10 March 2010

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Green car glossary

If you don’t know your hydrogen fuel cells from your hybrids, or if you don’t know the difference between a homogenous charge and regenerative braking, then this is the glossary for you. In this green car jargon buster we’ll decipher all those complex terms so you can make an informed decision when choosing the right green car for your needs.

Auto stop-start: A stop-start system switches off the engine when the car is stationery as soon as you take the car out of gear and your foot off the clutch. The car will then automatically restart when the clutch is pressed. This saves fuel and reduces CO2 emissions when idling in traffic.
Bio-diesel: A fuel that is derived from various plant oils – typically rapeseed oil, palm oil and soybean oil. It is usually blended with mineral diesel or used on its own. It is an environmentally friendly alternative fuel that reduces CO2 emissions.
Bio-ethanol: A petrol substitute that is derived from plant matter and can reduce CO2 emissions by approximately 70 per cent. The CO2 it does produce can be seen as ‘recycled’ CO2 because it comes from the plant matter, rather than being additional CO2 burnt from petrol or diesel.
BlueMotion: A trade name for fuel efficient vehicles produced by Volkswagen. The name was first introduced in 2006 for a fuel-efficient version of the Volkswagen Polo.
Bluetec: A system that injects ‘Adblue’ (ammonia) into an exhaust to convert the oxides of nitrogen into nitrogen and water which are comparatively harmless. This system has been championed by Mercedes.
CNG: An abbreviation for compressed natural gas it is purer than petrol and reduces CO2 emissions by 20 per cent.
CO2: An abbreviation for carbon dioxide. Carbon dioxide is essential to life as it forms a natural cycle in the photosynthesis of plants. However, industrial processes have led to an imbalance of CO2 compared to oxygen and this is a contributory factor in the Greenhouse effect. The lower the CO2 emissions from a car, the better.
CO2 air conditioning: As of 2011 all new cars sold must use a CO2 based refrigeration. This is because even though CO2 is harmful to the environment it is 1,300 times less damaging to the ozone layer when used in air conditioning compared to the fluorocarbon-based liquid used in R134a.
DiesOtto engines: A concept engine produced by Mercedes. It runs on petrol but is said to have the benefits of a diesel engine. It was first used in the Mercedes S-Class to achieve more than 47mpg.
Direct injection: An engine that turns fuel into energy efficiently. It does this because the injectors are positioned within the combustion chamber, the most efficient location for pollution reduction and power generation. Though initially criticised, direct injection engines are now used in the majority of new petrol vehicles.
Displacement on demand: Reduces the amount of power used by an engine working on the idea that you only need maximum power for limited periods. It closes down some of the engine’s cylinders and therefore its fuel consumption but uses them instantly when required.
Downsizing: Shrinks the capacity of engines to improve economy and reduce emissions but without a loss of power.
E85: E-numbers used in motoring terms refer to the amount of bio-fuel blended into a petrol/diesel mix. So E85 refers to 85% bio-fuel with 15% diesel/petrol.
ECOnetic: A range of vehicles from Ford that use diesel powertrains with a number of features specifically designed to reduce emissions.
Electric vehicles: Vehicles which rely on chemical energy stored within battery rechargeable packs alongside electric motors instead of traditional engines. They are referred to as EVs for short, producing no exhaust fumes and using minimal energy if charged from renewable sources.
EPS: An abbreviation for electronic power steering which uses an electric motor that comes into effect only when the wheel is actually turned. This uses less fuel because traditional power steering systems are constantly used regardless of whether the wheel is turned or not. If you drive extensively on the motorway it is estimated that EPS could save as much as three per cent on your fuel costs.
European emissions standards: The requirements that outline the acceptable limits for exhaust emissions on new vehicles.
Fuel cells: One of the latest concepts in the manufacturing of green cars, fuel cells combine hydrogen and oxygen to generate power. It is seen as the ultimate alternative as it is genuinely pollution free but there are still questions over hydrogen generation and the overall expense of the concept.
Greenhouse effect: The growing amount of CO2 causes radiation on the earth creating a gradual warming of the surface over a period of time. This has effects such as melting the ice caps, increasing sea levels (causing flooding), changing the land mass area and altering weather patterns.
GTL: An abbreviation for gas-to-liquid it is manufactured from natural gas and mixed with diesel to reduce nitrogen oxides and hydrocarbon emissions.
Homogenous charge: Combines the best features of a petrol engine with those of a diesel. They run on petrol, therefore reducing the hydrocarbons and nitrogen oxides diesels produce, but do so without spark plugs and with high cylinder pressures for combustion. The result is cleaner exhausts and economy at a rate 15-20 per cent below traditional petrol engines. These engines are expected to be on sale by 2012.
Hybrids: Combine an electric motor with a traditional engine so a car produces zero emissions when running at low speeds. The electric motor is driven by batteries which receive their charge during regenerative braking and from the petrol engine. It is estimated that hybrids improve fuel consumption by around 30 per cent.
Hydrocarbons: A compound consisting of hydrogen and carbon. They are the world’s main source for electric energy and heat because of the energy produced when burnt.
Hydrogen fuels: Hydrogen is the most common element in the universe and can be used as a liquid to power a conventional engine or as a gas in fuel cells. It is seen as theoretically the best energy source for green cars because it has zero emissions. However, it is usually bound with other elements so the challenge remains on how to extract it efficiently.
Lithium-ion batteries: Batteries which use the lightest metal (lithium) and do not suffer from power loss when they are repeatedly charged. They originated as watch batteries and are seen as a potential alternative for electric cars.
LPG: An abbreviation for liquid petroleum gas which is purer than petrol and reduces CO2 emissions by around 10 per cent. It had a spurt of popularity in the UK when the Government issued grants for LPG conversions however, these have been withdrawn.
Mild hybrid: Uses an electric motor for short periods to boost the conventional engine but cannot use the electric motor alone for propulsion. Regenerative braking and a stop-start system are incorporated and it is estimated that mild hybrids have 70 per cent of the benefits of regular hybrids for 30 per cent of the cost.
Nitrogen oxides: A combination of nitrogen and oxygen. The gas nitrous oxide is sometimes used to increase power in motor racing engines. Oxides of nitrogen produce low-level ozone which is a cause of respiratory problems.
Particulates: The soot, or black smoke, produced by diesels which can be a cause of respiratory problems. According to the Euro V standard a car can only produce 0.005g/km and to achieve this must be fitted with particulate filters.
Plug-in hybrids: Hybrids with batteries that can be recharged from a mains supply as well as by the engine. The advantage of this system is that for short journeys the conventional engine may not need to be used at all.
Regenerative braking: Braking traditionally wastes energy due to the loss of heat. However, with regenerative braking, this energy is recovered and stored in a battery reducing energy consumption. This energy can then be used for headlights, stereos and air conditioning. It is also used in hybrids to recharge the battery that propels the electric motor.
RTFO: The Renewable Transport Fuel Obligation which states that all road-transport diesel must contain at least 2.5 per cent bio-fuel. This will increase to five per cent in 2010.
Super caps: An abbreviation of super capacitors this advanced form of battery boosts the vehicle when it is electrically propelled. Effectively this works in the same manner as turbo-charging a petrol engine.
Turbocharger: Normally a turbocharger is used in high-performance cars to provide a power boost. However, recently they have been incorporated into fuel efficiency too as the pump pressurises the fuel and air mixture entering the engine. These will be used in downsizing to reduce the size of the engine without a loss of power.
Well-to-wheel: The total environmental impact from the extraction of the fuel to the point it is used by the car. Therefore this takes into account factors such as the impact of transportation of the fuel.