hybrid ICE wear

[tigrpal]

Since most engine wear occurs at startup and a hybrid ICE starts and stops significantly more often than a gas only car engine, can one expect more engine wear on the hybrid ICE?

I drive a hybrid mostly on a 10 mile drive to work with several stop lights. The gas engine starts and stops maybe 10-15 times on that drive. Over time this will add up to many more startups than in my gas only car. The hybrid ICE gets up to temp. quickly and stays there the entire drive.

Any thoughts?

 

[JHZR2]

Define startup...

Cold start?

Start after x minutes of oil dripping back?

When well-fit items reduce in size back by x percent?

Lots of ways to define it, these hybrid cycles to me arent the same as long-sit cold starts. And even those generally have some oil film remaining on some surfaces...

My issue is more the rapid shutoff of an engine after a decent load. Say, accelerate and climb a mountain, get to the top, engine immediately shuts off due to hybrid function. IMO that may cook local hot spots' oil more so than if it were constantly flowing.

The starter is built into the motor-generator, so is a much different beast, run off a high voltage battery pack, not a 12V battery. The start-stop function wouldnt worry me in the least in and of itself.

But I do wish there was a constant-on override for winter use and conditions like I described when I may not want the engine to shut off immediately. Again, more for getting the engine to temp in cold temperatures, and keeping oil flowing after hard, hot runs. Not start/stop.

 

[pbm]

I wouldn't have a hybrid if my commute was only 10 miles.

 

[AirgunSavant]

Originally Posted By: pbm
I wouldn't have a hybrid if my commute was only 10 miles.

I have no daily commute but only very long trips. Going to work shouldn't be the only consideration for driving a hybrid.

 

[14Accent]

I've actually wondered this myself, especially in terms of lubrication.

Consider my Volt: I can go 2, 3, 4 days without an engine start. Then days like today I used the engine quite a bit since I was out and about all day and put about 120 miles on. In those 3.5 days prior, you HAVE to figure that all the oil has dropped back down into the pan. How does GM design the engine to not succumb to metal wear due to lack of consistent lubrication?

For all I know, the PCM can engage the crankshaft while the car is moving, but keep the injectors and spark plugs off so the pistons are just "coasting". This would in turn spin the oil pump which would lubricate the engine without using any fuel, and if done only while coasting will use no battery power either.

 

[JHZR2]

Originally Posted By: pbm
I wouldn't have a hybrid if my commute was only 10 miles.


On the contrary, this is where they shine!

Long highway cruising negates the requirements for hybrids, because a battery is finite and so then you must rely on the energy density of fuel.

Stop and go, traffic, and short trips are where hybrids do great.

I get 60-70 mpg (EPA 47 city) in my hybrid when commuting.

I get 42-45 (EPA 45 highway) when driving high speed, long distance.

 

[slacktide_bitog]

What hybrid do you have? There are so many different hybrids out there, each with different amounts of on/off time for the gas engine, etc.

And if yours gets to temp quick and stays there, there is no problem at all.

 

[Dyusik]

Regarding post load shut off,

My RX refuses to shut off after I've been romping on it. The more I run wot or similar, the longer it will idle. I am sure it monitors something, whether it be oil temp or driving pattern, idk.

 

[CR94]

Originally Posted By: JHZR2
... My issue is more the rapid shutoff of an engine after a decent load. Say, accelerate and climb a mountain, get to the top, engine immediately shuts off due to hybrid function. IMO that may cook local hot spots' oil more so than if it were constantly flowing. ...
But I do wish there was a constant-on override for winter use and conditions like I described when I may not want the engine to shut off immediately. Again, more for getting the engine to temp in cold temperatures, and keeping oil flowing after hard, hot runs. ...
Part of what you're wishing for exists. Toyota (and I think also Ford; I can't speak for others) regular hybrids keep the engine spinning (without fuel), and thus the oil flowing when you start down that mountain, as long as the ground speed is above a certain level. That speed varies by model; it's about 45 mph for 3rd-generation Prius, for example.
Also, on the Prius (and probably other hybrids) the engine will not shut off when interior heat is requested and the coolant is below a certain temperature. In other words, it's burning gasoline solely to warm the passengers, just as you wish.

 

[AirgunSavant]

Originally Posted By: CR94
Originally Posted By: JHZR2
... My issue is more the rapid shutoff of an engine after a decent load. Say, accelerate and climb a mountain, get to the top, engine immediately shuts off due to hybrid function. IMO that may cook local hot spots' oil more so than if it were constantly flowing. ...
But I do wish there was a constant-on override for winter use and conditions like I described when I may not want the engine to shut off immediately. Again, more for getting the engine to temp in cold temperatures, and keeping oil flowing after hard, hot runs. ...
Part of what you're wishing for exists. Toyota (and I think also Ford; I can't speak for others) regular hybrids keep the engine spinning (without fuel), and thus the oil flowing when you start down that mountain, as long as the ground speed is above a certain level. That speed varies by model; it's about 45 mph for 3rd-generation Prius, for example.
Also, on the Prius (and probably other hybrids) the engine will not shut off when interior heat is requested and the coolant is below a certain temperature. In other words, it's burning gasoline solely to warm the passengers, just as you wish.


Yes! I drive with the heated seats on instead. Put the heat on and your mpg dives deep. AC doesn't keep the motor on. This is on a Ford C Max.
It also has a shutter in the grille and in winter warms up quickly

 

[AirgunSavant]

Short commute???
Ideal for that. I short trip 2 miles often to the store and never have the motor come on. Requires some skill but it's a nice feature.

 

[Shannow]

"startup" wear is a misnomer, except that in order to have warmup, you need to have started it.

Most of the wear occurs during the minutes after starting, one of the mechanisms is corrosion, another that the parts aren't all getting on together until they reach their final shape.

When you start it, the engine isn't dry...if you've ever pulled apart an engine, you will find the bearings and pistons/rings are full of oil held there by capillary action. that helps next time it's started.

Additives don't work well until surface temperatures are up.

There's almost definitely more wear per hour of engine operation in a hybrid, there's less "stable" operation.

That being said, the manufacturers are doing stuff to ensure that you will never experience the ultimate end result.
* for e.g Toyota Prius in some markets has a coolant "thermos" that holds hot water to add heat to the engine.
* manufacturers such as Honda are adding special coatings on bearings for stop start and hybrid
* dual operating volume sumps, that allow the hot drainback oil to circulate in the early stages of engine operation, getting temperature faster.

 

[JLTD]

Originally Posted By: pbm
I wouldn't have a hybrid if my commute was only 10 miles.


+1; that's electric range.

 

[JHZR2]

Originally Posted By: CR94
Originally Posted By: JHZR2
... My issue is more the rapid shutoff of an engine after a decent load. Say, accelerate and climb a mountain, get to the top, engine immediately shuts off due to hybrid function. IMO that may cook local hot spots' oil more so than if it were constantly flowing. ...
But I do wish there was a constant-on override for winter use and conditions like I described when I may not want the engine to shut off immediately. Again, more for getting the engine to temp in cold temperatures, and keeping oil flowing after hard, hot runs. ...
Part of what you're wishing for exists. Toyota (and I think also Ford; I can't speak for others) regular hybrids keep the engine spinning (without fuel), and thus the oil flowing when you start down that mountain, as long as the ground speed is above a certain level. That speed varies by model; it's about 45 mph for 3rd-generation Prius, for example.
Also, on the Prius (and probably other hybrids) the engine will not shut off when interior heat is requested and the coolant is below a certain temperature. In other words, it's burning gasoline solely to warm the passengers, just as you wish.


Agree, turning on heat drives mpgs way down - to the level of a standard ICE operating. I do this in the winter especially when bringing small kids, or when I know that there is going to be high speed/highway driving soon after startup.

Ive observed in my Honda that the engine will shut off a bit more aggressively than I'd really like. An example is after a hill climb when the load is reducing rapidly, and even during low load conditions on the interstate.

Not sure about zero fuel, engine spinning. Sounds like what a normal ICE does when coasting above a certain RPM with zero throttle. Believe per my OM, my car only does that in cases when the battery is too high SOC, to provide additional compression braking...

 

[Jooksing]

Originally Posted By: JHZR2
Define startup...
Lots of ways to define it, these hybrid cycles to me arent the same as long-sit cold starts. And even those generally have some oil film remaining on some surfaces...



I agree, the engine should be well coated during the ride even if the engine start/stops.

Another thing to consider for Hybrids(at least Toyota hybrids) is that loads the engine differently because it has a Power split device. I wonder as it kicks on the ice for demand what rpm does it ramp up to before cutting it off. I know Toyota lowers the HP rating of the ICE engine (my RX vs a Sienna with the same engine)

From WIKipedia of Toyota's Hybrid synergy drive
Quote:

The most efficient speed (RPM) for an ICE is often around 1500–2000 RPM for the typical power required to propel an automobile. An HSD vehicle will typically run the engine at its optimal efficiency speed whenever power is needed to charge batteries or accelerate the car, shutting down the engine entirely when less power is required.

Like a CVT, an HSD transmission continuously adjusts the effective gear ratio between the engine and the wheels to maintain the engine speed while the wheels increase their rotational speed during acceleration. This is why Toyota describes HSD-equipped vehicles as having an e-CVT (electronic continuously variable transmission) when required to classify the transmission type for standards specification lists or regulatory purposes."

 

[Jooksing]

Originally Posted By: tigrpal
Since most engine wear occurs at startup and a hybrid ICE starts and stops significantly more often than a gas only car engine, can one expect more engine wear on the hybrid ICE?

I drive a hybrid mostly on a 10 mile drive to work with several stop lights. The gas engine starts and stops maybe 10-15 times on that drive. Over time this will add up to many more startups than in my gas only car. The hybrid ICE gets up to temp. quickly and stays there the entire drive.

Any thoughts?



From https://en.wikibooks.org/wiki/Toyota_Prius/How_it_works

Quote:
Frequent starting up and shutting down of the engine does not cause additional wear and tear nor emission problems, as in conventional automobiles, because the drive motors have enough power to quickly and smoothly spin the engine to optimal rpm (around 1,000) before the engine actually begins to "fire up". This avoids wear when the engine is "running" (with fuel and spark) at very low rpm, as happens in most vehicles

 

[CR94]

Originally Posted By: JHZR2
... Not sure about zero fuel, engine spinning. Sounds like what a normal ICE does when coasting above a certain RPM with zero throttle. ...
Yes, pretty much so, except that in HSD cars, the engine speed in that situation is fixed at about 1000 RPM, not proportionate to wheel speed. Spinning the engine necessarily wastes some energy, unless you need to brake anyway.