It's not time to write the Rotary engine's obituary quite yet, says Mazda
11-27-2007, 05:01 PM
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edfred:
The number of vehicles which will be hydrogen retrofitted is going to negligible. Crude derived fuel will power the great majority of vehicles sold over the next 10 and maybe even 20 years. Hydrogen isn't suddenly going to become viable tomorrow. Gasoline, diesel, ethanol, cng/lng, propane and electric are all much more viable at the moment. Hybrids are going to help the gas price problem a lot, they will become pervasive as the cost of implementing them goes down and their performance goes up.
I think battery power will win out over hydrogen as far as a method of storing and transporting electrical power. Electrolysis of water is about 50-70% efficient in practical terms. Then there is the loss from compression or liquifecation, transportation, then some more loss from being recompressed to get into the car. I'm not sure what the conversion efficiency of hydrogen to power is, but I'm sure it's not more than 50% (gasoline is around 33%.) Overall, about 20% efficient (optimistically.)
Electrical distribution is about 60% efficient, chargers are about 90% efficient, Li-ions have energy storage efficiency of 95% (say 90% on average,) 90% for the motor control systems, and say 85% efficient motor (motors are well over 90% efficient at best, but not as good under load.) It's about 40% source to transmission power. Electric also has the benefit of regenerative braking.
The only thing I could see hydrogen used in would be plug-in hybrids. Electric from the wall would provide your daily driving power, but hydrogen fill-ups would allow for extended trips.
The number of vehicles which will be hydrogen retrofitted is going to negligible. Crude derived fuel will power the great majority of vehicles sold over the next 10 and maybe even 20 years. Hydrogen isn't suddenly going to become viable tomorrow. Gasoline, diesel, ethanol, cng/lng, propane and electric are all much more viable at the moment. Hybrids are going to help the gas price problem a lot, they will become pervasive as the cost of implementing them goes down and their performance goes up.
I think battery power will win out over hydrogen as far as a method of storing and transporting electrical power. Electrolysis of water is about 50-70% efficient in practical terms. Then there is the loss from compression or liquifecation, transportation, then some more loss from being recompressed to get into the car. I'm not sure what the conversion efficiency of hydrogen to power is, but I'm sure it's not more than 50% (gasoline is around 33%.) Overall, about 20% efficient (optimistically.)
Electrical distribution is about 60% efficient, chargers are about 90% efficient, Li-ions have energy storage efficiency of 95% (say 90% on average,) 90% for the motor control systems, and say 85% efficient motor (motors are well over 90% efficient at best, but not as good under load.) It's about 40% source to transmission power. Electric also has the benefit of regenerative braking.
The only thing I could see hydrogen used in would be plug-in hybrids. Electric from the wall would provide your daily driving power, but hydrogen fill-ups would allow for extended trips.
11-27-2007, 08:37 PM
#52
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E85 requires very high level of compression inside the engine to be used effectively. Wankel engines with 1.3L (650cc each rotor housing) have relatively low compression to take advantage of E85.
Mazada is rumored to be developing a 1.6L (800cc each housing) Wankel engine. The way Wankel works, bigger the housing, the higher the compression ratio.
If Mazada makes the 1.6L engine and mark it only for E85 or 93 Octane gasoline there would be quite a lot of torque out of the engine for given amount of fuel and air. This would mean not requiring so much higher level of engine rpm (and gas) to move the car at a given speed.
Mazada would probably refresh the RX8 with a bigger engine, which it all it needs and bring out a smaller and faster RX-7 style two seater. The MX-5 doesn't stand much against Soltice and Saturn Sky in terms of power anyway.
Mazada is rumored to be developing a 1.6L (800cc each housing) Wankel engine. The way Wankel works, bigger the housing, the higher the compression ratio.
If Mazada makes the 1.6L engine and mark it only for E85 or 93 Octane gasoline there would be quite a lot of torque out of the engine for given amount of fuel and air. This would mean not requiring so much higher level of engine rpm (and gas) to move the car at a given speed.
Mazada would probably refresh the RX8 with a bigger engine, which it all it needs and bring out a smaller and faster RX-7 style two seater. The MX-5 doesn't stand much against Soltice and Saturn Sky in terms of power anyway.
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