How to stop smoking

Diesel emissions are harmful, and operators across the globe face a stark choice: adapt your engines voluntarily, or be forced to by law.


Diesel emissions are harmful, and operators across the globe face a stark choice: adapt your engines voluntarily, or be forced to by law.

When talking about the environment there is always a cost, whether it is to the world or your company's profit and loss.

However, with the glut of used machines pouring out of Europe at the moment it is easy to lose sight of clean concerns and ‘invest' in smoky, inefficient old equipment.



There are two reasons why plant operators should concern themselves with emissions. Firstly, there is the global warming issue that we have been hearing so much about recently.

Anything that burns will emit a certain amount of CO2, the most common of the six greenhouse gasses that contribute to climate change.

The more carbon that your plant emits means the closer we are to bobbing past the top of the Etisalat building on old inner tubes as the flood waters rise - it as simple as that.

The other threat is to the local environment from the millions of tiny soot particulates emitted in exhaust fumes.

These will get in the lungs and will make seriously ill anybody who has to breathe them in all day.

Of course this means your site workers, especially if the site you are working on is underground or at least partially enclosed.

Besides soot, which is a carcinogen, diesel engines also produce unburned hydrocarbons that are likely to cause throat and eye irritation.

If this wasn't enough, all engines and especially older ones, produce carbon monoxide, an odorless and colorless gas that inhaled in any quantity will lead to brain damage and even death.

Employees are never at their most productive when they are ill, so there is a distinct correlation between investing in modern, clean machinery and increased productivity.


Even these facts won't move everyone to change. However, there is a more immoveable deadline. By 2010 pretty much all of the plant sold around the world will need to meet new and tough international emissions standards.

Though these emission standards haven't reached the Gulf yet, with growing environmental awareness as exemplified by the recent climate change conference in Abu Dhabi, it can only be a matter of time.

Also, manufacturers are looking at developing ‘world standard' engines that can be used in any market, rather than the various types currently on sale.

This means a switch to Ultra Low Sulfur Diesel (ULSD), which could soon become mandatory anyway. It isn't available in the UAE yet, though, the region's oil producer ENOC is working on it and says it will be ready in ‘maybe a year'.

A cleaner alternative is compressed natural gas (CNG) Either petrol or diesel vehicles can be converted to run on this fuel.

While not exactly perfect for a happy planet, it is significantly lower in soot and NO2 than regular diesel.

Pakistan, India and Bangladesh CNG are used in the majority of private cars, while cities such as New Delhi and Ahmedabad also use it to power all their public transport.

The Pakistani province of Punjab has gone so far as to convert the entire fleet of several thousand auto-rickshaws.

Hong Kong has gone one step further and declared it illegal to operate a non-converted diesel taxi.

ENOC has announced that it is to start production of CNG in Feburary, and a number of Dubai's traditional abras have already been converted.

Although measures to cut toxins from plant vehicles have been around for nearly thirty years, it has only been in the last decade that serious attempts have been made to cut smog and different countries, different guides.

However, the US and Europe now have similar standards which most other countries are now in the process of adopting.

The US was the first country to clean up oil-burners with the introduction of Tier 1-3 standards, beginning in 1994. Engines complying with these standards had their soot emissions slashed, but the gases weren't tested for sulfur content.

However, the new Tier 4 requirement being phased in now, demands that particle matter, sulfur and nitrogen oxide be cut by a massive 90 per cent.

This is only possible with USLD and exhaust gas after treatment.

New York has become the first city to introduce rules specifically directed at construction machines, with legislation slashing emissions from around 3,400 ppm to just 15 ppm.

Laws in the EU meant that all new engines, whether on or off-road had to meet a phased set of rules known as Euro Standards.

The most recent, Euro IV applies to anything with a diesel engine, but different standards are set for large commercial vehicles and plant machinery.

In certain areas such as the London Low Emission Zone vehicles that don't meet at least the Euro-3 standard are banned.

This is causing a major headache for site managers trying to get machines to work on the Olympic 2012 site as plant hire companies are reluctant to invest in new equipment until the exact standards are agreed upon.

Whatever the exact requirement of Euro IV is though, there are many countries outside the EU that will adopt it anyway, which in turn will put pressure on countries inside the GCC to clean up their act.

Fortunately it is possible to run an old diesel on ULSD and bring down emissions.

One of the quickest ways of upgrading an older engine to run the clean juice is to fit a particulate filter. There are several types, the most common being the Wall Filter.

This works by using cordierite, a substance commonly found in catalytic converters, to filter the debris out.

Surprisingly these were fitted to a handful of construction machines as early as 1980, some sixteen years before they found their way on to any passenger cars. The wall filter provides a massive 85 per-cent reduction in soot.

However, fitting one is not always entirely straightforward though there are several companies that can retro-fit them.

Although it is unlikely to be cost-effective for operators in the Middle East, engine manufacturer Cummins now offers a solution to convert some of its earlier products to Tier 4 status.

The firm uses a particulate filter as well as exhaust gas recirculation as part of an ‘integrated technology solution' extending from air intake to exhaust after treatment.

Other engine enhancements also include the use of the patented Variable Geometry Turbochargers, advanced electronic controls and High Pressure Common Rail fuel systems.

The company insists that the Tier 4 modifications will lose no power compared to the previous specification and fuel economy may actually be slightly improved, depending on rating and duty cycle.

Buying replacement

Having to upgrade your machine can take it off site for a while. It may be far better to buy a new or newer machine with a better engine and all the necessary filters already in place.

The machine will still puff out CO2 of course, but at least this won't actually poison the workforce.

However, even this is not enough to reduce the soot produced by a further 30 per cent as demanded by the new rules. UK-based engine maker Perkins seeks to solve this by employing air-to-air coolers for the turbo.

This works by external air is used to cool the inlet air via an additional radiator (the air-to-air charge cooler). It's a highly efficient system where temperatures can be reduced substantially to levels close to non-turbocharged engines.

Introducing more air into the engine gives you lower emissions and improvements in fuel economy of up to 5 per cent.

The oil has to work less hard and so is changed less frequently. The engine's components are operating at a lower temperature, so they last longer.

Also, there is more torque for a given capacity, making the engine more responsive, particularly at lower speed.

Hybrid power

There is a way of bringing consumption and emissions lower still. If you are planning on buying brand new kit in a couple of years' time, you may well have the option of combined diesel and electric power.

While various non-road hybrids have existed for a while on paper, the world's first wheel loader to mix volts with oil has been developed by Atlas-Weyhausen in conjunction with engine maker Deutz of Germany.

Based on the popular AR65 model and earmarked for production in 2010, the new machine is said to reduce fuel consumption by up to twenty per cent while reducing harmful emissions accordingly.

Unlike hybrid cars, the vehicle starts and runs normally on conventional power. However, when a load is placed on the engine, electric motors are engaged and are used for drive.

The diesel engine itself has a sophisticated motor-generator installed where the flywheel would normally be fitted.

Because it is constantly energised when the engine is running, the hybrid drive system creates electrical energy which is stored in a battery pack.

The makers claim that the electric boost can provide the non-turbo diesel motor with enough power to effectively double the machine's nominal 50hp output, so benifiting both operator and environment.

Future technologies

Of course most of the heavy old loaders that graze Dubai's unfinished highways could fit two diminutive AR65's in their front scoop.

However, it is likely that various hybrid technologies will find their way in to even the most giant machines in time. The next step will be to find ever more efficient ways of storing electricity.

Some giant plant machines have been electrically powered for years; for example mining cranes and various shipyard machines are often wired into the area's grid system.

It goes without saying, though, that it would be extremely impractical to have an extension cord trailing from the back of a grader.

One of the newest ideas is to store hydrogen electrical energy on strips of metal. This would involve extremely complex, and as yet undiscovered hydrides, and so has got no further than the drawing board.

However, one thing is absolutely clear. The diesel smoking ban is now being enforced, and there will be no getting away from it.



This is a wide-ranging and often misused term that describes several types of fuel.

However, the most common type refers to that made from transesterified plant and animal oils.

Heralded as the fuel of the future in the West, it is claimed to be a ‘greener' alternative as the amount of carbon dioxide produced is offset by the amount absorbed by the plants as they grew.

This is reckoned by some experts to reduce the net carbon emissions by as much as 60 per cent.

However, there are several major flaws in the bio-diesel argument. For a start it is only marginally cleaner than regular diesel in terms of soot. Nitrogen oxide emissions are actually about ten percent higher.

The main problem with bio-diesel is the way it thickens when cold.

Although commercially produced fuel has greatly reduced this problem, the major engine manufactures will not honour the warrantee if more than a third of bio-diesel is used in every tank.

The fuel can also contain small, but problematic quantities of water.

Put simply, unless you change your fuel filters regularly, the greenest thing about bio-diesel is the amount of time your machine is out of action while the injectors are replaced.

Most popular


CW Oman Awards 2020: Meet the winners
A round of the thirteen winning names at the Construction Week Oman Awards 2020 that


Leaders UAE 2020: Building a sustainable, 'resilient' infra
AESG’s Phillipa Grant, Burohappold’s Farah Naz, and Samana's Imran Farooq on a sustainable built environment
CW In Focus | Inside the Leaders in KSA Awards 2019 in Riyadh
Meet the winners in all 10 categories and learn more about Vision 2030 in this

Latest Issue

Construction Week - Issue 767
Sep 01, 2020