hydraulic retarder Flashcards
a hydraulic retarder is used as a supplementary or auxiliary breaking system used to
reduce the speed of off-road equipment through the use of hydrodynamic breaking
hydraulic retarders are identified by
where they are placed in the drive train
input retarders
located on the input to the transmission after the torque converter
output retarders
located on the output of the transmission
remote mount retarders
are located on the drive line
what type of retarder exerts breaking force directly on the driveline and acts independently of changes in engine rpm or transmission gear selection
output hydraulic retarders
why do some types of output retarders use a multi disc clutch pack
because there is a slight delay in the time it takes for oil to reach the retarder and begin breaking . the multi disc clutch eliminates this delay by engaging first to start the breaking and disengaging when retarder receives oil
what are the basic components of a hydraulic retarder
rotor - housing ( stator ) - oil pump - cooler - control valve - wet break - accumulator
retarder rotor is generally attached to
the torque converter output shaft - transmission out put shaft or drive line
because it is a stationary member of the retarder the housing is usually called the
stator
retarders that are mounted between the torque converter and the transmission will recieve their oil from
the same pump that supplies the trans and torque converter circuit
why is it critical to cool the oil from a retarder
because oil in a retarder can have its temperature rise very quickly
what are the three types of retarder control methods
manual operator - air over hydraulic - electronic -
an automatic control valve and control circuit requires certain switches and sensors that
may or may not be connected to an engine/transmission ECU
what are some of the basic switches that are not connected to an ECU
ignition switch - mode selection switch - clutch position switch and transmission gear indicator - fuel control position indicator
