Slashdot Mirror
New X-Prize for Fuel Efficient Cars Announced
miowpurr writes "A new X-Prize for ultra fuel efficient cars has been announced. The winning car must 'carry four or more passengers and have climate control, an audio system and 10 cubic feet of cargo space. They also must have four or more wheels, hit 60 miles per hour in less than 12 seconds and have a minimum top speed of 100 miles per hour and a range of 200 miles. Those that qualify will race their vehicles in cross-country races in 2009 and 2010 that will combine speed, distance, urban driving and overall performance.'"
Not mentioned in the summary.
It's all good.
carry four or more passengers and have climate control, an audio system and 10 cubic feet of cargo space. They also must have four or more wheels, hit 60 miles per hour in less than 12 seconds and have a minimum top speed of 100 miles per hour and a range of 200 miles.
My car does that now. The summary left out the most important piece of information: the car must get 100 MPG or more.
Developers: We can use your help.
Draft Guidelines can be found here: http://www.progressiveautoxprize.org/auto/prize-details/draft-guidelines [PDF Warning]
The energy gained from the hydrogen combustion will be less than the energy expended in the electrolysis. It's as simple as that. No system is 100% efficient, so you must lose some energy in the process of extracting the hydrogen from the water. If the hydrogen generator were plugged into the wall you could argue that the gains coming from the electricity used were greater than spending the equivalent money on petrol rather than electricity, even factoring in the inherent losses from the process, but inside the car's system all the energy ultimately comes from the petrol anyway.
I no very little about the chemistry involved in adding hydrogen to the combustion of petrol, so I can't say what (if any) impact it could have on emissions, but the physics of the situation mean that you must be expending more fuel overall than you would without the system.
Here is a brief summary of the rules as taken from the draft on X-Prise website.
Fuel economy >100MPGe
4+ passengers
Must meet US EPA Tier II bin 5
Must meet US safety regulations
Must have features considered standard in today's automobiles at a cost that is not prohibitively expensive, and must provide a business case proving so.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
Well conservation of energy for one. The energy required to split water in to hydrogen and oxygen is greater than the energy you get from burning it otherwise we'd all have perpetual motion machines running in our back yard.
/2 (as this is a 4 stroke engine) * .85 (assume this is not turbo charged so the cylinder is never completely full) = 2550 liters of air per min.
Flow rate.
Say an engine has a displacement of 3 liters and is operating at 2000 rpm.
3 liters * 2000 rpm
the electric power required to electrolyze the hydrogen equivalent to 1 gallon of gasoline is equal to (500 moles) x (0.06587 kWh/mole) = 32.935 kWh, and the approximate cost of that power = (32.935 kWh)
credit to this site http://www.stardrivedevice.com/electrolysis.html
How much current can you alternator put out? Maybe 100 amps. How much hydrogen could your car generate per min? How much power can your alternator produce 100A *13.7V 1.37 KW
How much hydrogen could your car produce per min?
1.37 * (.06587 kWh/mole) / 60min/hr * 22.4 liters/mol = 0.033 liters of hydrogen per min
Compare this to the number above for the volume of air entering the engine.
How much hydrogen would one need to run a vehicle?
If 500 mol of hydrogen = 1 gallon of gasoline
If the vehicle gets 30 mpg at 60 mph = 2 gallons of gasoline per hr or 1000 mol of hydrogen per hr * 22.4 liters / mol / 60 min / hr = 373 lites per min of hydrogen
Compare this to the number above.
If anything all those hydrogen generator scams are going to do is create a vacuum leak that will turn on your check engine light.
I don't think there is much likelihood that this prize will have any major impact on an environmental level. Addressing fuel economy globally is not at all about creating the most efficient technology. It will be about creating the most mass producible solution. The best solution will be the one that relies on the most abundant resources.
We see contention now in the number of hybrid electric vehicles that can be produced, because they all depend on a limited supply of some common parts. The more Prius vehicles produced means the fewer HEVs that can be produced by other manufacturers. Doesn't the Tesla run on something like 100 laptop batteries. That means that for each one, 100 fewer laptops can be produced. One factory produces seemless containment units for nuclear reactors. They produce 8 a year. That means that only 8 reactors based on that technology can be opened each year. Wind power is more viable solution for global impact because the materials for turbines are easily acquired, even if the power source is unreliable.
I suspect that this will produce a nice pet project for enthusiasts, but not one that will have a large impact.