Prius EV mode

The EV mode allows you to force the car to use the electric motor rather than the ICE but is subject to a number of constraints based on the hybrid battery's state of charge, ICE temperature, speed, and acceleration. For mine, it works up to 48 km/h (30 mph) if the battery is fully charged and the ICE is warm.

That said, there are few legitimate uses of EV mode. The Prius' computer is better at choosing the best driving mode than the driver is and using the EV mode a lot can result in reduced mpg and reduced battery life. The main use is when you know you're going to get a lot of charge soon (a long descent downhill for example) that the battery cannot handle.

Instead I would recommend watching the hybrid system indicator and keeping it within the hybrid eco range (the lower half) whenever this is reasonable. Even then, don't waste your battery charge on slow acceleration when using the ICE is more appropriate to reach the target speed. At speeds lower than 70 km/h (43 mph), briefly release the gas pedal after reaching the desired speed and the Prius will turn off the ICE and drive electrically.

IMHO pulse and glide is not suitable for most driving conditions (that is, if there is other traffic) and using it inappropriately can give Prius drivers a bad name.

The most effective ways to save gas are driving slower on the highway and avoiding braking. Braking wastes energy despite the regenerative brakes. Release the gas on time if you know you're going to brake soon. If you do need to brake, do so gradually to avoid using the brake pads (if safety permits of course).

 

So not to -totally- confuse a newcomer, ICE is "internal combustion engine".

EV mode will not be selectable unless the "temperature" is between certain limits (I think it's actually the battery temperature) and the battery has sufficient charge (whatever that means). It can be useful to move the car a short distance (very short) without starting the engine. I have found with Pearl S I can use it about 30% of the time I want to. For me, it's backing the car out of the garage and driving it into the back yard to wash it.

Oh, and when in EV mode you probably won't be able to drive more than a mile, with very low throttle use - that is, you basically crawl. Apply more throttle and the mode is cancelled and the engine starts.

 

Except for making the airco weaker, eco mode does not directly change your mileage. It simply remaps the gas pedal. In eco mode it responds slowly at the start of its range (and quickly at the end), in power mode it responds quickly at the start (and slowly at the end), with neither selected it responds more or less linearly. In all modes, the same power is available (response is the same when you floor it).

Myself, I find that I end up often flooring it in eco mode. I drive most efficiently in normal mode, where the throttle can be controlled most accurately.

Likewise, the impact of the cruise control will depend on your driving style. If you keep the same speed all the time, it won't matter. If you pulse and glide, it will be less efficient (but friendlier towards other drivers). If you disable cruise control too late when you need to slow down, it will be less efficient. If, like me, you are prone to speeding without cruise control, it will be more efficient.

For the situation you describe, I think not braking more than necessary is particularly important. By slowing down early, you can often keep some momentum while waiting for the traffic light. As for the ups and downs, be aware of what is coming. Try to avoid accelerating just before going downhill and braking just before going uphill. Both waste energy by not making good use of the height differences. More generally, look far ahead and to be able to plan and respond early to what is going to happen, which allows you to avoid unnecessary accelerating and braking.

In addition, keep the hybrid system indicator in view so you can run electrically at low speeds (for which the ICE is very inefficient). Personally I stay within the hybrid eco zone to accelerate from standstill to 30 km/h (20 mph) and use the ICE to accelerate from standstill to 50 km/h (30 mph) and then turn off the ICE by briefly releasing the throttle.

 

For when you can use EV mode or not and at what speeds, read up on the warmup stages of the Prius.
Gen3 warming up stages | Page 3 | PriusChat

 

Well, it depends. If you drive on a pancake-flat highway, cruise control will probably be as efficient as not. Anything else and you can always be more efficient than cruise control, as it tries to hold speed up hills (where you can relax speed a bit), and hold speed down going down the other side (where you can let the car accelerate more and take advantage of gravity).

For in-town driving, minimize your brake usage; coast as much as possible (try to keep the bar indicator invisible, right on the line between "charge" and power); try to time the lights so you don't have to stop and re-accelerate. Most drivers expend far too much energy driving from stoplight to stoplight; they'll keep their foot in the gas pedal until it's time to brake, which both wastes fuel keeping the vehicle under acceleration, converting most of it into heat when they brake, and wastes more fuel accelerating from a stop that could have been avoided had they coasted in the first place. Don't drive like them.

 

In my non Plug-In GenIII, I find hitting the EV Mode button to be basically all but useless. Most of the time it says not available and if you've driven a Prius for a good length of time, you know exactly how far to push the gas petal to not ignite the ICE at lower speeds.

Same goes for ECO, I used it for the first month or so, then never turned it on again. Proper petal control at all times is the best way to drive a Prius.

edit: Dead12 above pretty much summed up everything nicely.

 

Shift to neutral is always EV

 

Shifting to neutral is generally not recommended in the Prius. This is one of the few ways that allows you to completely discharge your hybrid battery, which is hard to fix afterwards (the other one is to continue driving after you run out of fuel). It also provides little fuel efficiency benefit as the Prius does not engine brake in drive mode.

 

Shift to neutral is in no way EV. Shift to neutral disables the driveline, you can not use the ICE nor the MG for propulsion or braking. The only time shifting to neutral would make any sense is when you're stopped (e.g. at a traffic light) and don't wont to keep pressing the brake.

 

If you get yourself a Bluetooth plug-in OBD2 adapter, the Torque Pro app for android can be very handy when using the 'Fuel Economy for Torque' software plug-in to learn how best to drive economically. Another plug-in that's quite useful is called 'Better Dash'.

A more complex and comprehensive stand-alone app is called 'Hybrid Assistant' - also for Android.