[juan37]

I have observed that the indication of fuel consumption, according to the indication of the onboard computer, varies from day to night, due to the variation of the ambient temperature, the variation is between 5 and 10 ° C. Like 20°C at day, and 10 or 15°C at night temperature.

The variation on the fuel consumption, when at day I got 20 km/liter, at night (at the same speed) I got 15 km/liter.

What I don't know, is whether this variation is due to the pressure variation of the tires (by the temperature variation), or a less efficient air-fuel mixture at low temperatures, as this engine does not have a shot of hot air, as had the old carburetor engines. Or the reason are the the factors combined (less pressure of the tires, and less efficient air-fuel mixture at low temperatures).

One factor that may influence, is the presence of ETHYL ALCOHOL, whose concentration can approach 20%, with the lowest temperatures, is not successfully gasified. In the case of Brazil, where the UP! can be used with 100% alcohol, the ambient temperature, on average, are at least 10 ° C higher than in Argentina.

I use on my UP! Esso energy 5000, which has 96 octane:
Substance (s) or reportable hazardous substance (s) complex (s).
Name
CAS#
Concentration*
ETIL ALCOHOL
64-17-5
<= 20%
GASOLINA
86290-81-5
>= 80%
METIL-TERC-BUTIL-ETER
1634-04-4
<= 9%
Constituent (s) dangerous (s) content (s) in substance (s) complex (s).
Name
CAS#
Concentration*
BENCENO
71-43-2
< 1.2%
ETIL BENCENO
100-41-4
1 - 5%
N-HEXANO
110-54-3
1 - 5%
NAFTALENO
91-20-3
<1%
PSEUDOCUMENO (1,2,4- TRIMETILBENCENO)
95-63-6
1 - 5%
TOLUENO
108-88-3
5 - 10%
TRIMETIL BENCENO
25551-13-7
1 - 5%
XILENOS
1330-20-7
5 - 10%

 

[ptae2000e]

I have digital sensors on tires, I can write down some measurements if you think it might be helpful. In my experience, the major factor regarding fuel consumption is traffic.

 

[Cadfael]

The motor itself has to be warm ...
A cold motor (even at 30°C outside) needs more fuel.
It takes much shorter to get a motor to 90°C cooling water temperature in summer than in winter.
I don't think that the consumption is different after 15 or 20 minutes. But until this, the consumption surely is higher.

Besides motor temperature, also tyre temperature has an influence - as pressure increases with tyre temperature. Snow or wet streets cool down the tyre much more than air temperature ...

 

[juan37]

I have digital sensors on tires, I can write down some measurements if you think it might be helpful. In my experience, the major factor regarding fuel consumption is traffic.

I verified this, at the same traffic conditions, and at constant speed, with the engine at 3500 RPM in 5th speed, but different hour and ambient temperature, and the engine is ever at 90ªC, and I have already covered half the way home, more than 20 km.

Yes!, if You can write down some measurements I think it might be helpful.

Thank You!

 

[juan37]

I have digital sensors on tires, I can write down some measurements if you think it might be helpful. In my experience, the major factor regarding fuel consumption is traffic.

I verified this, at the same traffic conditions, and at constant speed, with the engine at 3500 RPM in 5th speed, but different hour and ambient temperature, and the engine is ever at 90ªC, and I have already covered half the way home, more than 20 km.

Yes!, if You can write down some measurements I think it might be helpful.

Thank You!

I forgot to tell You, the complementary data of the ambient temperature, referred to the tyre pressure.

Thanks again!

 

[juan37]

The motor itself has to be warm ...
A cold motor (even at 30°C outside) needs more fuel.
It takes much shorter to get a motor to 90°C cooling water temperature in summer than in winter.
I don't think that the consumption is different after 15 or 20 minutes. But until this, the consumption surely is higher.

Besides motor temperature, also tyre temperature has an influence - as pressure increases with tyre temperature. Snow or wet streets cool down the tyre much more than air temperature ...

The only detail I forgot, is at night I have a additional weight from a passenger, of less than 70 kgr. In the user manual appear that the variation for this additional weight is from about 0,3 liter more for 100 km, and this variation represent 1.2 kilometer less with every liter of fuel.

Regards,
Juan

 

[Ed!]

I have noticed that the Up! engine is very sensitive to additional load in terms of fuel consumption - AC, extra luggage and roofracks all indiviually seem to add a noticeable consumption on.
I have also found a significant drop in fuel consumption over the winter compared to the summer because of the ambient temperature (in my previous car with a larger engine), I guess the cooler air means more losses through the engine block (though cool air into the engine should be more efficient as it's density increases balancing it a tad), as well as taking longer to get up to temperature.



Interested to hear what your conclusion is juan.
Edited by: Ed!

 

[juan37]

I have noticed that the Up! engine is very sensitive to additional load in terms of fuel consumption - AC, extra luggage and roofracks all indiviually seem to add a noticeable consumption on.
I have also found a significant drop in fuel consumption over the winter compared to the summer because of the ambient temperature (in my previous car with a larger engine), I guess the cooler air means more losses through the engine block (though cool air into the engine should be more efficient as it's density increases balancing it a tad), as well as taking longer to get up to temperature.



Interested to hear what your conclusion is juan.

<div id="gt--tools"><div id="gt--tools-l"><div style="display: inline-block;" id="gt--tool"><div id="itamenu">



<div id="gt-res-" ="almost_half_cell"><div dir="ltr" style="zoom:1">I disagree with your assessment of heat loss through the engine block, as internal combustion engines, they always have heat loss through the cooling system, necessary to maintain optimal operating temperature without damage to mechanical components, unless they are completely made of ceramic.

Other detail about the engine of the UP!, is that it belongs really to the series of the FSI and TFSI engines (EA211 with direct fuel injection), and with MPI the engine of the UP! have no regulation of air temperature on admission, to achieve optimum fuel evaporation.

It's not so easy to have a conclussion yet.

I'm waiting the data of tyre pressure variation with the temperature from other user in this topic, and today I will fill the tank with other fuel type, with less alcohol (which is added here to elevate the number of octanes, but has more evaporation problems at low air temperature).

Regards,
Juan

 

[ptae2000e]

A local newspaper made some interesting tests about fuel consumption. In Croatian only, sorry, but short translation of most interesting parts follows below: http://autoklub.jutarnji.hr/istrazili-smo--kako-ustedjeti-na-gorivu--skidajte-nosace-i-zatvorite-prozore-/1223746/ Car was Mazda 6, driver + two passengers.

Reference conditions are 6.5 l/100 km at 133 km/h and 3.6 l/100 km at 95 km/h (reasonably close to up!).

Roof carrier with bicycles (Thule, supposedly one of the more aerodynamic models)
+49,76 % at 133 km/h
+35,18 % at 95 km/h

Driver's window open
+24,51 % at 133 km/h, window 2/3 open
+49,30 % at 86 km/h, window fully opened, speed intentionally reduced a bit

Rear-mounted bicycle carrier
+41,59 % at 133 km/h
+31,38 % at 95 km/h

Winter tires in summer conditions (it was about 20 deg C and sunny in recent days)
+5,89 % at 133 km/h
+5,56 % at 95 km/h

Changes in tire pressure, nominal pressure 2.2 bars
-0.43 % at 1.7 bars (they notice this is strange and allow it might be a measurement error)
-4.4 % at 2.7 bars

 

[juan37]

I have noticed that the Up! engine is very sensitive to additional load in terms of fuel consumption - AC, extra luggage and roofracks all indiviually seem to add a noticeable consumption on.
I have also found a significant drop in fuel consumption over the winter compared to the summer because of the ambient temperature (in my previous car with a larger engine), I guess the cooler air means more losses through the engine block (though cool air into the engine should be more efficient as it's density increases balancing it a tad), as well as taking longer to get up to temperature.



Interested to hear what your conclusion is juan.

Again!
I'm experiencing with different brands of fuel (now with Shell), to find a fuel with less alcohol content to see what's happen.
Today with surprise I found on the user manual, this detail I observed, with less ambient temperature higher fuel consumption.
You can see on Your user manual if appear this detail?

 

[Cadfael]

Watch my post from 23. September ...
I didn't recognize the table in the manual - but I know that you need more fuel in winter.
My explanation is the "absolute" motor temperature as well as tyre temperature (> pressure).

UUUUUUUUUUPS!
And you should always refuel your car early in the morning or late in the evening!!!
You get more fuel as long as the fuel tank has no heating! The "hotter" it gets, the more fuel expands! This means that refueling in the morning, you get "colder" fuel. Expanding this fuel to "mid day temperature", it has more volume.

 

[Ed!]

I agree they need to maintain an optimum temperature, however in the summer and the winter, it will always maintain ~90degC, so with cooler air there are going to be more losses, whichever the system - so in my mind, that heat energy has to come from the fuel, which otherwise could be converted to useful energy?
Alternatively, it could just be the engine taking longer to get up to working temperature, so on longer journies perhaps it would become negligible.

 

[juan37]

Watch my post from 23. September ...
I didn't recognize the table in the manual - but I know that you need more fuel in winter.
My explanation is the "absolute" motor temperature as well as tyre temperature (> pressure).

UUUUUUUUUUPS!
And you should always refuel your car early in the morning or late in the evening!!!
You get more fuel as long as the fuel tank has no heating! The "hotter" it gets, the more fuel expands! This means that refueling in the morning, you get "colder" fuel. Expanding this fuel to "mid day temperature", it has more volume.

The reason, as I explained earlier, can be the content of ethanol, which needs more temperature to evaporate.
In Brazil the temperature is at least 10°C higher than in Argentina, and in Brazil the UP! can be used with 100% ethanol, without problems, but with a higher fuel consumption, and the engine (named Total Flex) erogates 82 CV.

About 30 years ago in Argentina, we have used an alcohol gasoline mixture, named "alconafta" with a high percentage of alcohol, close to 90%, and in this case, was problematic to start the engines at low ambient temperature. Because this problem, was discontinued the use of "alconafta", but few years ago, by the high cost of importing refined fuels, the government reimposed the use the alcohol gasoline mixture, but with lower percentage of alcohol than 30 years ago.

Actually all the fuels have a percentage of alcohol, by law. But many oil companies use the advantage to raise the octane of low-quality fuels, without declaring that percentage alcohol use, because with higher percentage of alcohol, higher number of octanes.

The only oil company which states the percentage of alcohol is Esso (Exxon).