achates finish 10l Opposed piston engineTrueOperating conditionsTesting, fuel saving 1
On December 11, 2023, Achates Power announced its 10Test results for 6-liter opposed-piston (OP) engines, including in-service test results recently completed as part of Walmart's California truck fleet.
Real-world measurements show that a 3-cylinder, 300 kW, 2-stroke cycle OP diesel engine has an average fuel economy advantage of 10% compared to a best-in-class reference engine. The engine has also demonstrated its ability to meet 2024 CARB and 2027 EPA emission standards and CO2 regulations, including applicable Low Duty Cycle (LLC) standards and in-service emission limits.
In the California trial of use, 10The 6-liter opposed-piston engine was installed on a Peterbilt 579 tractor, which Walmart used for more than 6 months in fleet service. In real-world operations on fleet services and simulated routes, opposed-piston engines deliver 4%-21% better fuel economy than best-in-class conventional engines, depending on the route. These impressive fuel savings can be attributed to the high efficiency of the OP engine, which has a wide range of high efficiency zones on the engine map, and the reduced energy requirements for the thermal management of the exhaust aftertreatment system.
The next step consists of a review of 10The 6-liter OP engine was tested, and the engine's aftertreatment system aged to 435K, 600K, and 800K miles to confirm its ability to meet 2024 27 CARB EPA pollutant emission standards and 2027 EPA GHG emissions requirements over its entire service life.
achates power 10.The development of the 6 L opposed piston engine in Class 8 heavy-duty truck applications was supported by the California Air Resources Board (CARB) under the Heavy Duty Diesel Demonstration Program to demonstrate that diesel engines can achieve 002 G BHP-HR (FTP) for CARB low NOx emission limits while also meeting applicable CO2 emission standards.
An important advantage of the opposed-piston engine construction is the low surface area-to-volume ratio of the combustion chamber, which results in lower heat losses and a higher braking thermal efficiency (BTE) – 10The 6-liter OP engine has a peak BTE of more than 49%.
The opposed piston construction – the engine charge is provided by the supercharger rather than the engine's pumping work – also provides greater flexibility in air-fuel ratio control and exhaust temperature management. 10.The 6-liter OP engine uses a conventional exhaust after-treatment system to achieve 002 G BHP-HR FTP NOX limits and meets 2024 27 Carb EPA emission standards without the need for a Closed-Coupled SCR system or other components such as those required for cylinder decommissioning for advanced thermal management strategies. achates 10.The 6-liter engine features a commercial 2021 model year aftertreatment system, as shown in the picture. For better control of N2O, the original SCR catalyst was replaced with a Fe Cu zeolite formulation.
achates 10.The aftertreatment system for the 6-litre OP engine is a change from Volvo Trucks' "all-in-one" conventional aftertreatment system.
Another advantage over the piston structure is the smaller number of parts, which means less complexity and lower cost. Importantly, the OP engine eliminates cylinder heads, camshafts, and engine valves. In conventional engines, these components – including the cylinder head itself, cylinder head gaskets, and exhaust valves – are a significant cause of engine failure and a major component of the engine manufacturer's warranty costs.
Achates Power expects that in mass production, the cost of the OP engine will not exceed or may even be lower than that of the current engine. The cost advantage will increase further if conventional four-stroke diesel engines are forced to adopt additional Closed-Coupled urea SCR systems and cylinder deactivation technology to comply with future emissions regulations.
Other opposing piston engine projects currently underway by Achates Power include:
Hydrogen opposed piston engine - a 1The 6-liter diesel engine was modified for use with hydrogen fuel and tested at the Argonne National Laboratory.
Cummins Advanced Combat Engines – Continued development of Cummins 1000 hp opposed-piston two-stroke diesel engines with Achates Power technology for the U.S. military for Bradley tanks, or manned vehicles (XM-30) and ABRAMS main battle tanks.
*：achates power