Australia has significant reserves of natural gas and has become a major global exporter of gas in compressed and liquefied forms. During the past few years, significant shortages for domestic use and network power generation have forced the Federal Government to act to ensure that suppliers give an undertaking to address local needs as a priority over the lucrative Asian export market.
The availability of natural gas for automotive use has suffered from the restricted number of fuelling stations, which has meant that the main uptake of Compressed Natural Gas (CNG) in Australia has been in the ‘back to depot’ sectors such as urban buses. Refuelling facilities are much more prevalent in Europe, however, with exponential growth in recent years – 348 per cent since 2013 – taking gas fuel from niche applications to a readily available and viable alternative to diesel.
Iveco’s parent company, CNH Industrial, is a global leader in agricultural and construction machinery and much of the development of natural gas engines has come from its expertise in tractors. The FPV engine division has sold more than 30,000 natural gas engines over the past 20 years and it is predicted that 400,000 Liquified Natural Gas (LNG) trucks will be in operation across all brands by 2030.
The application of natural gas to commercial vehicles presents a number of advantages even over electric hybrid trucks particularly in terms of tare weight – batteries are heavy – and operating range. In the energy versus weight conundrum for manufacturers, one kilogram of CNG can deliver the equivalent energy of a 60kg lithium ion battery.
The new Iveco Cursor 13-litre Natural Gas (NG) engine has been specifically developed for long haul applications and delivers 460hp at 1,900rpm and 2,000Nm of torque at 1,100rpm. These specifications place this new engine at the centre of the 430-489hp category which represented 52.3 per cent of Europe’s heavy truck registrations during 2016.
The new Cursor NG 13-litre engine is currently the most powerful of its type available and demonstrates that Iveco and the FPT engine division are serious about gas-powered long-haul transport. The engine can run on 100 per cent natural gas in either CNG or LNG forms as well as on bio-methane (see breakout box). The use of bio-methane also has the benefit of reducing dependency on fossil fuels as it can be generated from agricultural and urban waste, sewage or food industry waste. It remains to be seen what the Australian government will think of this concept: an environmental opportunity or lost excise revenue?
The gas-powered Cursor based gas engines are Euro VI complaint without any Exhaust Gas Recirculation (EGR), Supplementary Catalytic Reduction (SCR- “AdBlue”) or Diesel Particulate Filters (DPF). The exhaust is routed through a catalytic convertor which results in very low CO2 emissions that are nine per cent less than for diesel. There is also a 60 per cent reduction of NOx and 98 per cent less particulate matter compared with diesels operating at Euro VI standards.
The weight saving brought about by not having to fit items such as AdBlue tanks and DPFs results in a kerb weight that is comparable with an equivalent diesel powered truck. This includes LNG tanks with sufficient capacity to enable long-haul trips.
The cylinder compression ratio is 12:1 instead of 17:1 like a conventional diesel. Rather than relying upon a compression explosion to ignite the fuel vapour, the NG engines use a spark ignition system. The ‘corona’ igniters used in the Cursor bear little resemblance to the sparkplugs we are used to on petrol vehicles. The 13-litre engine has a steel turbocharger housing with liquid cooled bearings, and a thin wall cylinder head cast from compacted graphite iron.
Due to the cleaner combustion characteristics of a gas engine, there is a significant reduction in lubricating oil contamination, which allows for much longer service intervals and contributes to the lower cost of ownership. The LNG Cursor 13’s service interval is 90,000km for most applications. In Europe the gas engine models come with a purchase premium in the vicinity of 40 per cent yet the lower fuel costs and consumption rates at current prices still make the LNG option a viable financial proposition for an increasing number of European fleets.
One such operator is Italy-based LC3 Transport, which is heavily involved in container transport, general distribution and controlled temperature transport throughout Europe including the UK. General Manager, Mario Ambrogi, says that his company was involved in the development of the first LNG refuelling station in Italy in 2012 and initially obtained five Iveco prototype 330hp LNG prime movers in 2014, followed by a further 35 of the 400hp models in 2016.
The LC3 Ivecos are equipped with two 540-litre gas tanks that weigh a total of 420kg when full and provide a range of approximately 1,600km.
‘We use them a lot on the Italy to England route,” Mario says. “We now have 70 CNG Ivecos and for 2018 our aim is to have 70 per cent of our fleet of 190 trucks powered by LNG.”
To date, LC3’s LNG trucks have covered more than 15.5 million kilometres which has resulted in a reduction of more than a million kilograms of CO2 emissions than if the work had been done by diesel powered trucks. In recognition of this LC3 was presented with the Italian Sustainable Development Award in November 2017. During our visit to the Iveco facilities at Turin in Italy there are no 460hp vehicles available so we take the opportunity to take a nine-litre 400hp/1,700Nm LNG-fuelled Stralis for several laps of Iveco’s testing track.
The initial factor to be noticed is the higher speed that the engine cranks over when applying the starter: with less compression there is less resistance. The lower compression also affects the function of the engine brake – making it slightly less effective – which requires some adjustments to driving style. The second factor is the reduction in engine noise, particularly under power. The LNG engine is 3-5dBA quieter than the equivalent diesel Euro VI and as decibels are measured on a sliding scale the difference is definitely noticeable to the human ear.
The quieter operation and significantly lower exhaust emission levels has improved the access times for LNG vehicles in cities such as London, which has restrictions on truck movements particularly during the night.
The on-road performance suggests no apparent differences between gas and diesel versions from the driver’s perspective. On paper, the LNG engine has different torque characteristics from its diesel equivalent but exhaustive work on the recalibration of the engine/transmission software means it’s just like driving the Stralis models that we have in Australia, albeit with left hand drive. The 12-speed ZF automated manual transmission always manages to be in the right gear at the right time and the take up of the automated clutch on take-off from stationary is silky smooth.
In the form of this latest LNG/CNG
engine, Iveco has adopted what obviously is mature and effective technology and the solid environmental and financial logic will ensure that a rapid industry take up will occur in locations such as Europe where the price and availability of natural gas makes it all worthwhile.
Until the advent of this new 460hp 13-litre engine, the opportunities for natural gas vehicles in Australia have been restricted to urban delivery trucks and public transport vehicles.
The Cummins-based Westport CNG/LNG engines never really found acceptance here, mainly due to the weight penalty of the gas tanks. If the kerb and axle weight requirements for Australian applications can be met and still provide that 1,600km range, then this innovation from Iveco could be something worth considering for the long-haul interstate work on the east coast even if refuelling facilities are only available in capital cities.
The real challenge will be the Federal Government, which has its hands on the fuel cost levers via its excise charges. The mechanisms of the road user charge and fuel excise are under review and Iveco’s nine- and 13-litre natural gas engines add yet another complication into the mix.
What is natural gas?
Natural gas is predominantly methane (CH4) and at standard pressures has a very low energy density. To be suitable for transport applications natural gas must be compressed or liquefied to increase that energy density.
Compressed Natural Gas (CNG)
CNG is natural gas compressed to around 25 MPa (0.4 per cent volume). Even at such high pressure, CNG has around a quarter of the energy density of a conventional fuel.
Liquefied Natural Gas (LNG)
LNG is natural gas liquefied under high pressure and low temperature and has an energy density of about 60 per cent of conventional fuels.
