lockup clutch 6; a lockup clutch control 
solenoid valve 46 which controls switching over of the lockup clutch 
control valve 45; an auxiliary transmission control valve 47 which 
switches over the auxiliary gear transmission mechanism 10 by selectively 
either supplying hydraulic fluid pressure to clutch C0 and draining brake 
B0 or draining clutch C0 and supplying hydraulic fluid pressure to brake 
B0, an auxiliary transmission control solenoid valve 48 which controls the 
switching over of the auxiliary transmission control valve 47; a primary 
shift valve 49 and a secondary shift valve 50 which control in cooperation 
selective supply of actuating hydraulic fluid pressure and draining 
thereof to and from clutches C1 and C2 and brakes B1 and B2; and a main 
transmission control solenoid valve 51 which controls the switching over 
of said primary and secondary shift valves 49 and 50. All these control 
valves are per se known in the art and do not constitute any essence of 
the present invention. Particularly with regard to the combination of the 
primary and secondary shift valves 49 and 50 and the main transmission 
control solenoid valve 51, this combination is intended to generate such a 
hydraulic fluid pressure by the main transmission solenoid valve 51 that 
increases in accordance with the duty ratio of an electrical pulse signal 
supplied thereto from the electrical control device 60, as exemplarily 
shown in FIG.4, and to control the primary and secondary shift valves 49 
and 50 by the varying hydraulic fluid pressure so as to establish either 
of the low, medium and high speed stages of the main gear transmission 
mechanism 11 according to the level of the hydraulic fluid pressure. Such 
a transmission control system is disclosed in Japanese Utility Model 
Publication No. 38186/83 and U.S. Pat. No. 4,252,148, which should be 
referred to for further details, if required. 
The microcomputer 60 receives input signals from various sensor or switches 
which sense or indicate various operational conditions of the vehicle 
and/or the engine. In the diagram of FIG. 3 such sensors and switches that 
are usable for the control of the transmission according to the present 
invention are shown in parallel. However, it should be understood that all 
of these sensors and switches are not indispensable for executing the 
present invention in various embodiments and that some of them may be 
omitted in actual embodiments according to the balance between the quality 
requirements for the control and the cost required therefor. Such sensors 
and switches that may be useful to supply information for operating the 
electrical control device 60 are: a throttle opening sensor 61 which 
senses the position of a throttle valve (not shown) for the engine 100 of 
the vehicle and which produces an output signal representative of engine 
load; a road speed sensor 62 which produces an output signal 
representative of vehicle road speed; a shift pattern sensor 63 which 
senses the shift position among "P", "R", "N", "D", "S" and "L" ranges 
selected by the driver f the vehicle by the operation of a hand lever 43; 
an altitude sensor 64 which produces an output signal representative of 
the current altitude at which the vehicle incorporating this transmission 
is being operated; a shift pattern switch 65 which is operated by the 
driver of the vehicle to select a "P" pattern or an "E" pattern whichis 
described hereinunder; a brake switch 66 which produces an output signal 
representative of whether or not the brakes of the vehicle are being 
applied; a two wheel/four wheel drive change over switch 67 which produces 
an output signal representative of whether the vehicle is being operated 
in the two wheel drive mode or in the four wheel drive mode according to 
the setting of the hand lever 36 to be operated by the driver of the 
vehicle; a water temperature sensor 68 which produces an output signal 
indicative of the temperature of the cooling fluid of the internal 
combustion engine 100; a battery charge state sensor 69 which produces an 
output signal representative of the current stage of charge of the battery 
(not shown) of the vehicle; a partial cylinder operation sensor 70 which 
detects whether the internal combustion engine 100 is currently being 
operated in an all cylinder operational mode or in a partial cylinder 
operational mode in which some of the cylinders thereof are not being used 
and produces an output signal representative of this information; and a 
vehicle load sensor 71 which produces an output signal representative of 
the load carried by the vehicle. The microcomputer 60 executes a control 
program for setting the various clutches and brakes and the lockup clutch 
detailed above to be engaged or disengaged as well as for controlling the 
solenoid line pressure regulation valve 42. 
Referring to FIGS. 5a and 5b which are to be combined as connected at 
terminals A--A, B--B and C--C to show a flow chart of the program which is 
performed according to the present invention for controlling the 
transmission system shown in FIGS. 1 and 3, wherein the flow chart set out 
in FIGS. 5a and 5b includes various possible aspects of control which may 
be totally or partially adopted to practice the present invention into 
various actual embodiments. Therefore, it should be understood that all 
the steps herein shown are not essential for the constitution of the 
present invention. Again some steps in the diagram herein shown may be 
omitted in some actual embodiments of the present invention according to 
the balance between the requirements for the quality of control and the 
costs requires to be expended therefor. The routine through the flow chart 
is repeated at a predetermined time interval or at every predetermined 
progress of rotational angle of the crank shaft of the engine. After the 
start, at Step 1, the electrical control device 60 is supplied with input 
information from various sensors and switches as mentioned above. 
In Step 2, it is checked if the shift range selected by the shift change 
lever 43 is "L" range. If the answer is YES, the process proceeds to Step 
3, while if the answer is NO, the process proceeds to Step 4. In Step 4, 
it is checked if the shift range selected by the shift change lever is "S" 
range, and if the answer is YES, the process proceeds to Step 5, while if 
the answer is NO, the process proceeds to Step 6. In Step 6, it is checked 
if the shift range selected by the shift change lever is "D" range. If the 
answer is YES, the process proceeds to Step 7, while if the answer is NO, 
the process proceeds to Step 8. 
In Step 3, it is checked if 3/1 FALL PATTERN is selected. This selection is 
made by a manual switch (not shown or may be the shift pattern switch 65) 
adapted to be operated by the driver of the vehicle. If the answer is YES, 
the process proceeds to step 9, while if the answer is NO, the process 
procceds to Step 10. In Step 9, an "L" RANGE 3/1 FALL PATTERN such as 
exemplarily shown in FIG. 6 is selected as a pattern according to which 
the transmission is controlled, while in Step 10 an "L" RANGE 3/2/1 FALL 
PATTERN such as exemplarily shown in FIG. 7 is selected as a pattern 
according to which the transmission is controlled. When the "L" RANGE 3/1 
FALL PATTERN is selected when the transmission is operating at the 1st 
speed stage, no change of the operating speed stage occurs and the 
transmission is fixed at the 1st speed stage unless the rotational speed 
of the engine rises beyond a predetermined very high value above which 
there is a danger of damaging of the engine. When the transmission is 
operating at the 2nd or the 3rd speed stage when the "L" RANGE 3/1 FALL 
PATTERN is selected, the transmission is immediately shifted down to the 
1st speed stage. In others words, if the transmission is operating at the 
3rd speed stage when the "L" RANGE 3/1 FALL PATTERN is selected, the 
transmission is shifted down from the 3rd speed stage to the 1st speed 
stage without passing through the 2nd speed stage. In FIG. 6, the dotted 
line 3 to 1 (road speed V1) shows a downshift line for such downshifting 
in a diagram of road speed versus throttle opening. Further, in FIG. 6 a 
solid line 1 to 3 shows a shift line which causes upshifting of the 
transmission from the 1st speed stage to the 3rd speed stage which occurs 
only when the rotational speed of the engine exceeds the aforementioned 
high limit for the danger of engine damaging. This 3rd speed stage is 
shown in the Table in parentheses. Therefore, this solid line is not a so 
called shift line. 
When the "L" RANGE 3/2/1 FALL PATTERN is selected when the transmission is 
operating at the 2nd speed stage, the transmission is shifted down from 
the 2nd speed stage to the 1st speed stage across a dotted line 2 to 1 
(road speed V3). When the "L" RANGE 3/2/1 FALL PATTERN is selected when 
the engine is operating at the 3rd speed stage, the transmission is 
shifted down from the 3rd speed stage to the 2nd speed stage across a 
dotted line 3 to 2 (road speed V2), and then, as the road speed decreases 
from V2 to V3, the transmission is shifted down from the 2nd speed stage 
to the 1st speed stage across a dotted line 2 to 1. In FIG. 7, the solid 
line 1 to 2 is again a boarder across which the transmission is shifted up 
from the 1st speed stage to the 2nd speed stage when the rotational speed 
of the engine exceeds a predetermined high limit to avoid the danger of 
engine damaging. This 2nd speed stage is also shown in the Table in 
parentheses. 
The combination of Steps 3, 9 and 10 is optional, and this combination may 
be replaced by a single step of directly proceeding from the YES terminal 
of Step 2 to Step 10 so that when the "L" RANGE is selected at Step 2, the 
"L" RANGE 3/2/1 FALL PATTERN is selected, so that shifting down to the 1st 
speed stage is successively performed from the 3rd speed stage to the 2nd 
speed stage and then from the 2nd speed stage to the 1st speed according 
to the diagram shown in FIG. 7. 
In Step 5, it is checked if a "P" PATTERN is selected by the aforementioned 
shift pattern switch 65, and if the answer is YES, the process proceeds to 
Step 11, while if the answer is NO, the process proceeds to Step 12. In 
Step 11, an "S" RANGE "P" SHIFT PATTERN such as exemplarily shown in FIG. 
8 is selected as a pattern according to which the transmission is 
controlled. According to this "S" RANGE "P" SHIFT PATTERN, which is for 
power preference operation of the vehicle in the "S" RANGE, the 
transmission is shifted up from the 1st speed stage to the 2nd speed stage 
across a solid line 1 to 2 and from the 2nd speed stage to the 3rd speed 
stage across a solid shift line 2 to 3, while it is shifted down from the 
3rd speed stage to the 2nd speed stage across a dotted shift line 3 to 2 
and the 2nd speed stage to the 1st speed stage across a dotted shift line 
2 to 1. Upshifting to the 4th speed stage is of course suppressed. 
In Step 12, it is checked if the load W carried by the vehicle is equal to 
or larger than a predetermined weight value WSset for "S" range operation, 
and if the answer is YES, the process proceeds toward Step 11, and when 
the answer is NO, the process proceeds to Step 13. In Step 13, it is 
checked if the two wheel/four wheel drive changing over mechanism 35 is 
changed over to the four wheel driving mode, and if the answer is YES, the 
process proceeds toward Step 11, and when the answer is NO the process 
proceeds toward Step 14, where an "S" RANGE "E" SHIFT PATTERN, which is a 
shift pattern for operating the vehicle in an economical drive mode in the 
"S" range, is selected. Therefore, even when the "S" RANGE "E" SHIFT 
PATTERN is selected in Step 5 by the aforementioned pattern select switch 
65 being turned to "E" position, the selection of pattern is directed to 
the "S" RANGE "P" SHIFT PATTERN if the load carried by the vehicle is 
equal to or larger than a predeterined weight value or if the 2/4 wheel 
drive changing over mechanism is shifted to the four wheel driving mode. 
According to the "S" RANGE "E" SHIFT PATTERN, which is exemplarily shown in 
FIG. 9, the 2nd speed stage is omitted in upshifting as well as in 
downshifting, so that the transmission is shifted up from the 1st speed 
stage directly to the 3rd speed stage across a solid shift line 1 to 3 or 
the transmission is shifted down from the 3rd speed stage directly the 1st 
speed stage across a dotted shift line 3 to 1. By this arrangement the 
vehicle is operated in a greater part of its operation with smaller 
reduction gear ratio and lower rotational speed of the engine to save the 
consumption of fuel and to accomplish more economical operation of the 
vehicle. Further, as will be noted by comparison of the shift diagrams of 
FIGS. 8 and 9, the upshift line 1 to 3 in FIG. 9 is substantially biased 
toward the lower road speed side as compared with the upshift line 2 to 3 
in FIG. 8, and the downshift line 3 to 1 in FIG. 9 is also substantially 
biased to the lower road speed side as compared with the downshift line 2 
to 1 in FIG. 8. 
The Step 12 of checking the load carried by the vehicle to change the 
selection of "E" PATTERN at Step 5 to the selection of "P" PATTERN when 
the load carried by the vehicle is equal to or larger than a predetermined 
weight value is optional and may be omitted. Also the Step 13 of checking 
whether the vehicle is being operated in the four wheel driving mode or in 
the two wheel driving mode to change the selection of "E" PATTERN at Step 
5 to the selection of "P" PATTERN when the vehicle is operated in the four 
wheel driving mode is optional and may be omitted. When the two wheel/four 
wheel drive changing over mechanism 35 is not provided, this Step 13 is 
omitted as a matter of course. 
In Step 7, it is checked if the "P" PATTERN is selected by the 
aforementioned shift pattern switch 65 being switched over to the "P" 
position, and if the answer is YES, the process proceeds to Step 15, while 
if the answer is NO, the process proceeds to Step 16. In Step 15, a "D" 
RANGE "P" SHIFT PATTERN such as exemplarily shown in FIG. 10 is selected 
as a pattern according to which the transmission is controlled so that the 
vehicle is operated in a power preference mode in the "D" range. According 
to this shift pattern the transmission is successively shifted up as the 
vehicle road speed increases relative to the throttle opening from the 1st 
speed stage to the 2nd speed stage across a solid 1 to 2 upshift line, 
then from the 2nd speed stage to the 3rd speed stage across a solid 2 to 3 
upshift line, then from the 3rd speed stage to the 4th speed stage across 
a solid 3 to 4 upshift line, and then finally from the 4th speed stage to 
the 5th speed stage across a solid 4 to 5 upshift line. In turn, as the 
vehicle road speed decreases relative to the throttle opening, the 
transmission is shifted down from the 5th speed stage to the 4th speed 
stage across a dotted 5 to 4 downshift line, then from the 4th speed stage 
to the 3rd speed stage across a dotted 4 to 3 downshift line, then from 
the 3rd speed stage to the 2nd speed stage across a dotted 3 to 2 
downshift line, and then finally from the 2nd speed stage to the 1st speed 
stage across a dotted 2 to 1 downshift line. 
In Step 16, it is checked if the rate of increasing of the throttle opening 
on time base dTh/dt is equal to or larger than a predetermined value A, 
and if the answer is YES the process proceeds toward Step 15, while if the 
answer is NO, the process proceeds to Step 17. In Step 17 it is checked if 
the altitude AL at which the vehicle is operated is equal to or higher 
than a predetermined altitude value ALset, and if the answer is YES, the 
process proceeds toward Step 15, while if the answer is NO, the process 
proceeds to Step 18. In Step 18, it is checked if the engine is operated 
in a partial cylinder operation mode in which one or more of the cylinders 
of a multi-cylinder engine are idling for the purpose of saving fuel 
consumption, and if the answer is YES, the process proceeds toward Step 
15, while if the answer is NO, the process proceeds to Step 19. In Step 
19, it is checked if a temperature T representing engine temperature is 
equal to or lower than a predetermined temperature Test which indicates 
that the engine is not in the sufficiently warmed up condition, and if the 
answer is YES, the process proceeds toward Step 15, while if the answer is 
NO, the process proceeds to Step 20. In Step 20, it is checked if the 
battery charge condition BC is equal to or lower than a predetermined 
condition BCset, which represents that the battery charge is in a good 
condition, the process proceeds toward Step 15, while if the answer is NO, 
the process proceeds to Step 21. In step 21, it is checked if the load W 
carried by the vehicle is equal to or larger than a predetermined weight 
value WDset for "D" range operation, and if the answer is YES, the process 
proceeds toward Step 15, while if the answer is NO, the process proceeds 
to Step 22. In Step 22, it is checked if the 2/4 wheel drive mode changing 
over mechanism 35 is changed over to the four wheel drive mode, and if the 
answer is YES, the process proceeds toward Step 15, while if the answer is 
NO, the process proceeds to Step 23. 
The above Steps 16-22 are to check the above-mentioned various operating 
conditions of the vehicle and/or the engine from the view point that, even 
when the driver has selected the "E" pattern operation for the vehicle, 
whether such a selection is proper or not for the current operating 
condition of the vehicle and/or the engine, so as not to establish the "E" 
pattern operation, in spite of the selection by the driver thereof, and to 
change the selection of the "E" PATTERN to the selection of the "P" 
PATTERN. The Steps 16-22 are all optional in view of the essence of the 
present invention, and some or all of them may be omitted according to the 
consideration on the balance between the quality of operation of the 
automatic transmission and the costs required for the manufacture thereof. 
Further, the order of the Steps 16-22 in the shown embodiment is not 
essential. Even when those seven checking steps are employed, their orders 
may be changed according to the design principle, the use, the climate of 
the area of operation, and other conditions for the vehicles and/or the 
engine. Further, if the engine does not incorporate the system of partial 
cylinder operation, the checking thereof in Step 18 is omitted as a matter 
of course. Similarly, if the vehicle does not incorporate the system for 
selection between the two wheel driving and the four wheel driving mode, 
the checking thereof in Step 22 is also omitted as a matter of course. 
In Step 23, a "D" RANGE "E" SHIFT PATTERN such as exemplarily shown in FIG. 
11 or in FIG. 12 is selected as a pattern of shifting according to which 
the transmission is shifted. In this "D" RANGE "E" SHIFT PATTERN, an 
intermediate speed stage such as the 2nd speed stage in the shown 
embodiment is omitted so that the transmission is operated at higher speed 
stages in larger part of the operational area thereof so that the vehicle 
is more economically operated with lower rotational speed of the engine 
and with less consumption of fuel. In the shift pattern shown in FIG. 11 
the 2nd speed stage is completely omitted. In the shift pattern shown in 
FIG. 12 the 2nd speed stage is omitted in operation with the throttle 
opening less than a medium value. According to the shift pattern shown in 
FIG. 11, as the vehicle road speed increases relative to the throttle 
opening, the transmission is shifted up from the 1st speed stage directly 
to the 3rd speed stage across a solid 1 to 3 upshift line, then from the 
3rd speed stage to the 4th speed stage across a solid 3 to 4 upshift line, 
and then finally from the 4th speed stage to the 5th speed stage across a 
solid 4 to 5 upshift line. In downshifting, as the vehicle road speed 
decreases relative to the throttle opening, the transmission is shifted 
down from the 5th speed stage to the 4th speed stage across a dotted 5 to 
4 downshift line, then from the 4th speed stage to the 3rd speed stage 
across a dotted 4 to 3 downshift line, and finally from the 3rd speed 
stage directly to the 1st speed stage across a dotted 3 to 1 downshift 
line. Further, it will be noted by comparison of the shift patterns of 
FIG. 10 and FIG. 11 that the upshift and downshift lines in FIG. 11 is 
totally generally biased leftward in the figure toward the lower road 
speed side as compared with those in FIG. 10. By this arrangement, 
according to the "D" RANGE "E" SHIFT PATTERN the vehicle is operated in 
more part of its operation at higher speed stages than in the operation 
according to the "D" RANGE "P" SHIFT PATTERN so that the vehicle is 
operated in more economical mode with the engine being operated at lower 
rotational speed with less fuel consumption. 
It can be appreciated from FIGS. 10 and 11 that the spacing between two 
adjacent speed stage shift lines is substantially the same in FIG. 11 as 
in FIG. 10, and that the spacing between the 1-3 upshifting shift line and 
the 4-5 upshifting shift line in FIG. 11 is substantially smaller than the 
spacing between the 1-2 upshifting shift line and the 4-5 upshifting shift 
line in FIG. 10. That is, upon the elimination of the second speed stage, 
the shift lines for the remaining speed stages have been moved closer 
together so that a large gap between the speed stages is avoided. 
According to the "D" RANGE "E" SHIFT PATTERN shown in FIG. 12, when the 
vehicle is accelerated from the 1st speed stage with the throttle opening 
less than a predetermined medium opening, the transmission is shifted up 
from the 1st speed stage directly to the 3rd speed stage across a solid 1 
to 3 upshift line. However, when the vehicle is accelerated from the 1st 
speed stage with the throttle opening equal to or larger than said 
predetermined medium opening, the transmission is shifted up from the 1st 
speed stage to the 2nd speed stage across a 1 to 2 upshift line, and then 
from the 2nd speed stage to the 3rd speed stage across a 2 to 3 upshift 
line. Further upshiftings from the 3rd speed stage to the 4th speed stage, 
from the 4th speed stage to the 5th speed stage are performed across a 
solid 3 to 4 upshift line and a solid 4 to 5 upshift line, respectively, 
for all region of the throttle opening. In downshifting, the transmission 
is shifted down from the 5th speed stage to the 4th speed stage across a 
dotted 5 to 4 downshift line, and then from the 4th speed stage to the 
3rd speed stage across a dotted 4 to 3 downshift line, for all region of 
the throttle opening. When the vehicle is further decelerated so that the 
transmission is shifted down from the 3rd speed stage, if the throttle 
opening at that time is less than the abovementioned predetermined medium 
opening, it is shifted down from the 3rd speed stage directly to the 1st 
speed stage across a dotted 3 to 1 downshift line, whereas if the throttle 
opening at the time is equal to or larger than the aforementioned 
predetermined medium value, the transmission is shifted down from the 3rd 
speed stage to the 2nd speed stage across a dotted 3 to 2 downshift line, 
and then from the 2nd speed stage to the 1st speed stage across a dotted 2 
to 1 downshift line. Further, in the embodiment shown in FIG. 12, an 
additional solid 2 to 3 upshift line is provided between the area of the 
2nd speed stage shifted down from the 3rd speed stage at large throttle 
operation and the 3rd speed area shifted down from the 4th speed stage at 
small throttle opening, so as to upshift the transmission from the 2nd 
speed stage to the 3rd speed stage when the stepping on the accelerating 
pedal is soften at a road speed in this area. This additional upshift line 
is not absolutely necessary, but this ensures more economical operation of 
the vehicle intended by the "D" RANGE "E" SHIFT PATTERN. It will be noted 
by comparison of the shift patterns shown in FIGS. 10 and 12 that the 
upshift and downshift lines in FIG. 12 are generally the same except that 
the 1 to 2 upshift line and the 2 to 1 downshift line in FIG. 10 in the 
lower throttle opening area are changed to the 1 to 3 upshift line and the 
3 to 1 downshift line with deletion of the 2 to 3 upshift line and the 3 
to 2 downshift line, respectively, in this area in FIG. 10. 
After either of the Steps 9, 10, 11, 14, 15 and 23 the process proceeds 
through terminal "A" to terminal "A" in FIG. 5b. In Step 8, it is checked 
if an "R" RANGE is selected, and if the answer is YES, the process 
proceeds through terminal "B" to terminal "B" in FIG. 5b, and if the 
answer is NO, the process proceeds through terminal "C" to terminal "C" in 
FIG. 5b. 
Referring to FIG. 5b, in Step 24, it is checked if the current operating 
condition of the vehicle is on the right side of the upshift line from the 
current speed stage to the next higher speed stage in the shift pattern 
selected in the preceding pattern selecting process, as viewed in the 
shift pattern diagram, and if the answer is YES, the process proceeds to 
Step 25, while the if the answer is NO, the process proceeds to Step 26. 
In Step 25, the lockup clutch 6 is released, if the lockup clutch is in 
the engaged condition, and the process proceeds to Step 27. In Step 27, it 
is checked if a certain perdetermined time has lapsed since the lockup 
clutch was released, and if the answer is YES, the process proceeds to 
Step 28, in which the transmission is shifted up according to the shift 
pattern selected in the preceding shift pattern selecting procedure, and 
then the process proceeds to Step 29, while if the answer is NO, the 
process bypasses Step 28 and proceeds to Step 29. 
In Step 26, it is checked if the current operating condition of the vehicle 
is on the left side of the downshift line from the current speed stage to 
the next lower speed stage in the diagram of the shift pattern selected in 
the preceeding pattern selecting process, and if the answer is YES, the 
process proceeds to Step 30, in which the lockup clutch 6 is released if 
it is in the engaged condition, and then the process proceeds to Step 31, 
in which it is checked if a predetermined certain time has lapsed since 
the lockup clutch was released, and if the answer is YES, the process 
proceeds to Step 32, in which the transmission is shifted down, while if 
the answer in Step 26 is NO, or the answer in Step 31 is NO, the process 
bypasses the upshifting Step 32 and proceeds toward Step 29. 
In Step 29, it is checked if the braking action is applied to the vehicle 
by the driver, and if the answer is YES, the process proceeds to Step 34, 
in which the lockup clutch is released, and then the process proceeds 
toward RESET, while if the answer is NO, the process proceeds to Step 33, 
in which it is checked if the throttle valve is fully closed, and if the 
answer is YES, the process proceeds toward Step 35, while if the answer is 
NO, the process proceeds to Step 35. 
In Step 35, the shift pattern diagram selected in the preceding shift 
pattern selecting procedure in Step 9, 10, 11, 14, 15 or 23 is again 
referred to. In the shift pattern diagrams for the "S" and "D" RANGE 
operations shown in FIGS. 8-12, the boarders for controlling the lockup 
clutch 6 between the engaged and disengaged conditions thereof are 
included as shown by one and two dotted lines, respectively, such a 3rd 
L/C OFF to ON, 3rd L/C ON to OFF, 4th L/C OFF to ON, 4th L/C ON to OFF, 
5th L/C OFF to ON and 5th L/C ON to OFF, wherein one dotted line 3rd L/C 
OFF to ON indicates a boarder which shows that when the vehicle operating 
condition with regard to the vehicle road speed versus the throttle 
opening changes across the line from the left side thereof to the right 
side thereof in the figure in the 3rd speed operation, the lockup clutch 
is to be engaged, while the double dotted line 3rd L/C ON to OFF indicates 
a boarder which shows that when the vehicle operating condition changes 
from the right side thereof from the left side thereof in the figure in 
the 3rd speed stage operation, the lockup clutch is to be disengaged, and 
the like. In this Step 35, by referring to one of these shift pattern 
diagrams selected in the preceding shift pattern selecting procedure, it 
is checked if the current operating condition of the vehicle as viewed at 
a point in the shift pattern diagram is on the left side of the L/C ON to 
OFF line (except in "L" range operation), and if the answer is YES, the 
process proceeds to step 34, in which the lockup clutch 6 is disengaged, 
and the process proceeds to RESET, while if the answer is NO, the process 
proceeds to Step 36. 
In Step 36, by referring to the shift pattern diagram selected in the 
preceding shift pattern selecting procedure it is checked if the current 
operating condition of the vehicle as view at a point in the shift pattern 
diagram is on the right side of the L/C OFF to ON line (except in "L" 
range operation), and if the answer is YES, the process proceeds to Step 
37, while if the answer is NO, the process proceeds toward RESET. In Step 
37, it is checked if a certain predetermined time has lasped since the 
speed stage was shifted, and if the answer is YES, the process proceeds to 
Step 38, and the lockup clutch is engged, and then process proceeds to 
RESET. 
When the process proceeds through terminal "B", in Step 39 the lockup 
clutch is released, and then in Step 40 the transmission is shifted to the 
reverse stage, and then the process proceeds toward RESET. When the 
process proceeds through terminal "C", in Step 41 the lockup clutch is 
released, and then in Step 42 the transmission is shifted to the neutral 
stage, and then the process proceeds toward RESET. 
It will be apparent that the above-mentioned Steps 25, 27, 30, 31, 33, 34, 
35, 36, 37, 38, 39 and 41 are not required when the torque converter 2 is 
of the type incorporating no lockup clutch. 
FIG. 13 shows still another example of a speed shift pattern of the same 
type as that shown in FIG. 12, which is applicable to a gear mechanism 
which comprises a first gear mechanism which provides two speed stages and 
a second gear mechanism which provides three speed stages, said first and 
second gear mechanisms being connected in series to one another, said gear 
mechanism providing a 1st speed stage when said first gear mechanism is in 
a lower speed stage thereof and said second gear mechanism is in a low 
speed stage thereof, a 2nd speed stage when said first gear mechanism is 
in a higher speed stage thereof and said second gear mechanism is in said 
low speed stage thereof, a 3rd speed stage when said first gear mechanism 
is in said lower speed stage thereof and said second gear mechanism is in 
an intermediate speed stage thereof, a 4th speed stage when said first 
gear mechanism is in said higher speed stage thereof and said second gear 
mechanism is in said intermediate speed stage thereof, a 5th speed stage 
when said first gear mechanism is in said lower speed stage thereof and 
said second gear mechanism is in a high speed stage thereof, and a 6th 
speed stage when said first gear mechanism is in said higher speed stage 
thereof and said second gear mechanism is in said high speed stage 
thereof. 
In this speed shift pattern, in the lower half operational area for lower 
throttle opening as viewed in the diagram of shift pattern the use of the 
2nd and the 4th speed stages are omitted so that speed stage shifting is 
performed between the 1st speed stage and the 3rd speed stage, the 3rd 
speed stage and the 5th speed stage, and the 5th speed stage and the 6th 
speed stage. The operation of the transmission having six speed stages as 
described above will be apparent to one of ordinary skill in the art in 
view of the above descriptions with reference to FIG. 12, and therefore 
further descriptions about this embodiment will be omitted for the brevity 
of the specification. 
Although the invention has been described with reference to several 
embodiments thereof which incorporate various possible aspects of control, 
it will be apparent for those skilled in art that the present invention is 
not limited to the shown embodiment and various modifications thereof 
including omission of one or more of the mechanical constructions and/or 
the control steps incorporated in the shown embodiment would be readily 
possible without departing from and substantially losing the merits of the 
present invention. 
TABLE 
______________________________________ 
C1 C2 C0 B1 B2 B0 F1 F0 
28 29 17 30 31 18 32 16 
______________________________________ 
P RANGE X X O X X X F F 
R RANGE X O O X O X F F 
N RANGE X X O X X X F F 
D RANGE 1ST O X O X X X O O 
2ND O X X X X O O F 
3RD O X O O X X F O 
4TH O O O X X X F O 
5TH O O X X X O F F 
S RANGE 1ST O X O X X X O O 
2ND O X X X O O O F 
3RD O X O O X X F O 
L RANGE 1ST O X O X O X O O 
(2ND O X X X O O O .sup. F) 
(3RD O X O O X X F .sup. O) 
______________________________________