Compressed Energy

PowerTorque - by Dave Whyte

PowerTorque
Issue 44

The last ten years have been a boon for the commercialisation of alternative fuels. Once the domain of hippies and so called greenies, the environmental benefits of alternative fuels, such as ethanol and bio-diesel, have now become widely accepted.

The fact that most manufacturers now include the use of these fuels in their warranty coverage is a good indication of just how far things have come in terms of the quality and reliability of these fuels. The debate still rages as to whether electric vehicles (or hybrids for that matter) are actually better for the environment, given the materials and manufacturing processes involved in building them. Added to that is the need to recharge, which for the majority of Australians would mean using electricity from a coal fired power station.

In terms of cost, bio-fuels are, for the most part, on a par with the fossil-based fuels. Some vehicles may suffer a slight reduction in economy, but those who use bio-fuel are happy to wear it for the environmental benefits of sustainability and lower emissions. So, while these fuels offer environmental benefits, they don't seem to offer any great improvement in the operator's bottom line. As to finding a satisfactory solution, Isuzu believes it has the answer to both of these concerns, through the use of Compressed Natural Gas (CNG).

CNG, as an automotive fuel, has a lot of desirable qualities. It is affordable, burns very cleanly, has a high octane rating and is widely available. It burns so cleanly, in fact, that the current models in the Isuzu CNG range comply with European EEV standard, one level above Euro V, and are all but ready for Euro VI, for which there is no implementation date as yet.

The use of CNG as a fuel for light trucks is not a new concept, and Isuzu has been building CNG powered vehicles for the Japanese market since the early 90s. So while this might be new for Australian operators, twenty years of real world use means the bugs should have been ironed out by now, and Australian buyers can have confidence in the technology. The price of natural gas is also appealing to those paying the fuel bill, with the current price of CNG being around 72 cents per kilogram (c/kg), which equates to around 48 cents per litre (cpl). Another bonus relates to Australia's huge natural gas reserves, ensuring ongoing supply and more stable pricing.

With a GVM of 7,000 kg, the Isuzu NPR300 CNG fits in the middle of the current Isuzu CNG range. It is powered by a naturally aspirated 4.5-litre engine, which delivers 96 kW (129 hp), and driven through a 6-speed AMT transmission. The most obvious difference between the CNG version and its diesel counterpart is the reduction in noise. At idle, the engine is barely audible inside the cab, with car-like noise levels most of the time while working. Get the engine over 2,500 rpm, however, and the noise level increases substantially.

While empty, the gear change was clunky at times, but the addition of some weight meant the truck carried more momentum, smoothing things out a little. By operating the transmission in economy mode, the engine is restricted to 2200 rpm, which should save fuel, but makes for slow progress off the lights. It also created a tendency for the gearbox to get confused, meaning frequent periods of jumping up and down between gears. This was easily rectified by switching to the standard operating mode, and allowing the engine to gain more revs (and road speed) before changing up a gear.

Steering and stability were excellent, loaded or empty. Our test truck had been out on fleet duties with a major fleet before we got our hands on it, so was well worn in. Even so, the handling showed no sign of sloppiness, and the overall feel was that of a new truck.

A variety of roads were covered on this test, including a short section of gravel, and the NPR maintained its composure on all surfaces. The hilly sections, the winding roads and narrow lanes demonstrated how good the handling really was. Though not exactly car-like, it was more HiAce van than truck.

In the cabin, this truck has all the goodies. The touch screen multimedia unit includes Bluetooth audio and three exterior cameras, showing rearwards down each side and one straight out the back. This unit also operates the radio and CD player, and can be optioned with satellite navigation. Also fitted are driver and passenger SRS airbags, though the latter means doing away with the usual glovebox on the passenger side. There is, however, a pocket mounted on the rear wall and the usual fold down centre seat with storage space when folded forward. Inside the cab, noise levels aside, you wouldn't know you were in anything other than a standard Isuzu, it's still a very functional workspace with all the comforts a driver needs.

Over the course of the day, we covered just over 140 km, including both empty and loaded running over various terrain, as mentioned above. While not a proper fuel economy run, it was the sort of work I think this vehicle would be ideal for, so I took notice of the fuel used. The results were surprising to say the least. Over our 140 km, we used 20.45 kg of CNG (about 30 litres), giving a fuel consumption figure of 4.6 km/l. The astounding figure was the cost of the fuel to do this - $14.70! That's only 10 c/km! Had we put the same amount of diesel in the tank it would have cost around 30 c/km, three times the cost of CNG!

For all intents and purposes, this is an ideal local/metro delivery truck. Easy entry and exit, comfortable ride, and excellent vision all make this truck an ideal candidate for the hectic world of multi-drop courier work. Its easy driveability and comfort also means it could fill the role of country runabout. But there is one problem - it has a very limited range, up to 300 km, and there are very few public refuelling stations for CNG vehicles. For the larger fleet operators, there is the option of installing a refuelling point at a depot, if there is a gas main nearby, but, for the single vehicle or smaller fleet customer, this presents a real problem. The obvious vicious circle is at work here, where no one will buy the truck if they can't get the fuel, but no one will build the fuelling stations until enough vehicles are sold to make it worthwhile.