What does the engine do at 90mph?

Whine

 

At any speed the HV battery will run out rather quickly. The Prius is a gasoline powered car: all of the energy to move a Prius comes from the gas engine. The battery is just there as a temporary storage device - think of it as a flywheel and you will get the proper idea.

Cruising down the highway at speed, all of the power is coming from the engine. Part of it is transmitted mechanically through the PSD, part goes electrically via MG1 to MG2. Regardless, it all comes from the gas engine.

Even the 76 hp of the Gen II engine is plenty to move a Prius at 90 mph. Most modern automobiles are grossly overpowered.

Tom

 

Yep. Just don't expect impressive fuel economy.

 

100 hp will move the average medium sized car 100 mph. Prius aerodynamics aren't average.

A Gen 3 Prius has about the best aerodynamics of any production car and will go something like 112 mph on 98 hp, so 90mph is a piece of cake for a Gen 3. That would be roughly 55 hp.

IIRC, the Gen 2 was limited to 103 mph.

 

If you accelerate very quickly to 90mph, the battery power will be used for motor assist.
The battery level will be maintained at six bars by driving steady 90mph speed.

Ken@Japan

 

Car and Driver got a 2010 Prius to 90 MPH in 23.2 seconds.

http://www.caranddriver.com/var/ezf...lication/c4df488aab8502ae1efd564bc913ca03.pdf

 

That's a pretty cool file! Top speed 115, 0-100 in 30 seconds. I don't think I'll be trying that anytime soon...

 

What he implied was that the battery will maintain a steady 6 bar charge at 90 mph, he didn't say it would be helping the gas engine. There would be no need for it to help the gas engine because a Prius can maintain 90 mph on less than 60 horsepower.

 

I thought it was 112mph or something. I know in mine it has been up to 107mph with satellite checked speed on flat/slightly uphill terrain.

Agreed that modern cars are extremely overpowered, you would be surprised at just how much power the Prius has. It has enough to move you fast in any traffic density.

 

He was explaining that if you stomp on the gas the battery will help you accelerate. The battery is used to provide extra power for short periods of time. Think of it as a Turbo button. Once you back off a bit, the battery stops supplying power and starts to recharge.

Tom

 

This page has a great illustration on what will happen to the engines and motors at 90MPH.

Toyota Prius - Power Split Device

The ICE will spin 4435 RPM, MG1 will spin at 2192 RPM and MG2 will spin at 5298 RPM.

 

All power comes from gasoline in the non-plugin Prius. As you are cruising at 90 MPH, some boost comes from the battery, then it's replaced. This happens constantly, as the car uses the electric portion to maintain speed so it doesn't have to use fuel enrichment to accelerate (gasoline engines must do this - hence older carburetors had an "accelerator pump"). The car will be slowed by slight inclines (so small you don't notice them), wind gusts, etc. and it uses electric power to overcome those.

The important thing to remember is that while power can be taken from the battery for this "boost" it is replaced very quickly, from power generated by burning gasoline in the engine. The Prius will try very hard to maintain the charge level of the battery, allowing it to increase or drop, but not for more than a short time, typically a few minutes.

So your steady state top speed will be limited by the power the engine can generate vs the power needed to overcome inclines (gravity) and air friction. Your -peak- top speed will be limited by the combined power of the engine and battery (we refer to the electric portion power as the power the battery can provide, as that is the limiting factor) vs the air friction and gravity you must overcome (any hills - this could be negative as well if you are going downhill), taking into account the time limit that power can be taken from the battery (until the system won't allow any more).
But before you reach the -actual- top speed, the Prius systems will shut you down. There is a speed limiter in there.

 

Well this page is for genII so the genIII numbers would vary a bit but most importantly, the ICE and MG1 numbers will depend on how much power is requested to move the car (e.g. are you going 90 mph on downhill/flat/uphill terrain?). You can actually verify this by setting MG2 at 5298 rpm and moving the ICE around...

 

any time you cruise on the highway, or just cruise in general outside the city (above 45 mph), you are running solely on gas engine. Just look at the energy meter while you're cruising down the freeway, it shows the gas engine. occasionally the motor will kick in to provide extra power on hills and passing, but maintaining a steady speed uses just the gas engine. At 90mph though, your gas engine will be running higher RPMs than at say 70mph so obviously your gas mileage will suffer.

 

You are correct. The info on that site is from a Gen II. The Gen III uses the same Planetary Gear and the RPMs might change with the Gen III.

Everyone is correct. At some times at driving 90MPH you are just running on the ICE, other times the MG2 is assisting. At other times MG2 is generating energy to charge the battery.

It is false to say at 90MPH going down a step hill that the ICE is providing power to the drive train. This is an amazing machine.

 

I got it up to 100mph once on I5 in CA (because you have to see what the digital speedometer does after 99!) and it was really smooth, quiet, and stable.

 

Displays "100", same as the in dash thermometer, though I don't care to see that too often.