Prius engine has an easy life

Might help explain why 5K oil change for a Prius, and 3K oil change for a standard.

 

Have you ever considered that most engine wear occurs when the engine is started, and that the hybrid is starting its engine many more times than the non-hybrid?

Ok, that's true for cold starts, less true for warm starts. Also, I believe the Prius builds oil pressure before firing the spark when starting. But it is a significant factor that you completely overlooked. There is zero oil pressure at the time the engine starts spinning during a restart.

 

No, the oil pump is run by the power split device. Oil is flowing as soon as the MG starts moving the car. By the time the ICE starts the oil pressure is nominal.

 

It doesn't have a 'starter', either, so the mechanical action of starting the ICE is a little bit different, which, I believe, reduces the 'starting wear' on the engine.

 

Nothing to do with this. Engine/oil/oil filter can run more than 5k before change. The 5K recommendation in the US has to to with our fondness of lawsuit. In the UK, Prius oil change is every 10k.

 

If you are one of those data-driven people, just look at this, http://priuschat.com/forums/file-library/27820-uoa-used-oil-analysis.html

Many members have gone over 10k miles per oil change interval with good oil analysis results. All you need is good oil and a good filter.

 

ScottY,

Living in Manhattan, I don't drive much. Would you happen to know if there is a time factor involved, e.g., should I change the oil and filter every 10k or 12 months, whichever comes first?

 

If you are still under warranty, then change @ 5,000 miles, as instructed by Toyota.

Regarding the old 3,000 miles number, very few vehicles have an oil change interval that short. It's 7,500 miles on my conventional Civic, half that for "severe duty."

As for the original question, I have a BMW motorcycle which calls for oil changes @ 6,000 miles or at least once a year.

Harry

 

Jane's engine didn't do twice as many revolutions when you take into account that when Jane's engine is idling it isn't at anything like the RPM it runs at while driving along, however the Prius engine in John's car doesn't run when slowing, going down a slight slope at steady speed and sometimes while travelling on flat ground.

The idea that engine wear is greatest when first starting the engine is mostly correct however a couple of things to remember, when the engine has only been off a few short minutes and the engine is warm the oil stays in the bearings as if it was running. Put a drop of oil on your fingers and try to squeeze it out from between your finger, your fingers remain slippery. The engine spins to near 1000rpm with cam timing allowing it to do so with little load on any component before the cam timing alters and fuel gets squirted into the manifold to produce power.

An engine idling runs slightly richer than when underway causing dilution of oil with fuel, due to some fuel condensing on the bore and making its way past the rings. This is why if you took your conventional car on a long high speed trip when it was due for an oil change after using it in traffic for 3000 miles or so the oil level dropped to the low mark. This is the fuel that is in the oil evaporating off from the oil. That is why the oil level doesn't drop when all 4 stroke I/C engines use *some* oil by design.

I think the Prius engine as it pretty good, it gets plenty of rest because it only runs when there is work to do however I'm not sure it is 50% less work in the described scenario.

Maybe the car should have an hour meter like tractors and boats?

 

Uhh... Actually the transaxle oil pump is not active when the car is in EV mode. I believe hobbit or someone brought up the dangers of extended periods without the engine turning on.

 

the prius runs the pump off of the ice. this was mentioned several years back.


the prius engine only runs between set rpms.. no red lines.. so less wear that way too!

agreed, the prius engine should have an hour clock.

 

Agreed, the Prius needs a Hobbs or similar hourmeter.

I used to have a 2000 GMC Sierra pickup truck, with the Vortec 5.3 V8. I think this motor is also used in Australia, it's an LS-1 variant with iron block and aluminum heads

Anyway, with the motor off and key off, one could open the door and push and hold the odometer reset button. The odometer display would turn on and display the km's.

Continue to hold the odometer button, and the display would then display the engine hours, such as "897.2 hr"

That's a clever trick, don't you think? Despite all the reliability problems with my GMC truck, I must admit it had some clever engineering

 

Then it was mentioned incorrectly. The oil pump is on the same shaft as the MG. When the MG turns so does the oil pump. Here's a cut-away from 2004.

http://www.ornl.gov/~webworks/cppr/y2001/rpt/120761.pdf

I'll clarify this further. From here: Information Bridge: DOE Scientific and Technical Information - Sponsored by OSTI

"Oil inside the hybrid drive housing splash lubricates the
bearings, gears, and other moving parts while an oil pump supplies lubricating oil to the power
split device."

This is not the ICE oiling systme. It has its own. But, because it spins to 1000 RPM before start, startup oiling isn't an issue.

The MG sets and PSD have a separate oiling system that is functional during electric only mode. So, that's not the cause of the limited EV mode available. I've read elsewhere, though I can't put my finger on it, that the EV mode limitation is related to battery temps.

 

http://priuschat.com/forums/prius-t...e-glide-above-42-mph-possible.html#post561141

The thread that mentioned something about the PSD not being lubed when the engine is off...

speaking of engine... I noticed this interesting tidbit:


2.2.1 Engine
The design of the 1.5-liter engine in the 2004 Prius is based on the Atkinson Cycle in which compression
stroke and expansion stroke duration can be set independently. A supercharger is used with the engine to
increase its output.


Supercharger!?

 

There's one thing that hasn't been brought up and that is the negative effect of the added dead weight of everything that isn't contributing to engine horse power as in the case when the car is used in non stop and go driving and if the uphill grades are long. Here's an example if every day two Priuses both the same weight drove up pikes peak but one was altered to have a larger engine as much as allowed from the weight savings of the car not being hybrid then which car's engine would last longer ?

 

It's a trick question, isn't it. The Prius without the hybrid parts would not be a Prius and therefore the Prius with the hybrid parts would last longer.

 

Sorry Boo, I can't really predict the oil change interval.

This is what I'm doing. I sampled the oil around 4k miles. I use Blackstone for my analysis. They suggested that I can safely go another 3k. I sampled again at 8k miles. The numbers look good and the oil still has pretty high TBN. They suggested that I can go another 3k. But I think I'll play it safe and change the oil at 10k miles. When I do, I'll send them the sample again to see if the oil is still good at 10k miles. If it is, I'll use that interval, since my driving pattern is pretty much the same.

I use their oil pump because it fits nicely with their sampling kit. Blackstone Laboratories - Pump.

All this is going to cost you more in the beginning, but you will consume less oil and save some $$ in the long run.

If you are worry about warranty issue, I think the oil analysis reports will show that this is not damaging the engine. If you are still worry, I will suggest that you stick with the 5k mile/6 month interval and use regular oil.

 

Bob, the Prius does not have a supercharger. If you are reading that national lab report, I think they made a mistake. From what I've read, the Atkinson cycle engine has low torque in the low-RPM range. Cars with Atkinson cycle engine usually use supercharger to help in that area. In the Prius, the low-RPM torque is supplied by the MG's. The national lab find out that the Prius has an Atkinson cycle engine, and assumed that it has a supercharger.

Correct me if I'm wrong.