Road Test: Scania R410 CNG
Some readers will be fully conversant with gas-powered trucks and may well have driven a variety of them. Others will have had little to do with them and will be in the dark regarding the different types offered by several manufacturers. We were somewhere in the middle, with only a small amount of time spent behind the wheel of gas-powered trucks, but a working knowledge of the different technologies.
Gas-powered internal combustion engines (ICEs) were first used in the early part of the last century, and various types of gas conversions were employed to keep essential transport moving during WWII when oil supplies were under severe threat due to blockades on shipping. Liquid Petrolium Gas (LPG) has been used as a means of powering forklifts, industrial plant and other equipment for many years – there have been numerous conversion kits for petrol engines, but it has never been that successful when used to power heavy truck engines. Other combinations of different gases – or a mixture of diesel and gas – have been tried with varying degrees of success, but it required a cleaner gas to work properly in truck applications.
There are two main alternatives for use in modern gas-powered heavy trucks: CNG (compressed natural gas) or LNG (liquified natural gas). Each system has its benefits and drawbacks. CNG is a lot easier to handle in terms of refuelling, it doesn’t vent to the atmosphere when the truck is parked up, and there is minimal driver training required for refuelling.
LNG enables the vehicle to have a greater potential range, but the gas is very cold and requires the use of special PPE when refuelling, also the process is more complex to connect the pump to the truck and activate the system. If the truck is parked for an extended period, natural expansion will see some of the gas vented to the atmosphere – in effect reducing the available range. In recent years, CNG and LNG producers have developed processes where gas is created from food waste and other sources where it is a natural by-product.
This biogas obviously has a far smaller carbon footprint than drilling deep into the ground to extract gas; if this is used to power an ICE, it is possible to reduce the total carbon emissions by as much as 80-85% compared to other conventional fossil fuels. When Scania offered us the Bio-CNG powered R410, we were keen to try it out to see just how practical and flexible this source of power really is – particularly in terms of performance, range, ease of operation and refilling. Also, it was a chance to see if the current Bio-CNG network of filling stations is adequate for many operators.
This is something of a moving target, as new sites are currently under construction and more are planned at numerous other locations. Most sites are obviously based near major industrial areas and/or major trunk routes. The sites are quite expensive to build and you need to be close to a gas supply and have sufficient gas truck operators to make it viable.
Conversely, operators considering moving to gas power need to know if the range the trucks offer – and the refilling network – matches the areas in which they operate. This tends to favour distribution and own-account operators who have a clear idea where they are sending their trucks daily. As the networks expand, range will be less of an issue; but running into rural areas will still be a problem and it is important any gas-powered truck has sufficient capacity to make this possible.
We ran to West Wales on three consecutive days from our Wiltshire base, the closest fuelling site to the yard is the CNG Fuels site at Western Approach, Avonmouth. We were using their nationwide network of sites. The Avonmouth site is on route for us and perfectly suited for trucks heading to the South West and Wales, plus there are several large distribution depots running fleets of CNG-powered trucks in the area.
While we understood there are a significant number of gas trucks on the road, you only appreciate just how many there are when you visit several refuelling sites. 
We filled up on the outward journey and that gave us enough gas to run down to Lampeter, back to the yard, and down to Avonmouth again the next day.
But natural caution combined with the unpredictability of road transport meant we topped up the tanks on the way back through Avonmouth. This avoided the worst possible scenario of running low on gas, then a change of plan sending us in another direction and not having enough gas to get to another fuelling site. Being able to plan your route via refuelling sites makes things easier – we were able to go as far afield as central Scotland with the CNG Scania.
Forward planning meant we were able to use sites at Leyland, Motherwell and Birmingham, then backloading from Manchester and a Midlands pallet hub, with enough gas to get from the yard to Avonmouth the next day. All told, a gas-powered truck is eminently more practical than a battery-electric version, given the extremely limited charging network available at the moment.
Spec & Layout
Scania offer both 9- and 13-litre gas engines. Previously they offered LNG versions, but in recent years they have concentrated on CNG because they are simpler and offer operational benefits.
The growth in the use of Bio-CNG has also seen more operators opt for it. The 9-litre five-cylinder engine is offered at 260 and 340 bhp. Most are specified for rigid and lighter artic applications.
One of the biggest users of Scania CNG gas engines are Waitrose/John Lewis. They have a great many 340 P-cab tractor units and some have covered very high mileages. The power output meets their needs as a four-axle outfit, although one of their northern-based drivers said his gets a bit breathless heading out over Blubberhouses with a full load of ambient grocery goods behind it!
The current 13-litre 410 engine in our truck is soon to be replaced by a CNG gas version of the double-overhead camshaft Super 13-litre rated at 420 and 460 bhp, with an increase in torque that will make it a bit more comfortable at higher weights. The current OC13-101/410 is based on the long-serving DC13 12.74-litre diesel engine with individual cylinder heads, camshaft in the block and rear-mounted timing gears. It has a good reputation for reliability in all forms, but has reached the limit of development in the face of ever-tightening emission regulations.
It produces 410 bhp at 1900 rpm, and 2000 Nm between 11-1400 rpm – a reasonable output, but it doesn’t quite have the ultra-low speed torque of the latest generation of diesel engines. The combustion characteristics of gas engines mean they generally need a few more revs to perform effectively, but we were pleasantly surprised by how the 410 hung on at quite low revs on a long hill. Unlike a diesel – which will combust when mixed with air and is highly compressed between a rising piston and the cylinder head – gas engines, like a petrol, generally need a sparkplug to ignite the fuel and air mixture.
Volvo’s LNG 13-litre engine differs in this key respect, where a small quantity of diesel is used to facilitate combustion. There are pluses and minuses for both options, but the Volvo system does require a small separate diesel tank, gas tanks and AdBlue to clean up the emissions. The spark ignition gas engine just requires gas and nothing else, which makes refuelling a lot simpler and less prone to error.
The gas and air are premixed before entering the cylinders and achieve stoichiometric combustion, which in simple terms means all the gas and oxygen is burned completely when the engine fires. The system can cope with a mixture of natural and biogas if need be. The biogas we used is basically odourless, but it has additives to help detect leaks.
Exhaust emissions are dealt with via an EGR valve and three-way catalyst exhaust. Service intervals are lower than with a diesel at 45,000 km, with the main issue being sparkplug life. This generation of Scania gas engines are matched with the older GRS Opticruise transmission.
It doesn’t quite have the technical sophistication and ultra-fast changes of the latest G25/33CM gearboxes fitted to the Super range, but they will be used with the next-generation gas engine. The standard 2.53:1 axle ratio gives 56 mph at 1250 rpm with the direct-drive top gear; it works quite well with for 30-40 tonne operation, but possibly a lower axle ratio would be better if working in the hills on a regular basis. One feature fitted as standard to all gas Scanias is the effective gearbox retarder.
This is pretty much essential because exhaust and engine brakes cannot be fitted to sparkplug-equipped engines, hence the requirement for a retarder as an auxiliary brake. Volvo can fit an engine brake to their gas engines because the use of diesel to create ignition of gas removes the need for sparkplugs.
Filling up
The most obvious sign the truck runs on gas is the large group of storage tanks clustered together on either side of the chassis. The 3850 mm wheelbase 4×2 carries the maximum possible volume with a total capacity of 1080 litres of Bio-CNG.
Most operators go for the 4×2 layout because of the extra gas capacity; 6x2s have smaller tanks and we understand a 6×2 will be available with the new 460 bhp gas engine. On this truck, the combined filling points are mounted on the nearside and there are twin high- and low-pressure connectors. We were advised to use the smaller-diameter low-pressure point and the relevant filling nozzle on the pumps.
We found the system worked well once we were familiar with it: you activate the pump with a card and enter the required data with the keypad, lock on the connector and press the start button on the pump. The red indicator light on the pump is on when filling, then flashes and the green light comes on when full. The whole process takes 15-20 minutes if filling from near empty.
The gas tanks themselves are very robust and are protected by substantial side impact bars. The system has been thoroughly tested to meet the very strict Swedish safety regulations. Batteries are in the rear of the chassis to free up space, and there is a small diesel tank to power the night heater.
Drivers will be surprised to see the normal Scania catwalk steps are replaced by a custom-built steps made to fit around the extra bulk of the gas tanks. The standard R-cab on this truck was reasonably well-equipped for a fleet vehicle: it had fabric trim, underbunk storage and small overhead lockers at the front, the non-extending bunk, and a fold-up passenger seat. Extras included a fridge, air conditioning and a decent radio/media/phone/Bluetooth system.
We were surprised to see just one external locker on the driver’s side – some fleet trucks still must carry quite a lot of kit that’s best kept out of the cab.
On-road performance
We used the R410 on a mix of work, mainly running at 25-35 tonnes gross – although we did bring a near-full load of hanging beef up from West Wales that had us grossing just over 39 tonnes. It coped quite well on the numerous hills in the area, but the additional weight did blunt the performance a bit more than with an equivalent diesel engine. A colleague asked how it performed, and we said: “Not too bad really; it’s no ball of fire on the hills, but it does the job!” On reflection, this was probably not the best turn of phrase to describe a gas-powered truck!
Overall, the performance was slightly better than we expected and the journey times were quite respectable regardless of the terrain. Sometimes when some younger drivers describe the performance of certain modern trucks, saying they are ‘gutless’, we have to just shake our head and remember what they consider poor performance is not in the same league as a Gardner 180 with just six gears at 32 tons! 
The engine note is softer – a bit like a big petrol engine – and it needs a few more revs to pull away, but once on the move the CNG R410 drives very much like any other mid-range Scania. We anticipated it would need to rev a bit harder to make progress, but it was quite happy at 1150-1200 rpm on easier gradients. The older Opticruise transmission is a bit slower to change than the latest constant-mesh version and some of the ratio steps are a bit wider, which means the engine must rev a bit harder to build road speed before the next upshift.
Overall, the 410 engine makes decent progress and we only used manual mode when necessary. On one particularly steep gradient with a very sharp bend and a wet surface, we used it to ensure traction with a hanging load: we let the revs die right off, then dropped three gears. The truck responded well and just kept climbing.
The relatively new Welsh 20 mph speed limit in built-up areas makes trucks work a lot harder on hilly routes, and in some cases the limit combined with sleeping policemen in the road means you are barely above walking speed at the foot of a big hill. Alternatively, you descend a long gradient and find the limit drops from 40 mph or more to 20 mph, which means you need to both pay attention and make full use of auxiliary braking to keep the main brakes cool and at maximum efficiency. We used the retarder at all times, but unlike with other Scanias, the gas truck doesn’t have the exhaust brake helping along.
On really steep hills, it needed a few hefty shoves of the brake pedal to bring the speed right down. As with every other modern truck, the R410 had the full range of electronic safety aids. It also had Scania’s latest electro-hydraulic steering assistance system, and you could certainly feel its effects at times.
It’s linked to the lane guidance system and it is very sensitive to joints, marker lines and other indentations in the road. At times when we needed to deviate from the straight ahead, we could feel the increased resistance as the system tried to keep us in a straight line. On one occasion, we were running on the inside lane on a smart motorway and there was a stray ratchet strap lying in our path.
We couldn’t go right because of other vehicles, and it was right in line with our nearside tyres. Our only option was to go left onto the rumble strip – we had to push hard to get the truck to respond as the sensors judged we were drifting left. We also had a similar response when taking a roundabout with a hanging load.
Sometimes you need to unwind the lock a bit and let the truck take a wider arc to resist the roll of the truck and load, and once again the white lines on the road confused the system. We know a lot of this technology is being imposed by the authorities, but it seems like it needs a bit more development. Otherwise, the truck drove very much like any other R-series: it rode well with cab air suspension, the vision and cab access are very good, the cab is comfortable enough, there is enough headroom to stand in the centre, and the bed was fine for a couple of nights.
Storage was limited. An extra outside locker would make a big difference, but the target market for this spec is not long-distance operations. Also, you must remember the R142/R143 generation of Scanias that come in for so much praise on social media had less storage space, with an absence of any outside lockers.
The new 143 I had in 1988 was eventually fitted with the rare Scania option of an outside locker after much badgering of the boss – it was about big enough to hold a pair of boots and nothing else. We obviously carried a lot less stuff back in the day…
Our verdict
We were told to expect a range of around 500 km, but we found the CNG-powered R410 will do more if driven sensibly in relatively gentle terrain. It’s difficult to say just how far the truck will go on full tanks because of the potential problems posed by running out of gas – it’s not just a matter of tipping diesel from a can on the side of the road if you come to a halt, so we always had to err on the side of caution.
Over eight working days, we covered 3753 km and used a total of 877.59 litres of gas. This equates to 4.28 km per litre, and using the gas price quoted at the time gives a total fuel cost of GBP728.39. Covering the same distance with a diesel and assuming a generous 10.00 mpg, the amount of fuel used would be 234.56 gallons (1066.18 litres), so using the relevant ex-VAT price at the time of GBP1.25 per litre, we get a total fuel cost of GBP1332.72.
This snapshot shows there are considerable savings to be made if the price of gas remains stable. Also, there’s the bonus of no AdBlue to pay for as well. The downsides are the restricted gas network at present which limits flexibility, and the additional upfront cost of a gas-powered truck which we believe to be 20-25% more than the equivalent diesel model.
The dramatic reduction in CO2 emissions is a very attractive prospect for many larger companies, as is the ability to create gas from food waste or other organic material that might be by-products of the operator’s business. We were impressed with the overall performance of the gas Scania. Also, the CNG Fuels sites were easy to find, well laid out and user-friendly – with the bonus of no more dirty gloves smelling of diesel!
Pros:
- Diesel-like performance
- CNG is easy to fill
- Cheaper cost-per-mile than diesel equivalent
Cons
- Restricted gas network
- Not much storage space
- Steering assistance needs work
Specification
Model: Scania R410NA Bio-CNG 4×2 tractor unit
Plated GVW: 18,000 kg (design: 19,000 kg)
Plated GCW: 40,000 kg (design: 44,000 kg)
Chassis: 3850 mm wheelbase. Steel front suspension, plated 8000 kg (optional active steering linked to lane departure and attention support system). Two-bag rear air suspension, plated 11,500 kg.
315/80 tyres all round. R780/ADA400SA single reduction drive axle with diff lock, 2.59:1 ratio, separate diesel tank for night heater, sliding fifth wheel, full-width aftermarket catwalk
Gas storage: Steel CNG gas storage tanks (offside).
4x 118 dm3 (472 litres) / 4x 152 dm3 (608 litres). Total storage capacity: 1080 litres
Engine: Scania OC13-101/410, Euro 6c 12.74-litre Bio-CNG gas-powered, spark ignition engine.
Six-cylinder inline, turbocharged and intercooled. EGR & catalyst exhaust system
Max power: 410 bhp @ 1900 rpm
Max torque: 2000 Nm @ 1100-1400 rpm
Gearbox: Scania GRS905R 14-speed, two-pedal Opticruise automated with manual override. Economy and standard modes, eco-roll function, direct drive top gear.
Scania retarder auxiliary brake. Ratio spread: 16.41:1–1.00:1. Engine revs @ 56 mph: 1250 rpm
Cab: Scania CR standard-height sleeper with single-bunk layout.
Optional four-point air suspension, full deflector kit, external sun visor, single exterior storage locker.
Interior: Textile trim; suspended, heated and ventilated driver’s seat; fold-up passenger seat; underbunk and overhead storage; optional fridge; automatic temperature control; night heater; 800 mm fixed bed