Engine RPM @ 70 MPH

Bill,

It depends.

With a CVT (continuously variable transmission), factors such as engine load, vehicle load and terrain will affect engine revs. With cruise set, engine revs will climb when driving up a hill and drop when driving down a hill as the transmission seeks out the correct ratio for the circumstances.

 

Following is a copy of my post.
-----
The Japanese sales staff manual says following data at 120km/h(74.6MPH).

	item	2G	3G
1	engine RPM	2	470rpm	2	180rpm
2	MPG	40.5MPG	44.7MPG

Please note that higher speed always worsen your mileage at highway.

Ken@Japan

 

If you are curious how much it can vary, you can use this simulator. 114 km/h is about 70 MPH
A simulation of Prius's Planetary Gear

In theory, it can be anywhere from idle. (1000 RPM) to redline (5000 RPM)

 

I just bought a ScangaugeII (I, too, miss a tach) and I guess I can understand why a tach wasn't included in the MFD. Even at a steady/high speed, the rpms are all over the place. And, especially coming from a type-S RSX, they are *way* low. Amazing to see the slightest downhill drop the engine speed to ~ 900 rpm even at 70+. Generally (anecdotally), it seems to run about 1800-2500 at highway speeds.

Gotta keep those eyes on the road...
T

btw the scangauge is cool

 

That simulator's speed display is for Gen 2. Gen 3 has a different final drive ratio so the speeds are different.

The key point is that the combination of motor and engine torque has to balance the current road demand, with just enough power being produced to keep the electronics running (base load: 300-400W). Otherwise the battery will be slightly charging or discharging. In practice this means the engine has to run a lot faster than the limitations of that simulator would suggest. For a road speed of 113km/h (about 70mph) the simulator says MG1 can be running backwards at 6,500rpm and the engine at 1,150rpm, but in fact the engine can only achieve about 10kW down there, and just to overcome wind resistance requires about 15kW. My guess was that total losses are approaching 20kW; the power curve suggests that Gen 2 would be producing about 25kW at the engine speed that Ken indicated.

 

After adjusting for the temperature, 82-86F / 28-30C, there is good agreement:

Warmer temperatures make the air thinner and reduces aerodynamic drag. You'll notice the 80 mph / 124 kph test at 62F/16C had a significant drop.

Bob Wilson

 

Not sure about my Prius, but my 1988 VW Cabriolet runs at about 3500 RPM at 70 MPH.

 

You can order a ScanGaugeII for $170.

ScanGaugeII - Scan Tool + Digital Gauges + Trip Computers

It will display 4 parameters at a time. I have the tach and coolant temp all the time, presently displaying ignition timing and throttle position for the other 2.

Easy to mount and set up. They had them in the PC Shop for $160 a while back but they are no longer listed.

 

Still listed as $159.95 non-member price at CleanMPG.com. $149.95 member price. No one should pay the non-member price, but the member deal has to be 'slightly' disguised, so be sure to read the hints or the 'fund raiser'.

Amazon.com has occasional deals $10 cheaper, for those with plenty of patience to wait for the next offering.

 

my caddy used to run about 1800 rpm at 75 -hahahaha