Integrated, decoupled technology points the way forward

26 July, 2019

In mobile heavy lifting applications, as in many other areas within the industrial sector, there is motivation and a desire to improve efficiency and reduce fuel/energy use, primarily for reasons of cost, but also due to environmental, emissions and sustainability concerns. With this thought in mind, an industry shift towards electrification continues to witness a growth in momentum. Here, integrated, decoupled solutions offer an alternative to inefficient coupled power distribution approaches where the internal combustion engine (ICE) is sized for peak energy demand with no energy storage or recovery capabilities. Decoupled power distribution concepts can significantly enhance efficiency and allow the user to employ smaller, more fuel-efficient ICEs or remove the ICE altogether.

Electric dreams

With electrification delivering environmental, sustainability and performance benefits, many OEMs are looking to tap into the enabling technology. They can also hope to take advantage of improved maintainability, greater safety, and compliance with increasingly stringent emissions regulations.

Many drivers exist for this trend, not least the globe’s efforts to clean up pollution. Responsible governance around the world is steering a culture of change. In Europe, for example, there is an agenda to reduce carbon emissions by 20% by 2020, while many cities around the world are looking to achieve carbon neutrality in the coming decades.

To provide an idea of the scale of this drive, a number of major cities, including many capitals, have signed up to the Carbon Neutral Cities Alliance, including Berlin, Boston, Copenhagen, London, Melbourne, Minneapolis, New York, Oslo, San Francisco, Seattle, Stockholm, Sydney, Vancouver, Washington and Yokohama.

Reducing emissions

Cities striving for carbon neutrality recognise that averting the worst impacts of climate change will require cutting greenhouse gas (GHG) emissions by at least 80% by 2050. As urban areas account for nearly three-quarters of humanity's emissions, reaching this goal will depend in large part on the ability of society and industry to reimagine and reinvent cities in ways that promote economic prosperity, social equity, enhanced quality of life and climate resilience.

In short, there is growing emphasis on sharing and implementing best practices for achieving ‘transformative’ deep carbon reduction strategies in urban transportation and energy use. Such ambitions, in turn, mean that emissions regulations are being increasingly tightened, and it is these very regulations that are fuelling industry’s shift to electrification.

For the mobile machinery market, there exists continued pressure on increased urbanisation and growing global enforcement of tougher specifications. Thus, there is the greater cost and complexity of meeting the latest specifications; a major driver behind the demand for hybrid electric solutions.

Optimum technologies

Of course, choosing the optimum-enabling technologies means that the use of electrical power can provide numerous advantages. Conventional solutions in this area work with coupled power distribution, where the engine is sized for peak demand with no energy storage or recovery capability. In addition, the efficiency (torque / speed operation) of the ICE tends to be low.

In contrast, decoupled solutions have much to offer, not least regarding engine management and the potential to reduce the size of the ICE or remove it all together. In addition, there are many efficiency and productivity improvements available with respect to energy recovery, power on/off demand and the operation not being dependent on the ICE speed or torque. The configuration of these solutions also provides a more flexible installation and greater safety, largely through the elimination of hydraulic lines near heat sources. Crucially, these factors combine to improve the total cost of ownership (TCO).

Integrated system

One such solution is the Parker Electro-Hydraulic Pump System (EHPS) for materials handling and reach stacker applications. This type of integrated system provides the opportunity to realise energy cost savings of up to 50%, while also delivering the potential to reduce the size of the engine and thermal management provision, saving weight and further optimising overall efficiency.

The key point here is that this development has addressed a market requirement for decoupled loads and power distribution. Such a design concept facilitates enhanced engine management whereby energy storage and recovery functions can be introduced. The size of the drive system can be perfectly matched to the requirement, giving power on demand, eliminating any waste, whilst also capturing any returned energy on load lowering.

To break down the configuration further, Parker’s complete system solution comprises invertor driven electro-hydraulic pump sub-system to drive the lifting functions and to recover energy while materials are being lowered. The IQAN control system and embedded Parker-derived software provides the system function and operational interface, while peripheral manifolds and system components deliver functionality to key services throughout the wider hydraulic system.

Longer run times

Optimising efficiency and capturing energy also clears the way for the creation of hybrid and fully electric vehicles that have a fuel/charge period that enables extended running times, thus meeting the demanding duty cycles required in heavy duty mobile applications. Maintenance requirements are also reduced thanks to the benefits of a smaller constant-speed engine, lower generated heat related to efficiency improvements, and advanced system ‘health’ monitoring.

The capability of the EHPS has already been put to the test in a number of successful customer applications. For instance, a hybrid wheel loader achieved a 50% reduction in its energy requirement. Additionally, the system’s high-power density allowed a smaller frame to be deployed. The project also saw hydraulic heat reduced significantly, which in turn enabled reduced sizing of thermal management hardware such as the pump, fan motor, fan and radiator.

This integrated, space-saving solution also proved successful in a hybrid electric lift truck developed by Konecranes Lifttrucks, which again demonstrated fuel savings (30%) and productivity improvements with quicker operator responses in lifting, lowering and driving. In addition, maintenance proved easier due to the system’s modular design and self-diagnostics, while it is predicted that up to 100 tonnes less CO2 emissions will be generated based on 5000 hours running time per year.

Ultimately, energy recovery via electrification will of course allow longer equipment usage. Crucially however, this technology will permit end users to satisfy the requirements of environmental and emissions regulations. The world needs less pollution and this technology is a clear solution towards meeting that aim.

www.parker.com