Living Dangerously: The Fuel Light

I have heard of some advanced cruise control for large trucks taking topographic information into account, for fuel economy improvements. I haven't heard of any other systems using such topo detail.

 

That is correct. In the Gen 3, after engaging EV with the EV button, EV mode would disengage once you hit 10 MPH. With the Gen 4, EV disengages at 20 MPH.

But, when not in EV Mode and fully warmed up, with sufficient battery SOC, you can gently accelerate from Zero to well above 20 without starting the engine. There is a difference.

 

The U.S.-market Gen3 has several speed vs engine temperature steps:
* Below 68F, EV not available;
* Between 68F and 'engine warm' (sorry, I don't remember the specific temperature), EV available up to 10 mph;
* Engine warmed, EV available to 25 mph.

In many other markets, EV is available to colder temperatures than allowed in the U.S.

 

Yes, my reply was referring to a coldish start with Temp above 68F.

 

I know it is a bit out of topic, but if this is what I get with my Gen3, with original Michelin Primacy summer tires 215/45 R17 from fab (yes, they are 6 years old) and with regular driving speeds in city traffic (and a long stretch in a expressway at avg 50km/h-31mph) actually going at the boring speed everyone else goes on my commute, I am really looking forward to seeing fuel consumptions of the Gen4 around 2.xL/100km - 80+MPG
(BTW, the below are not unusual - not always and not easy, but not a rarity either, when the sun is shining and the temps are good)

@20C/68F outside temp, radio on, A/C set on Auto on 22C/72F - 67mpg


@14C/57F outside temp, radio off, A/C on Auto set on 19C/66F (this last Saturday - with actually about the same traffic as a regular commute day!) 71mpg

 

Tires rolling resistance seems to go down with age. We're rolling on Michelin Pilot 17's manufactured in Feb of 09, they seem to just get better.

 

So I have gathered a bit of data from my Gen3 regarding the MFD DTE estimation and I am bit puzzled.

I have written down the DTE and the Trip A (my tank counter) distances and tank's average fuel consumption. I took note of the values every now and then. I have calculated how much fuel has been consumed, also adjusted by MFD error (6.2% in my case) and then calculated based on that how many liters are left in the tank (i.e. 45L - "Trip A gas consumed"), and from there, the estimated DTE fuel consumption used to gives us the estimated DTE distance.



I have then calculated what the DTE+TripA range should be, and what would the fuel consumption be in order to achieve that total range based on a 45L and a 35L tank (that is the tank, minus the reserve that supposedly triggers the beep, at about 10L/2.6 gal), and only then the fuel consumption used by the DTE makes sense and is according to Trip A average fuel consumption value (adjusted).

Essentially the DTE seems to gives an estimation based on a 35L tank and current tank fuel consumption average, adjusted for optimistic MFD value.
The Gen4 manual says that the fuel light comes on when "Indicates that remaining fuel is approximately 1.7 gal. (6.4 L, 1.4 Imp.gal.) or less"...

I will continue to gather data for this tank and run another similar test on a second tank, in about a month (I tank like once a month typically ).

 

If you're getting "Trip A gas consumed" from a gas pump, you should know that when it automatically shuts off can vary by many liters depending on the particular nozzle, pump and even temperature.