Diesel and CVT

[ice15]

Saw a recent discussion about diesel engines and CVT transmissions earlier...

Why diesel cars don't come with CVTs

CVTs rely on the friction between the two cones and belt between them to deliver power to the wheels. Overpowering this friction will lead to losses in terms of power delivery. CVTs also scale poorly with torque, if the torque is greater than the friction, the steel belt in a CVT will just spin without putting any of the power to good use. When this happens the cones can get burnt out further damaging the transmission.

Another reason why CVTs and Diesel engines don't mix is because the operating rev range of a diesel engine is much lower than that of a gasoline engine. This means that peak torque comes in much earlier compared to its gas powered counterparts.This also means the risk of the belts spinning is much higher since peak torque comes in earlier.

[ice15]

Just to add...

Although India's 2018 Honda Amaze has a diesel CVT model... Honda India has announced that the next diesel City will not have CVT

[StockEngine]

toyota's cvt with its "1st" gear will work nicely with honda's small diesel engines. I don't think they'll partner though.

[ice15]

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2015 Subaru Forester (in some markets) was also released with a 2.0 diesel CVT

[travajante]

***

2015 Subaru Forester (in some markets) was also released with a 2.0 diesel CVT

They're even rethinking their petrol....

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[Egan101]

I think only Subaru uses CVT for high torque gas engines. It is the one used on the FXT, WRX, Levorg, Outback H6, new Outback XT, and the Ascent. This CVT is rated up to 400Nm even on low rpms (2k). However, it was not used on the retired Forester and Outback 2.0L diesel.

With much better technology on 8-speed and 9-speed traditional ATs, the fuel savings and power band distribution advantage of the newer CVTs might already be addressed.

Diesel engines are already cheaper in fuel expense conpared to gas engines so no need to apply CVT fuel efficiency on it.


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[LOLZ]

I think only Subaru uses CVT for high torque gas engines. It is the one used on the FXT, WRX, Levorg, Outback H6, new Outback XT, and the Ascent. This CVT is rated up to 400Nm even on low rpms (2k). However, it was not used on the retired Forester and Outback 2.0L diesel.

With much better technology on 8-speed and 9-speed traditional ATs, the fuel savings and power band distribution advantage of the newer CVTs might already be addressed.

Diesel engines are already cheaper in fuel expense conpared to gas engines so no need to apply CVT fuel efficiency on it.


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I thought the Forester diesel was later offered with a CVT as well ?

[travajante]

Fuel economy for the boxer was the main reason Subaru CVT'd. Though touted more robust than most, Subaru's, like any other CVT, still has cons....some below.
SubaruNA had to extend their CVT warranty....
Subaru Continuously Variable Transmission (CVT) - Lemon Law Case

[Egan101]

I thought the Forester diesel was later offered with a CVT as well ?

Sorry, I was wrong. The Forester Diesel was offered with a CVT and an MT tranny.

215 Subaru Forester Review : 2.D-L diesel CVT | CarAdvice

The other manufacturer that uses boxer engines prefers their own version of the DSG. Porsche’s PDK is one of the best in terms of performance.


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[LOLZ]

Sorry, I was wrong. The Forester Diesel was offered with a CVT and an MT tranny.

2?15 Subaru Forester Review : 2.?D-L diesel CVT | CarAdvice

The other manufacturer that uses boxer engines prefers their own version of the DSG. Porsche’s PDK is one of the best in terms of performance.


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Funnily enough audi cites efficiency reasons for axing the cvt (multitronic)in favor of the dsg
Audi kills off multitronic CVT automatic | CarAdvice

[Egan101]

Funnily enough audi cites efficiency reasons for axing the cvt (multitronic)in favor of the dsg
Audi kills off multitronic CVT automatic | CarAdvice

DCT or DSG (PDK for Porsche) behaves more like an MT and offers the same fuel efficiency. It also shifts quicker than an MT this offering better performance. However, a poorly designed DCT can lead to catastrophic failures like Ford’s dry clutch DCT.


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[babkalakal]

DCT or DSG (PDK for Porsche) behaves more like an MT and offers the same fuel efficiency. It also shifts quicker than an MT this offering better performance. However, a poorly designed DCT can lead to catastrophic failures like Ford’s dry clutch DCT.


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in house design ba yun much maligned and flawed ford dct?

[babkalakal]

Sorry, I was wrong. The Forester Diesel was offered with a CVT and an MT tranny.

215 Subaru Forester Review : 2.D-L diesel CVT | CarAdvice

The other manufacturer that uses boxer engines prefers their own version of the DSG. Porsche’s PDK is one of the best in terms of performance.


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i vaguely remember a video yun pdk ng Porsche executed 50 full acceleration with launch control in succession without a hitch. yung bmw version smg pa ata overheated with 5 if i remember correctly. this was the earliest days of dct pa.

[LOLZ]

in house design ba yun much maligned and flawed ford dct?

the DPS6 was codeveloped with getrag(as the 6DCT250) and also used in renault megane III 1.5D