Tier 3 / Stage III-emissions compliant Engine

The new generation ( Tier 3/Stage III-emissions compliant ) engines now on the market from leading construction equipment suppliers provide very low emissions levels to meet the latest environmental regulations. But how well do they deliver in terms of fuel economy and long-term durability? Angus Fotheringham, Komatsu Australia’s Business manager, general construction, provides some answers.

 

 

The current generation of Tier 3-compliant engines have been designed to meet very stringent emissions regulations put in place by environmental agencies in Europe, the US and Japan – and as such, represent the pinnacle of construction equipment engine technology.

 

Having said that, we can expect to see even more work on construction engines over the next few years, to achieve Tier 4 regulations (coming into force in the US between 2011 and 2015). Already, the on-highway transport industry is rolling out Tier 4-compliant engines.

 

 

To meet the current Tier 3 requirements, the current generation of engines use various methods to minimise the levels of nitrous oxide (NOx), particulate matter (PM) and other emissions that pollute the air.

 

Common to all engine manufacturers’ solutions are very precise electronic engine management systems that can very accurately measure and meter the levels of fuel and air being delivered to the combustion system.

 

As with all modern diesels, critical factors include clean fuel and correct filtration management, the correct engine lubricants, and proper engine maintenance management practices.

 

However, in achieving the lower emissions required under Tier 3, different manufacturers have adopted different approaches.

 

In Komatsu’s smaller ecot3 construction equipment engines, Tier 3 compliance is being achieved primarily through sophisticated electronic engine management.

 

In its larger construction equipment engines, Komatsu, as with most other major engine manufacturers, has opted for what is known as cooled exhaust gas recirculation (EGR) as part of its ecot3 solution to comply with lower emissions standards.

 

As its name implies, EGR involves recirculating a portion of cooled exhaust gases so that the NOx and PM levels are further reduced when the exhaust gases are released to the atmosphere. This process also helps to reduce any unburnt particulates during the combustion process.

 

 

EGR technology is not new; it has been around for at least 30 years, and is regarded as reliable and well proven – although today it is applied to modern engines in a far more technically advanced manner. In addition, EGR does not require the fitting of a particulate filter, which requires periodic replacement.

 

But in addition to EGR, Komatsu’s new generation ecot3 engines combine a number of other advanced-technology solutions. These include:

• A high-pressure common-rail multi-stage fuel injection system
• A patented piston/cylinder design to deliver more complete burning of fuel
• An advanced engine management system that controls the burning of emission-causing particulates inside the cylinder.

These processes, combined with a liquid-cooled heat exchanger, significantly cool the recirculating exhaust gases before they re-enter the cylinder, resulting in a system that runs more efficient than other EGR-based engines.

 

In addition, Komatsu’s ecot3 unique cylinder design results in greatly improved combustion, for a far more efficient fuel burn.

 

The end result of this technology, in addition to significantly lower emissions, is reduced fuel consumption – a major cost-saving benefit in today’s environment of high fuel costs.

So what are the key factors in engine life? There are five critical factors that all diesels – no matter what their age or technology – require for efficient, reliable and long-term operation. These are:

• The right operating temperature (in other words, correct cooling)
• Clean recommended engine oil
• Clean air
• Clean fuel that meets the required standards
• Regular maintenance (including oil analysis).

But there is one more factor that is often overlooked: Fuel burn.

 

An engine that burns more fuel – in other words, that is less fuel efficient – will have a shorter life than an engine burning less fuel.

 

Fuel burn, the amount of diesel that goes through an engine during its life, has a direct correlation to engine longevity. The more fuel an engine burns, the harder the components are working, and the sooner it will wear out.

 

Conversely, a more fuel-efficient engine – one that burns less specific fuel – won’t be working so hard and will have a longer life (all those other factors mentioned above being equal).

 

That’s why good fuel efficiency at optimum performance should be a key element that customers look at when choosing a machine.

 

Not only will the machine be kinder on your hip pocket every time you go to fill it up, but – provided you look after it and comply with the manufacturer’s maintenance requirements – you will get a longer life from it. That’s an important consideration when you think that approximately 30% of a machine’s repair costs over its life are in the engine.

 

In addition, the more fuel-efficient a machine is, the fewer emissions it will be producing per tonne of production, simply because it’s burning less fuel.

 

And that’s why Komatsu has paid considerable attention to developing Tier 3 engines that are more fuel-efficient than their Tier 2 predecessors.

 

As an example, Komatsu’s recently released WA600-6 wheel loader, with our new ecot3 Tier 3 engine is already proving more fuel-efficient in heavy duty quarrying face loading and load-and-carry operations in Australia than its Tier 2 predecessor.

 

In contrast, there are some Tier 3 engines around from other manufacturers which burn more fuel than their Tier 2 predecessors.

 

All this places Komatsu in a leading position in the move to Tier 4 requirements in the next few years, with Japan looking to demand the most stringent emissions requirements of any country.

 

And unlike other manufacturers’ solutions, Komatsu’s ecot3 technology is already “Tier 4 ready”, and therefore well positioned to meet these requirements, at the same time delivering unmatched fuel efficiency with longer engine life and better reliability.

 

Sumber : Komatsu Australia

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Komatsu Engine Technology

 

Diesel engines boast such excellent features as reduced CO2 emissions to which global warming is widely attributed. However, diesel engines emit nitrogen oxides (NOx) and particulate matter (PM), and concerns regarding their impact on the atmosphere and human body have fueled demand for the development of “clean” diesel engines that dramatically reduce these substances.

NOx is emitted during high-temperature combustion, while PM tends to be emitted when attempting to reduce NOx. This makes the reduction of both substances, while improving fuel efficiency, an immense technological challenge.

 

As shown on page 16, Tier III regulations for off road engines will be phased in from 2006 in such areas as the United States (Tier III) and Europe (Stage IIIA). The U.S. Environmental Protection Agency (EPA) plans to implement Tier III regulations from 2006 that call for a 40% reduction in NOx compared with Tier II regulations. There is a strong emphasis on reduction of off-road diesel engine emissions from construction equipment, particularly for engines used in heavy-duty (high-revolution, high-load) operations,which is a main factor underpinning increased technological development targeting construction equipment.

Building on more than 70 years of experience in off-road engine development for construction and mining equipment, Komatsu is able to design high quality engines that optimize machine functionality by leveraging a wealth of accumulated technologies and expertise as an equipment manufacturer.

In meeting the deadline for implementation of these regulations starting from 2006, Komatsu will be gradually releasing a new Tier III (Stage IIIA)-compliant engine from 2005 that combines reduced NOx and PM emissions with improved fuel efficiency.There are several notable features to these engines as follows.

1. Heavy-Duty High-Pressure Common Rail (HPCR) Fuel Injection System

Komatsu incorporated a heavy-duty High-Pressure Common Rail (HPCR) fuel injection system in designated Tier (Stage) II diesel engines to achieve both NOx and PM reductions and better fuel efficiency.The newly developed engine will see further improvement in heavy-duty HPCR functionality and more widespread application.

Specific features of the heavy-duty HPCR fuel system are its ability to inject high-pressure fuel accumulated in the common rail into the combustion chamber, thus atomizing fuel spray and optimizing combustion for better fuel efficiency, lower emissions and higher performance. Another feature is its flexibility to maintain the optimal fuel injection volume, pressure and timing through precision electronic control. This results in near complete combustion, contributing to PM emissions reduction and dramatically improved fuel efficiency.

The heavy-duty HPCR fuel system also reduces engine noise by compartmentalizing injection in a multi-staged injection process and enables high low end torque on account of its high-precision fuel control and flexible, high-pressure capability regardless of engine speed.

 

Komatsu was among the first construction equipment manufacturers to apply HPCR technology to Tier (Stage) II engines. Given its ever-wider application in trucks and automobiles since 1995, especially in Europe, HPCR is virtually the global standard for trucks and automobiles. For Tier III (Stage IIIA) engines, the fuel system has been upgraded and fuel Heavy-Duty HPCR

 

injection pressure of up to 1,800 bars can be achieved compared with 1,400 bars for Tier (Stage) II engines. In addition, more durable supply pumps, injectors and systems are employed to withstand any harsh conditions around the world. The Komatsu heavy-duty HPCR fuel system is likely to become the global standard for off-road heavy-duty machinery in the near future.

2. Heavy-Duty Cooled EGR (Exhaust Gas Recirculation)

 

Komatsu is one of the front runners in the construction and mining equipment industry to use the heavy duty cooled Exhaust Gas Recirculation (EGR) system in medium and large engines, which is effective in lowering NOx without sacrificing fuel economy.In the heavy-duty cooled EGR system, a portion of gases emitted from the engine is cooled through the
EGR cooler, and it is diverted into the cylinder as inert gas. This feature reduces the concentration of oxygen in the combustion chamber, and thus, the combustion temperature and NOx. Further, this system can reduce NOx without retarding fuel injection
timing. Cooled EGR is considered the best technology for reducing NOx in diesel engines, and most of the leading engine manufacturers have employed cooled EGR with resounding success in engines that meet stringent on-road engine regulations since 2002.

Komatsu has developed the innovative high capacity heavy-duty Twin-Valve Cooled EGR system in light of the rugged and high-load usage of construction equipment and industry regulations. Key features include a Twin-Valve EGR system with intake air bypass for high-load and wider speed- range usage (patent pending); highly reliable and durable,high-precision electronic-controlled hydraulic twin valves; and a highly durable EGR cooler for operation in rough environments.

 

Komatsu took advantage of its long-established Heavy-Duty Cooled EGR engine technologies for construction equipment. Tens of thousands of hours of bench tests and field tests have been conducted to assure quality for maximum reliability and durability. In consideration of heavy duty usage and various conditions all over the world,Komatsu employed extra-thick, corrosion-resistant materials in the EGR cooler.

The cooled EGR technology is bound to become the global standard in construction equipment engines, and will undoubtedly be featured on the next Tier IV (Stage IIIB) line of engines.

3. Total Electronic Control

Komatsu has employed electronic controls in the new engine to enable total control over the equipment,such as variable horsepower control, hydro-static engine control and torque-converter engine control.Variable horsepower control, for example, selects the optimal fuel-consumption map and output of construction equipment in accordance with actual condi-
tions. This is the kind of technology that Komatsu, as a manufacturer of both engines and equipment, has the proven capability to develop.

4. Combustion Technology

Several improvements have been made in the combustion chambers for better air/fuel mixing and optimal combustion. For small engines, in addition to employment of HPCR technology, a four-valves-per-cylinder design is applied so that the fuel injection nozzle is placed in the center of the combustion chamber, enabling much greater optimal combustion.

5. Air-to-Air Charge Air Cooling

 

The air-to-air charge air cooling system is effective for lowering the charge air temperature to inhibit NOx emissions without sacrificing fuel economy.For this reason, more Tier III (Stage IIIA)-compliant engines will be fitted with this system.

 

In the years ahead, Komatsu will strive for technological innovation in further developing low-emissions engines in preparation for future environmental regulations, while providing global customers with products that are both ecological and economical.

 

Sumber : Komatsu VIEWS Magazine

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Common rail injection: cleaner, greener engines

 

Operating principles of the Common Rail Injection system. 

 

Common rail injection systems are becoming increasingly common on today`s high-tech diesel engines. David Laidlaw, Komatsu Australia`s product manager, articulated dump trucks and large dozers, looks at the reasons why.

 

You may have started hearing the term `common rail injection` system in some recent television advertising for prestige diesel-engined cars.

 

Well, it`s also a term you`ll hear a lot more of in relation to earthmoving equipment.

 

Common rail injection (CRI) systems are delivering substantial benefits in terms of emissions and fuel consumption; they are seen by many as giving diesel engines the potential to become much cleaner than petrol engines in the future.

 

Komatsu, and a number of other heavy equipment manufacturers, are starting to introduce CRI system engines; in this article, I`ll look at how they work and what they mean for equipment owners and users.

 

First of all, what are the advantages of common rail injection systems?

 

In summary, they are as follows:

-- Cleaner / lower emissions and higher outputs due to high-pressure injection at in all usage ranges

-- More efficient combustion

-- Improved fuel efficiency

-- Reduction in noise and emission due to injection rate control

-- Improved performance due to increased flexibility in injection timing setting

-- Faster and smoother acceleration

-- Independent control of injection pressure in response to rotation and load.

 

How a CRI system works

Key CRI components are the supply pump, a `common rail`, an injector, sensors to detect running condition of engine and a computer (ECM) to control these devices.

 

A CRI system injects fuel to the engine at much higher pressures than conventional fuel injection systems. Typically, CRI injection pressures are around 20,000 psi, compared with 4000-5000 psi for a conventional system.

 

High-pressure fuel from the supply pump is distributed to an injector mounted on each cylinder by means of the common rail, with fuel injection quantity and timing determined by controlling the injectors.

 

Compared with conventional injection system characteristics, a CRI system has the following features:

-- Injected fuel quantity and injection pressure are independent of each other, and are definable for each and every engine operating condition, allowing optimum air/fuel mix formation

-- At the beginning of the injection process (during the ignition lag between the start of injection and the start of combustion), injected fuel quantities are very low.

 

Environmental benefits

Engine manufacturers have developed CRI systems as a method of getting diesel emission levels down to internationally specified standards.

 

You will have noticed that most new machines now being released have engines capable of meeting US and European `Tier II` emissions standards. In 2005, even more stringent `Tier III` standards will be introduced, and CRI engines will be essential to meet their requirements.

 

The end result is that equipment fitted with such engines produces substantially lower emissions than earlier models -- even those just a few years old.

 

The other major advantage is in fuel consumption -- which goes directly to a machine owner`s bottom line.

 

Typically, CRI engines provide fuel savings of 10-20% compared with equivalent sized earlier-model machines.

 

It has to be said that in Australia, CRI engines are not yet able to meet their full potential in terms of emissions levels and fuel consumption due to relatively high sulphur levels still allowed in Australian diesel.

 

Our sulphur PPM levels are significantly higher than those permitted in the US or Europe, but the federal government is about to introduce pricing incentives to encourage rapid take up of low sulphur fuel. High-sulphur fuels will be phased out in the next few years.

 

However, even with our high sulphur PPM levels, the high-pressure, clean-burning CRI engines are substantially more fuel efficient and less polluting. It`s just that the best is yet to come.

 

By : David Laidlaw,

Komatsu Australia`s Product Manager, articulated dump trucks and large dozers

 

Sumber : www.komatsu.com.au

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Komatsu’s Tier 3 Engine Technology

Innovative Engine Technologies for Construction & Mining Equipment

 

Tier III / EU stage IIIA regulations aim to slash NOx emissions in a big way. But if you lower combustion temperatures to try to do that, you also raise emissions of particulate matter and jack up fuel consumption.

KOMATSU’s innovations have reduced NOx and soot – while boosting fuel economy at the same time! We are using “total vehicle control” to improve performance using the best combination of our advanced technologies.

 

Key Technology-1

 

Electronic Control System

 

Komatsu's electronic control system uses a comprehensive set of sensors to optimize vehicle performance to meet the varying needs of operation. This system reduces environmental impact: cutting emissions of particulate matter and NOx, enhancing fuel economy and reducing noise. It also offers better performance in severe environmental conditions, including high altitudes, and extremely high and low temperatures.

 

Key Technology-2

 

Heavy Duty HPCR System

 

In this system, a high-pressure pump is used to pump fuel into an accumulator chamber – the so-called "common rail" in the common rail system. From there, the fuel is injected in the engine cylinders with injection optimized by an ECU (electronic control unit). In order to achieve both reduced emissions and high performance, the Heavy Duty HPCR optimizes control of multiple injection volumes ensuring maximum high-pressure performance. It also maximizes combustionÑwhich in turn reduces the production of PM. So, engine power is up; noise is down.

 

Key Technology-3

 

Heavy Duty Cooled EGR System

 

This system returns some of the low-oxygen exhaust gas to the cylinders, which helps prevent nitrogen and oxygen from bonding during combustion and has the effect of reducing the production of NOx. The Komatsu Heavy Duty Cooled EGR system has been especially designed for high performance under the most demanding conditions.The twin valves use Komatsu's own highly durable hydraulic drives.
By using "EGR gas" more effectively to meet the high-pressure requirements of construction & mining equipment, this system reduces NOx emissions and improves fuel efficiency at the same time. And the structure of the cooling unit of this system has been designed to enhance the efficiency of cooling by lowering thermal stress. In addition, the EGR cooler is made from special materials for better corrosion-resistance. These features make the system more reliable and durable, so as to meet the needs under the harshest conditions.

 

Key Technology-4

 

New Combustion System

 

The shape of the combustion chamber has been specially configured on the basis of computer simulations and analyses. Our New Combustion System optimizes combustion timing and ignition – reducing NOx and PM, improving fuel consumption, and cutting noise – all at the same time.

 

Key Technology-5

 

Air to Air Charge Air Cooling System

 

Komatsu uses a turbocharger to feed the engine cylinders with the larger volumes of air necessary to improve combustion efficiency, lower emissions, and enable higher engine power. However, compression generates heat, so we also use a high performance hydraulic cooling fan to cool the air to an optimum temperature and optimize air supply. This contributes to reducing NOx and fuel consumption.

Sumber : http://www.komatsuamerica.com/Tier3.html

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