oil for Prius

[ekpolk]

Looks like the ScanGauge-II is "lighter" than the Autotap, but the SG provides a very real-time usable display in the car. You can see the SG website by clicking here. I particularly like this unit, because it gives me easy access to an rpm display. The Toyots HSD cars don't display rpms, instead replacing that parameter with an mpg gauge (except the Prius, which has its own funky protocol, but still no rpms). I figure they do it this way since the rpm response of these cars is so alien to what "Joe Average" expects, they just discarded it for something else. OTOH, once you understand what the car is up to, you can use rpms to great advantage. Here's the setup in my car:

 

[lenjack]

A Prius owner filled with M1 and a single Fram filter, went 25,000 miles, and then sent a sample to Blackstone. The report said the oil was still good and he could go longer.

 

[Silber Igel]

Originally Posted By: a64pilot
.... I believe due to friction, pumping losses etc. that an engine operating at full throttle, but at a lower RPM is more efficient than one operating at partial throttle and higher RPM.

This Hybrid thing is counter intuitive, but the more I study it, the more sense it makes.

And indeed its, my friend!!! I've had to toss all my 'school solutions' when learning about this car and engine. I don't think that the theory of 'full throttle-low rpm =s more efficiency' applies when working with Atkinson cycle engines. I think these things work best and are most efficient at closed or partial throttle and at low to mid-rpm. (I suppose under 4K rpm is mid range??)

I keep going back to steam and early gas/distillate engines (from which they are derived)where a engine was asked to work all day/week at relatively low rpm but offer greater fuel efficiency than a conventional engine.

Hummmm... I wonder how a 'hit or miss' engine would work in one of these? Just get that big flywheel to hummin' and that stored energy would do the work. Recall that many of the old gas/distillate farm tractors used a similar approach. Great big heavy Dudes (like 20 or more tons; hit or miss engines coupled to monster fly wheels; they could pull a couple good sized plows through the prairie sod with only 14-20 drawbar ponies. I'll bet they had massive amounts of torque!

Cheers!

 

[Ed_T]

–verb (used without object)
4. to pull or tug laboriously.
5. (of an engine or machine) to jerk, hesitate, or strain: The engine lugs when we climb a steep hill.

OK well nobody likes my mis-use of "lugging". Yet it is possible, by maintaining light accelerator pedal pressure to keep engine rpm's to a minimum and the econometer needle at the high mpg end. Is this lugging? By definition, undoubtedly, no. Relative to conventional ICE behavior at same speeds? Undoubtedly not, given the protective nature of the hybrids programming.

Yet there is a range of speed (under 40 mph IIRC) where if the ICE is running it is possible to "lock" the PSD to deliver "60MPG" on the needle, and to accelerate mildly without moving the needle. In this condition one can feel the ICE definitely and plainly lugging. Is this by design? I'd have to say yes, and given terrain and speed, this condition can be maintained indefinitely. It reminds me of cruising through those same back roads in the Trooper II in 4th... My car has never been flashed, and still has factory programming. Perhaps other programs cannot do this.

At highway speeds with the econometer needle at or near the high end, I would imagine the rpm's of the ICE are at whatever minimums they can be. Is this lugging? Well, the ICE may not be tugging hard, and we all know on that next incline what the econometer needle will do.

So perhaps it should be called "SLUGGING" -- semi-lugging? Low rpm's and not working all that hard. A Toyota hybrid specialty.

OIL:
OK your oil comes out looking golden after 5,000 miles. The Citgo 5w-20 I've been using drains darker and has definitely been stressed. Maybe it works harder than your oil. Maybe it sucks. I dunno.

I can still see through it while it drains, and it's probably good for more miles. My guess is it's probably about 1/2 or better used up.

 

[a64pilot]

On the Gen III Prius at speeds below 46 MPH, pure electric mode is possible, but not as efficient as using the ICE directly. On level ground with the cruise set at 45 MPH the fuel consumption is around 70 MPG.
Once you understood the Hybrid operation, and with some feed back (scan gauge)fuel mileage of above 80 or even 90 MPG is possible with the Gen II. Gut feeling is the Gen III isn't as capable of ultra high mileage, but is bigger, and more powerful and will return at least as good a mileage from the average driver.
The scan Gauge seems to be a better item to be left in the car, but seems to be a lot less "powerful" than Autotap. Autotap will apparently monitor and display a lot more than the Scan Gauge, but requires some form of computer or PDA. In my case it will be a netbook as a PDA just isn't enough screen in my opinion and I don't mind the netbook being there.
Ed,
You can tell when the ICE in a Gen III get's efficient, it feels like it get's down real low RPM and kind of "rumbles" and the fuel consumption meter goes up to 90 MPG or so. Now is it really dropping the RPM low or is it getting "deep into the Atkinson cycle" or is it way advanced timing that's going on or what? That's what I hope the additional instrumentation will tell me. And of course once you can tell what's going on you can find ways to forge it into it's efficient modes and sacrifice a little hill climbing ability or acceleration or whatever to keep it there.
One of the real questions I had of course was what are the oil requirements of an engine that cycles off and on constantly. Old way of thinking is it ain't going to last long doing that. And admittedately I was of the old school way of thinking that 0W-20 oil was too thin to actually protect anything and it's use had to be to get a little better CAFE numbers at the expense of the life expectancy of the engines it was being used in. That's what brought me here.
Thanks Guy's you have made me feel better. Now to go back to the dealer and find out what kind of oil they put in it. The work order states 0W-20 Castrol GTX, and I don't think there is such a thing

 

[Silber Igel]

0W-20 GTX ... no such beast according to the Castrol site. Castrol doesn't make a blend in that grade. They do have 0W-20 SYNTEC. Perhaps the tech mis-wrote the name?

Good thinking there, Pilot. These motors are constantly 'starting and stopping' (a [censored] of a lot actually!!!) which would argue for a 0W or 5W-20 grade oil. Hadn't thought of that. This is probably the most important reason for using the '20' weights.

 

[Silber Igel]

Originally Posted By: Ed_T
So perhaps it should be called "SLUGGING" -- semi-lugging? Low rpm's and not working all that hard. A Toyota hybrid specialty.

OIL:
OK your oil comes out looking golden after 5,000 miles. The Citgo 5w-20 I've been using drains darker and has definitely been stressed. Maybe it works harder than your oil. Maybe it sucks. I dunno. I can still see through it while it drains, and it's probably good for more miles. My guess is it's probably about 1/2 or better used up.


Slugging... I love it!!!

I've not experienced that in the HyCam. Perhaps they TOYO boffins have re-programmed the HSD to 'lock' up for better efficiency? I did notice that with under some 5K miles the car would noticeably twitch, jerk, shudder, when the ICE cut on and off at lower speeds. It doesn't do that now so maybe its the engine loosening up?

 

[ekpolk]

Originally Posted By: a64pilot
. . .
One of the real questions I had of course was what are the oil requirements of an engine that cycles off and on constantly. Old way of thinking is it ain't going to last long doing that. And admittedately I was of the old school way of thinking that 0W-20 oil was too thin to actually protect anything and it's use had to be to get a little better CAFE numbers at the expense of the life expectancy of the engines it was being used in. That's what brought me here.
Thanks Guy's you have made me feel better. Now to go back to the dealer and find out what kind of oil they put in it. The work order states 0W-20 Castrol GTX, and I don't think there is such a thing


Time limited today so I'll address just this. As far as the multi-starts are concerned, while I'm sure the proper oil plays a role, the design itself addresses the problem. When the ECU decides to start the ICE, MG2 is used to spin the ICE up to approx 1000 rpms, before it turns on the gas and spark. In essence, the engine pre-oils itself before every ICE start. You can also use this feature when you're skirting the limits of stealth mode. If you learn to feel the feint rumble of the ICE pre-oiling, you can then quickly back off the accelerator a tad, usually aborting the start (unless it's for a must-start condition, like a low SoC), and keeping yourself in stealth a little longer. It's more obvious in the Prius, but there and usable in the Camry on all but the smoothest starts.

 

[Silber Igel]

Originally Posted By: ekpolk

Time limited today so I'll address just this. As far as the multi-starts are concerned, while I'm sure the proper oil plays a role, the design itself addresses the problem. When the ECU decides to start the ICE, MG2 is used to spin the ICE up to approx 1000 rpms, before it turns on the gas and spark. In essence, the engine pre-oils itself before every ICE start. You can also use this feature when you're skirting the limits of stealth mode. If you learn to feel the feint rumble of the ICE pre-oiling, you can then quickly back off the accelerator a tad, usually aborting the start (unless it's for a must-start condition, like a low SoC), and keeping yourself in stealth a little longer. It's more obvious in the Prius, but there and usable in the Camry on all but the smoothest starts.

EKP,

Pondering your logic. MG2 spin up pre-oiling.... well, sort of...

Regardless of how the ICE is 'spun up'.... MG2 spin start or a 'spark start' from zero rpm.... it's still a start. And starting is where the wear occurs. Using the MG2 spin start scenario, the oil would still have but a small opportunity to circulate to the critical parts before 'fuel on/switch on' at 1000 rpm. It certainally helps as there's 'more better' oil pressure when the ICE takes a load. Realistically, the "MG spin start" takes only second or two, hardly enough time to get the oil everywhere its needed or in sufficient quantity.

The use of '20 weight' oils would appear to play a very critical function, even more than we would initially think, in reducing start up wear in hybrid ICE cycles.

I think a far simpler answer is that by using the "MG2 spin up" technique you reduce the sudden drag and slow down of the car when the ICE dumps in making it far less noticeable to the driver.

The question for you, Sir, is: Do Prii and HyCams use some type of accumulator to store oil at pressure to avoid dry starts under these same conditions?? Perhaps, some type of internal nooks and crannies?, that help hold the oil in the upper part of the engine longer?

Cheers!!

 

[a64pilot]

Even though it may spin it up before it lights the fire, there is still compression and therefore some initial wear before the oil pressure comes up? Of course one way to mitigate this would be to have larger bearing surfaces than normal making the wear less important, but that would increase friction and therefore decrease efficiency wouldn't it? Maybe the initial wear thing on start up is over estimated? Can't do anything about it, just interesting to speculate. Would have though there would have been a pre-lube system of some form though, wouldn't be hard to do.
Anyway on the Gen III Prius, you won't feel engine start up, usually. Don't know if it's because the engine is bigger or what but you don't feel it anymore. That's OK though because there is a new screen called the "Hybrid System Indicator" which I think is simply a load meter, but it uses a horizontal bar to display regen and throttle position. There is a vertical bar in the middle that if you stay to the left your in stealth or warp stealth and to the right of the bar, the ICE runs. The "no arrow" state or glide is much easier to get on this screen as you get feed back and don't have to feather the throttle looking for the arrows to disappear. To the right of this meter is a "power" section where presumably your out of the efficiency map and now your sacrificing some things in the quest for power. Presumably in the power region some things like maybe RPM are allowed to increase in order to make more power? The Auto tap ought to tell me things like percent throttle opening, spark advance, and RPM etc. to see what happens in "power" as well as in the other regions.
Gen III brings in other things as well, like an EV button that inhibits the ICE if you want to move the car on pure electric, yes the Europeans have always had this. Also you get power and Eco buttons. Presumably power just makes the throttle more sensitive, but Eco does at least inhibit the AC from running at it's highest speed, what else, I'm unsure.
On the Gen III there are no drive belts at all, all accessories, even the engine water pump are electric and can be run at variable speeds, so the AC is much more efficient because it can actually be slowed down and not just cycled on and off. I assume there are much less parasitic losses now there is no belt. The thermos bottle for the coolant is gone and now the coolant is pumped through a jacket around the exhaust for heating, many differences, time will tell if they are improvements or not. Traction battery is still NI-MH though, not LI-ION and no plug in yet.

 

[smokey1]

PENNZOIL Platinum 5w-20 be fine . Inexpensive and good U.O.A.s . Enjoy .

 

[friendly_jacek]

Originally Posted By: a64pilot
Maybe the initial wear thing on start up is over estimated?


The so called start up wear is mostly ring/cylinder based and related to cold temp only. Most likely chemical/corrosive. There is some bearing wear on start up but paradoxically more in hot engine than cold and thus why you have the preoiling in Prius.

 

[ffhdriver]

Lots of good info in all the posts here. I just bought a 2010 Ford Fusion hybrid which calls for 5w20 conventional or synthetic blend Motorcraft oil. I plan on using the Motorcraft full synthetic or maybe Mobil 1 5w20. What are your opinions on Motorcraft versus Mobil 1? Your posts have convenced me to not go to 5w30 even in this warm climate in south AL. TIA