Why auto-transmission cars return less mileage?

[cooldhaya]

hey people can you explain why auto transmission cars give less mileage??

 

[RSM]

A manual transmission is inherently better equipped to prove better fuel economy. The manual transmission couples the engine to the transmission with a rigid clutch instead of an automatic transmission's torque converter, which bleeds off power. The automatic transmission wastes engine power to drive the high pressure hydraulic pumps required for its operation.

 

[cooldhaya]

oh i see thanks bro!!!

 

[ilango[speed thirst]]

RSM , it was short and sweet.
Though power is wasted , you don't find much drop in milage.

 

[cooldhaya]

@ ilango is it true?? i have heard that mileage also is less compared to a manual one!!

 

[ilango[speed thirst]]

Milage drop will be there. But small amount in highways and very high difference in city driving.

 

[cooldhaya]

thanks bro now i got it!!!

 

[RSM]

Now a days even AT gives good mileage, almost same as Manual.
Earlier the difference was more as there was only 3 stage transmission, now AT has upto 7 stage.

 

[vijay]

current auto tranny's makes difference of only 2kmpl compare to manuals

 

[racerdabba]

A quick overview on Automatics.
Planetary gear systems- remember the zen auto, or even humble 800 auto??
More recentely, the santro auto? All had planetary gear trains. 3 gears.
PRNDL.[ Parking,Reverse,Neutral,Drive,Low]. Used Energy sappping torque converters.Low mileage.

Robotised Manuals- Neccesarily manual transmissions, robotised using hydraulics and computer controls. Fast, less energy sapping, but bulky. Sonata H matic, Recentely The scorpio.

Cvt- Almost like the variators used in scoterrets, sunny, activa and the lyks.
Came later in cars, due to engineering constraints. It Primarily uses a belt sliding on cone shaped pulleys. The torque rating of cars being higher, the belt construction was dificult.Proggamble for paddle shifting. Used in city,Civic.

Sequential Gearboxes- Next generation robotised manuals.Very quick. Audi A4, A6, Bmw 3 series, 5 series.
DSG- Dual clucth sequentials. Lightning fast. Twin Clutch. 100 Milisecond gear changes. Ferrari california, A8 W12.

Still Somebody in the notion of automatics being slow, bulky energy sapping systems??

 

[Neil.Bhujbal]

Compared to the normal auto tranny cars the MT cars are quicker right ?

 

[raj_5004]

Compared to the normal auto tranny cars the MT cars are quicker right ?

not necessarily. high end cars with DSG & triptronic are faster than manual cars.

 

[Neil.Bhujbal]

Hmm kk thanks. That's the reason i asked compared to normal auto tranny.

Have some more questions. Will put them up soon.

 

[cooldhaya]

@ racerdabba.. the explanation is cool. i never till now thought about the foreign AT cars!! sure they are faster!![lol!]

 

[ilango[speed thirst]]

I have read about dsg boxes , but more confusing.

Any one explain the working of dsg , also paddle shifting work in dsg combo?