Torque con­verter

Seaway News - - AUTO TALK -

The torque con­verter por­tion has the abil­ity to mul­ti­ply torque from the en­gine. The im­peller ( some­times called the pump) has spe­cially curved vanes and is driven by the en­gine's crank­shaft. The tur­bine also has spe­cially curved vanes and is con­nected to the in­put shaft of the trans­mis­sion. Adding a third el­e­ment, the sta­tor ( also called the re­ac­tor), gives the as­sem­bly the ca­pa­bil­ity it is named for.

The sta­tor has vanes and is mounted on a one-way clutch, to al­low it to free­wheel in only one di­rec­tion. The sta­tor as­sem­bly is lo­cated be­tween the im­peller and tur- bine and redi­rects oil that bounces back off the tur­bine. The force of the redi­rected oil as­sists in ro­tat­ing the tur­bine, re­sult­ing in torque mul­ti­pli­ca­tion. When the im­peller's speed is high and tur­bine's speed is low, torque can be mul­ti­plied by as much as 2: 1. When the im­peller's speed and the tur­bine's speed are about the same, torque can be trans­ferred at al­most 1: 1. Beginning around 1980, car­mak­ers took the torque con­verter one step fur­ther by adding a lock-up func­tion. Lock-up con­vert­ers also con­tain a fric­tion clutch that locks the con­verter im­peller to the tur­bine, usu­ally in higher gears. A so­le­noid-con­trolled oil pas­sage, com­manded by the car’s pow­er­tain con­trol mod­ule ( PCM), locks and un­locks the con­verter based on driv­ing con­di­tions.

The torque con­verter, con­nected to the trans­mis­sion/ transaxle in­put shaft, con- nects, mul­ti­plies and in­ter­rupts the flow of en­gine torque into the trans­mis­sion. The torque con­verter sup­plies torque to the trans­mis­sion's in­put shaft in two sep­a­rate, dis­tinct ways: hy­draulic in­put and me­chan­i­cal in­put ( lock-up con­vert­ers only). Hy­draulic in­put comes from the torque con­verter’s tur­bine and the amount of in­put torque can vary de­pend­ing on the op­er­at­ing con­di­tions within the con­verter. Me­chan­i­cal in­put re­sults when the lock-up func­tion of the con­verter engages. The end re­sult is bet­ter fuel econ­omy be­cause all con­verter slip­page is elim­i­nated when the con­verter locks. The torque con­verter also helps to smooth out en­gine power pulses, as does the fly­wheel on a car with a man­ual trans­mis­sion.

The torque con­verter does not re­quire any reg­u­lar main­te­nance or ad­just­ments, but it may be pos­si­ble to change the trans­mis­sion fluid in the con­verter through drain­ing ( if equipped with a drain) or with a trans­mis­sion flush­ing and fill­ing ma­chine. Much of the trans­mis­sion’s fluid stays in the con­verter and since the con­verter pro­duces a tremendous amount of heat ( the en­emy of trans­mis­sion fluid) there’s good rea­son to change it if pos­si­ble.

Torque con­verter prob­lems fall into two cat­e­gories:

1) prob­lems within the torque con­verter it­self, or

2) prob­lems within the torque con­verter clutch.

If you sus­pect a prob­lem with the con­verter or trans­mis­sion, have it eval­u­ated by a qual­i­fied trans­mis­sion spe­cial­ist. With the com­plex­ity of to­day’s trans­mis­sions and torque con­vert­ers, there’s no room for guess­work. ( Car Care Canada)

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