Achates Power Inc, maker of opposed-piston engines, recently announced the development of an engine for a light-duty truck demonstration vehicle, which will surpass CAFE 2025 regulations. The opposed-piston engine will be 30-50 % more efficient than comparable engines, reduce emissions and cost less than alternative technologies under development for meeting CAFE, the company noted.
The new 2.7 l Achates Power opposed-piston engine develops 270 hp of power, with 650 Nm of torque. The company said that its engine will help the vehicle achieve a fuel economy of 37 miles per gallon, above the 33 m/g fully phased-in CAFE 2025 requirement for a full-size, light-duty pick-up truck. Achates noted that the demonstration engine will be integrated into a drivable prototype in 2018, with development engines also being available for automakers.
The opposed-piston engine uses fewer parts, including eliminating the cylinder head(s) and related components, valvetrain and related components, and a reduction in the after-treatment system size and cost, explained Achates. A comparison between the 2.7 l opposed-piston engine and a comparable V6 with supercharger shows part reduction of over 60 %, enabling about 10 % cost reduction.
The Achates Power opposed-piston engine features two pistons per cylinder, working in opposite reciprocating action. The engine does not need cylinder heads, which are a major contributor to heat losses in conventional engines. Ports in the cylinder walls replace the complex poppet valves and friction-creating valve trains of conventional engines. The intake ports at one end of the cylinder and exhaust ports at the other are opened by the piston motion and enable efficient uniflow air scavenging. The two-stroke, compression ignition engine has been engineered to achieve superior thermal efficiency by the virtue of its lower heat losses, higher expansion ratio, lean combustion and reduced pumping losses, Achates explained.
David Johnson, President and CEO, Achates Power, said the company is excited to showcase the fuel efficiency, low emissions and outstanding driving characteristics of its Opposed-Piston Engines. He added that this is while Achates continues to work on its customer programs, and research and development programs, such as gasoline compression ignition. There is no solution for the proposed 2025 CAFE regulation that is as cost-effective, compatible with existing vehicles and fuels, production-ready and adaptable to future renewable fuels as opposed-piston engines, noted Johnson.
In 2014, the company presented a technical paper at the SAE World Congress showing how it could achieve CAFE 2025 regulations in a full-size truck, noted Fabien Redon, Vice-President, Technology Development, Achates Power. He said that in 2018, Achates will have a demonstration vehicle that proves an internal combustion engine is able to cost-effectively meet the CAFE standard. Redon added that the vehicle will not require the adoption of costly modifications, infrastructure upgrades, or a change in how the driver operates or maintains the vehicle.