Hybrid Oil Pressure Question

Toyota has built bulletproof hybrid engines for 20+ years. I would imagine they have put considerable amount of time and effort designing a system that keeps the engine properly lubricated at all times.

 

Good point. I was trying to simplify things.

My point was, the oil pump in an ICE engine doesn't lose prime when the engine is off. Therefore, it only takes a couple of revolutions of the crank to build pressure, and that happens in fractions of a second at the speeds that an ICE engine operates at. Meanwhile, the residual oil that remains on the engine's components is enough to lubricate them in that short time frame.

Also, some data points to the conclusion that the ICE engine in a hybrid is actually subject to less wear and tear due to the electric motor assist, despite the constant on/off cycles. I know VCheng will have a hard time swallowing that one. LOL!

 

Of course Toyota has a well deserved reputation for making reliable engines, certainly at least until the Tundra engine recall. Any concerns probably have more to do with tightening EPA mandates getting in the way of long term reliability, that is all: turbos, thin oils, stop-start etc. etc., and nothing to do with the expertise of Toyota engineers, I am sure. After all, I still trust them enough to currently have several Toyotas, as well as a long list of previous ones, the latest being the Tundra, so my money is still bet on their expertise.

This thread is interesting more about the conjectures thrown about at random than for anything provable. For example, going through the posts above, one does not know whether the mechanical assembly stops or not in "hybrid mode", or the oil pressure drops to zero or not no matter what the display reads, and even if it does, does it really matter long term?

We do know for a fact that maximum wear happens at start-up, and the total number of start-stop cycles becomes an important consideration for longevity, everything else being equal, of course.

 

You keep pulling this card, but you leave out the important part. The vast majority of that wear applies to COLD startups, not the warm on/off cycles of a hybrid engine, or even the auto stop/starts on non-hybrid engines. Auto stop/start has literally been around for decades, with no evidence that it prematurely wears out an engine. That's simply a myth.

You also don't account for the significant engineering differences in the starting systems of auto stop/start and hybrids. A average ICE engine cranks 50K times in its lifetime. Auto stop/start and hybrid engines are engineered to startup over 300K times in their lifetimes.

Look, I'm not advocating for hybrids. And like you, I once believed the myths. But, I've educated myself on the topic. You should too.

 

To the OP, I believe the engine stops running and oil is not circulating when running only on battery power only. That's been my experience - I pull into my garage and the truck is just about silent. That would explain why the oil pressure drops off.

I've also wondered about oil pressure, but I trust the engineers making hybrids at Toyota.

 

I am just in the trust but verify camp.

 

Learned a bunch here in this blog. The original inquiry was about a logic on the IP for the oil pressure gauge turning off. Toyota has designed a very unique system to provide much more torque, and resulting HP increase, to exceed a V8 level of towing. IForceMax is not like any of Toyotas other hybrid systems. No electric wheel drive (Prius) or final drive motors (Rav4), but a clutched motor between the V6 & 10spd tranny. No question it comes in and adds power as needed, and can also at very low speeds operate for a limited time/distance on electric alone. I do see the orange high power cables going to AC compressor and secondary water circulation system. I have pulled up in hybrid mode down the driveway, parked, open the hood, the 2 electric it fans are running, but the mechanical fan off the water pump is also spinning. At that point there is no tach reading, no oil pressure reading, and assume the electric motor is turning over the V6 internals. Maybe there is another Toyota secret I’m not aware of. Wondering if there is a hybrid slow speed mode where it does circulate engine reciprocals.

 

As Nate Bargatze said in his famous General Washington clip in SNL:

“No one knows!”

 

This is very interesting, as I always thought the ICE engine shut down completely when in full electric mode.

It seems like this should be common knowledge, or at least easily verified. I, too, would have concerns, if the ICE engine continues to spin with no oil pressure or ignition.

Seems like something NotRyan would know.

It's a sobering reminder of how automotive technology has passed this old guy by. I can fix anything on 30 year or older rides. Not any more on modern shit.

 

My hybrid does the same……. Drive your truck and enjoy it!

 

OP - have you considered the reason you see the waterpump and dampener spinning is becouse the engine is running? I'm 6 for 6 in that truck is on, in electric mode, open door stays in electric, open hood ice starts - every time. Close hood and back to electric mode.

This is the same for wife's plug in hybrid volt. Open hood, engine starts.

 

^^^ This.

 

The gauge doesn't drop to zero exactly it has a tick of pressure that it is reading so it does something either via the oil pump or some other mechanical mechanism is running to keep pressure at a near zero level but not quite zero.

 

When you are driving in EV mode the engine doesn't spin because K0 is unlocked, the electric motor drives the 10 speed until there's demand for more power. This is when K0 locks and the momentum of the truck starts the engine, not the electric motor.

Hybrids have an electric AC compressor and they don't require the engine to be turning.

It would be really inefficient to drive the engine with the electric motor, and I'm not even sure where you read this but it's not true at all. You would be fighting the engine's compression ratio and every single rotating body would create drag ruining the whole point of a hybrid system. This is why oil pressure is zero while you are in ev mode.

 

And remember folks, it revs immediately right up to a few thousand rpm since the truck is at speed. Every time. Multiple times in a trip. Awesome. NOT!

 

I have 30,000 miles on my truck and almost 3 years of ownership. I also have a 125k mile 10-year warranty. I am covered if something happens which is Awesome. I like the additional power and the ability to go off leave 99 percent of the trucks on the road especilaly on 35s. The Toyota hybrid with 587 ft lb. of torque is pretty stout for a quarter ton.

 

This thread got me curious so I did some testing of my own, and here's what I found on my hybrid.
When I tried to see if the engine is being spun by the hybrid it's impossible to tell, why? As soon as I popped the hood the engine starts. I tested this several times and could not get the engine to stop running when the hood was open. As soon as I closed the hood the engine started.

I believe the hybrid is not rotating the engine when the oil pressure is zero and the tach is zero. Even if the hybrid was rotating the engine there would be oil pressure as the oil pump is mechanically driven.
As for concerns with the lower end getting oiled that is the job of the crank which is slightly submerged in oil and throws it all over the crankcase and up into the cylinders. The oil pumps job is to lift oil to the top end of the engine lubricating the camshafts and supply the piston oil squirters. As the turbos are liquid cooled there is no need to supply oil there.

This my opinion based on my findings so go easy on me if I'm wrong. I'm not looking for a keyboard battle, I'm here to learn.

 

Agreed. Of all the choices out there, the various flavors of the Tundra are probably the best half ton trucks available currently. Toyota has my money too for many of the reasons you have described, albeit for a non-hybrid unit.

 

I am of the opinion that if the wheels are moving then the crankshaft has to be moving and rotating. While oil pressure drops it would not be impossible to think that it is not exactly zero. There has to be some rotational pressure present from the crankshaft moving in synchronicity with the electric motor driving the transmission.

 

yea it works pretty good. You’re just paranoid

 

Not preferring an ICE revved up immediately after a start with zero oil pressure to a few thousand rpm to rev match the transmission multiple times per trip has more to do with simple facts, and not "suffering from delusions of being persecuted by the conspiratorial actions of others or having an unwarranted suspicion of the motives of others".

Hey, if it works "pretty good" for you, then great!

 

Found this in a prior thread. The K0 clutch is between the convertor and engine. It disengages the engine from driveline when under 100% electric drive as shared in thread above. The vehicle can and does move without the engine being coupled.

 

Question: There is an electric oil pump also? Is this only for the transmission and not the engine? If so, is this pump absent in the non-hybrid transmission?

 

im sure you were writing journal entries when fuel injection first came out expressing your concerns too

 

that would have to go back a long time especially since fuel injection has been around since the 50s and 60s.

 

Actually gasoline FI has been around since the 20s but in airplane engines, before transitioning to automotive uses in the 50s.