Why is there no turbo on the Atkinson motor?

[jonathan1994]

Lots of true info here, plus..
Part of Atkinson efficiency is high compression piston/head allowed by delayed intake timing.

Delayed intake decreases pumping losses and raises intake manifold pressure for even less pumping loss.

Higher compression piston head is just straight efficiency gains.

Adding a turbo means you would have to lower the piston/head compression ratio to prevent knock and lose that efficiency.

NO benefit to the turbo for internal pumping efficiency at low power and the exhaust pressure from the turbo actually costs some pumping power.

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[Donodo]

Please please, no stupid turbo! I want my vehicles to last more than the warranty period with no costly failures afterwards! This engine has a great reputation for working as advertised for hundreds of thousands of miles, no problems.

My son traded in a 2006 Escape hybrid, same 2.5 Atkinson engine, with 293k last year. All we did was change the oil and filters per maintenance schedule. Brake pads and rotors replaced at 178k.

 

[GroomLake51]

Like said above, the Atkinson is designed to have a short compression stroke and a longer combustion stroke (by valve timing). A turbo would actually cancel out this design, meaning it would be putting more compression on the compression stroke. So i would make since to put a turbo on this engine.

I be been thinking that the Atkinson effect of reducing compression effort when full charge is not needed could be (and maybe is) accomplished with a turbocharger. If the turbo is necessary for full power, then reduced or no pressure from it when lower compression is needed would accomplish this objective.

Like said above, the Atkinson is designed to have a short compression stroke and a longer combustion stroke (by valve timing). A turbo would actually cancel out this design, meaning it would be putting more compression on the compression stroke. So i would make since to put a turbo on this engine.

 

[gwrace14651]

I’ve been kind of confused trying to figure out why they wouldn’t have added a turbo on the Atkinson motor. Can anyone explain to me the science behind why they didn’t? And if we could put aftermarket turbos on for better fuel efficiency and power?

A turbo would just add more cost and complexity along with higher maintenance costs. It also adds just another failure point. They all burn oil. It's just a way for auto manufacturers to reduce engine sizes but provide the needed power.

In sport mode the current configuration has plenty of power. Loving the new 24 Lariat Hybrid we picked up two weeks ago.

 

[GPSMan]

It has been done. It's just not done in these.

See Miller cycle engine.

Also the Atkinson has LOW EFFECTIVE COMPRESSION. These are NOT high compression engines.

The "manual" and spec sheets are misleading you.

The geometry is 13:1 but one quarter to one third of the compression volume is allowed to leak out before the valves close. Net compression is unpublished but is about 9:1

 

[GroomLake51]

A turbo would just add more cost and complexity along with higher maintenance costs. It also adds just another failure point. They all burn oil. It's just a way for auto manufacturers to reduce engine sizes but provide the needed power.

In sport mode the current configuration has plenty of power. Loving the new 24 Lariat Hybrid we picked up two weeks ago.

Didn’t mean to suggest a turbo should be added to the Atkinson engine, but that it could be a simpler way to reduce compression effort in Otto engines.

 

[Optimus]

You already have a battery adding supplemental power, and you don’t have to wait for the battery to spool up. No need for “extra power” from another source.

 

[Automate]

Ford already has a turbo hybrid. It's coming out in China first. Makes up to 310 combined horsepower.
https://fordauthority.com/2023/09/new-ford-hybrid-engine-could-work-on-maverick-bronco-sport/

But due to the extra cost of the hybrid components (batteries, motors, VFD) plus the cost of the turbo, I doubt it will come to the Maverick soon.

 

[1929]

I’ve been kind of confused trying to figure out why they wouldn’t have added a turbo on the Atkinson motor. Can anyone explain to me the science behind why they didn’t? And if we could put aftermarket turbos on for better fuel efficiency and power?

Why not a Whipple supercharger?

 

[RichardCranium]

Ford already has a turbo hybrid. It's coming out in China first. Makes up to 310 combined horsepower.
https://fordauthority.com/2023/09/new-ford-hybrid-engine-could-work-on-maverick-bronco-sport/

But due to the extra cost of the hybrid components (batteries, motors, VFD) plus the cost of the turbo, I doubt it will come to the Maverick soon.

Interesting read. It looks like they would be using the same 2.0L ecoboost connected to the hybrid eCVT, but could mate it with an AWD system that runs off the ecoboost engine. Did I read that correctly? That would be an interesting, yet pricey way to add the AWD and 4K tow to a hybrid. I bet it would cost a bit more than the current $3000 to make the standard Ecoboost into a 4K.

 

[BradnChristine]

More (HP) is not always better. I have no trouble keeping with traffic on the 80MPH Interstate as it is. Why would anyone want to add another failure point? I love how much power the e-motor adds when I need to step on it.

 

[Automate]

More (HP) is not always better. I have no trouble keeping with traffic on the 80MPH Interstate as it is. Why would anyone want to add another failure point? I love how much power the e-motor adds when I need to step on it.

Maybe for those that want to tow 4K or more.

 

[BradnChristine]

Maybe for those that want to tow 4K or more.

Sure... But I really wouldn't expect 4k towing from a hybrid, even with a turbocharger.

 

[Automate]

Sure... But I really wouldn't expect 4k towing from a hybrid, even with a turbocharger.

Why not? Probably because of the stereotype of the Prius Hybrid.

Did you know that Formula 1 racing has been using Hybrids since 2014? And endurance racing's hybrid era started two years earlier in 2012, when the new-formed WEC series made hybrids mandatory for all manufacturers in the top-tier LMP1 class.

 

[Criss944]

It has been done. It's just not done in these.

See Miller cycle engine.

Also the Atkinson has LOW EFFECTIVE COMPRESSION. These are NOT high compression engines.

The "manual" and spec sheets are misleading you.

The geometry is 13:1 but one quarter to one third of the compression volume is allowed to leak out before the valves close. Net compression is unpublished but is about 9:1

The bottom line is the traction motor is effectively a turbo without the turbo lag.

I found the following video worth the 20 minutes.
https://www.bing.com/videos/rivervi...DAE46AD41F46E3A5D94CDAE46AD41F46&&FORM=VRDGAR

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