Featured Toyota false-advertised 5 minute refuel for Mirai

Anyone who is familiar with fueling vehicles with compressed gasses knows that trying to send the fuel through the hose too quickly can result in a frozen solid hose. It is the thermodynamics of the fluid flow. Physics is physics.

Bill the Engineer
(Engineer at a company that makes CNG powered Transit Buses.)

 

exactly. government intrusion not necessary.

 

That makes sense if high-pressure from a storage tank is being used to transfer to the vehicle tank. But I'm wondering if a 'rock crusher' (i.e., compressor) could be used to pump lower pressure gas into the tank and avoid or minimize the gas-expansion cooling?

For example, if the end target is 10,000 psi, could a 2:1 compressor, high volume, low pressure ratio, pump 5,000 psi storage gas into the vehicle tank with enough heat to counter act any initial cooling?

Although the inventory of storage tanks goes up, having a set of 1,000 psi, 2,000 psi, 5,000 psi tanks that switch into the compressor pump might be enough:

1. Pump 1,000 psi up to 2,000 psi
2. Pump 2,000 psi up to 5,000 psi
3. Pump 5,000 psi up to 10,000 psi

NASA rockets have used stages for a long, long time.

Bob Wilson

 

I think hydrogen heats up as it expands.

 

Isn't it the opposite, gasses cool as they expand?

Oh heck, I don't know.

 

The fastest fueling is liquid poured in. Its not a technical its a cost problem. To get liquid you need more expensive equipment and electricity. Your method is slower not faster. Using liquid hydrogen, or 14,000 psi hydrogen that has been pre-chilled will warm up less when fueling.

If you build a $5M station instead of a $2M station you can easily fill in 5 minutes Many of the existing stations in california are being upgraded for faster fills.

Still if you need to drive 5 minutes out of your way for hydrogen, and you are the second car, we have 5 + 5 + 5 or 15 minutes, not much better than a tesla supercharger.

 

Sorry my self righteous indignation over the false claims of automakers has been temporarily depleted by the VW scandal.

When 3 automakers all make the same claim, I tend to think it's LESS a case of "False Advertising" and more a case of selective presentation of possibility.

 

3600 psi was chosen for cng because it allows for low cost tanks and compressors. Go up and these things get more expensive. For natural gas the natural next step is lng. Lng is used for long haul trucks. lng carries 2.2x more energy per liter than cng.

 

Even the 3600-psia CNG tanks add $5000-$10000 in the USA due to US regulatory safety requirements. In EU they allow cheaper tanks.

As far as 20-min H2 pump time, the question is: Did Toyota lie? Or is California not installing the same robust re-filling technology that Japan is using ( I am thinking Lurgi is the Japan builder, but we had prior posts).

 

File a complaint with the FTC. In 5 minutes I am in and out of the gas station with 500 miles of range. Sorry no sympathy here. If people did their own fact checking they wouldn't be so disappointed.

 

Time for Wawa H2 stations in California. They are a convenience store and fast food gas station in the East. They are very popular and almost always busy.

Could get your morning donut and coffee while filling your H2 car. Just need 16 pumps, not 1 or 2 pumps that H2 stations currently have.

I would not like the long wait, but if I could sit in the car with the air and radio on, and do work on my IPad (internet connection) I could live with it. Or, a comfortable chair in a waiting room. No screaming children, thank you.

 

You are correct. Expansion cools the gas and compression heats them. A diesel works by compressing the gas ~20:1 and that heats it enough the fuel ignites when injected.

Bob Wilson

 

The small convenience store is disappearing replaced with the large convenience store with 16+ gas pumps usually just a block or two away.

 

From Wikipedia:

So, Hydrogen actually heats during expansion (as in from a nozzle into a storage tank) and this is backwards from what we are used to with most gasses. Hydrogen does act like other gasses during expansion but only when at extremely cold temperatures.

This is why H2 filling stations actually pre-cool the H2 in order to enable 3-5 minute vehicle tank filling. Perhaps the H2 filling station that takes 20 minutes isn't pre-chilling the H2 or perhaps earlier cars already used up the pre-chilled H2 and the stations chillers are not scaled up enough to keep up with the station use during the times that you have been visiting.

 

No. That was a goal, not an achievement reached yet.

Remember, the targets they've set are for early next decade.

Currently, we are still in the early stages of infrastructure setup and technology refinement.

 

Type A stations can pre-chill to -40, I'm assuming Celsius, and are the ones with a nominal fill time of 5 to7 minutes, but they can take longer, or even shorter.The type B and on so stations have progressively warmed pre-chill temps, and longer fill times. I think the older stations in California are type B.

 

In thermodynamics, the Joule–Thomson effect (also known as the Joule–Kelvin effect, Kelvin–Joule effect, or Joule–Thomson expansion) describes the temperature change of a gas or liquid when it is forced through a valve or porous plug while kept insulated so that no heat is exchanged with the environment.[1][2][3]This procedure is called a throttling process or Joule–Thomson process.[4] At room temperature, all gases except hydrogen, helium and neon cool upon expansion by the Joule–Thomson process; these three gases experience the same effect but only at lower temperatures.[5][6]

WaWa WaWa OK I'm from South Jersey I get it, but not too many here in Va. We like 'em but H2?

Fancy 7- Eleven (now with gas pumps) for the Ca. crowd

 

i don't know about the most expensive ones . . . . but here's one showing the cost/guess was missed by a factor of over 10.
Details on Tesla's First $35,000 Mobile Supercharging Station | Inside EVs
This presumes the power is already there . . . . which is the same presumed guess when 10k LB fuel cell compressors are being considered.
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