Question - could an E-turbo improve fuel efficiency?

[Thejackal151]

I'm aware that an Atkinson engine is already built for efficiency, but I was wondering if an E-turbo would help with power and efficiency. I figured it might work since it has a lower parasitic load and almost instant boost whenever the engine turns on.

Could someone explain to me if this would or wouldn't work to improve efficiency while keeping or improving power.

I just really like efficiency and my truck

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[Master Blaster]

No. The extra electric load and more inherent inefficiencies cost more than they give. To improve efficiency of an already excellent drivetrain would mean downsizing the gas engine and maybe utilizing the 1.5L engine from the Bronco and Escape, converting the cam and cam phasers to Atkinson cycle, and maybe beefing up the electric motor to compensate for less available torque from the smaller engine. Toyota has done this for example, and gets better highway fuel efficiency as a result.

 

[Gray Goose]

May also shorted engine life since it was not designed for a turbo.

 

[Thejackal151]

How would reducing the engine size improve efficiency and keep performance? At that point wouldn't the engine be better used as a dedicated generator for an electric motor?

 

[Thejackal151]

May also shorted engine life since it was not designed for a turbo.

In this hypothetical, let's not worry about engine wear

 

[Gray Goose]

In this hypothetical, let's not worry about engine wear

Well if its just hypothetical, where should I deliver the turbo?

 

[Master Blaster]

How would reducing the engine size improve efficiency and keep performance? At that point wouldn't the engine be better used as a dedicated generator for an electric motor?

The gas engine is the primary efficiency problem, so improving its efficiency, reducing the size of it and increasing the electric portion would improve overall efficiency and give the same or better performance. Switching to an Atkinson cycle has already been done in the Hybrid, so pulling even more efficiency gains within the gas engine are pretty questionable.

Reducing vehicle weight is another way to improve efficiency, both in acceleration improvements and in rolling resistance mostly from the tires. Its why you strip every non-essential part out of a racecar, even pickling the panels to cut their weight. This is why Ford went to a unibody in the Maverick and why the F150 is half aluminum instead of steel. Switching more Maverick panels to plastic or aluminum could probably pick up another 10% efficiency in the Maverick, but would obviously require the aluminum tarrifs to be removed.

Ignoring the pretend people who want to race, most people think performance is all about HP, but its really all about torque, especially in the low and midrange. That's why automatics with torque multiplication in the converter are quicker than manuals when you have more than enough engine (like a huge V6 or V8) to compensate for the large converter losses.

Think of Italian vehicles, where fuel costs 6 times as much, so efficiency is highly prized and as well you pay a very large road tax based on your engine size. The 500cc 2cyl Fiat can't haul what the Maverick can, but gets 100mpg without the addition of any torque from an electric motor and without the additional efficiency of the Atkinson cyle, and is a huge amount of fun to drive. It was never sold in North America because we don't like driving at 6,000rpm in normal traffic.

Toyota uses a smaller 1.8L engine with the same hybrid setup and the same eCVT to get them into the 60mpg area and roughly the same mileage city/highway. Ford with their bigger 2.5L engine cannot presently match that efficiency.

 

[notfast]

I'm aware that an Atkinson engine is already built for efficiency, but I was wondering if an E-turbo would help with power and efficiency. I figured it might work since it has a lower parasitic load and almost instant boost whenever the engine turns on.

Could someone explain to me if this would or wouldn't work to improve efficiency while keeping or improving power.

I just really like efficiency and my truck

Even if it does, it likely wouldn't make financial sense to justify it. Sort of like folks that buy parts to improve aerodynamics and/or fuel efficiency (like tonneau covers). Yes, they will marginally increase fuel efficiency, but for a large up-front cost that'll take tens of thousands of miles to break even. Same with, say, replacing the tires with ultra-low-rolling-resistance ones. If you already need new tires, it's something to consider, but I wouldn't suggest replacing perfectly serviceable tires just in order to gain better fuel economy.

To maximize fuel economy, I suggest starting with what's free. Do a lot of 1-pedal driving, don't drive around with excessive stuff in the car, keep the tires properly inflated, keep the car washed, remove the spare tire and carry a plug kit and inflator, and so on. If you don't have back seat passengers, you could just remove the seat entirely.

 

[wax87]

The gas engine is the primary efficiency problem, so improving its efficiency, reducing the size of it and increasing the electric portion would improve overall efficiency and give the same or better performance. Switching to an Atkinson cycle has already been done in the Hybrid, so pulling even more efficiency gains within the gas engine are pretty questionable.

Reducing vehicle weight is another way to improve efficiency, both in acceleration improvements and in rolling resistance mostly from the tires. Its why you strip every non-essential part out of a racecar, even pickling the panels to cut their weight. This is why Ford went to a unibody in the Maverick and why the F150 is half aluminum instead of steel. Switching more Maverick panels to plastic or aluminum could probably pick up another 10% efficiency in the Maverick, but would obviously require the aluminum tarrifs to be removed.

Ignoring the pretend people who want to race, most people think performance is all about HP, but its really all about torque, especially in the low and midrange. That's why automatics with torque multiplication in the converter are quicker than manuals when you have more than enough engine (like a huge V6 or V8) to compensate for the large converter losses.

Think of Italian vehicles, where fuel costs 6 times as much, so efficiency is highly prized and as well you pay a very large road tax based on your engine size. The 500cc 2cyl Fiat can't haul what the Maverick can, but gets 100mpg without the addition of any torque from an electric motor and without the additional efficiency of the Atkinson cyle, and is a huge amount of fun to drive. It was never sold in North America because we don't like driving at 6,000rpm in normal traffic.

Toyota uses a smaller 1.8L engine with the same hybrid setup and the same eCVT to get them into the 60mpg area and roughly the same mileage city/highway. Ford with their bigger 2.5L engine cannot presently match that efficiency.

Think Aerodynamics. While there are several aerodynamic trick incorporated onto the Maverick, it is a truck that is marketed to the general public. For starters they could have sloped and rounded the front end.

 

[HeyBales]

Wouldn't a turbo ruin the whole desired effect of the Atkinson cycle?

• Delayed Intake Valve Closing:
  In an Atkinson cycle, the intake valve remains open for a portion of the compression stroke. This allows some of the air-fuel mixture to be pushed back into the intake manifold, effectively reducing the amount of mixture that is compressed and subsequently burned.

With increased pressure wouldn't the amount of push back of AF mixture just be reduced or eliminated - in which case just skip the Atkinson method?

Or that's the idea - when power needed it's more like a Miller cycle forget MPG?

Are you thinking an e-turbo like the Porsche that can do some regen during non-turbo use?

https://www.mavericktruckclub.com/forum/threads/why-is-there-no-turbo-on-the-atkinson-motor.4941/

 

[dalola]

I'm aware that an Atkinson engine is already built for efficiency, but I was wondering if an E-turbo would help with power and efficiency. I figured it might work since it has a lower parasitic load and almost instant boost whenever the engine turns on.

Could someone explain to me if this would or wouldn't work to improve efficiency while keeping or improving power.

I just really like efficiency and my truck

You first need define "efficiency", in your context. It seems like you are specifically referring to fuel efficiency (FE)?

If so, turbos (or any forced induction) do not increase FE. It adds power. It allows a smaller engine to make the power of a larger engine. So, the FE comes from the smaller engine, not the FI. If all else is equal, a 2L NA motor will have better FE than a 2L FI motor.

Now, if your definition of "efficiency" is something else, there are other points to be made.

 

[Thejackal151]

Wouldn't a turbo ruin the whole desired effect of the Atkinson cycle?

• Delayed Intake Valve Closing:
  In an Atkinson cycle, the intake valve remains open for a portion of the compression stroke. This allows some of the air-fuel mixture to be pushed back into the intake manifold, effectively reducing the amount of mixture that is compressed and subsequently burned.

With increased pressure wouldn't the amount of push back of AF mixture just be reduced or eliminated - in which case just skip the Atkinson method?

Or that's the idea - when power needed it's more like a Miller cycle forget MPG?

Are you thinking an e-turbo like the Porsche that can do some regen during non-turbo use?

https://www.mavericktruckclub.com/forum/threads/why-is-there-no-turbo-on-the-atkinson-motor.4941/

Thank you, this is the type of answer I was looking for. Not to say the others weren't good and valid.

 

[Tiger Dude]

Can you add a turbo to an Atkinson cycle engine? Yes (also known as Miller cycle). Can you add one to this Atkinson cycle engine? Almost certainly no. It is a complex issue, since the Atkinson cycle acts differently at low and high speed. It seems to me that manufacturers haven't quite solved the problems, or else we'd see this tech already. Atkinson cycle engines sacrifice power density (which is a turbo engine's strength) for efficiency.

 

[wax87]

Wouldn't a turbo ruin the whole desired effect of the Atkinson cycle?

• Delayed Intake Valve Closing:
  In an Atkinson cycle, the intake valve remains open for a portion of the compression stroke. This allows some of the air-fuel mixture to be pushed back into the intake manifold, effectively reducing the amount of mixture that is compressed and subsequently burned.

With increased pressure wouldn't the amount of push back of AF mixture just be reduced or eliminated - in which case just skip the Atkinson method?

Or that's the idea - when power needed it's more like a Miller cycle forget MPG?

Are you thinking an e-turbo like the Porsche that can do some regen during non-turbo use?

https://www.mavericktruckclub.com/forum/threads/why-is-there-no-turbo-on-the-atkinson-motor.4941/

Not necessarily, you could use a smaller motor with a turbo to get the efficiency and the power you want. Toyota is working on a 1.2 L engine with that this purpose in mind.
For our purpose we have the electric motor to do that, you certainly would not what both and electric asset and a turbo. F1 cars have both E assist and turbos but they are not Atkinson motors.

 

[HeyBales]

Wouldn't a turbo ruin the whole desired effect of the Atkinson cycle?

• Delayed Intake Valve Closing:
  In an Atkinson cycle, the intake valve remains open for a portion of the compression stroke. This allows some of the air-fuel mixture to be pushed back into the intake manifold, effectively reducing the amount of mixture that is compressed and subsequently burned.

With increased pressure wouldn't the amount of push back of AF mixture just be reduced or eliminated - in which case just skip the Atkinson method?

Or that's the idea - when power needed it's more like a Miller cycle forget MPG?

Are you thinking an e-turbo like the Porsche that can do some regen during non-turbo use?

https://www.mavericktruckclub.com/forum/threads/why-is-there-no-turbo-on-the-atkinson-motor.4941/

I'll add the other neat idea for e-turbo is a motor - so no oil needed for cooling and bearings - just the normal coolant loop like the motors in the tranny.

But to not ruin the Atkinson MPG, you'd only want the turbo at certain levels of power request - when the EV motors can't give enough or long enough, maybe the highway speeds for passing, or towing scenarios.

I could imagine it working, just at the expense of MPG.

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