• Jan 15th 2007 at 7:14PM
  • 7

Mazda has already made some hydrogen powered RX8 concepts powered by hydrogen. They say that their Wankel rotary engines are perfect for hydrogen as the heat generated does not hinder their performance. According to this article, the high temperatures do not cause a pre-ignition problem, sometimes referred to as "pinging" in piston engines.

Now Mazda engineers have placed a rotary engine in their Mazda 5 model, a small wagon that is sold here in the States. The rotary engine can run on hydrogen or standard gas. Additionally, they have added an electric motor to the vehicle, making this a gas/hydrogen/electric hybrid... or should I say "tribrid" - perhaps not.

This vehicle is their second attempt at hybrid vehicles, with their Tribute SUV using the same hybrid gas/electric system developed by Ford. This is also their second hydrogen/gas foray, as they have converted some of their RX8 rotary vehicles to hydrogen power. This is their first vehicle combining both.

[Source: Auto Industry U.K.]

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    • 1 Second Ago
      • 7 Years Ago
      i want to know any technology update sites in automobile and any free membership sites there send me urgent
      • 8 Years Ago
      i feel that when it comes to passanger vehicles (such as the RX8 and Mazda 3 and so on including other makes and models) that as a Plug-in Hybrid (PHEV) with a compact efficient rotary as a backup and/or range extender is a very good idea and the future for the car economy as hydrogen is too far out there to be the savior fuel.. electric is a much more inexpensive and easier attainable power source that is clean and can be sourced from anything in large quantities. Now if only hybrids could go 55mph in electric only mode..they could go into more urban zones that have speed limits higher than 35 and less than 60.
      • 8 Years Ago
      Wankel engines are compact and have a high power-to-weight ratio. Unfortunately, they also have an odd shaped combustion chamber with a high surface-to-volume ratio and narrow corners, resulting in low efficiency and poor fuel economy.

      Wankels have not caught on because the disadvantages outweigh the advantages - especially with high fuel prices.
      • 8 Years Ago
      On second thought, with a "pluggable" hybrid similar to the GM Volt, where local driving is electric only, the reduction weight and size may be more important than fuel economy, making a Wankel a very good "standby range extender/backup" for those rare long drives.
      • 8 Years Ago
      The reason it avoids pre-ignition is because the hot ignition chamber is on the opposite side of the engine as the intake / exhaust ports, unlike a piston engine where the fuel burns AT the intake / exhaust site. So, the theory is, that as the hydrogen dumps into the piston engine, those HOT, pointy edges may ignite the fuel, causing serious problems. The rotary, on the other hand, avoids this.

      The great thing about adding the electric is that the already low-tourque rotary engine performs worse on hydrogen than on gasoline. That should 1) bump the torque up to piston levels in low RPMs and 2) make up for some of the power deficit hydrogen brings.

      If they could solve the gigantic hydrogen fuel cell problem (makes the trunk useless), I'd love to see something like this in the RX-8, as well as the Mazda 5. Now, if only they could make it run on ethanol out-of-the-box, the rotary would be very valuable to the green community.
      • 8 Years Ago
      CM- I agree! Rotary just makes more sense. You appear to be pretty current on this subject. What do you think about the StarRotor continuous-cycle engine as the "range extender?" http://peswiki.com/index.php/Directory:StarRotor_Corporation The StarRotor is said to be 3-4 times more efficient than the best IC engines and can be tuned to run on almost any combustible liquid or gaseous fuel. I know new engine tech is a really hard sell, but this concept is interesting regarding your above thermal efficiency comment. Any thoughts?
      • 8 Years Ago
      The only place for Hydrogen is to possibly improve the internal combustion of other (read better) fuels. Manufacturers claim that onboard electrolysis and injection improves combustion. http://en.wikipedia.org/wiki/Hydrogen_fuel_injection If it works as advertised, we should all be using it for this purpose ONLY. I used to use water mist injection to cool the charge for the same results in my old Dodge 360 some 20 years ago. I could advance the timing without pre-detonation.

      Hydrogen Fuel cells on the other hand are horribly expensive ($1Million/copy) and have a very short working life. According to Alec Brooks, a REAL expert on the subject "… Fuel cell vehicles consume 4x the amount of electricity per mile than BEVs…” http://www.autobloggreen.com/2007/01/12/listen-to-alec-brooks-presentation-at-the-california-air-resourc/ This report is well worth listening to. Alec actually coined the term "vehicle to grid" (V2G) We have a grid NOW, but we won’t have any H2 infrastructure for 20-30 years IF EVER.

      The bottom line is that the US gov't is pumping so much of our tax money into some magical (read fantasy) "Hydrogen Economy" via tax credits, that you can't blame the car manufacturers for getting in on it! They've become addicted to OUR money, tax or other. Then again, so are the pushers/prostitutes that we elected into our congress. Left, center or right seems to make no difference.
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