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Written by by: Farah AlKhalisi http://www.channel4.com/
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by: Farah AlKhalisi
How green is the future of motoring?
There's no doubt that cars and trucks seriously pollute our skies. But
there are ways to reduce emissions and do our bit to help save the
planet. Here's some essential reading for you eco-conscious motorists.
Progress towards making more environmentally-friendly cars may seem
frustratingly slow, but in the automotive industry, it's often the
smaller, less headline-grabbing advances which can prove the most
significant.
The Holy Grail of the practical, user-friendly, reliable and, most
importantly, affordable and commercially-viable zero-emissions vehicle
is still some way off, but there are a number of year-on-year
improvements, trends on the horizon and exciting developments which are
realistically achievable in the near future.
Much of this is
being driven by ever-more stringent legislation on emissions and
consumption, and increased pressure in commercially-important car
markets such as California and Canada as well as from the European
Union, and car makers are being strongly encouraged to clean up their
acts and offer more efficient, cleaner vehicles - quickly.
Don't underestimate the impact of enhancements to existing petrol and
diesel engine technology: the good ol' internal combustion engine has a
lot of life left in it yet. The average new car sold in the UK today is
far, far cleaner in terms of the emissions it pumps out than its
equivalent twenty, or even ten, years ago. Credit developments such as
multi-valve engines, variable valve timing, catalytic converters and
more advanced electronically-controlled engine management, for a start.
Improvements are particularly notable for diesel-engined cars: although
diesels have long been credited with better consumption levels and
lower carbon dioxide output, they have fallen short in terms of other
emissions, such as nitrogen oxides and harmful particulates - unburnt
byproducts of the combustion process, or the black smoke often spotted
coming from a diesel's tailpipe. But in recent years, not only have
diesels improved immeasurably in terms of performance, refinement and
general driveability, their fuel consumption is ever better and
emissions ever lower.
Direct-injection and common-rail diesel systems are now the industry
norm - for passenger cars, at least - and the new generation engines
feature ever-more precise and accurate injection of fuel into the
cylinders.
The Volkswagen Group, for example, has vaunted its Pumpe-Duse, or
unit-injection, engines, which are powerful and economical, but is now
moving towards a technology called piezo-injection: this involves an
electric current being passed through a stack of ceramic elements,
which expand to shoot fuel into the cylinders, instead of the
traditional magnetically-charged solenoids.
Piezo-injection also features in the Toyota/Lexus D-4D Clean Power
diesel engine, along with Toyota's D-CAT catalyst system. This engine
has the lowest-yet compression ratio of any production diesel engine,
and Toyota promises market-leading low levels of emissions such as
nitrogen oxide and particulates as well as excellent fuel consumption,
low carbon dioxide output and good refinement.
Technology such as this, combined with sophisticated engine management
and throttle control systems, backs up the claims of companies such as
Volkswagen who believe that, contrary to the popular image that diesel
is dirty, diesel fuel has a long-term future as an eco-friendly fuel,
especially since it can be derived from sustainable, organic sources
(more on this later).
And even in less high-tech engines, emissions can be cleaned up by the
fitment of particulate traps or filters: although these are by no means
widely available, they now demand no maintenance during the projected
lifespan of the car, and are offered in an increasing number of
mainstream diesel models. There have been calls to make them
compulsory-fit on vehicles which do not otherwise meet acceptable
emissions standards, as a quick-fix solution.
imilar advances are being made in petrol engines, too. Early
direct-injection petrol units such as the Mitsubishi-Volvo GDI engine
weren't particularly inspiring, and progress has been slowed by the
poor availability of low-sulphur fuel, especially in the UK, but the
new wave of advanced petrol engines such as the VW-Audi FSI (fuel
stratified-injection) units, the Fiat-Alfa JTS and the Mercedes-Benz
CGI are more sophisticated.
As with direct-injection diesel
engines, these shoot fuel directly into each cylinder's combustion
chamber at much higher pressures: the higher the pressure, the cleaner
and more efficient the combustion. FSI, however, incorporates a mode
known as "stratified charge", which gives the fuel-air mixture in the
cylinder an extra swirl to create an electric charge (much as a
thunderstorm is created) at the point it reaches the spark plug.
This allows for a leaner fuel-air mixture, using less fuel, and the
excess air forms an insulating layer in the cylinder to guard against
heat energy losses.
Exhaust gas recirculation systems - now frequently fitted to non-FSI
engines as well - divert some of the waste exhaust gases back up for
re-combustion, working with catalytic converters which process the
remaining surplus harmful nitrous oxides into inert nitrogen.
Besides reducing such emissions, FSI technology can reduce
fuel consumption by an estimated 15 percent - which was why it was used
in Audi's all-conquering R8 Le Mans racers, cutting down the number of
refuelling stops needed. The Mercedes-Benz CGI engine - Mercedes
actually developed the first direct-injection petrol unit, for its
original 300SL - works in a similar way.
There are numerous other promising developments in petrol engine
technology; one with a lot of potential is a British-developed
innovation, an engine which can switch between two- and four-stroke
operating modes. A collaboration between consultancy Ricardo and
Brighton and Brunel Universities, the government-funded 2/4SIGHT
project promises emissions improvements of up to 30 percent, the
potential for significant engine down-sizing and production costs no
greater than those of an equivalent diesel unit.
The first test engine built will be a 2.0 V6 giving performance similar
to a conventional 3.4 V8, and the next a little 1.0-litre unit which
could be used in large family cars, with performance equivalent to a
1.8-2.0-litre. This is a good five years off production reality,
however.
Advances just entering into the motoring mainstream include
Displacement on Demand, stop-start and hybrid technology. Displacement
on Demand (DoD, or cylinder shutdown) is arriving in high-performance,
large-engined cars like the Chrysler 300C HEMI.
Cadillac first tried this out in the early 1980s on the Eldorado 4-6-8,
so called because it could run on four, six or eight cylinders
depending on demand. It was a resounding non-success, but this time
round, it looks to be a go-er.
n a similar concept to the Cadillac V8, the HEMI 5.7 V8 (so named for
its hemispherical-shaped combustion chambers), four out of the eight
cylinders imperceptibly shut down when the car is cruising, yet kick in
again when the throttle is pressed more urgently.
The fuel
consumption gains aren't spectacular, but in a car that would otherwise
struggle to do 20mpg, every little helps. Expect to see it appearing in
new 4x4s and large MPVs, as well as in large-engined luxury models and
sports cars in the not-too-distant future.
As with so many new advances, the cost of fitting such technology is
initially high, limiting it to expensive, top-end vehicles, but it
should gradually appear in a wider variety of ranges.
Stop-start, however, has made its debut at the other end of the car
market. Volkswagen used such a system in its rather disconcerting Golf
Eco of the early '90s - it didn't take off - but it has since been
honed and resurrected by PSA Peugeot-Citroen.
As its name suggests, the C3 Stop-Start (with the 1.4i
petrol engine and SensoDrive clutchless gearbox) cuts out when you come
to a halt at traffic lights or in slow-moving traffic, and re-starts
itself when you want to start off again and lift off the brake. It's an
effective and cheap way to reduce fuel consumption - Citroen claims 15
percent savings in the C3 - and is also available with the smaller C2.
The technology grabbing all the headlines, however, is hybrid
technology: cars like the Toyota Prius - the must-have vehicle for
Hollywood stars with an environmental conscience (or those seeking
positive PR) - and Honda Civic IMA, Honda Insight and Ford Escape
Hybrid have outsold all manufacturers' expectations.
These effectively combine an efficient petrol engine with an electric
motor; the electric motor propels the car silently and cleanly from
start-up and at low city speeds, with the petrol engine kicking in when
more acceleration is needed, and is assisted again by the electric
motor when, for example, more urge is required for overtaking.
Other manufacturers have also pledged to offer hybrids in the near
future. Cynics have argued that hybrids still offer little - if any -
advantage in terms of fuel consumption and cost-per-mile than a
comparable diesel engine, and they are more expensive to produce and
buy, but the electric 'city' mode is an undoubted plus point, and after
all, Leonardo DiCaprio owns a whole fleet of Toyota Priuses...
Diesel-electric hybrids promise even greater advantages, and the first
production examples should appear in the near future, although these
are even more expensive to produce than petrol hybrids.
Hybrids are still seen as a relatively short-term solution, however, as
they still depend on finite-source fossil fuels, and companies such as
BMW have refrained from jumping on that bandwagon. BMW has been
focussing on hydrogen and fuel cells. Unlike other manufacturers,
though, BMW uses hydrogen in a conventional combustion engine to
convert energy directly into drive power.
Other manufacturers believe fuel cells driving electric motors is the
way forward: a fuel cell car basically takes hydrogen as a fuel source,
uses a platinum converter to set up a chemical reaction to break it
down into steam - the only by-product - and releasing electrical
energy, which is stored in batteries to power electric motors.
Although at the moment hydrogen is expensive to refine for fuel use, it
can be extracted from water, and if it becomes widely adopted,
economies of scale will make it more commercially-viable.
Other companies such as General Motors are working with fuel companies
to establish an infrastructure for supply and retail of hydrogen, and
specialists such as Ballard are getting closer to solving problems such
as on-board storage of the potentially explosive gas, which demands
very high pressure containers.
There are test fleets running in Europe and the US, however, and
hydrogen powertrains are being fitted in a number of buses and
specialist commercial and industrial vehicles - bulky storage tanks are
less of an issue with such applications. Popular opinion is that
hydrogen probably is the fuel of the future - but not just yet.
Companies such as Ford may have canned their electric vehicle
programmes in favour of concentrating on hybrids and hydrogen, but we
shouldn't rule out the EV, either.
GoinGreen sells the Indian-built G-Wiz in London, which offers tax and congestion charge breaks to those willing to live with its limited range.
Although in general, EVs have failed to make much of an impact as they
have typically been a bit slow, have been heavy and had limited load
space due to the need to carry huge battery packs, and because they
have had limited range (the distance possible between re-charging).
They have also tended to need a lengthy recharging process, usually
overnight.
Some local authorities have been enlightened enough to provide
on-street recharging facilities - France, in particular, has taken to
EV use - the infrastructure for recharging is still an issue in many
areas, causing problems for people without their own driveways and
garages for plugging-in - typically city dwellers, the people most
likely to want an EV in the first place.
There are new breakthroughs on the horizon in terms of smaller, lighter
batteries, affordable home-recharge kits, batteries with much greater
range and so on, and if these can be applied to automotive use, the EV
could well stage a comeback.
Also falling out of favour have been alternative fuels such as LPG
(liquid petroleum gas). LPG was hailed a few years back as an ideal way
to cut your motoring costs - but this was largely due to the tax breaks
the British government offered on the fuel, and the government grants
to fund LPG conversions, rather than any large improvement in fuel
consumption.
True, LPG has different combustion properties to petrol in liquid form,
burning more cleanly, but the gains aren't that spectacular, which is
why the government is moving away from incentivising LPG use.
CNG (compressed natural gas, as in your cooker) is cleaner-burning
still - and popular in Scandinavian countries - though it is not widely
available in the UK. Volvo has offered CNG-compatible models, but these
have not sold in any great numbers.
Alternative fuels with more of a future are the so-called biofuels,
derived from organic, sustainable sources rather than finite
fossil-fuel stocks. These typically also burn more cleanly than
conventional diesel and petrol.
Basic low-tech diesel engines can use oils from a variety of sources -
from byproducts of the food and catering industries to more refined
substances obtained from rapeseed oil, sunflower oil or indeed, oils
from a number of biological, re-growable substances.
There are numerous anecdotes about drivers running their cars on
filtered chip-shop waste oil and off-the-shelf sunflower oil in Britain
alone, as well as motorists in more exotic climes using coconut, peanut
or palm oils.
Caution is advised if you fancy trying this out: modern diesel engines
with complicated injection technology (as described above) aren't
compatible with these relatively crude substances as yet - their
complex electronic control systems can't cope - but the hurdles to
overcome are fairly minor.
It's similarly easy to convert petrol engines to run on alcohol-type
fuels such as ethanol, popular in many countries and championed by
General Motors, amongst others.
Of some concern are ethical issues: notable environmentalists have
pointed out that to substitute even a proportion of international fuel
demand with biofuels, the land requirements to grow the crops to supply
the raw materials are such that Third World countries could end up
growing such crops at the expense of their own food needs, and at risk
to damaging their local eco-system with such intensive farming.
However, on a small scale, even using land which is currently set-aside
under EU subsidy could produce significant amounts of fuel to offset
the use of so-called 'dinosaur derv'. In the short term, biofuels are
increasingly being used in a blend with conventional fuels.
Whilst it's easy to take the view that the oil companies are just nasty
global capitalist corporations sucking the world's natural resources
dry and ruining the eco-structure in fragile areas, they do have a
financial interest in environmental issues: they can't keep selling
fossil fuels when they run out or it becomes less viable to extract
them from inaccessible areas. This factor alone is likely to stimulate
sustainable-source fuel development.
And back at base, the car companies themselves are cleaning up their
acts as well. Though opening manufacturing plants in less-regulated
regions such as China and Russia side-steps some barriers, the main
manufacturing clusters in Europe, Japan, the US and Canada are subject
to ever-more stringent controls on harmful emissions, and pressure to
reduce their immense energy demands for the manufacturing processes.
The air quality in areas like Detroit, and around the huge facilities
in Ontario, Canada, for example, is said to have improved significantly
in recent years, and as ageing facilities are upgraded and updated,
this can only improve.
Legislation on the safe scrapping of vehicles and recycling is pressing
home further issues, especially in Europe, where manufacturers are
forced to take back all the cars they have produced when they reach the
end of their viable working life.
All in all, it's fair to suggest that the motor industry is now the
cleanest it has ever been, and it's getting cleaner every year.
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