The latest emission laws are putting crane engine suppliers to the test
By Euan Youdale27 October 2009
The latest emission laws are putting engine suppliers to the test and leading to some innovative projects.
One of the challenges faced by crane engine manufacturers comes with fuel specifications, says Steve Nendick, Cummins communications director for Europe, Middle East, Africa and CIS. "Due to the Tier 4 engines being fitted with after treatment, they need to use ultra low sulphur [diesel] fuel (ULSD). This is particularly difficult for mobile cranes, which may use a number of different sources for fuel as they move around.
"Also, if a crane is rented, it is more difficult to ensure the user follows the correct processes and use the correct fuel and oil, etc. We are working on some form of notification about ULSD to be placed on the crane to prevent any issues arising."
According to Nendick, the company's provision of an air intake to exhaust out solution means that its engineers can work with equipment manufacturers to ensure the product meets the latest emission requirements. "It also offers value to customers in terms of fuel economy and running cost benefits."
Examples of Cummins installations in cranes are the QSK23 in the Liebherr LR 11350 lattice boom crawler crane and a QSC8.3 in the 50 tonne capacity Terex Demag MAC 50 military all terrain. The latter engine was replaced with the next generation Stage IIIB and EPA Tier 4 Interim complaint engine, launched at the Intermat exhibition in Paris in April. It is a fully integrated air-intake to exhaust aftertreatment system that has cleaner, more efficient combustion, says the company, reducing fuel consumption by up to 5%, dependent on rating.
The QSL9 increases top-rated power to 283 kW with peak power rising to 298 kW at a lower rpm to respond to higher load demands. This compares to a Tier 3 top-rated power of 272 kW with a rated peak power of 280 kW, adds Cummins.
Features of the 8.9-litre unit include the Cummins XPI Extra-High Pressure Injection fuel system which provides multiple injection with high injection pressure across all engine speeds. A variable geometry turbocharger, with a sliding-nozzle design, is also installed to vary the air-flow boost to precisely match engine rpm and load demands.
Crane manufacturer Liebherr produces its own range of engines. Its latest developments are the 4 and 6 cylinder in-line and 8 cylinder V-type. Their benefits reflect the current trends in engine design. According to Wolgang Beringer, at Liebherr, the engines meet regulatory approval and have no regional restrictions. This helps when putting the crane on the used market.
Beringer says the challenges of further restricted exhaust emissions, including NOx and diesel particles, are being met with a range of solutions. These include optimised diesel injection, optimised combustion, complex after-treatment of exhaust, particle filters, ad blue, exhaust gas recirculation and two-stage charging. The introduction of further restrictions from the simple diesel combustion to the complex "chemical plant", adds Beringer, has also brought considerable challenges.
Crane chassis design has also developed to incorporate these upgraded engines. "The integration of the new engines is an extensive intervention in the total crane due to new weights and dimensions of the engine and the exhaust gas recirculation system, new performances and temperatures (heat rejection)." This means the steel structure has to be adapted, as well as the drive train, cooling systems and other ancillaries.
Bosch, Deutz and Eberspächer, an exhaust gas after treatment specialist, are considering putting their experience together to tackle future challenges. The result would be a joint venture in off road exhaust gas technology.
It would include the joint development, production, and sale of diesel exhaust gas treatment systems and provide technical solutions concerning the stricter emissions regulations from 2011.
"The demand for exhaust-gas treatment systems for this segment is growing significantly. The complete system would be made up of standardised modules with customised tubing. In mobile machinery, especially, this would significantly increase flexibility with respect to installation space."
Depending on how the talks progress, the objective is to launch the joint venture and start series production as soon as possible.
Sauer-Danfoss has been taking similar steps. It created a global emissions team to assist off road machine manufacturers with the diesel engine emissions legislation change. The plan includes an emissions solutions section on the company's website.
"For off road vehicle manufacturers, it is no secret that lower emission requirements for new engines will have a significant impact on future generations of machines," says Rick Sporrer, Sauer-Danfoss sales quality and technical services director. "By our estimates, over 10,000 different machines will need to be redesigned. This is much more than an engine issue - machine design is taking a quantum leap in complexity right now."
To meet the required emission regulations, a number of engine characteristics will be affected, says Sporrer. For example, engine application operating speeds and speed bands will be reduced. Engine power levels and torque will change. Along with all this, there will be greater system for cooling.
"All this will change components and the way power is distributed in the machine. How we determine the most viable solutions is dependent on any of number of technologies which may be employed."