Start-up wear and hybrids

[Vaca]

There's been quite a bit of chat about start-up wear, and warm oil vs. cold oil effecting the wear, etc....

I wonder what the lifespan of these newer hybrid engines will be with all the starting and stopping of the engine.

I'm sure Toyota and the other manufacturers have put forth a lot of R&D into these drivetrains and I'm sure they know a lot about start-up wear.

It would be great to learn just a little bit of what is already known...any ideas on how to find this info? I know Dr. Haas has generously given his time to summarize that SAE paper....I'd imagine there is a lot more info out there...how can we get to it?

 

[Laminar Lou]

One advantage I can see to the hybrid design is that it doesn't idle in startup. Once started, it immediately goes to work therefore reducing the amount of time it takes to warm up the engine.

Interestingly, EkPolk has said that the Prius uses large electric heaters for the catalytic converters. My guess is that also would help with wear, as the engine doesn't have to run in a rich to lite up the cat. That should help with fuel dilution and consequently reduce wear.

 

[JohnBrowning]

So far all of the UOA's we have seen from Toyota's Prius have been great all things considered. THe wear metals have been good even on extended OCI's wich is something consider these engines start and shut off freq.!I think it is all going to dependonthe manufacture even more then it normaly does!

 

[Quest]

You shall be corresponding this msg with Elkpolk, our Prius Hybrid guru.

 

[rpn453]

Cold starts are the concern, and hybrids usually see no more of those than any other vehicle. I believe it's the process of coming up to operating temperature that causes most of the wear. If you turn your warm engine off for a couple of minutes and then restart it, I'd expect less engine wear than would be caused by idling for that same period.

 

[mstrjon32]

x2, I think the wear incurred by starting and stopping the engine while it's at or near operating temperature is no more than it would incur idling for a few minutes.

 

[smokey1]

we have a '07 PRIUS and will be putting in PENNZOIL PLATINUM 5w30 for next oil change for the reason that the I.C.E. is not used as much , so kinda like more cold startups , especially on downhill coasts , stop and go driving where it uses the electric engine more . Hopefully the synthetic will help quiet down the 1.5 ltr. when on highway and hills as well . Figure the P.P. at $1.99 + tax a quart ( < 4 qts. to fill w/ oil filter ) and a $3.50 + tax TOYO filter can't wrong for the price and would change oil at < 5,000 mile intervals .

 

[jim_a]

This is from Elkpolk. I quoted it to an article I posted on the Prius:

As for all the on-off cycling, at least in the Prius, it's designed to pre-oil itself. MG1, the smaller of the two motor-generators actually spins the gas engine up to just under 1k rpm before the ECU adds spark and fuel. Wear? Check out our typical Toyota UOAs. Also, consider that a Prius can never wear out a starter motor — it doesn't have one, MG1 performs that function. Alternator? Doesn't need one of those, and doesn't have one. So again, while you get some complexity, you get a lot of simplicity.

 

[smokey1]

JIM a , if you happen to own a PRIUS , it talks of fuel dilution and other oil related matters on pages 322-323 in the OWNERS MANUAL . This is another reason for use of an inexpensive synthetic , such as the PENNZOIL PLATINUM in our '07 .

 

[Dr_No]

Your grammar is a little off.

 

[Johnny]

Quote:

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we have a '07 PRIUS and will be putting in PENNZOIL PLATINUM 5w30 for next oil change for the reason that the I.C.E. is not used as much , so kinda like more cold startups , especially on downhill coasts , stop and go driving where it uses the electric engine more . Hopefully the synthetic will help quiet down the 1.5 ltr. when on highway and hills as well . Figure the P.P. at $1.99 + tax a quart ( < 4 qts. to fill w/ oil filter ) and a $3.50 + tax TOYO filter can't wrong for the price and would change oil at < 5,000 mile intervals .

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Smokey1: Don't dump 4 quarts of oil in there, you will be way over full. Start out with 3.5 quarts and see where your at. Mine takes about 3.7 quarts to fill it up, and from what I've been told you do not want to over fill it.

Back to wear: I also believe the Prius keeps some of the antifeeze pre-heated so even on first start up things are not totally cold.

 

[ekpolk]

Quote:

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This is from Elkpolk. I quoted it to an article I posted on the Prius:

As for all the on-off cycling, at least in the Prius, it's designed to pre-oil itself. MG1, the smaller of the two motor-generators actually spins the gas engine up to just under 1k rpm before the ECU adds spark and fuel. Wear? Check out our typical Toyota UOAs. Also, consider that a Prius can never wear out a starter motor — it doesn't have one, MG1 performs that function. Alternator? Doesn't need one of those, and doesn't have one. So again, while you get some complexity, you get a lot of simplicity.

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That's correct. The gas engine is designed so that is has oil pressure before it actually fires off. The car also mitigates the "true" first cold start of the day, via what's informally known as the "thermos". There is a 3L insulated bottle that stores hot coolant on shutdown. Immediately upon pushing the Power button, it pumps the hot coolant into the passages in the head and block. Now, that doesn't instantly heat the oil, of course, but it does help bring the engine to operating temps amazingly fast. I'm sure that being a small Aluminum I-4 also contributes, but this engine shows normal coolant temps literally within a minute or so from startup except on all but the coldest mornings. And as mentioned above, even with some fuel dilution, our UOAs are generally fantastic, giving no signs at all that the frequent on-off cycling is having any negative impact.

 

[smokey1]

did oil change about 2,500 miles ago and put in 3 and 3/4 quarts ( give or take a few ounces ) of regular PENNZOIL in a 5w30 , check the oil level on dipstick every week or so and is at or little below full mark .

 

[Cicero17]

Since the Prius engine is not running all the time, it seems to me the oil changes intervals might be extended to take into account how much the engine actually runs.

 

[JohnBrowning]

Well I am not a big beliver in start up wear anyways since it has never been an issue for me. I have UOA that have 3000 miles or less over the course of 6 months that have hundreds of trips of .3 miles or less in freezeing temp.s.THe rest of the trips were mostly sub 12 miles trips with about 80% being less then 3 miles also in freezeing temps. with winter gas etc.... The UOA did not show anything alarming at all. Then when my driveing habits changed and most trips were 20 miles or more at HWY speed we did not see a huge drop in wear or anything even dureing warm weather 6 month OCI. Do not get me wrong sometimes we do see a huge impact in UOA results but not universaly.

I also have some experince with Hybrids and most do not run long enough to warm up. I might start a Prius up and go around town under 35mph and never have the engine turn back on. Often I would start them up and once I put it in reverse the engine would shut off. Then when i went to drive it stayed off as long as I did not accelerate agresively or exceed 35 mph. It takes a more then a minute or two of running to reach operateing temp. So I think that their are a good many Prius that are never reaching operateing temp. dureing the drive so each start would be a cold start even with the warm thermos of coolant. I think that materials, programing, machineing precision etc..... all play a role. I do not think we can make any broad general rules of thumb yet in reguards to hybrids and cold start wear. I think some companies are not going to be a thorough in their approach to hybrids and they wil basicly strap their system to or into an exsisting powertraing. I doubt that these types of approach's will produce the same low wear rates we see with the Prius!

 

[Lonnie]

The Prius is engineered to warm up quickly, stay warm and save heat for the next drive. I'm using a 5w-20 esther based oil that in theory should get going quickly and keep an oil film on parts between runs. If this car is hard on oil I can see it and uoa's that others have done show things are working well.

 

[ekpolk]

Quote:

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. . .I also have some experince with Hybrids and most do not run long enough to warm up. I might start a Prius up and go around town under 35mph and never have the engine turn back on. Often I would start them up and once I put it in reverse the engine would shut off. Then when i went to drive it stayed off as long as I did not accelerate agresively or exceed 35 mph. It takes a more then a minute or two of running to reach operateing temp. So I think that their are a good many Prius that are never reaching operateing temp. dureing the drive so each start would be a cold start even with the warm thermos of coolant. I think that materials, programing, machineing precision etc..... all play a role. I do not think we can make any broad general rules of thumb yet in reguards to hybrids and cold start wear. I think some companies are not going to be a thorough in their approach to hybrids and they wil basicly strap their system to or into an exsisting powertraing. I doubt that these types of approach's will produce the same low wear rates we see with the Prius!

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John:

Good info, as usual, but I do disagree with your statement that, "It takes a more then a minute or two of running to reach operateing temp."

Remember, the Prius uses the stored hot coolant to bring the engine up to operating temps amazingly fast. I have CAN View on my car, and one of the values on my default display is actual coolant temp (not an idiot light, and not a simple H-C indicator). It is not uncommon to see 185F in less than two minutes, even coming out of the garage in the morning. Now, of course, I live in a hot climate, but this is still a nifty feat. And on a warm start, it's even faster. All this said, the hot coolant from the "thermos" does not heat the oil (at least not directly), but the faster the block and head get hot, the faster, in turn, they're going to heat the oil. Alas, CAN View does not provide an oil temp reading...

 

[Lonnie]

And the valve train and cylinder walls get up to temp quicker with the injection of hot water. The cylinders really depond on some heat to lubricate properly.

 

[ekpolk]

Follow-up note: this morning driving to work, with temps at a cool 68 degrees (it rained heavily in the ~2 hrs before dawn), my Prius reached 175 degrees in only 1.8 miles. It stabilized at that point, though that's low-normal, and in hotter, harder run conditions, 185-195 is not uncommon. Yes, this car does reach operating temps very quickly.