To address the significant discrepancy between real-world operating conditions and standard test cycle for non-road diesel mobile machinery, the emission characteristics of three representative prototype engines at operating points outside the conventional control zone were investigated using portable emission measurement systems (PEMS) and engine bench testing. The feasibility of expanding the regulatory cycle control zone to cover non-standard operation conditions was examined. The test results revealed that all three machines spent a substantial proportion of time at operating points outside the current control zone during actual operation. Notably, NOx emissions in low-speed and low-torque regions increased substantially, with prototype 2 exhibiting a peak emission of 9.278 g/(kW•h). Additionally, two operating points for prototype 2 and one for prototype 3 exceeded regulatory limits for NOx and HC emissions, but these could be effectively mitigated through calibration optimization. The study demonstrated that expanding control zones would incorporate more high-emission operating conditions into regulatory oversight. Technical adjustments by manufacturers could ensure compliance, providing a theoretical basis for dynamic emission control strategies in non-road machinery.