How to Improve Thermal Efficiency?
2 Answers
Using CVVD technology provides an opportunity to increase the maximum thermal efficiency of these engines to over 50%. CVVD (Continuously Variable Valve Duration) technology is an engine technology developed by Hyundai Motor to balance fuel consumption, performance, and environmental requirements.
I think improving engine thermal efficiency requires focusing on fundamental design. For instance, increasing the compression ratio, like Mazda's Skyactiv technology, which pushes gasoline engine compression ratios up to 14:1. Ensuring faster and more uniform air-fuel mixing is also crucial—nowadays, 350-bar high-pressure direct injection is mainstream, with injector nozzles as fine as a strand of hair. I remember disassembling a new engine recently and noticing how meticulously designed the piston crown was to guide flame propagation. The timing of exhaust valve opening is also critical—retaining high-temperature exhaust gases in the cylinder can help push the piston further. Additionally, recirculating cooled exhaust gases back into the cylinder reduces knocking and fuel consumption. Thermal management must keep pace too—some new engines even apply thermal insulation coatings on cylinder walls. Combining these methods, achieving over 40% thermal efficiency is no longer uncommon these days.
