Petrol engine in 'idle' mode for a long time after restart

[Rafal K]

Hi, its my first post here so I wanted to greet everyone.

I have my 2022 Corolla TS Hybrid wit 2.0 engine for over 2 years now.
I am quite happy with it but there are some caveats I would like to discuss. One especially.
When I start the car in the morning and begin my journey to work, I see that the hybrid system is reluctant to rev up the petrol engine and despite the engine running, its the electric system moving the car. That is totally understandable. The hybrid system wants to let the oil flowing through petrol engine at low rpm to reduce wear.
What bothers me, is that if I shut down the car for like 5 minutes to go to a store, and start the car again, the same thing happens. The petrol engine starts up but it is not moving the car forward but instead it is idling while the electric drive moves the car. The worst part is, that in this scenario it takes 3-4 times longer for the hybrid system to consider petrol engine ready. Wasting a lot of Battery charge and gas in the same time.
Please consider the following scenario:
In the morning, I start my car, then turn up the cabin temp in order to force the petrol engine on. I sit for 1 minute sending some messages on my phone and then take off. after 300M of idle RPM, the petrol engine spooled up to 2k RPM and I could drive as usual.
After 30 minutes of my regular commute, using pulse and glide technique when possible, I needed to stop at the pharmacy, the car is off for 5 minutes.
When I start the car again, it starts in EV mode. After 100M it fires up the petrol engine but in "idle mode". I drove around 1.5KM, slight uphill, over the span of 5-6 minutes. The car used 2 bars of the Battery (which at this point was down to 3 bars) at which point the car decided it hast to charge it so the RPM gone up and I stood at a red light, @2k RPM smelling my money being thrown out through the exhaust pipe.

If I have to pop to multiple stores on my way back from work it can turn my typical 4,5 l/100km to over 6l/100km on that particular route.

This issue bothers me so much that I started to leave my car on when doing quick errands just taking keys with me. Even though the car stands there the same amount of time, with petrol engine off, after I get back to it, when I step on the gas, the engine starts normally and revs appropriately.

Similarly, when I get trapped  in heavy traffic downhill, just inching forward exclusively in EV mode for up to 10 minutes sometimes, with petrol engine off the whole time, when I finally can step on it, everything is as expected, the engine fires up and revs normally.

Is this maybe some fault with my car ? I don't have any warning indicator lit one the dash and I recently had an yearly service done at the dealer, they didn't have any comments.

Did any of you experience this behavior ? Is there a reason I do not know about, which would justify this?

I'm eagerly awaiting any comment or suggestion.

Regards.
Rafal.

[AndrueC]

My comment is: Let the ECU do what its programmed to do. Your car is the result of over two decades of R&D by Toyota and it knows best.

It is expected that during the colder months it will behave a little differently and that fuel consumption will increase slightly. The ICE needs to be warmed up and so does the cabin. As long as you're not seeing more than a 10% increase in fuel consumption everything is fine. And a 20% increase wouldn't be out of order if you're based in the far north of Europe.

[Rafal K]

@AndrueC Thanks for the reply,
I didn't intend to imply that Toyota engineers under-developed the hybrid system, after all, my car is a 4'th generation hybrid. I just try to understand the reasons behind certain behaviors and also make sure that my particular car is not faulty in some way.

During my first winter with my Toyota hybrid I noticed that my car would not shut down its petrol engine sometimes, even if Battery was at decent charge level and the engine was up to temperature. It kept the engine running even at stand-still. After some research I found out, that intermittent engine operation causes buildup of exhaust contaminants on the catalytic converter and other parts of exhaust purification system and the car needs to get the exhaust up to temp in order to burn the deposits off. After learning that I was able to adjust my driving style and chase better and better economy, after all, I wouldn't buy a hybrid if I wasn't going to try and utilize it to the best of my ability.

I like to understand why and when my car does what it does so I can work around its limitations and quirks. If I have to accept the answer: "It does that because it has to", I will, but if I can find out the actual reason, I have to try.

[Cyker]

We get a lot of posts like this this time of year - In most cases it's because the engine is trying to generate heat for the cabin. When the car is running with the engine off it sheds heat quite quickly, and if the heater is also taking heat from the engine to warm the cabin it can struggle to stay at operating temperature and so fires up.

You can test this by turning off the heating and see if that makes it behave more 'normal', but it's not worth freezing to have higher mpg!

It's the one downside of more efficient cars, as less efficient cars generate so much waste heat you don't notice, but even in my old Mk1 diesel Yaris it'd take aaages for the cold engine indicator light to go out in winter. Being even more energy efficient, hybrids and EVs get affected the worst because they have the least amount of wasted heat so have to 'waste' energy to generate it especially.

 

[sportse]

There’s a lot of information around about the first few generations of the Prius, I found it really useful to understand the hybrid system. there are some good diagrams and videos too  

there are different modes for warmup/etc that the car runs depending on many variables. 
 

the newer cars have a more advanced system, but it’s based on the original so much of the information is similar. 

[TonyHSD]

Perfectly normal behaviour and absolutely every Toyota hybrid works the same. You don’t waste petrol at all and in your circumstances if you were driving a petrol only or diesel from 6.5/100 you will be looking at 10/100 Ltr/100km. , still the hybrid is more efficient. 
Your car starts and runs the engine to propel the car , charge or discharge the batteries, both hybrid and the small one and to supply heat to the cabin. So there is always a reason why the engine is on , usually one of the above or combination of two or more. 
If you after super short trips most efficient cars are bevs, but you know they doesn’t fit everyone’s  lifestyle, likes or ability to charge. 
 

[Rafal K]

Thanks for all the answers.
Unfortunately my particular problem/question is a little bit deeper. I am not worried by the petrol engine being on, I fully understand the need for heat and power which require it being on when the car decides it needs it. My problem is that despite of the petrol engine being on, the car doesn't use it for propelling the car forward, it just idles. Pushing the gas pedal causes no change in rpm (~@1k) and the car is driving basically on electric power only.
As I described in the original post, I understand, why my car might want to idle the petrol engine when the engine is cold, but after a short power-off, with the engine still warm, Battery over half capacity I don't get it. Especially considering that in this "restart" scenario this "idle" period is many times longer than with the car being cold in the morning...

[Tomv]

I think it has to do something with the heating, imho it’s is more efficient to use the engine to directly heat the cabin , then use engine to charge Battery and then use electricity to heat the cabin, since with each additional step there are more losses. 

[Stopeter44]

56 minutes ago, Rafal K said:

My problem is that despite of the petrol engine being on, the car doesn't use it for propelling the car forward, it just idles.

Are you over thinking ? The engine will run more in cool/cold weather, and there's a pattern between Summer and Winter use, where you'll have about 1l/100km more fuel consumption in winter. On very short trips in cool weather I turn the AC/Heat off. 

[Rafal K]

49 minutes ago, Stopeter44 said:

Are you over thinking ? The engine will run more in cool/cold weather, and there's a pattern between Summer and Winter use, where you'll have about 1l/100km more fuel consumption in winter. On very short trips in cool weather I turn the AC/Heat off. 

Sure, its a minor thing. I also don't use heating on most trips. I even strategically turn the heating on on a fast section of my commute to warm up the cabin and shut it off on the last 3km downhill stretch through the city so I can do it on electric power only.

Maybe there is actually something wrong with my car and no one here experienced such behavior in their car. Everyone seems to think that I am bothered by the petrol engine running more in cold weather. I bet that you had to explain that dozens of times but that is not the issue here. I fully understand why that happens. The issue, again, is that after a short power-off (and I mean short, even 5 minutes), the car seems to be in "engine warming up mode" and for much longer than after completely cold start in the morning.

• cold weather = more petrol engine usage | OK
• cold weather = higher fuel usage | OK
• cabin heat set above ambient = petrol engine has to be on to provide the heat | OK
• cold start = petrol engine idles in order to distribute the oil and refuses to rev up even if gas pedal is pressed causing electric motor to handle the driving | OK
• restart after short power-off = petrol engine idles even in motion and the car refuses to use use petrol engine even with gas pedal pressed quite far* and all wheel power comes from the Battery. Identical to cold start scenario but for way longer and, again, on a warm engine. | why ?

*If I floor the gas pedal I can force the petrol engine to rev up past idle RPM, but that seems like forcing an abnormal behavior.

[TonyHSD]

1 hour ago, Rafal K said:

Sure, its a minor thing. I also don't use heating on most trips. I even strategically turn the heating on on a fast section of my commute to warm up the cabin and shut it off on the last 3km downhill stretch through the city so I can do it on electric power only.

Maybe there is actually something wrong with my car and no one here experienced such behavior in their car. Everyone seems to think that I am bothered by the petrol engine running more in cold weather. I bet that you had to explain that dozens of times but that is not the issue here. I fully understand why that happens. The issue, again, is that after a short power-off (and I mean short, even 5 minutes), the car seems to be in "engine warming up mode" and for much longer than after completely cold start in the morning.

• cold weather = more petrol engine usage | OK
• cold weather = higher fuel usage | OK
• cabin heat set above ambient = petrol engine has to be on to provide the heat | OK
• cold start = petrol engine idles in order to distribute the oil and refuses to rev up even if gas pedal is pressed causing electric motor to handle the driving | OK
• restart after short power-off = petrol engine idles even in motion and the car refuses to use use petrol engine even with gas pedal pressed quite far* and all wheel power comes from the battery. Identical to cold start scenario but for way longer and, again, on a warm engine. | why ?

*If I floor the gas pedal I can force the petrol engine to rev up past idle RPM, but that seems like forcing an abnormal behavior.

Because the engine itself needs to warm up even in the summer, in ice cars also known as normal working temperature. 
The engine after each start up will need to be at certain temperature or after slow town drives during cold weather will lose heat and it will start again. There are 4 stages of engine warming up process in Toyota hybrids and when the car is in stage S1 sometimes even In S2 the engine only works as generator to supply electricity while warming up itself and the MG2 propels the car.
During this process the engine timing is adjusted to help with warming up process and will only help drive the car if you push it harder and then switch back to generator until reaches working temperature S3 , S4 or you increase the speed over 40mph. During these warm up stages the car feels like electric car with range extender ( bmw i3, Vauxhall ampera, London taxi ev). Nothing unusual here and typical hybrid behaviour. 
Here an example 12 seconds after start up from cold engine temperature at 35C° warming up stage S1a. 

You can buy a Carista obd 2 reader and download hybrid assistant app for android and watch all these processes while driving the car. Check engine, hybrid Battery and other things on your car. 

[ThomasL]

I think your car is broken.

I have 2019 2L.

When I press accelerator beyond the green "eco" band on the eco monitor display, the RPM goes up. The further I press accelerator, the more RPMs rise.

If your car is not rising RPMs even with foot flat on the floor something is surely wrong?!

PS to enphasize others points: you keep saying the engine "idles". It doesn't. It either produces heat for itself or the cabin, charges the traction Battery, or cleans the GPF. It never burns petrol for no reason (unless something is broken I guess)

[ThomasL]

Here's another thought:

On the energy monitor screen (the one with the engine, Battery, wheels, and arrows between them) what do the arrows show the energy flow is doing during first drive, after 5 mins, and after stopping at the pharmacy?

I expect two arrows from engine to wheels + Battery.

Are you saying engine has no arrows from it, only an arrow from Battery to wheels?

What does your instantaneous fuel consumption meter read when it's doing this?

 

[Rafal K]

1 hour ago, TonyHSD said:

You can buy a Carista obd 2 reader and download hybrid assistant app for android and watch all these processes while driving the car. Check engine, hybrid battery and other things on your car. 

This is a tremendously helpful suggestion, I was not aware of hybrid assistant and I will get obd reader ASAP. Thank you very much. I will play with it and report back if what I found

[Babar13]

@Rafal K 

I would add that if the Battery has high "state of charge SOC" (could be due to warm up phases), the "current charge limit CCL" will pretty fast go to low values (especially with a cold battery) and then tends to maintain engine on due to limited regeneration ability.

This is very true if your car stays outside in winter since traction Battery takes a very long time to heat.
All that will be easily seen with Hybrid Assistant.

 

[Cyker]

9 hours ago, Rafal K said:

Thanks for all the answers.
Unfortunately my particular problem/question is a little bit deeper. I am not worried by the petrol engine being on, I fully understand the need for heat and power which require it being on when the car decides it needs it. My problem is that despite of the petrol engine being on, the car doesn't use it for propelling the car forward, it just idles. Pushing the gas pedal causes no change in rpm (~@1k) and the car is driving basically on electric power only.
As I described in the original post, I understand, why my car might want to idle the petrol engine when the engine is cold, but after a short power-off, with the engine still warm, battery over half capacity I don't get it. Especially considering that in this "restart" scenario this "idle" period is many times longer than with the car being cold in the morning...

This behaviour is normal for a few minutes when the car is first turned on.

The time when an engine gets most routine wear is when it's first started up and is then used heavily.

When it's started, the hybrid system will fire up the ICE at some point and start it on a gentle idle to get the oil pressure up, coolant circulated etc., and will isolate it from the rest of the drivetrain so it is running idle but not really participating in moving the car, and the majority of the work is done by the beefy MG2. It should go back to normal once this cycle finishes until it's started again.

It tends to do this for longer the colder it is, but it should finish once it's happy the engine is at a safely usable state.

If, however, it's doing that for the *whole* journey and you have the heating turned off (It will do something similar to the above, but not quite the same, when the Battery is nearly full, but the engine is still being forced to run just to generate heat) there there may actually be something wrong with the car.

 

[sportse]

20 hours ago, Rafal K said:

 

• restart after short power-off = petrol engine idles even in motion and the car refuses to use use petrol engine even with gas pedal pressed quite far* and all wheel power comes from the battery. Identical to cold start scenario but for way longer and, again, on a warm engine. | why ?

*If I floor the gas pedal I can force the petrol engine to rev up past idle RPM, but that seems like forcing an abnormal behavior.

This is normal, it’s part of the cold start warm up routine. 

id researched it when I first bought a Yaris hybrid as it seemed weird. 

the car has a normal level of EV power but this is boosted during the warm up cycle while the petrol engine warms up. The petrol engine stays in idle until warmed up, preferring to use the electric motor  

in the Yaris it was very noticeable as the EV motor was fairly low powered, but during the warmup cycle was more powerful. 

the Prius technical articles I found explained it as there are various modes of warmup routine. 
 

mine used to just do it on the first start of the day, but with short trips it may not be getting fully warmed up so that it doesn’t do it on the next start up. Perhaps the engine/exhaust temperature is dropping low enough it triggers another full warmup cycle. 
 

this link might be useful explaining the different warm up cycles in an earlier model Prius 

https://priuschat.com/threads/gen3-warming-up-stages.76501/

• the ignition timing is very late, after the top dead center. therefore the engine does not have enough power to drive Prius or charge Battery.
• basically, Prius can not use the engine power when you drive. Prius is driven by Battery power and the Battery is discharged.
• it is good idea to drive slowly or stand still warming up in this stage.

[Rafal K]

@Cyker @sportse
I guess you are right, by all signs, it looks like a warmup routine.
I am still confused as to why, in my case, it takes about a minute when the engine is cold (and I mean cold, 4C today) but many times that when the engine is already warm (temperature indicator right in the middle after parking, and in the same place when I got back to my car after 5 min).

I ordered Carista obd reader and will play with the hybrid assistant app. I will post an update on the issue once I have more data.

[Obsidian Estate]

If you're not happy take it back to Toyota. Presumably it'll still be in warranty at 2 years old.

If you go fiddling it may invalidate that.

[Tomv]

5 hours ago, Rafal K said:

@Cyker @sportse
I guess you are right, by all signs, it looks like a warmup routine.
I am still confused as to why, in my case, it takes about a minute when the engine is cold (and I mean cold, 4C today) but many times that when the engine is already warm (temperature indicator right in the middle after parking, and in the same place when I got back to my car after 5 min).

I ordered Carista obd reader and will play with the hybrid assistant app. I will post an update on the issue once I have more data.

The temperature indicator show temperature of coolant, but you need to warm up the oil, which takes more time then water. My company Skoda is showing exact coolant and oil temperatures and in summer the coolant reaches 90C in about 5min of highway drive and the oil reaches it in 10-15min and then it takes another 10 min to reach optimal 100C. Would be nice if Corolla could show you this values too. Coolant is possible with Carista app but oil is not possible.

Not to mention that the temperature gauge is a bit misleading. It works in steps. For example, it will be in “full warm position” if the temperature reaches 70C but the coolant will still be warming up to optimal 90C but the indicator will not move any more. You can check this behaviour Carista app.

You will see that the temperature is not constant, it’s is changing a bit all the time, but the indicator will not move until the temperature will drop underneath 70C or go over 110C (this values are for my car,can be a bit different for hybrids )

[fred88]

I came across this gauge behaviour years ago. They are "centre weighted", the reason, I was advised, is because of the number of enquiries, complaints, queries or whatever, they were getting from nerds, sorry customers, like us because the gauge would wander around the centre point quite normally. Also thermostats might be slightly out so the gauge (in the days before centre weighting), would never centre exactly. So now if the temperature is anything near the right temperature they go bang in the middle. Everyone is happy, the technician's can stop spending hours or days trying to fix a non problem and the customer to happy that all is well.

[AndrueC]

Puts me in mind of an incident I experienced many (many, many) years ago when I drove an Austin Mini Metro.

I was driving along the M6 and youth had got the better of me so I was actually dicing it up in the outside lane. Quite frankly in hindsight it's shocking but somehow I was managing to keep up with everyone else doing 80mph.

Anyway someone further ahead did lose the plot so we all had to come to a screeching halt. We waited. And we waited. Me in the outside lane. And I noticed the temperature gauge rising. As it rose I remembered the sage advice of my Dad and despite it being a fairly warm day I put the car heater on maximum and opened the windows.

The gauge kept rising.

Now I was worried. How embarrassing to have the engine overheat in the outside lane causing further problems to everyone behind me.

The gauge kept rising, finally it reached the red line. And there was a whoooosh! from under the bonnet as the fan started at which point the temperature gauge dropped back almost immediately to the normal position.

If I ever meet the person who designed that cooling system strong words will be exchanged.

😁

[taxidriver50005]

On 11/14/2024 at 10:18 AM, Rafal K said:

Sure, its a minor thing. I also don't use heating on most trips. I even strategically turn the heating on on a fast section of my commute to warm up the cabin and shut it off on the last 3km downhill stretch through the city so I can do it on electric power only.

Maybe there is actually something wrong with my car and no one here experienced such behavior in their car. Everyone seems to think that I am bothered by the petrol engine running more in cold weather. I bet that you had to explain that dozens of times but that is not the issue here. I fully understand why that happens. The issue, again, is that after a short power-off (and I mean short, even 5 minutes), the car seems to be in "engine warming up mode" and for much longer than after completely cold start in the morning.

• cold weather = more petrol engine usage | OK
• cold weather = higher fuel usage | OK
• cabin heat set above ambient = petrol engine has to be on to provide the heat | OK
• cold start = petrol engine idles in order to distribute the oil and refuses to rev up even if gas pedal is pressed causing electric motor to handle the driving | OK
• restart after short power-off = petrol engine idles even in motion and the car refuses to use use petrol engine even with gas pedal pressed quite far* and all wheel power comes from the battery. Identical to cold start scenario but for way longer and, again, on a warm engine. | why ?

*If I floor the gas pedal I can force the petrol engine to rev up past idle RPM, but that seems like forcing an abnormal behavior.

Well described and all perfectly normal on 2.0, I too was a little confused why mine did this and yes it does use more fuel on short stop start journeys. I'm come from 18 prius and the smaller motor doesn't do this at all. 

Wife's chr 1.8 only does this on first cold start of the day and that's it. 

Turning off heater helps as they really don't store a lot of heat and driving in slow traffic ev mode forces the motor on just to heat cabin up, as a taxi driver I noticed this cold start or restart procedure used more fuel. 

I now stop in between jobs and leave car in ready mode with heater turned off unless it's really cold and just drive off when I get a job as normal without all the cold start hassle. 

Does this affect mpg.... Well yes.... Mine went from 51-55 to 60-65 so it's worth doing when you're doing 220 plus miles a day. 

[ThomasL]

Are you all really having the car being driven only by the motor for a few minutes after a short stop in cold weather, even though the engine is running?

And putting your foot on the accelerator doesn't change this or even cause the revs to rise?

I've never noticed this... Am I just unobservant or maybe something is wrong with *my* car?!

[TonyHSD]

Prius has slightly different exhaust than all other Toyota hybrids and this may make a slight difference however still there will be exactly the same behaviour like 2.0 2.5 1.5 or all generations 1.8.
All Toyota hybrids work exactly the same way no exceptions and no matter engine size or year they are made. If you haven’t noticed yet you will probably do next time when it happens. No warning lights on dashboard no problem. Enjoy your cars.