33 mpg 2004 Civic

Gordon McGrew wrote:
> On Thu, 24 Jan 2008 19:09:58 -0800, jim beam
> <spamvortex RemoveThis @bad.example.net> wrote:
>
>> Jeff wrote:
>>> jim beam wrote:
>>>> Jeff wrote:
>>>>> Edward W. Thompson wrote:
>>>>>> On Tue, 22 Jan 2008 17:03:01 GMT, Jeff <kidsdoc2000 RemoveThis @hotmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> rick++ wrote:
>>>>>>>> In the summer I get 40 mpg highway.
>>>>>>>> I just did a long road trip last weekend at an average
>>>>>>>> temperature of -17C (0F) and got 37 mpg. 15% ethanol.
>>>>>>> How much ethanol in the summer? The ethanol should have dropped the
>>>>>>> mileage down 4.5% or 2 mpg. Engines don't run as efficiently in the
>>>>>>> winter, in part because they take longer to warm up. Of course, the
>>>>>>> air conditioner usually isn't running nor is the sun roof down. And
>>>>>>> the gas is denser in the winter, because liquids contract in the cold.
>>>>>>>
>>>>>>> Jeff
>>>>>>
>>>>>> Gas is denser in winter and this contributes to fuel economy? I judge
>>>>>> you missed out on 'science 101'.
>>>>> Actually, I taught science 101. If the gas is denser, that means that
>>>>> in every gallon or liter that is colder, you get more energy. More
>>>>> energy means you go farther.
>>>>>
>>>>> If the gas is 20 degrees F colder, it contains about 1% more energy
>>>>> or about a 0.4 mpg difference. If the gas is stored in an underground
>>>>> container, the gas temperature should be pretty constant. However,
>>>>> the gas can get colder or warming in transport and when going through
>>>>> the pipes in the ground.
>>>>>
>>>>> http://www.users.qwest.net/~taaaz/AZgas.html
>>>>
>>>> yes, colder is denser, but formulation changes seasonally. winter gas
>>>> has more ethanol, and ethanol has a lower calorie content, hence lower
>>>> mpg.
>>> yes, I already pointed out that E15 has about 4.5% less energy that E0 gas.
>>>
>>> I don't know how much difference the cold temperature makes, because
>>> most tanks are underground. In theory, none, because the underground
>>> temperature is fairly constant usually about 10 to 15 C, but, the
>>> gasoline may be significantly colder when it is dumped from the trucks
>>> into the ground. And gasoline is not immediately heated or cooled in
>>> those huge underground tanks. It might take a couple of days until it
>>> reaches a steady temperature of about 15 C. But the gasoline might not
>>> last that long in the tank. In addition, the gasoline might be cooled as
>>> it is passing through the pipes in the ground. If the gas is around 0 C,
>>> when it warms up to 15 C (about 59 F), it will expand by about 1.5%.
>>>
>>> So the question is, what is the temperature at the point where the
>>> gasoline volume is measured as it is pumped?
>>>
>>> http://www.users.qwest.net/~taaaz/AZgas.html
>>> http://www.usatoday.com/news/nation/2007-07-04-hot-fuel_N.htm
>>>
>>> Jeff
>>>
>>>
>> gasoline shouldn't be sold by volume, it should be sold by the therm,
>> like natural gas. that way, there's no gaming of the energy content, no
>> class action lawsuits over gas being sold short in the summer because
>> it's warm, etc...
>
> It would still likely be metered by volume so you still have to either
> compensate for temperature or... not. The density of gas might vary
> by +/- 2% over any reasonable temperature range compared to it's
> density at 60F which is where it is theoretically sold. You get
> cheated a little in the summer and you cheat them a little in the
> winter, unless someone is intentionally heating it up.
>
> Energy content by mass varies +/- 4% around the nominal 44.4 Mj/kg.
> 10% ethanol knocks it down another 3.3%.

i'll take another 7.3% increase in revenue please! if you sell food,
you're a brewer or a public utility, you get slammed for that game.
oilco's? no problem!


> Economists would argue that
> the market is already compensating for this variability (in
> temperature and energy content), but economists never compensate for
> the fact that the butcher has his finger on the scale.

indeed. well said.

Gordon McGrew wrote:
> On Thu, 24 Jan 2008 19:09:58 -0800, jim beam
> <spamvortex.DeleteThis@bad.example.net> wrote:
>
>> Jeff wrote:
>>> jim beam wrote:
>>>> Jeff wrote:
>>>>> Edward W. Thompson wrote:
>>>>>> On Tue, 22 Jan 2008 17:03:01 GMT, Jeff <kidsdoc2000.DeleteThis@hotmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> rick++ wrote:
>>>>>>>> In the summer I get 40 mpg highway.
>>>>>>>> I just did a long road trip last weekend at an average
>>>>>>>> temperature of -17C (0F) and got 37 mpg. 15% ethanol.
>>>>>>> How much ethanol in the summer? The ethanol should have dropped the
>>>>>>> mileage down 4.5% or 2 mpg. Engines don't run as efficiently in the
>>>>>>> winter, in part because they take longer to warm up. Of course, the
>>>>>>> air conditioner usually isn't running nor is the sun roof down. And
>>>>>>> the gas is denser in the winter, because liquids contract in the cold.
>>>>>>>
>>>>>>> Jeff
>>>>>>
>>>>>> Gas is denser in winter and this contributes to fuel economy? I judge
>>>>>> you missed out on 'science 101'.
>>>>> Actually, I taught science 101. If the gas is denser, that means that
>>>>> in every gallon or liter that is colder, you get more energy. More
>>>>> energy means you go farther.
>>>>>
>>>>> If the gas is 20 degrees F colder, it contains about 1% more energy
>>>>> or about a 0.4 mpg difference. If the gas is stored in an underground
>>>>> container, the gas temperature should be pretty constant. However,
>>>>> the gas can get colder or warming in transport and when going through
>>>>> the pipes in the ground.
>>>>>
>>>>> http://www.users.qwest.net/~taaaz/AZgas.html
>>>>
>>>> yes, colder is denser, but formulation changes seasonally. winter gas
>>>> has more ethanol, and ethanol has a lower calorie content, hence lower
>>>> mpg.
>>> yes, I already pointed out that E15 has about 4.5% less energy that E0 gas.
>>>
>>> I don't know how much difference the cold temperature makes, because
>>> most tanks are underground. In theory, none, because the underground
>>> temperature is fairly constant usually about 10 to 15 C, but, the
>>> gasoline may be significantly colder when it is dumped from the trucks
>>> into the ground. And gasoline is not immediately heated or cooled in
>>> those huge underground tanks. It might take a couple of days until it
>>> reaches a steady temperature of about 15 C. But the gasoline might not
>>> last that long in the tank. In addition, the gasoline might be cooled as
>>> it is passing through the pipes in the ground. If the gas is around 0 C,
>>> when it warms up to 15 C (about 59 F), it will expand by about 1.5%.
>>>
>>> So the question is, what is the temperature at the point where the
>>> gasoline volume is measured as it is pumped?
>>>
>>> http://www.users.qwest.net/~taaaz/AZgas.html
>>> http://www.usatoday.com/news/nation/2007-07-04-hot-fuel_N.htm
>>>
>>> Jeff
>>>
>>>
>> gasoline shouldn't be sold by volume, it should be sold by the therm,
>> like natural gas. that way, there's no gaming of the energy content, no
>> class action lawsuits over gas being sold short in the summer because
>> it's warm, etc...
>
> It would still likely be metered by volume so you still have to either
> compensate for temperature or... not. The density of gas might vary
> by +/- 2% over any reasonable temperature range compared to it's
> density at 60F which is where it is theoretically sold. You get
> cheated a little in the summer and you cheat them a little in the
> winter, unless someone is intentionally heating it up.

I am sure that if they are delivering 1% more gasoline, they are
increasing the price by 3%. But, I am not sure that in the summer that
they lower the price by that amount.

> Energy content by mass varies +/- 4% around the nominal 44.4 Mj/kg.
> 10% ethanol knocks it down another 3.3%. Economists would argue that
> the market is already compensating for this variability (in
> temperature and energy content), but economists never compensate for
> the fact that the butcher has his finger on the scale.

No, the market is not compensating for either of these. The competition
is based on the volume of gas, not the energy content. I have yet to see
a sign that says, "our gas has 44,000 kJ per kg." And I rarely see signs
that tell you if there is any ethanol in gasoline (I only remember one
at a Sunoco station).

Most consumers are not aware that ethanol has less energy content that
gasoline nor are they aware of the energy content of their gasoline or
even if there is ethanol in their gas.

So the market doesn't compensate for the different energy contents.

A lot of people want to buy high octane gas to give their car a treat.
People don't always make logical decisions. And, they don't gather info
to make decisions.

Jeff