Very poor fuel consumption corolla HB 2021 1.8. 33mpg. why. 120miles non stop with cruise on 110kmph

[AndrueC]

12 minutes ago, AisinW said:

Driving in stop and go traffic is always worse than any scenarios.

I don't agree with that. I've mentioned previously my experience of stop/go traffic toward the end of a long journey. It reduced my fuel consumption quite significantly. It's bad for a simple ICE but it seems to suit hybrids very well. It allows the ECU to operate the ICE purely as a charger for the Battery which allows it to operate it at its most efficient. Probably why taxi drivers like hybrids.

But I do agree that the 1.8 offers ample power for most people if they know what they are doing. I've almost never felt underpowered and on the rare occasions when I have it was because I was being silly.

[AisinW]

1 hour ago, AndrueC said:

I don't agree with that. I've mentioned previously my experience of stop/go traffic toward the end of a long journey. It reduced my fuel consumption quite significantly. It's bad for a simple ICE but it seems to suit hybrids very well. It allows the ECU to operate the ICE purely as a charger for the battery which allows it to operate it at its most efficient. Probably why taxi drivers like hybrids.

But I do agree that the 1.8 offers ample power for most people if they know what they are doing. I've almost never felt underpowered and on the rare occasions when I have it was because I was being silly.

It depends on how fast you go and how hectic the traffict. in Stuttgart, I often get 6L/100 Km or more meanwhile if I drive on smaller city with average of 50km/h or 30mph with rare stop or traffict light, 4L/100 Km is reachable. On Landstrasse with maximum speed 80km/h or 50mph, I always get 4L/100Km or 71MPG (imperial), 

[Cyker]

I find it depends on how long you're in the stop-start traffic; Normally it improves my mpg as I can use the electric to go further, but if I'm in it so long that the Battery depletes and the ICE has to run, it ends up undoing all the gains, esp. when the ICE runs to charge while the car is stationary as that is less efficient than the ICE charging the Battery while moving the car.

 

[AndrueC]

8 hours ago, Cyker said:

I find it depends on how long you're in the stop-start traffic; Normally it improves my mpg as I can use the electric to go further, but if I'm in it so long that the battery depletes and the ICE has to run, it ends up undoing all the gains, esp. when the ICE runs to charge while the car is stationary as that is less efficient than the ICE charging the battery while moving the car.

When I got stuck on the A55 a couple of years ago it was walking pace at best with long periods of waiting. The dash display was mid 60s when I got to the jam and high 60s when it was over. That jam was two or three miles long and I was in it for nearly an hour.

I don't see that the car being stationary should make the ICE particularly inefficient. It does in a conventional vehicle of course because it's idling but in a hybrid the ICE is doing useful work.

When I was stuck in that jam the ICE was sitting about 1,300 rpm when it ran and that was presumably chosen by Toyota as the ideal RPM for running the generator.

 

[Roy124]

A couple of years ago, in a Merc 220D I was stuck on the A27/A23 interchange outside Lille.  We were going South East with German traffic going South West.  Walking pace does not begin to describe it.  It took a couple of hours to travel under a mile.  That knocked the fuel consumption from 40+ to near 20.  

A hybrid would have fared much better though the ICE would have been running a lot to maintain aircon.  

It might be tempting to economise, open windows, and switch aircon off, but remember the hybrid Battery needs temperature control.

[AisinW]

Yes, the AC is important for the health of hybrid Battery. It only has air cooled system unlike RAV4 Prime. 

[Cyker]

5 hours ago, AndrueC said:

When I got stuck on the A55 a couple of years ago it was walking pace at best with long periods of waiting. The dash display was mid 60s when I got to the jam and high 60s when it was over. That jam was two or three miles long and I was in it for nearly an hour.

I don't see that the car being stationary should make the ICE particularly inefficient. It does in a conventional vehicle of course because it's idling but in a hybrid the ICE is doing useful work.

When I was stuck in that jam the ICE was sitting about 1,300 rpm when it ran and that was presumably chosen by Toyota as the ideal RPM for running the generator.

 

It might be different with the 1.8 in yours, but in my Yaris I see drops of 2-3 mpg of my tank average if I'm stuck in traffic for so long the ICE has to charge the Battery while stationary.

It makes sense - When the ICE runs while stationary, you're effectively doing 0 mpg, so that will obviously bring down the average, esp when you're in the 70+mpgs the Mk4's tend to operate at, where little things start to have a greater effect on the mpg!

My old Mk1 diesel Yaris could sit in traffic for ages with the AC on and it made little noticeable difference to the final average, but that ran a good 10-15mpg lower than the Mk4.

If I'm moving even a bit then this is greatly lessened, but if I'm literally stationary for 20 minutes or something with the ICE running the drop is very real!

The problem, as I think I've talked about in a previous thread, is the ICE can only hit its maximum efficiency in certain situations, and charging the traction Battery while stationary isn't one of them!

I reckon the ICE is maybe 20-25% efficient when charging the traction Battery, vs 41% when it hits its maximum efficiency, which it can only get when it's pushing the car along AND charging the battery at the same time - The system optimizes the load just right so the engine runs at maximum efficiency as much as possible and excess work that would otherwise go to waste is sent to the battery, but it can't do this while stationary.

This was the goal of the Toyota hybrid system from day one - The battery charging is almost free, as it's from energy that would have been wasted; Everyone thought the battery energy would mostly come from regen braking, but brake regen actually doesn't contribute that much energy - The majority is from being able to run the engine at e.g. 40% efficiency to do work that in a non-hybrid would force it to be only 25% efficient - The hybrid system takes the 15% 'wasted' energy and stuffs it into the battery for later use! It's very clever.

At the end of the day, the engine is designed to move the car, not be a generator, so when it's just running without moving it's wasting energy that could be turned into motive force.

 

[Cyker]

5 hours ago, AisinW said:

Yes, the AC is important for the health of hybrid battery. It only has air cooled system unlike RAV4 Prime. 

Yup, if your lady is comfortable the Battery will be too!  

(Batteries like cooler temps when stored but warmer temps when being used, and I read somewhere the slightly higher temps women tend to prefer compared to men is closer to the temps the batteries like to be at  )

[Roy124]

I wish.  Mrs 124 runs hot and turns the heating down.