Explaning ESS to a middle schooler

[AnnDee4444]

Doesn't the system also scavenge/regenerate energy from engine braking as well? Thought I read that somewhere, but not really sure if it occurs only when brakes are applied or perhaps when going down a hill with your foot off the gas.

Yes, and a few other ways too.

before I can get the transmission into park and turn off the engine myself can't really be good for fuel consumption or component wear either.

You can open the door to trigger auto park... then I think putting it in park won't start the motor.... there's some convoluted sequence I don't remember to keep the motor from starting up again.

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[JuzaMe]

" For every action, there is an equal and opposite reaction" Newton had it correct and I'm sure he was referring to ESS.

 

[BXFXJeep]

There is ESS the electronic stop start, and then there is etorque, etorque is a hybrid(mild) system, not a stop/start system, it has a stop/start function but that is not it's main function.

I would have gone for the etorque if it was available when I got the 2018.

 

[Fudster]

@AnnDee4444

It's true that there are additional benefits to ESS than gasoline savings alone (air quality.)

But if ESS didn't provide these additional benefits it could still be shown, and more than using theoretical physics, to save gasoline---again not a lot but some.

Additionally, to simply look at the savings of gasoline while stopped at a traffic light over the additional gasoline to re-crank the engine after the ESS event sees ESS in an unfairly advantageous light. There were other energy depletions in that ESS event, namely available ESS battery power, that unless put back to the way they were before the ESS event, risks unfair comparison.

I'm referring to ESS in vehicles that don't currently use regenerative braking or for that matter any power source to recharge the (ESS) battery other than liquid fossil fuel. Still more, by EPA ESS standards (long story) any action that puts the vehicle into park starts the engine again.

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I've got an analogy I think a kid could get.


I'm at a construction site. The crane there has this really big engine (the vehicle's engine) designed to move some really heavy loads (the vehicle) at the same time that I want to put some far lighter garbage, but too heavy to pick up (the vehicle's appliances) into the dumpster.

No way would I run that crane, given how much power it consumes, to simply load the dumpster.

But it cases where the crane's powered up anyway to move the really heavy loads (the vehicle's engine is on because its mobile) I can use the crane to put that garbage in the dumpster AND recharge the batteries on the forklift (the ESS battery.)

After quitting time, when the crane operator's gone home for the day there be some more heavy stuff (vehicle appliances) to throw away in the dumpster and I can use the forklift (the ESS battery) for that, recharging it in the morning from the crane when its operator gets busy again.

Even if I were licensed to use the crane, my doing so would use so much fuel and putting to task a goliath to move a miniscule amount of mass, that putting that crap in the dumpster with it would be "killing a fly with a baseball bat." But the crane's enormously efficient at moving really have loads. I'd use a lot more energy going out an using 5 forklifts to move the same really heavy construction stuff.

How's that?

 

[AnnDee4444]

I would have gone for the etorque if it was available when I got the 2018.

eTorque was available in 2018.

 

[calemasters]

Of course on the highway, there are no fuel savings or reduced emissions. In the city, where ESS functions, I think the fuel saving / reduced emissions are very minimum and not worth the effort.

 

[mwilk012]

You have to factor in the efficiency of the engine (low) compared to the efficiency of a battery (high).

Efficiency is everything when It comes to energy capture and distribution.

 

[58Willys]

I would say the amount of additional work needed to run the alternator to charge the battery is negligible. The alternator only really runs when needed, per the IBS.

ESS saves fuel when stopped, decreases emission, and save engine wear when not running. Also increases effective mpg for CAFE standards.

 

[Stonerider]

How hard would it be to have the ESS system removed from your Jeep Wrangler...asking for a friend?

 

[Tncdrew]

How hard would it be to have the ESS system removed from your Jeep Wrangler...asking for a friend?

For the standard aux battery based ESS system - relatively easy.
For the etorque mild hybrid system - I wouldn't even contemplate it.

 

[BXFXJeep]

eTorque was available in 2018.

Sorry should have specified 3.6 etorque

 

[AFD]

You can open the door to trigger auto park... then I think putting it in park won't start the motor.... there's some convoluted sequence I don't remember to keep the motor from starting up again.

I'll have to try that.. or just continue my regular pattern of constantly playing with the ESS on/off button so it only works when actually warranted (if it feels like it).

While some of its behavior is just a mild nuisance, there's a really dangerous blind intersection I need to turn through near work. It's 25MPH w/flashing yellow lights and oncoming traffic indicators, where large triaxles and semis barrel through at over 50MPH. Stopping to turn here or pulling out from there is scary af and losing even a split second from the engine being stopped isn't a comfortable scenario imo and of course, there's no way the ESS would ever know that.

 

[40Caliber]

"that's just the way it is"

That was my answer to my kids for almost everyhing... it seem to work. they are well functioning adults regardless ?

 

[jaymz]

You’re overthinking it. ESS is simply one of the many ways that auto manufacturers use to meet the government’s near impossible fuel economy standards. If not for those f/e standards, ESS would not exist in any vehicle. There’s no real benefit to the consumer.

 

[Fudster]

You have to factor in the efficiency of the engine (low) compared to the efficiency of a battery (high).

Efficiency is everything when It comes to energy capture and distribution.

.but that higher efficiency battery is charged by a low efficiency engine. That battery can't really shine if its power is derived from a poor power energy conversion mechanism right? (i.e. the engine, which takes the chemical energy of fossil fuels and converts it to mechanical energy , which is converted to electrical energy in the alternator, which is converted to chemical energy in the battery.)

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