Cranes components seldom come from one source alone, with different parts of these machines coming from a variety of sources and manufactured by a range of companies. There are few more important examples of this than the engine of an all terrain crane.

With the exception of Liebherr, all the major manufacturer s of this type of crane use engines developed by specialists who they work with to tailor to the needs of the machine they are making.

The engine of an all terrain crane has always been an area that crane buyers and owners focus upon for obvious reasons, the nature of the crane means that versatility and efficiency are key. The engine must be able to function as well on the jobsite as it does on the road. In recent years engine regulation both on the road and on the jobsite has brought even more focus to the engines of these cranes.

A partnership
The process of developing the right engine for an all terrain crane is a long and complex process. Normally relationships are built up over many years with changes planned years in advance. Changes in regulation are anticipated by the two manufacturers and solutions conceived to maintain capacity and efficiency whilst also complying with regulation.

Engine manufacturer Volvo Penta works closely with several manufacturers to ensure that they produce the best possible machine as Darren Tasker, director industrial business, Volvo Penta Region America explains: "Most crane manufacturers source engines and power systems from engine suppliers. There are no ownership relationships. There is a need of a very close collaboration between engine supplier and crane manufacturer in order to get a well functioning power train."

"A crane is in need of an engine that can govern the sensitive movements needed in a very precise way. Therefore the governor characteristics need to be very accurate and tunable so that the load can be moved in a precise and safe manner. Modern electronically controlled engines are ideally suitable for this type of governing.

"Many crane manufacturers operate globally and are in need of an engine supplier that has products that can be used anywhere, in any country. This means that an engine installation preferably shall be possible to use both in non regulated and regulated markets."

One of the few crane manufacturers that makes its engines completely in house is Liebherr. The company therefore has a unique vantage point from which to measure engine development, Wolfgang Beringer head of sales promotion at Liebherr-Werk Ehingen describes how the company has found the shifting regulatory landscape: "The cooperation between the crane manufacturer and the engine manufacturer has to be very close as for many years both have had to work permanently on fulfilling new emissions standards.

"The time between the last exhaust emissions standard 97/68/ EC IIIB and Tier 4 interim in the USA and the new Stage IV/Tier 4 final (valid from 1 January 2014) was just 3 years. Work on implementing the old exhaust emissions standard had only just been completed when the first activities towards fulfilling the successor standard were initiated.

"Diesel engine manufacturers are hardly able to keep up with the speed of these steps, so that when we convert a machine, we initially have to plan and design it with engines which have not yet been fully developed. The design, construction, conversion and testing effort is gigantic and has been dominating the production of mobile cranes in many areas for years."

Cummins are another engine maker who collaborate closely with crane manufacturers to produce efficient regulation-compliant machines. One firm that the company works with on all terrain cranes is the US manufacturer Link Belt. The crane manufacturer made its design decisions in partnership with the engine maker and decided to use one engine rather than two on the crane as Kevan Browne, Cummins’ communications director explained: "Link-Belt chose to use two Cummins engines rather than a single engine in its all terrain crane design. The use of an upper industrial engine specified for crane operation and a lower truck engine for transport means that the ideal engine configuration is installed to power each of these key functions – rather than compromising performance by using a single engine.

"The lower engine in the ATC- 3210 is a Cummins ISX15 for crane mobility with a 564 hp (421 kW) output, meeting the EPA 2013 and Californian on-highway near-zero emissions standards. The ISX15 is the most widely used heavy-duty truck engine in North America, providing the power needed for relaxed high speed travel and instant torque for climbing steep roads or enhanced mobility on difficult job sites. The 15-liter engine comes with an integral engine compression brake and cruise control. The ISX15 also complies with 2014 EPA greenhouse gas and U.S. Department of Transportation (DOT) fuel efficiency standards."

Size and weight
Tough economic conditions in certain regions have heightened the importance of versatile machinery. All terrain cranes are just one type of equipment that has become more useful for firms at these times of difficulty. The engines of these cranes are important too because they need to function as well on road and off road. Regulation has presented a range of challenges for such machines and manufacturers have different solutions.

One particular consideration with new engines as Darren Tasker from Volvo Penta explains: "Installation space is usually critical in an all terrain crane. Having a solution with as little complexity as possible makes it easier for a crane manufacturer to install an engine, being non regulated or Tier 4 Final. Volvo Penta has chosen to develop a specific aftertreatment for non road applications with as little complexity and maximized uptime as possible, using only SCR and avoiding: heavy cooled EGR, DOC and DPF.

"The highly regulated engines are normally not suitable to use together with high sulphur diesel. This makes it necessary for OEMs to use different engine specifications for different markets."

Installation requirements are also important issues to take care of. Nowadays more and more engine manufacturers move towards in-line engines and this will be the most common engine configuration in the future. Across its range of engines Liebherr has also found weight to be an important issue, Wolfgang Beringer explains: "Besides the performance requirements, weight is of great importance for mobile and crawler cranes. In addition, the available installation space for the engine plays an ever increasing role as current and upcoming emission limits for diesel engines can only be met by complex exhaust gas after treatment. Especially in mobile cranes there is little to no room for this. Engine and crane development teams have to find a suitable installation position, with enough space and where the proper functioning of the exhaust gas after treatment system can be ensured with the required efficiency.

"Weight increases caused by the introduction of the new exhaust emissions standards Stage IIIB and IV (Tier 4 Interim and Tier 4 Final) can be partially compensated for in the configuration of the cranes, but additional lightweight construction measures are also required. Weight can be saved, for example, by implementing optimisations in the field of wheels/rims/brakes/axles.

The single-engine concept of our new models naturally also saves weight. Liebherr developed the "SCRonly" exhaust gas after treatment system for EU Stage IV and USA EPA Tier 4 Final. This works completely without exhaust gas recirculation, oxidation catalytic converter and particulate filter, making it very compact and weight-optimised. Compared to Stage IIIB and Tier 4 Interim, there is no loss of power attributable to the exhaust gas after-treatment system."

Around the world in regulations
The problem with engine regulation as with many other rules is that there is no global standard.

Europe and America have led the way when it has come to engine emmisions but many regions have shown a reluctance to follow suit.

It’s understandable particularly in regions where the market is not as developed, as the majority of working cranes tend to be older and the finances to comply with stringent regulations not there. Another issue is fuel, in certain geographies the ultra low sulphur fuel required to run engines that meet the European and US standard to engines is simply not available. This means if a crane is to have a second life outside of Europe or America the engine must be retrofitted with an engine that takes regular sulphur fuel, a long and potentially expensive process.

It’s an issue that Liebherr has had to wrestle with more and more as Wolfgang Beringer explains: "The difference between the fuel qualities available on the different markets has become more important, in particular because the highly regulated markets of Europe and North America have introduced stricter emissions regulations.

These can only be satisfied using exhaust gas after-treatment systems such as SCR catalytic converters – which have higher requirements on the fuel composition. If, for example, the sulphur content is too high, we – the engine manufacturer – can no longer guarantee that the chemical processes in the SCR catalytic converter will run as required to ensure that emissions limits are not exceeded.

"To reflect the differences between the different markets, we offer different equipment versions for our engines. The base engines (without exhaust gas after-treatment) are ideal for use in unregulated markets. An external exhaust gas recirculation system makes them suitable for partially regulated markets, and the SCRonly exhaust gas after treatment system enables them to be used in highly regulated markets.

"Liebherr engines for highly regulated markets with the SCRonly system can be converted for resale to unregulated markets.

The exact procedure, whether the conversion has to be performed at our production facilities or if it can be done at one of our service centres, is established individually for the specific application. Besides technical questions and economic considerations, we also have to comply with statutory stipulations relating to engine certification and warranty factors. In short, it can be said that the international resale of engines is becoming much costlier and more complex."

Volvo Penta has also had to deal with these challenges, says Darren Tasker: "There is no contradiction between lifting capacity and compliant engines. Many solutions for complying with EU and US regulations offer better performance and lower operating costs compared with previous models. It is important to have solutions that can operate in any condition without interruption.

The avoidance of DPF with regeneration needs is important in this type of application.

"At present the majority of the volumes are in non-Ultra Low Sulphur Diesel (ULSD) markets.

This is however changing. Both as more and more markets are being regulated and as the availability of ULSD becomes more widespread. Most engine manufacturers offer a "de-tiering" solution so that the product can be sold to non-regulated markets. This should not have an impact on the resale value."

The future
Rarely do rule makers stay inactive. There are constant reports and meetings analysing what exactly the next move from the regulators should be. New measures are constantly being drafting and compliance dates being set. When it comes to crane engines the area is no different and there are already new rules in the pipeline in both the US and Europe. Wolfgang Beringer says that Liebherr has made changes to ensure they keep up with the changes: "In order to keep pace with the increasing emissions requirements, we have thoroughly revised our modular system to make it easier to modify the engines more flexibly to different requirements.

Secondly, we have expanded our development and production knowhow to other subsystems and we now manufacture our own Common Rail fuel injection systems and engine control units. The extensive system expertise for diesel engines allows us to match the individual engine components even better and to respond faster to new requirements.

"In preparation for emissions level Stage V, which is currently being discussed in the various EU committees, we are testing a combination of SCR catalytic converter and particulate filter. This solution will also be employed in tunnel-building applications."

Volvo Penta is also planning for the future says Darren Tasker: "There is already a stage V foreseen in Europe in the year 2019-2020. Solutions of how to meet this in the best way are already under development. Volvo has the solutions already in place for the on road applications. These solutions will need to be tuned to suit the different types of usages in the crane sector."

It’s not only regulation that drives innovation, the regular search for greater efficiency also pushes manufacturers forward. Liebherr has been working on a range of new engine developments says Wolfgang Beringer: "Besides the further development of the engines to satisfy future emission standards, engineering measures are moving primarily towards greater efficiency, i.e. reduced fuel consumption. Here, for example, we are investigating downspeeding concepts and the optimisation of the entire drive-train to achieve higher levels of efficiency.

Besides major innovations, we are also working on many lesser measures to decisively improve the power-to-weight ratio of mobile and crawler cranes.

"Liebherr and some other manufacturers have also introduced single-engine concepts in the field of larger mobile cranes. The engine in the uppercarriage has been omitted, and with it the complex exhaust gas aftertreatment system. In addition, the weight that has been saved can be used for load bearing construction elements.

"Other innovations are control engineering solutions for optimising fuel consumption, for example ECOmode, which Liebherr presented at the Bauma 2013 exhibition."

Volvo Penta is also working on new ways to make their engines more efficient as Darren Tasker explains: "There are many new exciting technologies for this market.

The possibility to go more and more towards electro mobility solutions is there. With this (being hybrid or fully electric) there is a good potential to save fuel (CO2) and lower noise from the operation. The control of the crane can be further enhanced with electric drives.

"Normal diesel engines will still remain as the major power source for a number of years. But in the future there will be movement towards more environmentally friendly alternatives."

With so much attention being paid to crane engines, it seems that this is one area that manufacturers will have to consider in even more detail with every new model. Future regulation will no doubt play a significant role. It’s hard to predict what manufacturers will do to come up with modern products that are both regulation compliant and offer greater efficiency but it will be fascinating to see what they come up with.