Page 201 - Mechatronics with Experiments

MECHANISMS FOR MOTION TRANSMISSION 187
Impeller (Neutralizer)
clutch
Impeller (Neutralizer)
Impeller
Turbine clutch
Lockup
clutch T I
S
From
Stator
engine
To gear set
Lockup
clutch
S
T I

(a) (b)

1000 100%
2.5
Primary torque
Efficiency
800
2.0
Torque ratio Efficiency
Torque ratio 1.5 600 Primary torque

400
1.0

200
0.5
0.0 0%
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Speed ratio
(c)
FIGURE 3.29: Torque converter: (a) components: impeller, turbine, stator. There are also
impeller (neutralizer) clutch and lock-up clutch in heavy equipment applications. (b) Functional
relationship torque converter components. (c) Steady-state input–output relationship for torque
converter: torque ratio and primary torque as a function of speed ratio, and efficiency of torque
converter as a function of speed ratio.

connected to the impeller shaft with a one-way clutch which allows it to turn only in
the same direction as the impeller, not reverse.
There are two common modifications to the torque converter in heavy equipment
applications (Figure 3.29a and b):
Neutralizer clutch (also called impeller clutch) which is used to disconnect the input

shaft of the torque converter (shaft of the impeller) from the engine shaft so that
partial power or no power is transmitted from the engine to the torque converter. It
is typically a proportionally controlled, not ON/OFF, type clutch. When it is fully
engaged (ON), the full power transmission from engine to torque converter occurs.
When it is fully disengaged (OFF, in neutralized state), there is no power transfer