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To pre-warm the engine? Facts found.

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Hey all. Ex mechanic here. I was a little worried coming in to ownership of my 21, Prime SE. What would happen when its time to kick on the engine? What if im at highway speeds on a cold day? Course in a regular car you dont want to turn the engine over and speed off. You want to give it a couple seconds to warm the cylinders and get the engine oil moving. We all know big business trying to get you to buy more products, planned obsolescence, poor maintenence schedules. Etc. This is my first Toyota and I admit I came in skeptical. For my first year with the car I was working locally and very rarely used the gas engine. Once a week i'd run hybrid mode doing errands just to keep the gas moving a little bit and engine oiled.

Told you that story to tell you this one. Now im commuting a 120 mile round trip 5 days a week. 70mph highway speeds. This worried me. I bought a OBD2 scanner to tell me what and when the engine was doing and here is what I found. Pleasantly surprised too. As the battery gets to its last few miles the car will kick on the gas engine and idle it to about 100F degrees. The colder out it is the earlier itll start it running so its warmed by the time it needs to provide power. If I manually tell it to change over when I have say 10 miles of supposed battery range and it doesnt start actually loading the engine till maybe 5 miles, itll take it upon itself to "charge" itself back up to the 10 miles when I originally pushed the button. When I first hit the highway I notice if the ambient temps are below 50 degrees I think it is the engine will idle and warm up ready to go.

I was greatly impressed by all this to be honest. That toyota put the effort in to programming the computer to essentially make the engine last as long as possible. This is my first Toyota coming in from a few decades of Hondas and I believe its safe to say ill be stickin with Toyota for the forseeable future.
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Hey all. Ex mechanic here. I was a little worried coming in to ownership of my 21, Prime SE. What would happen when its time to kick on the engine? What if im at highway speeds on a cold day? Course in a regular car you dont want to turn the engine over and speed off. You want to give it a couple seconds to warm the cylinders and get the engine oil moving. We all know big business trying to get you to buy more products, planned obsolescence, poor maintenence schedules. Etc. This is my first Toyota and I admit I came in skeptical. For my first year with the car I was working locally and very rarely used the gas engine. Once a week i'd run hybrid mode doing errands just to keep the gas moving a little bit and engine oiled.

Told you that story to tell you this one. Now im commuting a 120 mile round trip 5 days a week. 70mph highway speeds. This worried me. I bought a OBD2 scanner to tell me what and when the engine was doing and here is what I found. Pleasantly surprised too. As the battery gets to its last few miles the car will kick on the gas engine and idle it to about 100F degrees. The colder out it is the earlier itll start it running so its warmed by the time it needs to provide power. If I manually tell it to change over when I have say 10 miles of supposed battery range and it doesnt start actually loading the engine till maybe 5 miles, itll take it upon itself to "charge" itself back up to the 10 miles when I originally pushed the button. When I first hit the highway I notice if the ambient temps are below 50 degrees I think it is the engine will idle and warm up ready to go.

I was greatly impressed by all this to be honest. That toyota put the effort in to programming the computer to essentially make the engine last as long as possible. This is my first Toyota coming in from a few decades of Hondas and I believe its safe to say ill be stickin with Toyota for the forseeable future.
We also own a 21 SE and I have been wondering the exact same thing. The thought of a cold engine kicking on at highway speed made me nuts. If I thought my drive would kick the engine on I would put the car in hybrid mode while still in the driveway so that the engine would kick on while I was still driving slowly in the neighborhood. Your findings are refreshing and a relief. Thanks for posting it.
 

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Hey all. Ex mechanic here. I was a little worried coming in to ownership of my 21, Prime SE. What would happen when its time to kick on the engine? What if im at highway speeds on a cold day? Course in a regular car you dont want to turn the engine over and speed off. You want to give it a couple seconds to warm the cylinders and get the engine oil moving. We all know big business trying to get you to buy more products, planned obsolescence, poor maintenence schedules. Etc. This is my first Toyota and I admit I came in skeptical. For my first year with the car I was working locally and very rarely used the gas engine. Once a week i'd run hybrid mode doing errands just to keep the gas moving a little bit and engine oiled.

Told you that story to tell you this one. Now im commuting a 120 mile round trip 5 days a week. 70mph highway speeds. This worried me. I bought a OBD2 scanner to tell me what and when the engine was doing and here is what I found. Pleasantly surprised too. As the battery gets to its last few miles the car will kick on the gas engine and idle it to about 100F degrees. The colder out it is the earlier itll start it running so its warmed by the time it needs to provide power. If I manually tell it to change over when I have say 10 miles of supposed battery range and it doesnt start actually loading the engine till maybe 5 miles, itll take it upon itself to "charge" itself back up to the 10 miles when I originally pushed the button. When I first hit the highway I notice if the ambient temps are below 50 degrees I think it is the engine will idle and warm up ready to go.

I was greatly impressed by all this to be honest. That toyota put the effort in to programming the computer to essentially make the engine last as long as possible. This is my first Toyota coming in from a few decades of Hondas and I believe its safe to say ill be stickin with Toyota for the forseeable future.
The Toyota Hybrids all do this (at least in recent years). The engine starts and idles at 1300 rpm while warming up. Power is taken from the battery until the engine is adequately warmed. Then the engine rpm increases and power is provided to the wheels. I would expect that in very low battery situations (probably does not occur in the R4P), the engine may be used.
 

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The Toyota Hybrids all do this (at least in recent years). The engine starts and idles at 1300 rpm while warming up. Power is taken from the battery until the engine is adequately warmed. Then the engine rpm increases and power is provided to the wheels. I would expect that in very low battery situations (probably does not occur in the R4P), the engine may be used.
I'm just curious, Since when has it been possible for a Rav4 Hybrid to be going along on the highway at 70 mph on battery only and suddenly have the engine come on from cold?

BTW, @TheStreetForce , thank you for confirming what I had though my R4P was doing. I've had it now almost a year and a half, and what you describe and able to confirm with your OBDII scanner is pretty much what I guessed it was doing.

dp
 

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I'm just curious, Since when has it been possible for a Rav4 Hybrid to be going along on the highway at 70 mph on battery only and suddenly have the engine come on from cold?

BTW, @TheStreetForce , thank you for confirming what I had though my R4P was doing. I've had it now almost a year and a half, and what you describe and able to confirm with your OBDII scanner is pretty much what I guessed it was doing.

dp
I don't think @wscan explicitly was talking about the highway situation, but more generally that cold Toyota hybrids prioritize battery until the engine is at least a little bit warm. I live in a neighborhood with serious rolling hills, and my 2012 prius ICE would start as soon as I put it in gear, but the engine wouldn't rev on the first couple of hills (unless I floored it). I think the prime has a lot more capacity to do this, but in my experience wscan's observation is accurate.
 

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Seems Ford decided to take the opposite approach with the Escape PHEV. I've been noticing lately now that it's below 30F, it will immediately turn on the ICE, even in EV mode with plenty of charge. And almost all driving power comes from the ICE for about 3 minutes, gradually switching over to full electric by about 7 minutes (when the engine hits running temp). This is on city streets.
 

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I don't think @wscan explicitly was talking about the highway situation, but more generally that cold Toyota hybrids prioritize battery until the engine is at least a little bit warm. I live in a neighborhood with serious rolling hills, and my 2012 prius ICE would start as soon as I put it in gear, but the engine wouldn't rev on the first couple of hills (unless I floored it). I think the prime has a lot more capacity to do this, but in my experience wscan's observation is accurate.
This is what I intended to say. The hybrid generally starts much earlier in the drive cycle, but it still has the same warmup cycle as the R4P.
 

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Personally, I am not concerned with over laboring the cold engine. As shown, the computer is plenty smart to prevent that.

I am more concerned with the oil in the crank case chronically not reaching temp and retaining fuel and moisture. Case in point, EV charge runs out 2 miles before getting home and ICE comes on to supplement that. Since in most use cases, the ICE has way lower duty cycle than straight ICE or hybrid, does this negatively impact engine longevity? Difficult to say.
 

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question on the hybrid hvac system.
does it still work with the gasoline engine coolant like in the old classic cars and trucks?
is the heating and cooling a shared unit is the question.

if it is, then the gasoline engine block would be pre warmed when cool temps.

and yes i am a strong believer in engine block heaters for pre heat when below 40 deg F.
and battery chargers as well.
 

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question on the hybrid hvac system.
does it still work with the gasoline engine coolant like in the old classic cars and trucks?
is the heating and cooling a shared unit is the question.

if it is, then the gasoline engine block would be pre warmed when cool temps.

and yes i am a strong believer in engine block heaters for pre heat when below 40 deg F.
and battery chargers as well.
You need to watch this:
 

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Personally, I am not concerned with over laboring the cold engine. As shown, the computer is plenty smart to prevent that.

I am more concerned with the oil in the crank case chronically not reaching temp and retaining fuel and moisture. Case in point, EV charge runs out 2 miles before getting home and ICE comes on to supplement that. Since in most use cases, the ICE has way lower duty cycle than straight ICE or hybrid, does this negatively impact engine longevity? Difficult to say.
If you are concerned about stopping a cold ICE, why not start it manually 10 miles back and give it a chance to warm up?
 

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Hey all. Ex mechanic here. I was a little worried coming in to ownership of my 21, Prime SE. What would happen when its time to kick on the engine? What if im at highway speeds on a cold day? Course in a regular car you dont want to turn the engine over and speed off. You want to give it a couple seconds to warm the cylinders and get the engine oil moving. We all know big business trying to get you to buy more products, planned obsolescence, poor maintenence schedules. Etc. This is my first Toyota and I admit I came in skeptical. For my first year with the car I was working locally and very rarely used the gas engine. Once a week i'd run hybrid mode doing errands just to keep the gas moving a little bit and engine oiled.

Told you that story to tell you this one. Now im commuting a 120 mile round trip 5 days a week. 70mph highway speeds. This worried me. I bought a OBD2 scanner to tell me what and when the engine was doing and here is what I found. Pleasantly surprised too. As the battery gets to its last few miles the car will kick on the gas engine and idle it to about 100F degrees. The colder out it is the earlier itll start it running so its warmed by the time it needs to provide power. If I manually tell it to change over when I have say 10 miles of supposed battery range and it doesnt start actually loading the engine till maybe 5 miles, itll take it upon itself to "charge" itself back up to the 10 miles when I originally pushed the button. When I first hit the highway I notice if the ambient temps are below 50 degrees I think it is the engine will idle and warm up ready to go.

I was greatly impressed by all this to be honest. That toyota put the effort in to programming the computer to essentially make the engine last as long as possible. This is my first Toyota coming in from a few decades of Hondas and I believe its safe to say ill be stickin with Toyota for the forseeable future.
We also own a 21 SE and I have been wondering the exact same thing. The thought of a cold engine kicking on at highway speed made me nuts. If I thought my drive would kick the engine on I would put the car in hybrid mode while still in the driveway so that the engine would kick on while I was still driving slowly in the neighborhood. Your findings are refreshing and a relief. Thanks for posting it.
in my teen years i had a toyota celica that had a cold air intake and an exhaust, and it sounded AMAZING after a cold start especially in the morning. So every morning I would start the car and hammer the throttle as fast as i could towards my high school. drove that baby for atleast 120k miles (after buying it used at 50k miles) and sold it for like $1000 to someone still running. if cold engines are a bad thing i would never know.
 

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One thing to also keep in mind, the ICE is started by using the traction battery; there is no conventional starter. So the fact that the engine is started before the battery runs out could be to warm the engine, but it's probably doing this since there is no other way to start the ICE. The small 12V battery doesn't start the ICE.

Yes, I know, I do not have one; they hadn't been released them when I had to buy my gas only version. I am, however, fascinated to learn as much as I can from conversations like this and watching all the videos I can to understand the systems; especially the Toyota one.
 

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One thing to also keep in mind, the ICE is started by using the traction battery; there is no conventional starter. So the fact that the engine is started before the battery runs out could be to warm the engine, but it's probably doing this since there is no other way to start the ICE. The small 12V battery doesn't start the ICE.
The traction battery never truly runs completely down. There is a reserved portion of the battery to operate in hybrid mode. That reserved portion is enough to be able to start the ICE. The system will never let the traction battery run down low enough so that it will not be able to start the ICE.
 

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Interesting. I've noticed that both the Volt and R4P show a drop in estimated battery mileage of 1 to 2 miles after manually switching to engine mode, even though the engine is running. Now I have an explanation - the engine initially just idles and doesn't power the wheels immediately.
 

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All very interesting. Now, can someone explain how or why the Auto/EV HV mode exists? It has been explained as a way to operate in EV, unless the driver wants or needs more power, and then the vehicle will shift to HV, presumably unleashing the 302 hp. Seems like hitting the throttle in this mode won’t actually engage the ICE to provide the power when needed by the driver, because the computer will limit the RPM until some level of engine temp is reached. As a result, why have it as a choice, or try to use it? Unless the ICE is already fully warmed it seems to me it will not function as advertised.
 

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I would assume the auto ev mode when chosen will warm up the ice without engaging it until needed. I use this mode everyday before switching to HV for long distance freeway commute. Although, I also notice the ice doesn't quite engage immediately so my assumption all this time may not be correct and I might have done all this mode switching for nothing lol.
 
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