Heating up the prius engine

The engine has a warm up cycle it goes through. During this time the engine runs more than normal and in some cases continuously to get it up to operating temperature. In the Gen II the warm up stages are well defined. The Gen II stages although similiar are not as well exactly the same and are not well documented yet.

See explanation of the Gen II warm up stages here

 

Just drive. When warm air comes out the heater/demister vents the engine is starting to warm up.

 

Normally it's best to get in and drive. Try to take it easy with the gas for the first minute. The first short stage of operation mostly draws from the battery. Forcing the Prius to use the ICE during this warmup is inefficient.

The only exception to this advice comes from having to pull into fast traffic. If your commute involves immediately pulling into high speed traffic, your mileage will probably be improved by warming the engine for a minute.

Tom

 

No but it may be desirable depending upon your morning commute:

• Prius friendly - a gentle, downward slope about 1-2 miles long, speeds of 20-25 mph, so the car can warm-up without having to burn much fuel.
• Prius hostile - uphill with speeds over 35 mph so the car has to burn a lot of fuel. Something Ken@Japan inspired is the concept of letting the NHW20 (2004-09) warm-up until the engine stops on its own. The ZVW30 (2010-) warms up the same way and this can improve overall efficiency

In reality, there are many shades of gray between the "Prius friendly" and "Prius hostile" routes. So 'it depends' and the best answer is experimentation. Alternate warm-up styles for 10 days and make a record. Let the data dictate the best answer. BTW, it may change depending upon temperatures.

FYI: I've noticed the engine continues to run at a stop light if the heater is on in the early warm-up phase. I just turn the heater off and the engine stops. When the light changes, I start the heater again.

GOOD LUCK!
Bob Wilson

 

What the above are saying is the -car- doesn't need to warm up, except that -all- cars should be driven gently for the first few minutes when cold to allow the parts to expand to their designed sizes.

YOU, however, may want a warm car. The best way to warm up the car is to drive it. While idling a Prius takes a long time to warm up because it is just so efficient (so there is less "waste heat" to warm it up).

For safety, sometimes you may want to warm up the car before driving. Particularly if you are getting mist or frost on the windshield. In this case "mileage be darned", warm it up so you can see! Note that you can start the car and keep the FOB with you as you leave. You will have to lock the door with the key.

 

We left early on morning to go to the airport, it took a while for the windows to defog, missed the Bimmer that morning
The car sat for a week at the airport, not problem starting it

 

As all others said, need to warm it up - the most efficient way is to get in and drive it very moderately for the first 1-2 mins. BTW: the same concept goes with *all* cars. Heating an engine is a waste of time, money and highly polluting (running the engine idle is forbidden is some EU countries, unless you are waiting for a traffic light - difficult to check from the police, but the concept is there...).
Now that is it winter, I notice that mainly my fuel consumption is affected by more than one heating cycle. Better said, I get it, turn on and the engine starts almost immediately - I have 1-2 mins drive slowly but then I need to speed up to 60-70km/h, after that, 1-2 mins, I hit a (regular) traffic jam. If I am lucky the engine is warm enough already (and not being a diesel, it helps, as it warms up faster than a diesel engine would do) and stops. Otherwise it continues a while longer.
Now comes the problem....because the Prius can run without the ICE on at all times, the ICE gets "cold" when the outside temperature is cold....the colder, the faster - this means that if you are in traffic jam long enough, and it is cold, the engine will start more than one heating cycle. In this case the EV mode can be of help if the battery is charged enough. It essentially avoids the extra heating cycles for staying stuck in the traffic jam. The Prius does not see how long the jam is, I do...so I can tell it to stop heating up, because there is nowhere to go anytime soon.
The only trouble with this approach is that when I have gone through the traffic jam, the battery is empty and it needs to be charged again and that costs fuel...(this is also why EV mode is not advised by Toyota in the user's manual...).
But I think EV mode for long, predictable, traffic jams might help keep consumption lower during winter. If the car is warm already inside, turning the heater off, might be a good idea as well as that will not drain the battery anymore.

 

Congrats and I'm sure you'll love it like we all do.