Interrelated power delivery controls – including engine control – Transmission control – Transmission controlled by engine
Reexamination Certificate
1999-11-30
2001-07-31
Estremsky, Sherry (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
Transmission controlled by engine
C477S143000, C477S155000
Reexamination Certificate
active
06267708
ABSTRACT:
This application is based on and claims priority under 35 U.S.C. § 119with respect to Japanese Application No. 10(1998)-340531 filed on Nov. 30, 1998, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to a vehicular automatic transmission. More particularly, the present invention pertains to a speed shift control apparatus of a vehicular automatic transmission and a method of detecting the start of a torque phase in clutch to clutch speed shift of a vehicular automatic transmission.
BACKGROUND OF THE INVENTION
When switching between two speed stages of a vehicular automatic transmission is carried out, there must frequently be carried out simultaneously engagement and release of two frictional engaging elements, including a so-called speak clutch for connecting and disconnecting two rotating members and a so-called speak brake for connecting and disconnecting a rotating member and a fixed member. Such a speed shift is referred to as clutch to clutch speed shift.
By way of example, in the vehicular automatic transmission shown in
FIG. 1
, the speed shift constitutes clutch to clutch speed shift between a forward first speed stage and a forward second speed stage. The vehicular automatic transmission is provided with a torque converter
10
, a transmission gear unit
20
, a hydraulic control apparatus
30
, an electric control apparatus
40
and various sensor groups
50
.
The torque converter
10
is provided with a front cover
101
connected to integrally rotate with an engine output shaft, a pump impeller
102
integrally connected to the front cover
101
, a turbine runner
103
rotatably arranged relative to the front cover
101
and the pump impeller
102
in a chamber surrounded by the front cover
101
and the pump impeller
102
, and a stator
104
.
The transmission gear unit
20
is provided with an input shaft
101
connected to integrally rotate with the turbine runner
103
of the torque converter
10
, an output shaft
202
rotatably connected to the wheels, a first planetary gear mechanism
203
, a second planetary gear mechanism
204
a carrier of which is connected to integrally rotate with a ring gear of the first planetary gear mechanism
203
and a ring gear of which is connected to integrally rotate with a carrier of the first planetary gear mechanism
203
, and a gear mechanism
205
rotatably connected with the carrier of the first planetary gear mechanism
203
, the ring gear of the second planetary gear mechanism
204
and the output shaft
202
. In addition, a first clutch C
1
which is a hydraulically-operated frictional engaging element rotatably and selectively connects and disconnects a sun gear of the second planetary gear mechanism
204
and the input shaft
201
, a second clutch C
2
which is a hydraulically-operated frictional engaging element selectively connects and disconnects the ring gear of the first planetary gear mechanism
203
as well as the carrier of the second planetary gear mechanism
204
and the input shaft
201
, a first brake B
0
which is a hydraulically-operated frictional engaging element selectively connects and disconnects the sun gear of the second planetary gear mechanism
204
and a fixed member, a second brake B
1
which is a hydraulically-operated frictional engaging element selectively connects and disconnects a sun gear of the first planetary gear mechanism
203
and a fixed member, and a third brake B
2
which is a hydraulically-operated frictional engaging element selectively connects and disconnects the ring gear of the first planetary gear mechanism
203
as well as the carrier of the second planetary gear mechanism
204
and a fixed member. Both of the clutches C
1
, C
2
and the brakes B
0
, B
1
, B
2
are of a well-known multiple disk type.
The above-described speed shift unit
20
can carry out speed shift among one rearward speed stage and four forward speed stages.
FIG. 2
shows an engaging operation table of the respective clutches and the respective brakes for setting these speed stages. In
FIG. 2
, notation P designates parking, notation R designates rearward speed stage, notation N designates neutral, notation 1st designates forward first speed stage, notation 2nd designates forward second speed stage, notation 3rd designates forward third speed stage and notation 4th designates forward fourth speed stage, respectively. Further, marked areas designate engaged states and blank areas designate released states.
As is apparent from
FIG. 2
, speed shift between the forward first speed stage and the forward second speed stage constitutes clutch to clutch speed shift of the first clutch C
1
and the second clutch C
2
. In up shift from the forward first speed stage to the forward second speed stage, the second clutch C
2
is switched from release to engagement and at the same time, the first clutch C
1
is switched from engagement to release.
Engagement and release of the respective clutches and the respective brakes are executed by controlling four electromagnetic valves provided to the hydraulic control apparatus
30
(SOL
1
and SOL
2
which are normally-opened valves and SOL
3
and SOL
4
which are normally-closed valves shown in
FIG. 2
) in duty control by the electric control apparatus
40
. As is well known, the electric control apparatus
40
is constituted by a microcomputer, ROM, RAM, timers, an input interface, an output interface and an electromagnetic valve drive circuit and the electric control apparatus
40
is inputted with signals from the various sensor groups so, for example, an engine rotational speed signal from an engine rotational speed sensor (Ne sensor), a turbine rotational speed signal from a rotational speed sensor (Ni sensor) of the input shaft
201
, an output shaft rotational speed signal from a rotational speed sensor (No sensor) of the output shaft
202
and a throttle opening degree signal from a throttle opening degree sensor (&thgr; sensor). Further, in
FIG. 2
, the O marks related to operational states of the electromagnetic valves indicate a duty ratio of 1.0 and the X marks indicate the duty ratio of 0.0.
FIG. 3
shows a behavior when power on up shift (up shift in the midst of driving a vehicle by engine output) from the forward first speed stage to the forward second speed stage in the vehicular automatic transmission of
FIG. 1
is carried out properly.
In
FIG. 3
, in the forward first speed stage at and before a point in time of issuing the speed shift start instruction (time point t1 of FIG.
3
), the released side instruction value (duty ratio provided to electromagnetic valve SOL
1
) is 0.0, the hydraulic pressure of the first clutch C
1
which is the clutch on the released side is at a predetermined maximum value and the first clutch C
1
stays in the engaged state. On the other hand, the engaged side instruction value (duty ratio provided to the electromagnetic valve SOL
2
) is 1.0, the hydraulic pressure of the second clutch which is the clutch on the engaged side is at a minimum value and the clutch C
2
stays in the released state.
When the speed shift start instruction is issued, the engaged side instruction value is changed temporarily to 0.0 to increase the engaged side hydraulic pressure (hydraulic pressure provided to the engaged side clutch C
2
) as swift as possible and after a predetermined constant period has elapsed (time point A in FIG.
3
), the engaged side instruction value is changed to an initial value Ci which is set to be able to shift the speed smoothly. On the other hand, the released side instruction value is maintained at 0.0 during a time period in which a release awaiting time period of tr has elapsed from issuance of the speed shift start instruction and when the release awaiting time period tr has elapsed (time point t2 in FIG.
3
), the released side instruction value is changed to 1.0 to reduce the released side hydraulic pressure (hydraulic pressure provided to the released side clutch C
1
) as swift as possible.
Further, when idle run of the pi
Kimura Fuyumi
Sato Katsutoshi
Aisin Seiki Kabushiki Kaisha
Burns Doane , Swecker, Mathis LLP
Estremsky Sherry
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