Pump says octane is min. rating, any tests?

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In Canada, Ontario specifically we have fuel pumps showing the following:

87 / 89 / 91 / 94 for regular/midgrade/premium/ultra premium. The pump sticker states the octane levels are minimum amounts, so my question is what margin of safety could be expected to exist for each grade?

Is mid-grade really 90 and premium 92 ? or could you expect to test these and find that the refiners are able to produce to +0.01 / - 0 tolerance?
 
I don't know about Ontario, but my state tests for it at least once a year. Unlike quantity calibration, which has been turned over to private industry, fuel quality is still monitored by .gov.

I don't know what the allowed tolerance is, but, in my lifetime, I've never had a sample fail, and I've never seen an actual test result - perhaps you only get that with a fail.
 
My wife's uncle is an engineer for a prominent oil company. I was talking to him a few years ago. He said that it's pretty detailed in how the mixes are made. For example, let's say that the end product is 87 grade octane, what they do is take, for example, some volume of 85 grade fuel and mix it with some volume of ethanol at 105 (?) octane, and the resulting mix is 87 octane. So I don't know if this answers your question but it's perhaps an insight into the detailed procedure that goes into it.

I've often wondered how each individual molecule functions in practice, in this situation. But it seems to work.
 
The most accurate way of testing the actual octane value is to use a Combustion Fuel Research (CFR) engine (also known as a knock engine). Currently the American Society for Testing and Materials (ASTM) uses the CFR engine method, developed in the 1920s to obtain official octane measurements. The CFR engine measures octane by combusting the fuel and physically measuring the knock that occurs. These tests have a repeatability (same operator/same lab) of 0.2 RON, and a reproducibility (different operators in different labs) of 0.7 RON. Each sample is tested for research octane number (RON) as prescribed by ASTM Method D2699. This is the method used for testing at fuel refineries. This is also the method used for all our testing, which makes them certified and independent tests that can be reproduced by anyone wanting to confirm the results.
 
Every batch of gasoline tested at the point of manufacture before bei g certified yo leave the facility. If it is shipped by barge or tank ship it may also be tested at point of discharge to check against change in quality in transit.

The ASTM test if both RON & MON by engine is the standard and the referee in case of dispute. However advances in near IR instruments have led to this technology in many places.

If the delivered at ghe pump octane exceeds the minimum by 1 to 1.5 numbers consistently, that's a lot of giveaway and is hwrd to picture as being sustainably competitively economic operation. My experience was typically 0.1 to 0.2. Higher than 0.2 would typically entail a reblend adjustment to reduce the giveaway to 0.2 or less. This includes accounting for blends where ethanol is added at the point of delivery.

Anything below minimum would require a reblend adjustment to bring it to minimum to minimum plus 0.2.

Samples are retained for each batch for months at the point of production in refrigerated storage facilities away from light to minimize potential quality changes in storage in case of dispute or other need to retest.

I'm speaking for in the USA.
 
This was from distribution to the bulk station. Besides, you know how the wording is. When they say a point or a point and a half, they very likely mean 0.1 to 0.15, rather than 1.0 to 1.5.
 
I see nothing that would raise the octane of a batch between point of manufacture and delivery to the terminal, unless it was significantly reblended somewhere in between, which would require recertification of that entire shipment.

I used to be the gasoline blendineer at a refinery for manufacturing 50,000+ US barrels a day of various grades of gasoline both for domestic US consumption and export.

Canada sure seems different than US or other countries for export from US based on your posts; I have not dealt with exporting gasoline to Canada though.
 
I have no idea. I was just going by what the rep said. What he seemed to be indicating to me was that it was a bit higher than the minimum to be on the safe side and to allow for some deterioration in small volume locations, which was a concern in rural Saskatchewan. He was talking delivery from the refinery to the bulk storage locations in the province. I didn't mean to indicate that there was a change somewhere along the line between the refinery and the final retail location.

Like I mentioned, when he said a point or point and a half above, he may very well have meant like 89 +/- 0.1 or 89 +/- 0.15, rather than 1 or 1.5, using the same terminology that the additive guys do, which talks up the game more than anything else. I'm not sure what legislative requirements there are here on octane rating. I do know that permissible pump volume error is different on the plus side than it is on the minus side, so one does run across some peculiarities at times.

Or, he could have been totally out to lunch and you've straightened me out on his tall tales, which is the most likely explanation.
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After the supercharger went on my car I went and filled up with some Conoco 91 octane. Tons of knock. Sensors were showing +4.9 during the first pull which was awful.

Ran the tank out, filled up with some Exxon 91, and ran the test again. This time it was advancing timing not retarding it.

Examination of the logs showed no other possible reason for the problem. The "91" fuel I bought at the Conoco station was not what it as supposed to be.
 
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Keeping the quality of a batch of gasoline intact from point of manufacture to point of distribution (terminal) isn't terribly difficult. It's difficult to adulterate material inside a pipeline without extreme disruption to the pipeline, and there are all sorts of checks & balances on waterborne vessel transport, especially when import / export is involved.

In pipelines as long as turbulent flow is maintained, each batch moves in plug flow kind of like a railcar without end caps with minimal interfacial commingling. If a batch of regular is followed by a batch of premium for example, to keep things intact quality-wise, a bit of the premium batch will be routed to the regular tank at the end of the regular batch / beginning of the premium batch delivery. In this case a small amount of premium is downgraded to regular as it meets or exceeds regular quality specs to keep any regular from contaminating the premium batch, as the regular does not meet or exceed the premium quality. So the regular tank gets a miniscule "boost" of premium as an economic way to do business transporting these materials, and the premium delivery is slightly shorted to preserve its quality. Small volumes in each batch but it adds up in the volumes transported.

Interfaces of gasoline and distillate, and of diesel and jet fuel, are "slopped" into a separate tank reserved for such mixtures known as transmix. The transmix is reprocessed to separate the gasoline & distillate components again.

The difficult area is transporting material from the terminal to the correct underground storage tank at the point of retail sale. "Missed Drops", events where the material drained from the delivery truck compartment doesn't match the contents of the station's underground storage tank, are the most problematic.

If you've ever pulled into a station that normally sells more than one grade and suddenly all the pumps are selling regular temporarily, chances are there was a missed drop of regular into the premium tank. There's less economic pain to just sell all the commingled material as regular since it meets and exceeds requirements for regular to clear out the tanks than try to vacuum it out and transport it somewhere to be reprocessed.

Riptide's experience may well have been such a missed drop that wasn't caught.

More difficult are missed drops that commingle gasoline & diesel - these must be reprocessed. The most dangerous missed drops I know of are those where gasoline is unloaded from the truck into the kerosene pump tank. These cause real damage & injuries when not caught before the commingled product is used for home heating.

A brief article

http://bulktransporter.com/fleet-managem...eaching-webinar
 
I've run into "difficult" batches of fuels over the years only twice. One was in the taxi years after LPG died down, and someone was filling at a pretty terrible station. The car would just ping with the slightest touch of the throttle. Once with the Audi, when filling at a local station from nearly empty, it just started running bad almost immediately, unable to hold idle very well. It didn't smoke or anything, but just ran rough as heck. As soon as that tank was near empty and I refilled, the problem disappeared.

I posted this link shortly after it occurred. My brother once dumped diesel into the rototiller and wondered why it smoked and stopped running. I just dumped it out and rinsed the tank with fresh gasoline, and refilled it, and all worked out fine a short while thereafter.
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Those are interesting. A few weeks ago, I got lucky enough to buy Shell premium at regular price. I believe this time they ran out of regular. A few years ago, a Shell here got some water in the regular tank, and it set off alarms, and they were only selling premium, and at regular price. I got lucky that time, too.
 
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