The transport industry continually strives for efficiencies as operating costs increase. For truck fleets of all sizes a major cost input is fuel and lubricants. Viva Energy, the licensee of Shell products in Australia, set about an extensive research study to identify direct fuel economy benefits from using synthetic lubricants. According to the company, the results have been unprecedented.
There have been a number of evaluations targeting fuel efficiency through the use of different lubricants in recent years, with most, if not all, conducted in Europe or the US thus limiting the relevance to the unique conditions transport companies face daily in Australia.
Viva Energy set out to do something about this by investing in building a credible research model to test Shell mineral and synthetic transport engine and drivetrain lubricants in a controlled environment.
The ultimate aim was to provide a focus whose relevancy applied to transport company owners and decision makers in this country.
The theory behind the research brief was relatively straight forward but involved some challenges in the application.
It was decided that a series of chassis dynamometer tests on a heavy duty highway truck would offer the best grounds in which to determine whether a fuel consumption benefit can be derived from the replacement of mineral based engine, transmission and axle oils with synthetic alternatives.
According to Viva Energy’s Product Support Engineer Paul Smallacombe the Shell Lubricants team devised a wide ranging research study that was totally focused on Australian driving conditions.
“We took the step to commission the work after highly credible partners were identified to independently oversee the research,” he said.
“As the licencee of Shell Lubricants in Australia, the importance of rigorously testing the full range of Transport Lubricants was an important step to allow us to further understand the performance of the Shell Synthetic Lubricants range across a broad range of conditions.”
Working with industry specialists who have a track record and equipment in identifying potential fuel efficiency gains, Viva Energy engaged Melbourne-based Kangan Institute Automotive Centre of Excellence to supply the chassis dynamometer together with expertise on the operation of the sophisticated dyno.
The transient drive cycle selected provided a representative mix of Australian congested city, urban fringe and highway driving.
The test, it was agreed upon, should be conducted by a specialist research company and ABMARC, an independent team of highly experienced engineers and research staff offering a broad range of services in the transport and energy sectors came aboard.
As specialists in precisely measuring fuel efficiency improvements, ABMARC has a long history of similar projects in the industry.
“Viva Energy approached ABMARC with a brief to better understand the real-world performance of synthetic lubricants as an influencer on fuel consumption when compared with traditional mineral lubricants,” says James Payne, ABMARC Environment & Technical Services Manager.
“The design of the study simulated real world conditions on a heavy vehicle but in a controlled laboratory environment. The fuel measurement technology we used is the only one of its type in Australia and provides the most precise measurements possible. Our test methodology delivered excellent repeatability and statistical significance, which gives Viva high confidence in the results”.
Rather than utilising a brand new low km vehicle, Viva Energy elected to use a representative on-highway configuration truck for the testing – a Western Star 5800SS, running a Detroit Diesel 14.8L engine with 370,000km on it before clear parameters for the testing commenced.
The overall strategy of the testing program consisted of multiple repeats of drive cycles, with the engine starting from a warm condition.
Drive cycles were configured to replicate Australian driving conditions akin to those a typical truck operator would encounter.
A mix of metro stop-start, outer urban and highway running were repeated to reflect road conditions.
Fuel consumption in transient conditions and simulating driving the heavy duty on-highway truck in an Australian environment served as the basis for assessments predicated on the impact of changing the lubricants.
The fuel measurement system was connected to the three fuel lines.
These included fuel flow from the tank at the exit of the pre-filter, fuel flow to the engine at the entry to the main filter and fuel return from the engine at the tee.
By allowing the new fuel consumption to be measured with a single fuel flow meter, test measurement accuracy and repeatability was improved.
In order to simulate the test vehicle towing a trailer under load to the degree it provided the closest realistic indication of the fuel consumption in the real world, the maximum inertia possible was simulated by the dynamometer while minimising tyre slippage on the rollers.
Simulated vehicle inertia, representing the gross vehicle mass recreated during testing, was 25,000kg.
Critical to the testing regime outcomes were the Shell Transport Lubricants used. Test cycles were undertaken with mineral oils and repeated with synthetics.
All lubricants, according to Viva Energy, were filled to the dipstick maximum in the case of the engine oil and filled to level via the transmission and axle fill points.
To limit the effect of carry-over from previous oils used in the Western Star, a process was devised for oil changes to remove any chance of cross contamination of products despite the mineral and synthetic lubricants having been approved for use by original equipment manufacturers.
In the process previous oils were drained and filled to level with fresh oils, while engine and transmission oil filters were replaced.
The vehicle was then warmed up and flushed by operation on a transient cycle whereupon the oil was drained and a final fill with fresh oils was administered before again replacing engine and transmission oil filters.
The first round of tests was conducted with Shell mineral oils then substituted with Shell Synthetic oils.
All testing was conducted to the same parameters and conditions by ABMARC at the Automotive Centre of Excellence.
The results pointed to a potential fuel economy benefit of up to 2.5 per cent, when using Shell Synthetic Lubricant products, which accommodated delivery of potential fuel efficiency improvements and better component protection including reliability over longer oil drain intervals.
Conclusions were drawn from 16 tests evenly divided between mineral and synthetic evaluations.
Based on the drive cycle tests, there was on average a 2.5 per cent reduction in fuel consumption using the Shell Synthetic Technology Oils in the Western Star test vehicle compared to using the mineral based oils.
ABMARC’s report confirmed with 95 per cent confidence that this fuel consumption reduction can be attributed to replacing the mineral engine, transmission and rear axle oils with the Shell Synthetic Oils.
“The fuel consumption saving results achieved in the testing were impressive. The Shell Synthetic Lubricants range of products performed faultlessly throughout the testing regime and this research offers real substantive benefits to the Australian transport industry,” Paul says.
“A 2.5 per cent reduction in one of the largest cost components of transport operators is significant.”
The series of testing and monitoring on the chassis dynamometer coupled with the high sophisticated fuel measurement system utilised for this study has provided, according to Viva Energy, new data that is a potential first in testing on Australian driving cycles.