FUEL EFFICIENT LUBRICANT

March 11, 2011 12:35 pm

Collaboration between research teams at Shell and Gordon Murray Design (GMD) has led to the development of an innovative concept engine lubricant capable of achieving a 6.5% improvement in fuel efficiency – a step change compared to the improvements of around 2.5% achieved in typical fuel economy lubricant development programmes.
 
An Unprecedented Challenge
The European Automotive Manufacturers’ Association (ACEA) estimates that new EU carbon dioxide (CO2) legislation, with its staggered implementation from 2012, will add an average of Euro 1,500 to the cost of each car. Today, new cars for use in the EU produce, on average, 150 g/km of CO2 per vehicle. By 2012, with exceptions and exemptions, manufacturers whose cars exceed a target of 130 g/km will be fined on excess-gramsper- kilogramme basis for every car sold.
 
To balance the higher emission levels from larger cars, smaller cars will need to be well inside the target.
•      By 2012, a single “neutral” weight vehicle that is 100 g/km over the target will be fined Euro 9,500.
•      By 2020, the target looks set to be even lower at 95 g/km; similar legislation may also be implemented in other parts of the world.
 
Does this mean reduced original equipment manufacturer (OEM) margins and increased prices for customers, or can dramatic fuel economy improvements be achieved?
Like ACEA, Shell acknowledges that breakthrough technologies will be needed if these ambitious CO2 emission targets are to be met. These will include both internal-combustion engine technologies, such as start‑stop systems, and longer-term breakthrough technologies, for example, completely new power train designs. And the tightening legislation makes investing now in relatively small potential fuel economy improvements attractive. By 2012, even a 1% fuel economy CO2 reduction across the European fleet will save the equivalent of Euro 2.25 billion in avoided fines.
 
Long-term technology partnerships between OEMs and lubricant companies can help to deliver significant lubricant‑related fuel economy improvements. To demonstrate the potential benefits, Shell teamed up with Gordon Murray Design (GMD) and took a fresh look at lubricant technology.
 
A Car for the future
GMD has responded to the twin challenges of CO2 emissions and congestion with its T.25 city car, a revolutionary vehicle that rewrites the design rule book.
 
In Formula One, Prof Gordon Murray’s technical expertise helped Brabham to win two world championships and McLaren to secure three consecutive titles. He then went on to head the team behind the famous McLaren F1 Road Car, a racing version of which won the Le Mans 24-hour race.
 
Prof Murray and his team have used this design experience from the cutting edge of motorsport to create the T.25 city car. In the process, they have challenged conventional thinking and taken a radical new look at familiar problems.
 
Shell has done the same with its lubricants and worked with GMD to test a concept oil that breaks the specification mould and shakes off the constraints accrued over time by modern oil specifications.
 
Co-Engineering: The Lubricant of the future
Selecting the best current Shell lubricant for an existing engine design can help to considerably improve fuel economy. To reach the next level of fuel economy benefits, Shell design a lubricant specifically for a manufacturer’s engine and optimise the formulation for piston temperature and other engine parameters. But, engine lubricants need to provide an even greater fuel economy benefit if the new targets are to be met.
To squeeze more fuel economy from cars through engine oils, Shell thinks that oil and engine technologies need to be developed together. This approach will require longterm technology partnerships and rewriting of the oil specifications rule book.
 
Breaking The Specification Mould
Are established industry lubricant specifications suffocating innovation?
Punitive vehicle-related CO2 emissions legislation could be the incentive that encourages Shell to reassess lubricant specifications. The number of assessed parameters and the severity of performance limits increases as the specifications evolve; it is very rare for outmoded aspects to be removed completely. This evolution reduces formulation freedom and effectively excludes more innovative formulations, thus making only compromised performance possible.
 
For example, low-viscosity lubricants, which may be otherwise acceptable in a suitably designed engine, are excluded by current volatility specifications, and the level of dispersant used is limited by seal tests, which many see as being poor or outmoded.
 
Testing Concept Lubricants in the T.25
What can be done with a clean sheet?
Shell and GMD wanted to demonstrate the potential for fuel economy improvement offered by crankcase lubricants. Shell worked with GMD, using its T.25 prototype, to test a concept ultra-low-viscosity 0W-10 lubricant.
 
The T.25’s fuel economy was carefully measured at an independent laboratory in a series of chassis dynamometer tests using the concept 0W-10 oil and a 10W-30 lubricant, which is a typical European midtier product. The tests were run in a random sequence and repeated to ensure that the results were statistically robust.
 
The T.25 was subjected to an accurate simulation of the New European Driving Cycle combined and urban cycles. The fuel economy improvement was 4.6% for the combined cycle and an impressive 6.5% for the urban cycle (both figures have a 99% statistical confidence). The urban cycle is particularly appropriate for an innovative city car, as it is likely to be the closest to the car’s real-world use.
 
The T.25 uses a modern, low-friction, 660‑cc engine. The fuel economy benefits may be even greater for vehicles with larger engines as more and larger cylinders means more potential to reduce friction.
 
“We have challenged every aspect of car design to create the T.25 and the environmentally positive iStream manufacturing process,” says Prof Gordon Murray, Chief Executive Officer and Technical Director of GMD. “The lubricant is no exception. It is a vital engine component that has more potential than most for improving a vehicle’s fuel economy and cutting its CO2 emissions. That is why we are working closely with Shell to test its exciting new ultra‑low‑viscosity concept oil.”
 
Commercialising Concept Oils
To get as close as possible to the 6.5% fuel economy improvement demonstrated in the test, a co-engineering approach between the vehicle and lubricant research and development teams is required. The challenge is balancing the friction reduction, the engine protection and the oil life so that the motorist has the benefit of fuel economy without sacrificing reliability. Only by understanding the interactions between the engine components and the lubricants in an integrated way can the balance and full fuel economy benefit be achieved.
 
Shell believes that by working together, it can solve other challenges to commercializing ultra-low-viscosity oils, particularly given the commercial incentives that the new legislation creates.
 
Selda Gunsel, Vice President Lubricants and B2B Products Technology at Shell Lubricants, says “Blending low viscosity oil to improve fuel efficiency is actually relatively simple; the challenge comes when you look to balance it with engine protection and acceptable oil drain intervals. There are products on the market that have made great strides in achieving this balance, such as Shell Helix Ultra but they have to work within the parameters of current industry specifications. We believe that now is the time to start looking at lubricant technology that goes beyond current specifications to enhance the efficiency of the cars of tomorrow.”
 
“Although in the concept stage, this represents a major advancement in lubricant technology; what we have learnt feeds in to the products we are developing for use in the near future. Of course, engine oil is just one part of the fuel efficiency story, but when we take into account the pressure and incentives for vehicle manufacturers to reduce CO2 emissions the contribution from lubricants can become very significant. This is due to the fact that with less engine friction comes less fuel use and ultimately less CO2 is emitted,” Selda adds.
 
Shell’s Approach: Six Steps to Enhanced Fuel Economy
 
1.     Mathematical modelling of friction, fuel economy and CO2 emissions
 
2.     Lubricants’ perspective engine and driveline technology audits
 
3.     Ideal lubricant for each component and the optimum for the whole engine
 
4.     Formulation expertise to create the optimal lubricant
 
5.     Analytical studies, laboratory testing and field trials prove the benefits
 
6.     Supply chain for large-scale, global delivery