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Say you're driving on the highway and you run out of electricity. Will the engine get damaged since all the oil is at the bottom of the oil pan but the rpms are quite high? how does the engine lubricate itself fast enough?
how does the 4xe warm up It's engine so fast?
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Modern internal combustion engines typically don't require the same warmup process as prior generations for emissions or lubrication. Oils are better, metallurgy is better, tolerances are better, and the systems are designed for start-stop use. There are heated arguments pro and con for sure, but this is how the manufacturers explain how start-stop doesn't affect engine life.
I've been trying to find a deeper dive into how the Jeep system works, though, because I have noticed the engine temperature increases to optimal very quickly when the turbo engine does kick in while in hybrid mode. Curious if 1) the engine coolant is warmed by the EV component cooling system and 2) does the electric motor clutch in the transmission allow the ICE to warm up at a specific RPM before engaging it with the drivetrain? I would think they would need to give it 10 seconds or so on a cold start just to get through the cold-start mappings to and to warm up the cats.
I've been trying to find a deeper dive into how the Jeep system works, though, because I have noticed the engine temperature increases to optimal very quickly when the turbo engine does kick in while in hybrid mode. Curious if 1) the engine coolant is warmed by the EV component cooling system and 2) does the electric motor clutch in the transmission allow the ICE to warm up at a specific RPM before engaging it with the drivetrain? I would think they would need to give it 10 seconds or so on a cold start just to get through the cold-start mappings to and to warm up the cats.
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I drove about 15 miles yesterday on electric from a cold start with the EV button pushed, so the ICE was never on. I got onto the highway and drove another 5 miles at 75 MPH, still on all electric. When the battery got to 12%, I pushed the hybrid button. At that point the tach jumped to 1800 RPM, a moment passed and the temperature gauge was at 40%, and I never really felt it happening. I want to think they are merging the ICE RPMs with the electric motor's RPMs where appropriate and keeping it disengaged while it does some warmup process, but I don't know for sure. I would love to read more about it if anyone has more details!
This is my understanding. That there is a merging that happens to allow a quick warmup. I don’t think it takes much. I’ve also read PHEV lube is very lightweight and moves like water at any temp.
This is a great question, to be answered by people way smarter than me.
Im tuning in.
I’m sure a brilliant engineer will be along shortly to break this all down for us. 🙂
Def the wrong kind of engineer to know this so
don’t quote me but I think it’s the same tech that allows for the stop/start. I know Toyota held the patent for a long time on the “Permanently engaged” tech where the piston gear never disengages from the fly wheel. Couple that with standby pressure in fuel pumps that can hold pressure without being on per say… basically I think now that everything is electric driven there is no “lag” in the starter anymore.
Most engage when the break is depressed not when the accelerator is pressed, giving you the illusion it’s faster than it is
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It is a genius system actually.
First, let's consider that PHEVs have come under harsh criticism for excessively polluting while the ICE is warming up. So stricter regulations have been put into place and our 4xe is quite responsible in this regard.
The 4xe appears to have the ability to transfer waste heat from the electrified drivetrain into the ICE coolant system. Have you ever noticed the engine temp increasing while driving in EV mode even though the ICE hasn't been run?
Almost all direct injected engines have some sort of anti-drain back valve in the lubrication system so the engine is actually ready to go when needed.
And since the engine is able to be completely disconnected from the driveline, it can be started and run at higher RPMs to bring the cats up to temp without dumping excessive fuel into the exhaust.
First, let's consider that PHEVs have come under harsh criticism for excessively polluting while the ICE is warming up. So stricter regulations have been put into place and our 4xe is quite responsible in this regard.
The 4xe appears to have the ability to transfer waste heat from the electrified drivetrain into the ICE coolant system. Have you ever noticed the engine temp increasing while driving in EV mode even though the ICE hasn't been run?
Almost all direct injected engines have some sort of anti-drain back valve in the lubrication system so the engine is actually ready to go when needed.
And since the engine is able to be completely disconnected from the driveline, it can be started and run at higher RPMs to bring the cats up to temp without dumping excessive fuel into the exhaust.
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great overview! Thanks! I also found this article, which explains how the forward clutch controls interactions between the ICE and the electric motor, and how the rear clutch controls interactions between the electric motor and the transmission. Working both clutches independently lets the system do all of those things you mentioned nearly seamlessly. I recall how much time it took for automakers to get automated manuals like BMW’s SMG working well with only one clutch, so we can hope this system will only get better as the software evolves.
www.media.stellantis.com
New Jeep® Wrangler 4xe: the best of 4x4 goes electric to go anywhere
The new Jeep® Wrangler 4xe combines the best of 4x4 and the best of electric to reinforce its iconic status within the brand portfolio.
www.media.stellantis.com
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I've been wondering the same, and Googling it for a while now. The best answer I found was from a former auto engineer, who stated that part of the testing they do for plain ICE cars is a "gorilla stomp" on the accelerator with a cold engine. Apparently modern engines and their oils are just fine going to WOT cold. I'm not sure I really want to do that, but I don't think going from off cold to moderate load will hurt new cars.
Hmm, I never noticed my engine coolant warming up while driving with it off, but it seems to hover around 80F in the summer heat, so maybe the 4xe does pre-warm the engine in cooler temps. Now I'm curious...
Hmm, I never noticed my engine coolant warming up while driving with it off, but it seems to hover around 80F in the summer heat, so maybe the 4xe does pre-warm the engine in cooler temps. Now I'm curious...
Nice article… it’s just missing the fine print “because we can we did, don’t expect your local Jeep mechanics to have even read this article”… kidding it really is the best of both worlds… as long as I’m not the test subject for the water fordinggreat overview! Thanks! I also found this article, which explains how the forward clutch controls interactions between the ICE and the electric motor, and how the rear clutch controls interactions between the electric motor and the transmission. Working both clutches independently lets the system do all of those things you mentioned nearly seamlessly. I recall how much time it took for automakers to get automated manuals like BMW’s SMG working well with only one clutch, so we can hope this system will only get better as the software evolves.
New Jeep® Wrangler 4xe: the best of 4x4 goes electric to go anywhere
The new Jeep® Wrangler 4xe combines the best of 4x4 and the best of electric to reinforce its iconic status within the brand portfolio.
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Not sure. I think the electronics dump heat into the PTC and passes to the hearer core and eventually the radiator and engine.
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Well this is exactly how it works
You have to make sure all the fuses are pushed in while you're driving
And thats actually it, simple as that
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I was watching the engine, coolant, oil pressure, and oil temps from the offroad pages while driving around the other day when the ambient temp was in the mid 80's. All the gauges showed ambient temp with zero oil pressure when the engine was running. However, when I eventually forced an engine start by moderate acceleration the temps climbed quickly, but normally.
I was expecting like you mentioned, @SnB4xe , that things would electronically heat up but wasnt seeing it. I wonder if that occurs when it is colder outside? Any thoughts on that?
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I have been watching the Ask the Expert videos and this is largely addressed in #3:
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My suspicion is just waste heat might be transferred. Probably not running the PTC heater as that is a pretty big energy draw.
What I think may be happening is the MGU2 (large motor in bellhousing) is cooled by the transmission oil and that is cooled by the oil-to-water cooler in the radiator. So, the water in the radiator warms up as a result and then might be allowed to flow into the engine block if the thermostat opens.
That would make some sense because Jeep can use the engine block as a giant heat sink when it isn't running. (Might as well get some use from the lump of metal while it rides around in EV mode.) If the engine is needed, then it is half way warmed up already. If not, then the heat just radiates to atmosphere while parked anyway so there isn't really any downside that I can think of.
If it is cool outside.....then the heat is likely to be transferred from the radiator just by the airflow of driving around even if the fan isn't running. I only notice the engine temp increasing when it is fairly warm outside. When it's cool out, I suspect any waste heat might be sent to the PTC and the heater core to exchange heat with the cabin interior.
That is how my BEVs work. Waste heat from the battery, motors and electronics will go to the cabin heater on cold days.
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