07 March 2008
Engine emissions regulations are becoming more stringent and environmental concerns are growing in the construction industry.
Therefore producing cleaner engines is increasingly important. Engine manufacturers are also looking at increasing the use of bio-diesel in their engines.
In order to comply with the Stage IIIB engine emissions regulations particulate matter (PM) emissions must be reduced by - 90%. The legislation also requires a -45% reduction in Oxides of Nitrogen/Hydrocarbon (NOx) and by 2014 – Stage IV – this level will be reduced -90% to near zero emissions.
Stage IIIB legislation comes into force in 2011 and the first engines to be affected will be in the 130 to 560 kW powerband. The 75 to 130 kW and 56 to 75 kW powerbands follow this in 2012 as well as the 37 to 56 kW powerband in 2013. The Stage IV/Tier 4 final regulations will be implemented in January 2014 affecting the 130 to 560 kW and 56 to 130 kW powerbands in January and October respectively.
Some engine manufacturers, such as Cummins, have already revealed the technologies they will use to meet the Stage IIIB emissions standards across the first powerband to be affected (130 to 560 kW). The company's core technology includes diesel particulate filters (DPF) and cooled exhaust gas recirculation (EGR) systems. These form part of a solution that includes air intake to exhaust aftertreatment, a spokesman for the company said. Engine enhancements will also include the use of Cummins variable geometry turbochargers (VGT), advanced electronic controls and high pressure common rail fuel systems.
Communications director for Cummins, Kevan Browne, said the company has long invested in all the critical engine technologies. “Which means we now design and manufacture all the key sub-systems to enable Tier 4 (Stage IIIB) and can integrate them beter,” he said.
He added, “When we initially designed the diesel particulate filter it was designed for both on-and off-highway vehicles because we knew at some stage it would have to be used in the latter.”
Ric Kleine, vice president of Cummins off-highway business added, “While exhaust aftertreatment may be new technology for the off-highway industry, it is not new to Cummins. Our Cummins Emissions Solutions business is one of the world's leading manufacturers of this key component technology. For Tier 4 (Stage IIIB) applications of the Cummins particulate filter, we are factoring in off-highway requirements such as high shock loads, angularity, space restrictions and working environment conditions.”
Product marketing manager for Perkins, Tim Cresswell, said the company is borrowing similar technologies to those that have been used by parent company, Caterpillar, in the engines it supplies to the US on-highway market. He added the technology itself does not need much adaptation for off-highway equipment – the issue is finding space on the equipment for extra components such as aftertreatment. Mr Cresswell said the company is not revealing the technologies it will be using in order to comply with Stage IIIB standards until later in the year.
“Much work has been done on evaluating the most appropriate technologies to use. It's not a question of meeting the limits, I think we can all do that – it's about finding the best technologies which least inconvenience the customers and the users,” he said.
Mr Cresswell said the biggest challenge of adapting new technology for construction machinery is f two-fold, “Firstly, it's the packaging of the equipment on the machines without grossly inconveniencing people and also retaining machine serviceability. The other challenge is the cost for installing engines with most manufacturers talking about cost increases of between +50% and +100%. The message is that it's not going to be cheap.”
He added there is hope that as particulate filters and after treatment systems are used more and more, particularly in the on-highway industry, costs will come down.
Mr Browne agrees that one of the biggest challenges in preparing for Stage IIIB has been installing the technology and exhaust after treatment int the OEM equipment.
“That's simply because there is such a huge variety of equipment, duty cycles and loadings and environments in which the equipment works and some of the equipment is very compact,” he said.
Mr Browne said Cummins has initiated a programme of ‘concept installation work' to look at the types of construction machinery in which engine installation would be most difficult. He added, “We will soon be undertaking field test work with OEMs beyond that programme – this gives us a great basis to prepare the OEMs to make the installation as easy as possible.”
Research and Development
Mr Browne said, “We are working on the next technology to meet the final regulations (Stage IV) and it's a matter of a -90% reduction in NOx as opposed to the reduction of -45% in 2011.”
He said there are various alternatives that can achieve this reduction such as Selective Catalytic Reduction (SCR), which is currently in use in some European on-highway applications. He added there are discussions about adapting it for off-highway use.
“However, it is not the only option. Cummins is evaluating SCR but at this point is unable to is evaluating SCR but at this point is unable to confirm which technology route it will take. Given that it's some years yet we don't think it's an issue and there could be some new developments and some technological breakthroughs that we could utilise between now and the final stage,” Mr Browne said.
Meanwhile, many engines from John Deere Power Systems' (JDPS) under 75kW are now Stage IIIB ready. Four ratings of the Power Tech M 2,4 litre engines are planned for Stage IIIB as well as four new ratings of the PowerTech E 2,4 litre engine and one new rating of the Power Tech E 3,0 litre.
A spokesman for JDPS, said, “We have narrowed down the technologies we are exploring for Tier 4 (Stage IIIB), but have not yet settled on the solution that will be right for our customers and us. For Tier 4 (Stage IIIB) we are planning to continue with the multiple-platform option. The goal is to determine which concepts work best together in order to provide a solution that meets the needs of each given application.”
JDPS is also optimising the combustion system for reduced emissions, the spokesman said. This includes the use of multiple injections, increased fuel injection pressure, modified combustion bowl and fuel injector geometry. JDPS is reviewing a number of aftertreatment technologies, including diesel oxidation catalyst (DOC) and including diesel oxidation catalyst (DOC) and diesel particulate filter systems, according to the spokesman. He added the company is also working on NOx adsorbers, lean NOx catalysts and SCR solutions. Homogeneous charge compression ignition (HCCI) continues to be explored as an alternative solution.
Engine manufacturers are recognising the potential benefits of using bio-diesel in their products and are investing in research and development in this area. The renewable, oxygenated fuel made from agricultural crops such as soybean or rapeseed is biodegradable and free of sulphur. A spokesman for JDPS said, provided the fuel meets the EN 14214 standard, B100 – 100% bio-diesel may now be used in construction equipment fitted with the company's PowerTech Plus or PowerTech E engines that comply with Stage IIIA emissions regulations, as well as in engines of earlier designs.
Gérard Ozanne, product support manager for John Deere in Saran, France said, “John Deere has gained a significant amount of experience with f B100 bio-diesel in recent years. Since this type o fuel operates at approximately -10% less power density and older machines may experience a loss of sealing properties, the conversion from normal diesel to B100 bio-diesel should be handled in close cooperation with the local John Deere dealer or OEM engine distributor. distributor.”
The company has researched the use of native rapeseed oil in Stage IIIA engines since 2006.
“John Deere's leadership in the use of bio-diesel is another example of our commitment to environmentally friendly engine solutions,” Brian Brown, manager of worldwide marketing support at JDPS said. He added using bio-diesel fuel reduces particulate emissions and decreases dependence on crude oil.
“We recognise the importance of bio-fuels to our customers and to the environment. Use of bio-fuels in John Deere diesel engines is the right thing to do from a long-term economic and environmental standpoint,” Mr Brown said.
Grant Suhre, JDPS field service manager said, “We still get questions about higher bio-diesel blends and warranty, but our position on warranty for customers that use B20 has not f changed. While we prefer the use o B5 bio-diesel blends, we also know that when high quality B20 blends are available, they work well in John Deere engines. If customers make sure the bio diesel meets – the ASTM D6751 standard, is stored and mixed properly, and is used shortly after manufacture, they can continue to rely on John Deere engines while using B20.”
Cummins is also researching the use of bio-diesel for use in its engines. Mr Browne said the company's Stage IIIB product range will be compatible with B20 bio-diesel.
Mr Browne added the company is actively looking at what the compatibility of fuel beyond B20, such as B50 and even B100 is like with the company's diesel engines.
“At this point we are not entirely sure that the market will move in that direction because looking ahead there are some concerns now that the supply of bio-diesel by virtue of agricultural production may not meet the demand for B50 or B100. We see our Stage IIIB products as B20 certified but we are not discounting that at some stage it could go beyond that but at the moment we don't see that need.”
Mr Cresswell said, “We have a position where the majority of our Stage IIIA/Tier 3 certified engines are capable of using 20% bio-diesel blends.”
He added that Perkins is looking to increase the bio-diesel percentage but not with any great speed. He said there is a wider debate over whether bio-diesel will become popular and said the problem is that it is more hydroscopic than regular diesel and unless it is stored properly is prone to significant water contamination.
Meanwhile, all JCB Dieselmax engines have been approved for the use of B20 Bio-diesel since 1 January 2007.
Engine manufacturers are already preparing for the Stage IIIB engine emissions regulations, despite the fact they are still three years from enforcement. They know that researching and developing solutions now will better place them to face the installation challenges that the variety of construction equipment may present. Meanwhile, the awareness of using bio-diesel in engines for construction equipment is rising but manufacturers are still uncertain about how this market will progress. What is certain is that for the next five or six years at least, the issue o engine emissions will continue to play the biggest part in new engine design.