Mechanical and brake thermal efficiency in CI engines initially increases with load, reaching a peak before declining, particularly at constant speeds. This peak occurs due to wider throttle openings at higher loads, optimizing engine efficiency. However, as power increases, thermal efficiency may decrease exponentially, suggesting a complex relationship between load and efficiency. Additionally, volumetric efficiency tends to decline as engine speed rises, indicating that performance is not linear across different operating conditions. Understanding these dynamics is crucial for optimizing engine performance under varying loads and speeds.
