> Bob,
>
> I was really impressed with your post about the Octane rating! It confirmed some of the myths about higher octane gas. I was curious as to how you obtained the data from the car? You must have some type of computer interface to the car.
>

>
> I have a Hybrid Camry and I would be interested in collecting this data. I spent some time collecting information related to fuel density when I first bought the car last summer. I was measuring the temperature of the gas and found some big differences between stations. I settled in on Phillip 66 that was always 60 degrees (85 Octane) In Colorado we have lower Octane due to our elevation.
> What is the true value of the gasoline? The price is getting high enough to start asking these questions.
>
> I appreciate your help.
>
> Bill Lund

 

Hi Bill,

I have a Graham miniscanner in my 2003 Prius that allows me to record up to six data points every second. What I do is:

• record mass air flow - to calculate fuel burned
• MG1 torque - this is 28% of the engine torque in the opposite direction
• MG1 and MG2 rpm - this records the speed and together, reports ICE rpm and distance
• climb the same, 525 ft. hill at 55 mph during each test run

I use 55 mph to make sure the hill climb power comes from the engine, not the battery. If I climb at 65 mph or faster, the car draws significant energy from the battery and this can give a false indication of how much fuel it takes to climb the hill. It is about 1.2 miles on the trip meter up the hill.

It is important to make sure the fuel in the car is known. So I carry a one gallon spare can of the next fuel to test and drive the car until it runs out of gas. I then use the battery to pull into a safe place to pour the one gallon of gas into the tank. I then drive to the gas station selling the test fuel and add four more. Depending upon the temperature and time, I either head over to the hill for a hill climb test or to the station selling the next test gas to fill the one gallon, spare can. If the temperature is too far off, I wait until the morning or next day and drive for at least 15 minutes to make sure the car is warmed up before doing the hill climb. With this protocol, I get about one sample tested per week.

Now you can do a similar if somewhat less accurate test using just your mileage display. Find a fairly high hill or mountain that you can climb at a cruise control set speed. It needs to have at least four lanes so you can go up the hill at your speed without having to worry about other traffic backing up. I don't know enough about the Camry but would suggest using 55 mph, certainly not more than 65 mph, to climb the hill. Identify a set "START" and "STOP" point on the hill climb.

Approach the hill on cruise control and adjust it to exactly the climb speed you plan to use. When you get to the "START" spot, reset the mileage display. When you reach the "STOP" spot, look over and memorize the MPG. Get to your turnaround spot and write it down on your log with date and temperature. For more accuracy, do three runs and average the results. Even more accuracy, do five runs and toss out the highest and lowest. Repeat until all gas brands have been tested.

Then come back here and share your results. <GRINS>

I'm especially curious about the performance of the lower octane gas you can buy at high altitudes. I strongly suspect it has a higher energy content but won't know until someone tests it.

GOOD LUCK!
Bob Wilson

 

I thought I would stop back into this page again and let you know I am still working on this project. I have tested three stations so far with some really interesting results to be posted with the final results in the next two weeks. We don't drive enough each week to empty the tank between gas stations. We have a long steep hill on I70 for 5 miles that has been doing a nice of job testing the performance of each brand of gas.

One interesting problem we have in Colorado we have only one refinery so much of the gas comes from the same pot. A few stations get their gas from one of THREE refineries in Wyoming. So far Wyoming is winning!

Alabama has three refineries including Shell...

I will keep you posted!

Bill

 

FWIW, I just filled up after using Shell V-Power 93 and only got 39 mpg, way below my usual.

 

I was truly impressed with Bob Wilson’s post listed above and I would like to post my results. In my neighborhood we have a wide variety of stations to choose from. Last summer I checked the temperature at all at these stations and found Phillip 66 to be the most consistent @ 60 degrees. I was surprised how hot the gas was at the other stations.



Over this past winter my mileage had dropped to 33 – 34 mpg for what I thought was the cooler weather.


At Bob’s suggestion, I followed these steps: I live near a long STEEP grade on I-70 called Mont Vernon Canyon. My test was from Mile post 260 to 255 near the top, a 5 mile testing hill. I set the curse control at 60 and turned the heating and cooling off.


I did not run the car out of gas between tanks but emptied the tank to the “Cursing Range” read about 10 miles to go and then added 10 gallons. At least 90% of the gas was from the station listed below. I used only the 85 octane, (Colorado’s 87 octane). I have not tested the mid-grade or higher yet.


I made three trips up and down the grade, a total of 16 miles round trip on each brand of gas. The mileage would drop for each trip and then level off. I believe this was the extra battery power level being used up in the first trips. I believe the last trip value to be the most accurate reading.
Overall the MPGs variances were not significant but I notice a large increase in the overall tank averages.


Safeway was the clear winner. What was most interesting was that the overall tank average moved up from Phillip 66 - 34 mpg to Safeway’s--41 mpg. Sinclair’s overall tank average was 39 mpg.


I understand Safeway receives most of its gas from a refinery in Wyoming. Most of the gasoline in Colorado comes from one refinery located in Denver. The downside of Safeway is that they will buy from the local refinery from time to time.


Here are the results:
Safeway Outside Temp 36 degrees
Trip Number 1—18.9
Trip Number 2—18.9
Trip Number 3—18.8

Sinclair Outside Temp 37 degrees
Trip Number 1—18.4
Trip Number 2—18.2
Trip Number 3—18.2

Bradley Outside Temp 41 degrees
Trip Number 1—18.3
Trip Number 2—18.3
Trip Number 3—18.2


Shell Outside Temp 41 degrees

Trip Number 1—18.1
Trip Number 2—18.0
Trip Number 3—18.0

Phillip 66 Outside Temp 43 degrees
Trip Number 1—18.1
Trip Number 2—17.9
Trip Number 3—17.7
Trip Number 4—17.7


Much is made about pumping gas slowly, buying gas in the morning to get colder gas. It appears the power produced by the gasoline will have a greater impact on improving the value received from your purchase. This will become a greater issue as the price of gas climbs later this summer. Nothing like knowing the REAL value for the prices paid.


My final thought would be the computers in the TCH have the ability to measure performance of gasoline over time considering all the data points that are available within the computers. The car’s computer could set benchmarks for the best performing tanks of gas and measure against the current tank. Engineers could design a Power Scale from poor to average to excellent. Hybrid cars are sensitive to minor changes that can make a big difference. Know the true quality of the gas could help making better decisions about what brands and locations to make your purchase. I'm sure these values will change over the coming summer months. Each station's delivery could be different, tank to tank.




Cheers!

Bill

 

Excellent report!
This is exactly the approach, first embedded in the mileage database, that first attracted me to GreenHybrid.com. It is the controlling of variables to the maximum extent possible and making just one known change. Then measure as accurately as is available, the results.

I've been testing Huntsville gasoline, Bill has tests Colorado gas but there west coast and northeast haven't been heard from nor the upper plains near the Canadian border. We really need to map out our gasoline energy supplies and share the results. Hopefully, others will 'get a clue' and help us understand what local brands work and which ones . . . should be avoided.

Bob Wilson