In meeting future emissions requirements, industry experts believe there will be a range of technologies that will prove vital for gasoline and diesel engine development. One technology in particular may stand above the rest in helping OEMs and engine manufacturers meet these targets.
Prevailing technology
Speaking to Automotive World, Timothy Johnson, Director, Emerging Technologies and Regulations at Corning, highlights some of the prevailing technologies that will remain important when looking towards the future of internal combustion engines (ICEs).
In order to meet emissions requirements, Johnson suggests there will be “lots of progress in both gasoline and diesel-based engines. Gasoline engines are moving forward with compression ignition design architectures, and although there is a lot of work that still needs to be done, preliminary numbers suggest a 20% reduction in CO2 over the downsized and turbocharged gasoline direct injection (GDI) engines of today. These are lean-burn engines, and I think they will come into the market by the end of this decade.”
The lean-burn engine uses a system that allows far greater ratios of air than fuel in the combustion process. As a result, the engine is much cleaner as it produces fewer emissions. What is more, the process ensures the engine is less likely to suffer from parasitic losses.
Johnson also believes that the development of some alternative powertrain architectures is beginning to slow down, which presents more avenues for gasoline and diesel engines. He states that the evolution of mild hybrid solutions, “whereby you capture braking energy, is not going any further. This leaves a very attractive environment for both diesel and gasoline solutions.”
“Full hybridisation does not bring a lot of advantages relative to an automatic transmission,” he continues. “With lean-burn compressed ignition, the sweet spot in the engine opens up. You can enter the zone of low fuel consumption with relative ease,” he adds.
As for diesel engines, Johnson details consistent progress in the development of technologies for the last ten years. Looking ahead to 2025, he believes that “there will be more injection pressure, more turbocharging, variable valve technology and cylinder deactivation. These methods will become incremental and standard. We will be seeing much more of these technologies in the five to ten years to come,” he depicts.
In short, Johnson, like many other industry experts, is confident that there is a lot of life left in diesel and gasoline engines, and suggests that there is still room for improvement.
The trump card
Of all the technologies he notes, Johnson believes there is one in particular that is the “best out of all of them – the two-stroke opposed-piston design.” The design enables an increase in volume to surface ratio within the cylinder, preventing heat losses through the engine walls. Furthermore, pumping losses are reduced because of the two-stroke design. “Fundamentally, they are perhaps the most efficient internal combustion engine design,” he says.
Only a small number of companies have invested in the two-stroke opposed-piston engine technology, namely Achates Power and EcoMotors. Johnson thinks that the development of two-stroke opposed-piston technology is “progressing very nicely. Reports from these companies show significant improvements in addressing the trouble spots and the issues that people are concerned about.” In the past, engine manufacturers were apprehensive about the durability of the two-stroke opposed-piston design, as well as the amount of lube oil consumed within the engine. However, Johnson suggests these issues have been addressed as both Achates and EcoMotors announced solutions.
He continues, “I think it’s a matter of progress and keeping things moving forward, as well as getting appropriate partners. That is going to be the major challenge over the next year for EcoMotors and Achates Power.” The next step for these companies, says Johnson, is to get an OEM on board: “Two years ago, EcoMotors reported that it had a Chinese OEM that was investing in multimillion dollar plants to build these engines for the light-duty diesel segment. And then Achates Power mentioned that it has a partnership with Tank Automotive Research Development and Engineering Centre (TARDEC) to develop an engine for ground vehicles. So there is money going into the engines from outside investors, and I think it’s just a matter of time before we see an OEM catch on and move them forward.”
Michael Nash
