At What Speed Does Prius Go All Gas-No Battery?

I can use no battery at low speeds, if I apply the right pedal pressure under the right situation. The same can happen at high speeds. The opposite is also true. I can get into warp-stealth at high speeds and use only battery but no gas.

In short, there is no one speed. It all depends on the situation.

 

The Prius always uses the electric motor or motors. Part of the torque from the engine is passed mechanically through the PSD, and part is passed electrically from MG1 to MG2. As for the battery, it is constantly being used as a buffer to smooth out small changes in the electrical flow, but you will often find yourself driving without any significant contribution from the battery. The main use of the battery is for starting, acceleration, and passing; in other words short bursts of power. The battery is also used during regenerative braking, where it absorbs power recovered from the drive wheels.

Tom

 

It uses "gas only" whenever you hit the accelerator just enough to enable "deadband" acceleration.

 

Keep in mind that in this "gas only" mode electrical current is still doing a lot of the work, only the electricity is not coming from the battery. It comes from the ICE powering MG1, which then passes the electricity to MG2.

Tom

 

Hi All,

I think SHM (Super Highway Mode) may be such a speed/mode where the engine alone is pushing the car, and the motors are just being used as a fixed electrically coupled gear? In SHM mode the battery current is very low, down around 2 amps and flickers back and forth between charge and deplete. There probably is more current flowing between the motors to make the gear ratio.

With a very careful left foot and with the battery up above 60 % SOC (more in the winter) one can drive the car in SHM about 53 mph and 1280 RPM on level terrain. Mileage will be in excess of 70 mpg.

If you push the pedal just a little hard, or lift too much, the car will then jump out of that mode, and use or create electricity.

 

Hi Again,

Based on a reread of the OP's question, he may have intended to ask at what speed does the Prius have to use the gasoline engine. That would be around 60 mph, as his friend said. 62 to 64 mph is where the gearing models people have made indicate.

So, if your going down a hill so steep the car would roll 65 mph without the engine, just because of gravity, the engine would still have to run at above idle (960 rpm) so that the MG1 would not overspeed the artificial 6000 RPM limit.

For engine at 0 RPM, not idle, its 41 mph.

Now some extreme hypermilers have dropped down below 40 mph at the top of a highway hill, got the engine to quit, then put inverter in neutral (transmission gears are not shifted) , and then rolled down the hill. In such a situation to keep MG1 from exceeding its specified maximum destruction RPM of 10000, the car needs to stay under 62 mph. Wayne Gerdes did this by opening all the windows, and using his jacket on the end of his arm as an air-brake.

 

The engine would have to spin, but not run. Of course it takes a pretty steep hill to coast at those speeds.

Tom

 

Wasn't there a poster that went above 62mph in neutral ice off?

 

Hobbit has done it a time or two.