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Auto Stop Start
Pros: Why burn fuel when the car is not moving?

Cons: Adds a significant cost to the vehicles where it could give the greatest advantages ie small city cars. Of little benefit on motorway journeys.

Switches off the engine when the vehicle is stationery, and then starts it again when the driver wants to move off. It's a relatively simple system, which aside from the electronic control, only requires an uprated starter motor and a heavy duty battery.
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.

Fitted to: BMW, MINI, Citroen and Land Rover models.





Bio Diesel
Diesel fuel oil derived from plant material

Pros: Can be used in some existing diesel cars. Needs no special refuelling arrangements. Can seriously reduce CO2 outputs.

Cons: Energy required to produce the fuel makes its green credentials questionable. Most cars require a blend of fuel using up to 95 per cent fossil based diesel. Growing raw materials could have an impact on eco system.

Not to be confused with straight vegetable oils or waste cooking oils which can be used to fuel some converted vehicles, Bio Diesel is derived from a variety of plant sources - predominantly rapeseed or soybean oil. Although it can be used neat, most commercially available bio diesel is blended with fossil diesel. Few vehicle manufacturers are happy to guarantee their cars on 100 per cent bio diesel and will only allow vehicles to run on B5 type (5 per cent bio diesel) if the warranty is to remain valid.
Both Renault and PSA are happy to recommend B30 (30% bio diesel) for some of their vehicles, although this type of fuel is not readily available in the UK. Bio Diesel does offer the potential for serious reductions in the output of CO2, especially when taking into account the offsetting potential of growing the raw materials. Environmental legislation may ultimately force the hands of car manufacturers to make their vehicles completely compatible with the fuel.





Bio Ethanol
Petrol substitute produced from plant material

Pros: Fuel from a sustainable source. Some compatibility with existing cars. Needs no special refuelling arrangements.

Cons: Growing materials could affect economies or even food supply in third world countries. Poor energy density means low MPG.

A petrol substitute fermented from plants as diverse as sugar beet, corn, soya beans or even waste straw, bio ethanol has long been used to supplement fossil fuels in some South American countries. Most petrol engines could use up to a 10 per cent Bio Ethanol mix with little modification, but the benefits are marginal unless the engine is specifically engineered for the fuel. Bio ethanol has 34% less energy by volume than petrol, and therefore burns at a greater rate to give the same power outputs.
The burning process also creates CO2, but it could be argued that some of this is offset by the growing process of the raw materials.





Bluetec
Technology designed to reduce Nitrogen Oxides output of diesel engines

Pros: Lower emissions from an already efficient combustion system.

Cons: Expense, limited availability for now.

Nitrogen Oxides are one of the more unpleasant by-products of burning diesel. Primarily developed by Daimler Chrysler to bring its diesel engines into compliance with the ever stricter emissions regulations of some US states, Bluetec is actually a combination of several technologies.
DeNOX uses an oxidising catalytic converter combined with a particulate filter, where the AdBlue system injects a water based additive - which contains ammonia -into the exhaust system which reduces the Nitrogen Oxides to nitrogen and water in a catalytic converter fitted further down the system.
The system has already been adopted by VAG and Jeep.







CO2 Air Conditioning
Air conditioning system using CO2 based refrigerant

Pros: Reduces the risk of further damage to the ozone layer caused by escaping refrigerant.

Cons: CO2 is a major factor in global warming.

By using CO2-based refrigerant as opposed to fluorocarbon-based mediums, these systems pose a reduced environmental threat - although neither could be regarded as environmentally friendly. Fluorocarbon-based refrigerants have long been known as a major factor in damage to the ozone layer - whether they have escaped from damaged air conditioning systems or domestic fridges.
Even though CO2 is major contributing factor to global warming, its use is preferred to the fluorocarbon-based type. As such, all new cars sold in the European Union from 2011 must be equipped with a CO2 air conditioning.







Direct Injection
Fuel is injected directly into the combustion chamber for maximum efficiency

Pros: Low fuel consumption, lower emissions.

Cons: New and expensive technology.

In direct injection equipped engines, fuel is highly pressurised and injected directly into the combustion chamber as opposed to siting the injectors in the induction tract as in more conventional engines.

Coupled with state of the art engine management systems, direct injection enables the engine to run much leaner mixtures, which means vastly reduced consumption and emissions.
Surprisingly, this isn't a new technology - Mercedes used a Bosch system in the 1950s - but it has only been with the advent of the latest management systems and highly accurate injectors that the system has come of age. Expect to see direct injection become a common feature on many more petrol engined cars in future.







. Displacement On Demand
An engine which shut down some of its cylinders when they're not needed

Pros: Improved fuel economy.

Cons: Doesn't have an enormous impact on CO2 emissions.

Displacement On Demand (or Active Fuel Management) works on a very simple premise - smaller engines use less fuel big engines. Why use all of the engine's capacity when you don't need it, for instance, while cruising under light load? DOD systems shut down some of the engine's cylinders when they're not needed, thus saving fuel and reducing exhaust emissions. The theory also dictates that when an engine is cruising on light throttle it is actually having to work harder to draw air into the engine which is an inefficient process - known as pumping losses. By closing down some of the cylinders, these losses are also reduced.
Developed by General Motors for use on their V6 and V8 engines, the system showed a fuel saving of between 6-8 per cent.







Down Sizing
High Tech small engines with the power outputs of larger, conventional engines

Pros: Great performance with reduced fuel consumption and CO2 emissions.

Cons: Expensive.

Down Sizing describes the process of replacing a naturally aspirated engine with one of a smaller cubic capacity, but to ensure the power output is maintained, the smaller engine usually features forced induction, courtesy of either a supercharger or turbocharger. Or in exceptional cases, both. Manufacturers are already demonstrating that downsizing works, and it allows motorists to enjoy performance, good fuel economy and be kind to the environment in one high tech package.

Fitted to: VW Golf Twincharger, Vauxhall Astra 1.6 Turbo

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