E85 blend of bio fuel
Most bio fuels which are already available are, in fact, blends of fossil and organic material derived fuels. E85 is one of the 'greenest' of these fuels as it consists of 85 per cent bio ethanol mixed with just 15 per cent conventional, fossil-derived petrol. During each trip, Bosch claim that their Smart Electronic start stop system reduces fuel consumption and carbon dioxide (CO2) emissions by as much as eight percent, depending on the type of vehicle. In heavy traffic where the vehicle spends a greater amount of time at a standstill, the reduction of CO2 emissions and fuel consumption can be significantly higher.
Electronic Power Steering
Removes the need for the conventional engine driven hydraulic power steering pump
Pros: Increased fuel efficiency.
Cons: Steering can feel over light on some systems.
Conventional power steering systems feature an engine driven, hydraulic pump. This is usually belt driven, so as long as the engine is running it is having to power the pump - even if the car is being driven in a straight line and the steering is not being used. Any extra load on the engine reduces power output and increases fuel consumption. Electronic power steering substitutes the pump and hydraulics with an electric motor which only comes in to play when needed - when steering effort is applied. Some systems even offer variable assistance, applying more force at lower, parking speeds when it is most useful, and little when the car is travelling at speed.
The end result is lighter steering without increased fuel consumption.
Fitted to: Most manufacturers now offer some sort of Electronic Power steering.
Fuel Cells
The Holy Grail - energy with zero emissions.
Pros: Power where the only emission is distilled water
Cons: Fuel is hydrogen which is not easy to handle. Technology is extremely expensive. The production of Hydrogen requires electricity, the generation of which can be polluting.
Viewed by many as the future power source, at first glance, Fuel Cells appear to be the ideal solution. Producing electricity from hydrogen and oxygen with the only by-product being distilled water, this is real Dan Dare technology. Fuel cells are electromechanical devices - a more familiar example of which is a battery. But unlike batteries which are totally self contained and ultimately consume their fuel in the production of electricity, fuel cells are constantly fed new fuel so they have an indefinite life span.
Huge investments are being made in fuel cell technology and several manufacturers are already pinning their hopes on producing a commercially viable fuel cell car. The technology already exists, but manufacturing a fuel cell is still prohibitively expensive.
The only cloud on the horizon for hydrogen fuel cell technology is the production of hydrogen itself. This is conventionally produced from water through electrolysis, producing hydrogen and oxygen. Of course, this process requires electricity and if this is generated from unsustainable sources, the system's green credentials are bought into question.
Gas To Liquid - GTL
Liquid fuel converted from natural gas
Pros: Can reduce NOx emissions from diesel engines. Easily manufactured from natural gas.
Cons: Bulk of GTL is still derived from unsustainable sources.
As the name suggests, GTL is a liquid fuel converted from natural gas. The process was originally developed for reasons of transportation - liquids are much easier to transport from remote locations than gasses. GTL is usually mixed with diesel for automotive applications, but unless the gas used is derived from biomass, the true reduction of CO2 emissions would be negligible.
Homogeneous Charge
Hybrid petrol engines which function much like a diesel engine
Pros: Low emissions, high efficiency.
Cons: High cost, still contributing to CO2 output.
Homogeneous Charge engines take the best qualities of the diesel engine and apply them to a petrol engine. These high tech units do without spark plugs, and instead use high compression - as in a diesel - to cause the fuel/air mixture to ignite. This results in a more complete and efficient 'burn' of the fuel. More power can be extracted from the fuel and emissions - in particular nitrous oxides - are reduced due to the lower cylinder temperatures. They can also run much leaner fuel mixtures than conventional petrol engines, leading to much reduced fuel consumption - up to 20 per cent. Ford, GM and VAG have invested heavily in this technology, and it should be commercially available by the end of the decade.
Hybrids
Vehicles which use a combination of electric motors and petrol engines
Pros: Zero emissions when driven on the electric motors. Reduced fuel consumption.
Cons: Highly complex and expensive. Heavy. Huge batteries are not environmentally friendly.
Hybrids were developed to answer the shortcomings of both conventionally fuelled and electric vehicles. Battery powered electric vehicles may be quiet and emission free in use, but their range is limited by the life of their batteries. By coupling the electric motor with a small petrol or diesel engine, the car can then be driven around town using battery power, and then the conventional engine can take over on longer trips or on motorways. Other technologies, such as regenerative braking can also be used to top up the batteries.
Hybrids do have some serious drawbacks. They’re heavy and technologically complex, and as a result, expensive. The weight also harms the fuel efficiency when the conventional engine is in use. But in their element - around town - they can't currently be beaten in terms of both fuel efficiency and emissions output. Available from: Toyota, Honda
Hydrogen Fuels
The ultimate green fuel - zero CO2 emissions
Pros: Zero emissions.
Cons: Technology not yet commercially available. Fuel could not be distributed through existing infrastructure
Hydrogen fuels can not only be used to power fuel cells, but in liquid form, they can also be burnt in more conventional internal combustion engines. As hydrogen can be harvested from water, it’s readily available and burns without producing CO2.
The downsides of using liquid hydrogen could cause the engineers a few headaches though. To remain in a liquid state, hydrogen must be kept at -235 degrees C. Also the energy yield from hydrogen when compared with conventional fuels is much lower, so consumption would be much higher. Producing enough hydrogen from environmentally friendly processes is still a question that needs to be answered, but if this can be overcome, fuel cell technology where hydrogen in a gas form is the main fuel may provide a more realistic solution for a zero emissions vehicle.
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