Achates showcases 2.5L opposed-piston engine at ACT Expo
22 May 2024
At ACT Expo, Achates Power (API) is displaying one of three engine variants of what it calls the cleanest and most efficient combustion engine architecture to date. With the industry facing massive disruption due to stringent limits on both criteria and CO2 emissions, API’s demonstrations of its opposed-piston engines have shown this architecture can satisfy regulatory requirements without detriment to the fleets or ultimately the economy.
The light-duty 2.5-liter opposed-piston engine displayed at ACT Expo represents all three displacement variants undergoing testing and validation work—with the smallest having been demonstrated in a Class 2a pickup. Not shown are the 5-liter and 10-liter engines which, due to their superior power density, have ratings comparable to today’s medium and heavy duty engines in the 7 to 15 liter space.
Benefits of the API opposed-piston engines include lower heat rejection, higher power density, and fewer moving parts for better reliability and increased fuel efficiency. With this configuration, every stroke is a power stroke which translates to optimal thermal efficiency. Where this matters to the fleets is 2027 and beyond emissions regulations where combustion efficiencies and thermal management are critical for aftertreatment cost, simplicity and functionality. Conversely, the Engine Manufacture Association estimates that total engine and aftertreatment system level pricing of 4-stroke engines could increase as much as $31,000 per truck to meet 2027 emissions standards.