Power and control - Steve Skinner reports on the technologies available to OEMs
06 May 2009
As Stage IIIB compliant engines come onto the market, so too do refined drivetrains and hybrid technologies. Steve Skinner reports on the technology that's bringing efficiency to construction equipment.
With Stage IIIB emissions legislation looming for engines over 56 kW, pressing areas of development for Original Equipment Manufacturers (OEMs) include engines, high pressure injectors and electronic management systems.
In December, Delphi released its first common rail fuel injection system for engines in the medium to heavy duty construction equipment sector.
"Combining the flexibility of our rail based fuel management with the ultra high pressures that Delphi has achieved with our electronic unit injection (EUI) technology, the new common rail systems will provide a highly effective and affordable path right through and beyond Stage 4 compliance," said David Friday, general manager at Delphi diesel heavy duty.
The new system is available with a conventional common rail design, in which fuel pressure is provided by a cam driven pump, developed by Delphi from its established medium duty common rail technology, and in two distributed pump variations.
"These highly sophisticated devices use a miniature valve to close the path to the nozzle when pressure is being directed to the rail," said Mr Friday. "When fuel is required at the nozzle, the pumping element is isolated and fuel is directed from the rail to the outlet metering valve."
Delphi has spent almost five years refining the technology and much of the knowledge used builds on experience gleaned from the company's twin valve E3 EUI, which operates at 2500 bar.
At last month's Intermat show many of the leading engine manufacturers unveiled their Stage IIIB compliant engines. "We believe it's important that OEMs look at Stage IIIB and Stage IV as a package," Steven Nendick, European communications director at Cummins told CE.
"Our Stage IIIB engines feature the major engineering work that will be necessary for Stage IV compliance in 2014, so selecting supplier now should ease the progression," said Mr Nendick.
Cummins has so far installed over 100 stage IIIB compliant engines across a wide range of construction equipment to trial its cooled exhaust gas recirculation (EGR) and diesel particulate filter (DPF) solution prior to the 2011 deadline.
In Paris the company showed its four cylinder QSB 3.3 and QSB 4.5 engines producing up to 82 kW and 119 kW respectively. Also unveiled was the six cylinder QSB 6.7 with peak power of 298 kW.
"The QSB 6.7 features XPI common rail extra-high pressure fuel injection and a variable geometry turbocharger with sliding nozzle, which varies air-flow boost to match rpm and load demands," said Mr Nendick.
"Beyond meeting legislative requirements, we also strive to add value in areas such as noise reduction and fuel economy to improve our offering to OEMs," Mr Nendick told CE.
Scania too launched its 2011 compliant engines in France, also stressing that the engine platform will remain the same across Stage IIIB and Stage IV.
"Our stage IIIB engines have been designed to attain Stage IV compliance with minor modifications," said Dick Burger, director of commercial and industrial motors at Scania France. "It's an expensive exercise for OEMs to fit new engines, so we've worked hard to ensure the footprint remains the same, thus easing integration and spreading cost."
Scania has elected to adopt its extra-high pressure fuel injection (XPI) and selective catalytic reduction (SCR) to meet Stage IIIB compliance across the range which also features the company's engine management system (EMS).
The DC9 EMS is a 9,3 litre in-line five cylinder engine producing up to 294 kW, while the DC13 EMS is a six cylinder 12,7 litre engine producing up to 368 kW. The range topping 16,4 litre V8 producing up to 515 kW is designated DC16 EMS.
"It's our responsibility as a supplier to offer OEMs a flexible solution," Mr Burger told CE. "In line with this we've developed a combined muffler and SCR catalyst as well as stand-alone units to give our OEMs the greatest freedom regarding installation."
In Paris, Perkins showed its new Stage IIIB compliant twin turbo 225 kW 7 litre engine with 2000 bar common rail fuel injection.
"Emissions controls don't make more power or increase efficiency," said Oliver Lythgoe, Tier 4 marketing manager at Perkins. "But they have driven us to put on more technology.
"When you have that technology it puts you at a different price point, so we feel we have to give more value back to OEMs. Increased power density is a distinct advantage of the Stage IIIB engines and I believe there will be a trend in the industry to smaller engines that produce similar power to their predecessors."
Mr Lythgoe told CE, "The relationship with OEMs has evolved in tandem with emissions legislation and now they want to talk to us not only about engines, but also integration, cooling systems and performance issues."
Also in France, Caterpillar introduced its 7,1 litre and 9,3 litre Stage IIIB compliant engines. The C7.1 ACERT produces up to 205 kW, up from the 130 kW found with the Stage IIIA version, while the C9.3 ACERT produces up to 328 kW. Both engines feature 2000 bar common rail fuel injection and double compression, two stage turbochargers for low speed response and maximum top end power.
"Because of the increased power density, we're assuming that OEMs will move down to smaller engine sizes to liberate space for the after treatment side of things," said Alister Dennis, product marketing manager for industrial power systems at Caterpillar.
"This will enable OEMs to keep a compact machine while achieving good fuel economy by having a smaller engine working harder," Mr Dennis told CE.
Caterpillar has conducted integration workshops for the past 18 months with OEMs. As a result, at the core design stage the company moved fundamental components such as turbochargers and manifolds to better suit applications.
Mr Dennis told CE, "We then looked at attachments such as fans, sumps and inlet positions to fine tune their placement to make our engines bespoke for each given piece of equipment.
"We've been diligent to ensure that our Stage IIIB engines meet the extremes of the operating envelope, be it temperature or altitude," said Mr Dennis. "We can offer the engine, the emissions module and the integration to an OEM, thus removing much of the anticipated pain of Stage IIIB compliance."
With its ‘Cat clean emissions' module, Caterpillar has taken a modular approach with a common cradle featuring the air cleaner, the muffler and in a single can the diesel oxidation catalyst and diesel particulate filter featuring active regeneration.
"There are multiple configurations to the after treatment module, so there's flexibility for OEMs," said Bob Christmas of Caterpillar's marketing and product support division.
"The size of the module will not change for Stage IV, so OEMs will be able to relatively easily switch from Stage IIIB compliance to Stage IV without further worries concerning space," Mr Christmas told CE.
In December, Sauer Danfoss launched its H1 80 cm3 and 110 cm3 bent axis motors designed to mate with the company's H1 series of pumps to create a proprietary hydrostatic drive system. "With the introduction of the H1 bent axis motors, we're now able to provide a complete H1 transmission, optimised around electrical control," said product portfolio manager Hans-Peter Nissen.
"The H1 motors not only provide OEMs with improvements in reliability and flexibility, but also provide increased efficiency, resulting in reduced fuel consumption and lower life cycle costs," said Mr Nissen.
The H1 propel system provides OEMs with improved power management and enables anti-slip or wheel-assist control functions. "Stage IIIB emission standards will require intelligent use of engine power," said Mr Nissen, "and this will be strongly supported by our new H1 family of products."
Transmissions, as with many components for construction equipment, are destined to get lighter as legislation and operating costs demand a reduction in the unloaded weight of machinery.
"Using higher quality steels and improved manufacturing techniques help us reduce weight and give value to our OEMs," said Alan Stoyell, product director for drivetrain systems at Dana.
Dana, last month, introduced its new drivetrain system for hydrostatic-driven wheeled loaders up to 3,5 tonnes featuring the company's latest version of its Spicer 110 axle, specifically engineered for compact equipment.
The new Spicer 110 axle has a modular design with a flange-to-flange distance of between 880 mm and 1530 mm to increase flexibility. A drum brake on the front axle supplies both service and parking brake capabilities, while the overall compact dimensions aid installation.
Also at Intermat the company showed its drivetrain system for 30 tonne wheeled loaders featuring a Spicer TE-32 transmission, a Spicer 53R300 front axle, a Spicer 43R183 rear axle and a Spicer 10 series 1710 driveshaft.
Rated at up to 325 kW, the electronically controlled TE-32 is available with three or four speed powershift transmission featuring helical gearing in which the teeth are cut at an angle to allow the gearing to run more smoothly and quietly.
Both axles are equipped with internal fade-and-maintenance-free liquid cooled brakes and limited-slip differentials for improved traction.
Beyond its more traditional drivetrains, Dana used Intermat to debut its Spicer TE-15HX hybrid transmission designed for 15 tonne wheeled loaders. "The motor generator is able to recoup energy each time the loader slows," Mr Stoyell told CE. "Braking From 12 km/h down to zero charges the capacitors, so depending on duty cycle we're expecting this system to offer up to a +20% saving on fuel consumption."
"We believe that future C02 legislation will drive hybrid technology and with the TE-15HX transmission moving to the test and evaluation stage in 2010 we are aiming to offer our OEMs leading technology ahead of the game for products that carry out Y cycle type duties."
ZF too is working on an efficiency package that the company believes will offer fuel savings of +20% and fuel efficiency of up to +60%.
At the heart of the package is ZF's Ergopower transmission which features five gears, up from the four gear system previously used.
The package also uses the company's Ergotraction which is a differential lock management system and intelligent clutch cut-off (ICCO) which dynamically adjusts the clutch cut-off point depending on transmission output torque.
"Fuel saving and fuel efficiency will be key in the future," Gernot Hein, head of marketing communications for ZF's off-road division told CE. "Like in the passenger car industry, machines will have to be lighter to make gains in fuel efficiency and we are working in this direction with our drivetrain systems."
Rexroth, part of the Bosch Group introduced a ‘shift-on-fly' transmission last year offering improved efficiency over existing powershift transmissions using converters.
"Shift-on-fly is a no-load shifting transmission combined with a hydrostatic traction drive which results in higher speeds while retaining the high traction force of a hydrostatic system during acceleration," said a Rexroth spokesman.
The system optimises the number and timing of gear shifts to meet the demands of the application and because the electronic controls and the A6VM hydraulic motor are the only additional components to an existing transmission, only slight modification of the gearbox is required, thus the system has little impact on installation space.
"Shift-on-fly has overcome the earlier mis-selection issues often associated with simpler automatic gearboxes, so we now offer a system that enables uninterrupted travel through the entire speed range on fast moving construction machinery," said the spokesman.
Germany's Hawe Hydraulik launched its CLK pressure control valve at Hannover Fair in April. Fitted with a safety valve function, the CLK is designed for hydraulic systems in which temperature increases or external load peaks cause unwanted pressure increases.
"The CLK can provide up to 22 litres/minute at 380 bar and can be fitted to systems up to 500 bar," said a Hawe spokesperson.
Meanwhile, Mico introduced its S12 series electro-hydraulic brake valve (EBV) earlier this year which provides more than triple the flow capacity of traditional EBVs. "In large, spring applied, hydraulic release brake applications the S12 has been able to replace two standard EBVs operating in parallel," said a spokesman. "This lowers cost and improves reliability for OEMs."
HydraForce recently launched its RVD50-20 high performance 345 bar pressure regulating relief valve as well as its EHPR series of valves for replacing high flow stack and sectional valves. "Major OEMs will continue to develop new products to meet legislation and to position themselves for the future," said Paul Spratt, manager of marketing and international sales at HydraForce.
"This gives suppliers an opportunity to participate in the development of new technologies and control concepts," Mr Spratt told CE.
"The future of the construction equipment market will see increased use of electro-hydraulic and proportional controls as designers continue to integrate the power transmission into the common control system," said Mr Spratt.
Axiomatic has released a multipurpose valve controller with one universal signal input and two proportional outputs. "The dual output CAN valve controller is an economical solution to meet the complex control requirements of today's off-highway equipment," said marketing manager Amanda Wilkins.
The relationship between OEMs and suppliers is necessarily getting closer as technologies become ever more complex. As Mr Hein told CE, "We are specialised in producing transmissions and axles, so we cover this aspect for OEMs."
Clearly, specialist component suppliers offer OEMs some respite from research and development in terms of both cost and time, and with legislation driving equipment forwards, any qualified assistance could make the difference between meeting deadline or not.