The truck show I visited the other day was held on the premises of a fuel, oil and lubricant supplier. Naturally, a good number of their own vehicles was also on display. It was all too obvious that the event’s host relies heavily on the Volvo FM-series to distribute the precious loads.
Like this 2018 Volvo FM 4×2 tractor with a 2019 LAG tandem axle semi-trailer. The combination is rated at a gross weight of 40.5 tons (89,287 lbs).
Until 1990, the LAG company from Belgium also built buses and coaches. That division was taken over by Van Hool, a renowned name in the business and Belgian based too.
A Volvo FM straight truck with a tridem axle 8×2 chassis and LAG tanker body. Both the pusher and the tag axle are steering axles.
Capable of towing a full trailer, given the coupling.
Yet another Volvo & LAG couple. You can’t miss the owner’s name, not even from a country mile.
Let’s see, there are five separate compartments with a grand total capacity of 35,000 liters (or in short: 35 m³). Equal to 9,246 US gallons.
Traxx -in red letters, on the left- is a diesel fuel brand, only supplied to customers with an own fuel station. Like hauling companies, farmers and agricultural contractors.
A bit of a lost soul, this 2016 DAF CF 440 FT 4×2 tractor, towing a tridem axle tanker semi-trailer.
Further down the road, a 2012 Volvo FM 6×2/4 tractor unit in the former, slightly different Van Kessel livery.
Since the main theme is fuel, parked in front of the Volvo was this 2020 Iveco S-Way tractor. Its 460 hp, 12.9 liter engine is running on LNG (liquefied natural gas). Both in regular and bio form, as stated on the roof’s side. The claimed range is 1,600 km (close enough to 1,000 miles).
These days, multiple truck makers offer heavy vehicles with an LNG engine. It won’t be long till BEV trucks and tractors will show up at such events too.
Are these LNG powered trucks using spark ignition engines, or modified diesel (compression ignition) engines?
Both. 🙂
These big LNG truck/bus/industrial engines generally use largely (or totally) the same basic block and internal components (except for the pistons) as the diesel versions, but obviously a different head design, including provisions for the spark ignition.
Since there hasn’t been any real market for large gasoline engines for decades, the starting point is a diesel engine. Of course modern designs quite likely are designed for both versions from the get-go.
I had read that some CNG/LNG conversions were based on the diesel, of course, but retained compression ignition. So I looked into details about this Iveco specifically and yes, it uses spark ignition and a 12:1 compression ratio vs 17:1 on the equivalent diesel. Interestingly this info was buried pretty far down in the Iveco website.
https://www.iveco.com/en-us/press-room/release/Documents/2017/NewStralisNP460.pdf
I’m still not 100% sure of what you were asking. I assume that staright LNG engines have to have spark ignition. I see there’s a “dual fuel” ignition compression design where diesel is the pilot fuel, but LNG can replace some portion of that, up to 60% or so. Are these in production?
I can’t see how a 100% LNG engine could not have spark ignition and not have serious detonation issues, since undoubtedly LNG vapor burns much more rapidly than atomized diesel fuel.
I don’t know if in mass production as such, but there’s plenty of LPG/CNG conversions for diesels out there, which work more as a power booster, with any savings being in total fuel cost. Some more sophisticated ones also reduce the time of the diesel injector opening, letting the gas do more work in the right computer-controlled load/throttle parameters, so that would save fuel. They can also revert to pure diesel when the gas runs out, and re-map instantly so as to maintain power. No measured reduction in emissions, though. Like any dual fuel operation, it is a compromise. Pure gas, as on this IVECO, is logically a better bet.
In the last two pictures I don’t see any crash safety rails for the LNG tanks. Yikes! Perhaps they are removed for servicing. I would think those two big LNG tanks would have an even more robust safety cage.
The crash safety is an integral part of the whole tank construction.
There is little to no CNG infrastructure here for this, though there is for LPG, which I believe can be adapted for use.
Diesel was always a nasty, putrid fuel, and the clever paraphernalia conjured up to clean up its act has proven a bit of a mirage (or in some cases, an outright scam, VW). By that, I mean things like the DPf filters, which clog and cost and fail to work too often, or EGR’s getting clogged and stuffing up turbos and sensors, etc. A vastly cleaner-burning natural gas engine needs no DPF or adBlue, and the gas can be (theoretically) be made from cow farts. Talking of which, less internal engine pressure means less blow-by work for EGR systems to control. It’s all a lot quieter because of the lower comp ratio, too.
I wonder about fuel consumption. The figures talk about 25% lower costs, but is that because CNG is so much cheaper, or is it getting close to diesel figures? Hard to work out from a quick squiz at what’s online.
Sadly, it seems that Hall-Scott were just slightly ahead of the game with their giant OHC engines, but they might catch up yet.
You mention EGR. Several big truck diesels don’t even need an EGR system to meet the very latest emission standards. Like the FPT Cursor 13, the biggest engine available in Iveco trucks and tractors:
https://www.fptindustrial.com/global/en/engines/on-road/trucks/cursor13
In the end, it’s all about costs/efficiency, they’re called commercial vehicles for a reason. And there’s the weight aspect (example: batteries). Especially in countries with low gross weight limits, like the US, you don’t want too much extra kilos/pounds that seriously eat into the payload capacity.
By the way, here’s something you will like. A big DAF with an ICE-engine, running on hydrogen: