Lowest RPM's at highway speed?

Probably in EV mode at that stage - it selects what is appropriate for the condition. The Hybrid Synergy Drive's main drive is by way of the 2 Motor/Generators, with the Petrol motor kicking in and running at whatever speed it needs to.

G

 

I don't go 80 mph, but next time I'm driving I'll check my ScanGauges for RPM. I do seem to recall a number of around 3200 RPM around 60, but I'll check to confirm.

 

I drive a lot at 61 mph in a v, 1700 is doing well, 1500 is minimum.

 

Here's a look at the transaxle if you haven't already seen it.
Weber State on Prius transmissions | PriusChat

 

I seem to remember someone posting (could have been Gen 2 or 3) a long time back, that the RPM varies continually on the highway - it's either off, or about 1500 up to in the 4000s, but that depended on the topography. It was someone with a ScanGauge.

 

Checked today at 60mph and the scan gauge indicated about 2088 rpm.

 

Uphill, down, level (relatively)?

Interesting if it sat steady, as from what I read about Hybrid Synergy drive, it's unlikely to sit steady for more than a few seconds. It is supposed to be dependent on Battery Charge, battery temperature, terrain, speed and load - rather than on one factor. WIKI says "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."

Before I bought my PRIUS, someone on PriusChat posted this simulator:

Toyota Prius - Power Split Device

 

I live in the Mississippi Delta, very flat. (it gains 90 feet in 156 miles, 30 meters in 250 km) Even if you take terrain and speed out of the picture, (cruise control for 55 miles) RPMs vary with temp, wind speed, rain, engine temp, etc. It is never stable day to day and varies in the third digit on a given day.

 

That was on the flat while accelerating to 60 mph so that the ICE was actively providing power. I primarily drive rural roads with a fair number of moderately sized hills. I can always tell if I'm in EV mode, as the ScanGauge will go to 0 RPM.

 

My v idles at 1280, but can run as low as 960 RPMs.

 

Same as my '12 Liftback, though that idle speed is cold, not warm.

I.e. accelerating, not steady speed. It should drop significantly lower for steady cruising, unless you are going slightly uphill, or into a strong headwind.

To answer OP's question, at highway speed, the RPM can be anywhere between redline and slowest idle, depending on conditions. The Prius HSD's engine RPM is not directly linked to road speed as it is in traditional transmissions.

My Gen3 normally runs 1200 to 1600 RPM on the level roads I frequent. Gen4 shouldn't run any higher.

 

If you don't want to spend that much, there are lots of inexpensive ELM27 OBDII devices that will give you that info on your phone with either the Torq or Engine Link app.

 

Although ScanGauges are a bit pricey, they do have the advantage of not having to be disconnected when the car is off as they automatically power down when the ignition is turned off, and also display continuously. I find it very useful to be able to monitor voltages, temps, and even individual tire pressures, which can give you an indication that something might be amiss before you get a warning light.

 

I bet there's a crystal ball on your Christmas wishlist.

 

A CVT has a min and max ratio between which it is continuously variable. I believe this should define the engine speed range at a given wheel speed.
There may be other factors that I don't know about such as the coupling technology between engine and transmission, but the CVT itself shouldn't prevent an RPM range from being calculated.

Just bought my Prius yesterday!

Posted via the PriusChat mobile app.

 

Here's an example of what you can do with that $10 reader and $5 app:

That's my Prime, shortly before it runs out of plug-supplied electricity. Following that is warm-up, then a jump onto the highway.

In this next video, I added data for engine-load. There's lots of other informative gauges available. In this case, I wanted to show what happens when charge-mode is engaged... something you can't do with the regular Prius, but you get the idea:

 

Yes, grab a scangauge, it will check codes in any car, and reset them, great company to deal with if you have any future problems, and they are constantly upgrading their product.

For example, if your tires are undersized and your speedometer is inaccurate, the scangauge can make the adjustment to the electronics to give you the correct speedometer reading.