What is the Max EV speed no ICE

"The Kick" in the 3rd gen was more pronounced, you can definitely feel it shifting from EV to Engine. In the 4th gen however, it almost feels seemless. there wasn't a a real kick, but you can slightly feel it on the throttle and if you keep your tune on the engine you'll feel it kick in. However you won't feel the momentum change on the car or it won't feel like it the 3rd gen did

 

Thanks! Check out my tips in my signature. I'll eventually make a post of my hypermilling tips when I get enough data

 

Great find! Thanks

 

got up to 73 MPH today with the EV icon lit!

 

It takes fuel just to rotate the internal machinery inside the motor. If the car covers distance with the motor not spinning, then the frictional loss factor is non existent for that time, and MPG' are infinite when the motor is not spinning.

 

You are right that there are transfer penalties but there are also losses associated with keeping the gas engine spinning at very light loads, where gas engines are inefficient. When loads are slight (say on level or only slightly inclined roadway at moderate speeds) the battery's charge will last long enough that there is probably more to be gained by running on battery with the gas engine off than by keeping the gas engine running at very low output. If you're lucky, when the battery is depleted you'll come to a hill where the gas engine will be needed anyway, and the extra load to charge the battery just adds on to the hillclimbing load, so that the combination of loads puts the gas engine into a range where it runs more efficiently. If you're unlucky and the road is still flat when the battery needs to be recharged, the gas engine will still experience a greater load: battery charging + moving the car on the flat.

The other situation where the battery helps out is starting from a dead stop. Gas engines are also inefficient at producing torque at low rpm, so the Prius tries to use the battery to get going before the gas engine kicks in. If you are not pressed by traffic behind you, try pressing the accelerator moderately and building up speed on the electric motor say to 20mph if you can before the gas engine cuts in.

The Prius' gas engine is so quiet it's hard to tell if it's running, so I use a ScanGauge to see what's going on and try to control it, by modulating my pressure on the accelerator. Around town when the car is warmed up, the gas engine usually cuts in when the load reaches the halfway marker on the display bar. I set the Scangauge to monitor RPM, fuel flow (GPH), MPG (instantaneous, in numbers because the bar graph on the display is hard to read), and coolant temp (to see if the gas engine is warmed up, which affects various other behaviors of the car).

The other condition when it can be helpful for mpg for the gas engine to be off is downhills, at least ones steep enough to coast at whatever speed you want to go**. Unfortunately the Gen 3 gas engine will not shut off at speeds above about 46mph, something to do with avoiding overspeeding one of the electric motors. Flipping the "transmission" into neutral roughly doubles mpg under these conditions, but the gas engine continues to run, consuming about 0.2 GPH.

When I am tempted to try to keep the battery topped up, I remind myself that there's no point in driving around with a fully charged battery - that would be like driving a non-hybrid, albeit with a very efficient gas engine!

I am VERY curious to see how fast the Gen 4 goes before the gas engine insists on running. I'm supposed to get my Model 2 ECO at the end of the week, and hopefully I can test it using the Scangauge.

** - If the downhill is so steep you GAIN speed on it, it's best to flip the "transmission" back into D so that the engine spins and recharges the battery. If engine braking is not enough, you can use the brake pedal to keep the speed down and gain even more battery regeneration. Avoid braking while in neutral as you'll just wear the friction brakes without capturing any energy into the battery.