Lightweight Electric/Hybrid Vehicle Design

Current EV design approaches 5
there is now a solution to this problem, with a reforming process developed by Hydrogen Power
Corporation/Engelhard called Thermal Catalytic Reforming. Put simply, it is the chemical
process:
3Fe + 4H O = Fe O + 4H and Fe O + 2C = 3Fe + 2CO 2 3 4 2 3 4 2
The first process takes place with a catalyst at 130° C. The hydrogen is stored in a hydride tank
until required. The iron is returned to a central facility for reduction by the second process. The
main points about this cycle are that a high proportion of hydrocarbon heat energy is converted
into hydrogen and that 1 kg of iron provides enough hydrogen for a small car to travel 6 km on a
fuel cell.
IC engines and gas turbines run well on most hydrocarbons and hydrogen. Fuel cells need
hydrogen. Hydrogen has to be used and stored safely. This could be achieved by reforming it on
demand at fuel stations – the waste heat would be used to generate electricity to be pumped back
into the national grid. The primary fuel could be any hydrocarbon such as petrol, diesel, methanol,
propane or methane. The only constraint is that the fuel source must have low sulphur content so
as not to poison the catalyst. In the UK, we have a head start called the Natural Gas Grid. This is
likely to become of critical importance for energy distribution, removing the need to distribute
petrol and diesel by road. To satisfy future transport needs, we retain our ‘fuel’ stations as the
means of distribution. This brings us to the problem of on-board hydrogen storage.
l. Petrol car: A journey of 68 miles each day consumes 2.5 gallons of fuel and takes 2 hours.
Amount of energy in fuel = 5.14 x 10 8 joules
Thermal power = 71.3 kW
Mechanical power = 20 kW average
Efficiency = 28%
2. Battery electric car as secondary transport.
Power station efficiency 40%
Electric car efficiency 80%
OVERALL 32%
CONCLUSION: Pollution is moved from car to power station. There is only an environmental
return if the car’s performance is sacrificed or the power station is non-thermal and range/
performance is limited.
3. Hybrid car as primary transport.
Hydrocarbon to electricity
Via lean burn petrol engine 45%
Electricity to mechanical power 90%
OVERALL 40.5%
CONCLUSION: Pollution reduced by 55% and fuel consumption is 70% of petrol vehicle with
performance/range as the petrol vehicle.
4. Fuel-cell electric car as primary transport.
Hydrocarbon to hydrogen conversion 80%
Fuel-cell hydrogen to electricity 60%
Electricity to mechanical power 90%
OVERALL 43% (potential for 48% in 10 years)
CONCLUSION: Pollution reduced by 90%; fuel consumption is 66% of petrol vehicle and
performance/range is as petrol vehicle.
Fig. 1. 2 Some crude comparisons for fuel related to pollution.