OEM: Component improvements help meet the efficiency challenge
By Chris Sleight12 April 2011
Fuel efficiency has never been more crucial for construction equipment. Efficiency gains start with components, and key players are refining existing technologies as well as introducing radical new ideas to meet the efficiency challenge.
Construction machines have always had a big thirst for diesel and with the oil price on the rise again, this could translate into spiralling costs. It is a fact that component manufacturers are aware of and there is a realisation across the industry that innovations that can reduce fuel consumption or increase fuel efficiency will ultimately help equipment owners - providing a competitive advantage across the supply chain.
The most obvious place to start is the engine, and the wave of new exhaust emissions legislation introduced in key markets around the world since the late 1990s have also been a big driver in fuel efficiency improvements.
High pressure fuel injection systems, electronic engine management and efficient new turbo chargers for air delivery are all common technologies in off-highway engines today.
Allister Dennis, product marketing manager for Perkins said of the company's new Tier 4 engines, "We've achieved on our 1200 series four-cylinder engine something like an 8% improvement in fuel economy on machines in real-world applications."
As well as being more fuel efficient, Perkins and other manufacturers have increased the power they can get out of their engines, and this increase in power density could also have fuel saving applications.
"Like-for-like we've achieved savings of 8% or so, but if you can downsize from a six cylinder engine to a four cylinder engine, you will get double-digit fuel savings," said Mr Dennis.
To take the 60 kW to 225 kW 1200 series as an example, these four and six-cylinder engines deliver +23% more power and +35% more torque than their predecessors, yet still consume -8% less fuel.
ConExpo also saw Perkins unveil the 400F, an engine with an output up to 45.5 kW, which meets the requirements of the Tier 4 Final (Stage IV in Europe) legislation due to come into force in January 2013. Mr Dennis said Perkins had kept the basic engine the same as the previous 400 series, so it had the same physical dimensions, mounting points and hook-up points. The only change was in the after-treatment system, minimising the amount of design work equipment manufacturers would have to do to incorporate the new unit into their machines.
Cummins also showed Tier 4 Final engines at ConExpo in the shape of the 503 kW QSX15,
392 kW QSX11.9's and 298 kW QSL9. Like Perkins, Cummins has improved power density, with the QSX15 offering 56 kW more output than the model it replaces.
"The QSX15 and QSX11.9 not only meet the challenge of near-zero emissions, but they are able to achieve this with higher power output and lower fuel consumption," said Jennifer Rumsey, Cummins' executive director for heavy duty engineering.
MTU's larger Tier 4 Final engines are currently under development, and the company says that while it is confident of reaching the emissions requirements using a diesel particulate filter (DPF) to remove soot alongside selective catalytic reduction and other technologies to deal with NOx, it is hopeful that it will not need the DPF on big engines.
The company has already unveiled its Tier 4 Final offering for engines below 560 KW in the shape of the 1000, 1100, 1300 and 1500 Series, and it says that if it can eliminate the DPF from the final designs, it will make life easier for OEMs, when it comes to packaging everything into the engine compartment. The company added that its Tier 4 Final engines had -5% lower fuel consumption and up to +20% more torque at low speeds than their Tier 4 Interim equivalents.
As well as exhibiting a variety of engines, Deutz used ConExpo to show its DVERT modular aftertreatment system. The various elements such as oxidising catalytic converters, open and sealed particulate filters, regeneration burners and selective catalytic reduction (SCR) can be employed in different combinations to produce the desired result in terms of engine performance and emissions compliance limits.
Among the engines on display was the TCD 2.9 L4 - an interesting four cylinder diesel in the 25 to 55.4 kW range, designed for very tight and narrow installations.
Various options include the choice of natural aspiration or turbo charging, and the ability to add charge air cooling. The aftertreatment system meanwhile is modular, with a maintenance-free and inexpensive diesel oxidising catalytic converter and the particulate oxidising catalytic converter for most applications, while a sealed DPF is also available.
These new emission control systems will of course add complexity and cost. As reported in this month's feature on portable power, they could add as much as +40% to the purchase price of generators and compressors, where the engine is the main component. However, in larger earthmoving machines, the price increase will be much less dramatic, and may be recouped within three years thanks to the saving in fuel costs.
Reliability is another understandable concern with these more complex engines, and manufacturers are at pains to point out that they have done their homework. Volvo Penta for example says it has carried out more than 100000 hours of 'real world' reliability testing with its Interim Tier 4 engines, which has added a diesel particulate filter to existing combustion, fuel injection and exhaust gas recirculation technologies.
The advent of electronically controlled engines also means manufacturers can do a lot more in terms of monitoring and reporting. John Deere Power Systems (JDPS), for example, now offers its JDLink telematics with its electronically controlled Interim Tier 4 engines (Stage IIIB in Europe).
The system automatically collects, transmits and manages information about where, when and how equipment is being used, as well as critical machine health data.
"The new JDLink telematics system maximises productivity and lowers operating costs by helping users make informed management decisions in real-time," said Scott Clair, manager of product market extension for JDPS.
Two versions are available - JDLink Select and JDLink Ultimate. The first offers information on location, engine hours, geofencing and maintenance alerts, while the 'Ultimate' version adds in information on oil temperature, idle time, utilisation, fuel consumption, maintenance intervals and a variety of other engine settings. The data collected by JDLink is communicated to a central John Deere server and made available to registered users via the JDLink dashboard or through SMS text messaging or e-mail.
But improvements in fuel economy and productivity do not end with the engine. Far from it.
The hydromechanical variable transmission (HVT), the first fruits of the co-operation between Dana and Bosch Rexroth, is a good example. The system shown at ConExpo was designed for 20 tonne wheeled loader applications and featured Dana's Spicer Hercules 37R and Spicer Model 114 axles.
However, the addition of a Rexroth hydrostatic drive in the powertrain along with a traditional torque converter makes for fuel savings of more than 20% over a traditional powershift transmission.
The hydrostatic drive is employed at low speeds - up to about 7 km/h - where it is more efficient and precise than a mechanical drive. It is also used to aid braking. This means the mechanical drive is only employed in parts of the cycle where it is at its most efficient, rather than at low speeds.
Rexroth and Dana have designed the system to be modular and flexible. Besides wheeled loaders, the two companies see its application in graders, road building machinery and forestry applications.
ZF used ConExpo to unveil a similar innovation in the shape of its continuously variable transmission, the ZF cPower. The company says the device offers significant productivity and fuel consumption improvements over traditional transmissions, due to its ability to shoulder high loads at low speeds. Like the Dana/Rexroth HVT, ZF's cPower uses a hydrostatic drive in tandem with a mechanical drive to get the advantages of both systems.
The system exhibited at ConExpo was designed for wheeled loader applications, with power being delivered in all ranges by a combination of the hydrostatic and mechanical drives. In wheeled loaders, this includes the 0 to 10 km/h range, which is a common feature of stockpiling and truck loading applications. The company said that this 'powersplitting' concept led to up to -30% less fuel consumption and +20% better efficiency.
It added that the cPower could be installed in applications currently using ZF's popular Ergopower transmissions.
Allison meanwhile, which is known in the construction industry for providing transmissions to on-highway vehicles such as concrete mixers and tipper trucks, used ConExpo to show transmissions adapted to new trends in this part of the market.
The new 5620 and 6620 models, for example, were introduced to respond to changes in engine characteristics that are increasingly prevalent in the construction sector. Greater use of digital control for engines delivers sharper torque response through the driveline, necessitating upgrades to protect the drivetrain.
The lock-up clutch, turbine shaft, turbine hub and flywheel have all been redesigned and feature upgraded materials to reduce maintenance costs and downtime. The transmissions have also received software updates.
Other features of the company's products include its load-based shifting schedule (LBSS), which automatically selects between performance, economy and super economy modes, depending on the vehicle payload and road gradient. The company's Prognostics system meanwhile monitors parameters such as oil level, oil life, filter life and transmission health, sending alerts if there is a problem and helping to safeguard against unnecessary filter and oil changes.
Sauer-Danfoss has expanded its range of electronically controlled H1 piston pumps, with new 60cm3/68cm3 and 89cm3/100cm3 sizes. The H1 range, first introduced in 2005, now covers six displacement ranges.
Branko Horvat, Sauer-Danfoss product marketing manager. "Together with a range of electronic control options, our H1 solutions can help compensate for the reduced power levels of Tier IV/Stage IV emissions-compliant engines."
The new H1 frame sizes are designed for telehandlers, wheeled loaders, concrete and asphalt pavers and road rollers, among other applications. All sizes share a common electronic control platform, so software developed for one size can be easily transferred to any other.
Options include a high-response pressure limiter, which can help improve vehicle performance, by controlling pressure, which reduces the load on the engine and cuts down on the cooling required.
These innovations in engines, transmissions, hydraulics and sub-systems all illustrate how a series of improvements can make for a drastic change in a machine's performance and fuel efficiency. The remarkable changes in transmission design in particular could set a new benchmark in the equipment industry.