<p>To investigate how various factors affect the low-temperature light-off properties of hydrocarbons (HC) in Catalytic Particulate Filters (CPF) during cold starts, a mathematical model of the CPF was initially created and validated. Following this, Fluent was employed to simulate and analyze the HC conversion process at low temperatures. On this basis, the influence of different parameters on the low-temperature ignition characteristics of HC, reaction rate and hydrocarbon distribution were investigated by taking the conversion rate and mass fraction distribution of propylene in CPF as the criteria of ignition performance. The observed propylene conversion efficiency and light-off temperature exhibited direct dependence on three key factors: oxygen (O₂) concentration in exhaust gases, material porosity, and filter length. In contrast, these metrics displayed inverse sensitivity to exhaust flow dynamics and moisture content in the exhaust. The porosity mainly affects the HC conversion of the first half of the filter body. A longitudinal temperature gradient was established across the filter matrix, with the central segment demonstrating heightened thermal response corresponding to elevated HC ignition thresholds. The porosity has a significant influence on the temperature rise of the filter body at a low ignition temperature, while the length of the filter body has a small influence on the temperature rise in the middle. The HC (propylene) mass fraction increases gradually along the axial direction.</p>