Hunters and injectors
Gas fuel system specialists are chasing big business, writesGRAHAMSMITH
WHILE the CSIRO’s Future Fuels boffins were coming to their conclusion about natural gas, one company was getting on with developing a system suitable for Australian heavy-duty trucks.
Canada’s Westport Innovations is a gaseous fuel-systems specialist with a new system of direct injection that can be adapted to a heavy-duty diesel engine without modification to the core engine.
The Westport HDPI (high pressure direct injection) system replaces the diesel fuel system and the engine is ready to run. Though the engine doesn’t need modification, the truck does need to be re-engineered to accept the LNG tanks and the fuel supply-system hardware needed to supply the LNG to the injectors has to be fitted.
The Westport HPDI injector delivers diesel and vaporised LNG to the engine. About 5 per cent of the total volume is diesel, which is injected as a pilot shot to get the combustion process going. The vaporised LNG follows as the main injection.
Both fuels are injected through the same injector, the diesel through a central needle and the vaporised LNG through a concentric outer needle.
The benefit is the system not only delivers substantial fuel cost savings, along with worthwhile environmental benefits, but there’s no loss of engine power, torque, or efficiency relative to the base diesel engine.
Though there has been intense focus on the hike in diesel prices, Westport — with the support of the Australian Government through the Australian Greenhouse Office— has completed a trial with a number of local fleets to establish the credibility of its system.
Four Kenworth T404/408 SAR trucks were especially built for the project and deployed in late 2007 with fleets in Western Australia and Victoria for a six-month trial.
Two were run by Mitchell Corp in Western Australia, where they were grossing out at 100 tonnes hauling crude oil on a 800km round trip.
Perth company Sands Fridge Lines ran a test truck on a refrigerated goods delivery run on which it grossed out at 38-90 tonnes.
The fourth truck was run by Murray Goulburn Co-operative in Victoria, where it was on a milk run between Melbourne and Gippsland and running at 68-tonne GCM.
The test program was completed in March, by which time the trucks had accumulated 275,000km. So positive were the results that all agreed to keep the trucks in their fleets and Mitchell ordered an additional four trucks, Kenworth K108 cab-over prime movers, for their fleet.
The engines used in the test trucks were 15-litre Cummins ISX units that were converted to HPDI by Westport. Emission tests on the HDPI engines showed a reduction in greenhouse gas of more than 25 per cent, and particulates were slashed 60 per cent. The engines were certified by Westport to ADR 80/02 emission limits.
Westport’s system doesn’t come cheap. Depending on the number of tanks that need to be installed, it will cost more than $120,000, but with LNG costing significantly less than diesel that can be recovered quite quickly if doing big mileage.
Following the successful conclusion of the trial Westport has offered its HDPI engine in an off-line fitment in a new Kenworth K108 to seed the market.
Kenworth managing director Joe Rizzo says LNG interest is growing, despite problems still to be resolved like distribution and the upfront cost of the system.
‘‘It’s still early days because there are a lot of issues to overcome, such as filling stations and the initial cost, but for some operations it makes a lot of sense,’’ Rizzo says.
Test pattern: a Mitchell Corp Kenworth T404/408 SAR, part of the high pressure direct-injection experimental fleet.