I. Project Background and Procurement Requirements: Winter Campaign of a Municipal Sanitation Department in Shenyang In winter 2025, a municipal sanitation department in Shenyang launched a procurement initiative for sewage treatment vehicles to address frequent pipeline blockages in aging residential communities within its jurisdiction and the risk of freezing under low winter temperatures. Key procurement requirements included: China VI emission compliance, a 3308 mm wheelbase, high maneuverability, and low-temperature freeze protection capability. After multiple rounds of technical evaluation and on-site inspections, the department selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng chassis solution. The department’s procurement lead stated: “Shenyang’s winter temperatures often drop below -20°C; reliable vehicle cold-start performance, hydraulic line sealing integrity, and sewage tank freeze protection are critical pain points. Among several suppliers evaluated, Chengli not only offered a proven Dongfeng chassis solution but also customized heating and thermal insulation systems specifically for Northeast China’s climate—this became the decisive factor in our final selection.” According to publicly released tender information, the project budget was capped at approximately RMB 499,000, covering three units at an average unit price of around RMB 150,000. II. In-Depth Chassis Selection Analysis: Comparative Evaluation of Dongfeng, Sinotruk, Foton, and FAW Chassis Platforms In the specialized vehicle segment with a 3308 mm wheelbase, chassis selection directly impacts payload capacity, maneuverability, and long-term maintenance costs. Below is a horizontal comparison of the four leading chassis platforms—based on real parameters from Chengli’s internal knowledge base (e.g., model CLW5070GSSD6) and actual procurement cases: Comparison Item | Dongfeng (e.g., EQ1075SJ3CDF) | Sinotruk (HOWO Series) | Foton (Ouman) | FAW (HuV Series) ---|---|---|---|--- Engine Characteristics | Yunnan Internal Combustion / Chaoyang Diesel engines—proven cold-start performance in low temperatures; extensive service network across Northeast China | Weichai engine—high power output but slightly higher fuel consumption | Cummins engine—low noise level but expensive spare parts | Dalian Diesel Engine (DAE)—fuel-efficient but limited availability of cold-climate variants Payload Capacity | Front axle: 2.5T / Rear axle: 5T—suitable for 4–6 m³ sewage tanks | Front axle: 3T / Rear axle: 6T—higher load capacity | Front axle: 2.5T / Rear axle: 5T—comparable to Dongfeng | Front axle: 2.5T / Rear axle: 5T—standard configuration Maneuverability (3308 mm wheelbase) | Small turning radius—ideal for narrow alleys in aging residential neighborhoods | Slightly wider body—reduced agility in tight urban spaces | High cab design—excellent visibility but relatively lower maneuverability | Robust chassis construction—but slightly lower ground clearance Maintenance Convenience (Shenyang Region) | Nationwide Dongfeng warranty network; two authorized service stations in Shenyang | Limited Sinotruk service stations; appointments required | Strong Foton service coverage—but high Cummins part costs | Numerous FAW service stations—but slower deployment of DAE cold-climate variants Low-Temperature Adaptability (-20°C) | Standard pre-heating system; optional fuel-fired heater available | Weichai engine includes built-in pre-heating—but higher fuel consumption in extreme cold | Cummins engine requires add-on heating modules | Cold-weather package must be specially ordered Reference Winning Cases (Chengli) | 10 units of 5 m³ water sprinklers for Henan sanitation bureau (Dongfeng chassis) | Rarely used for 3308 mm wheelbase sewage vehicles | Water sprinklers + fog cannons for Guangdong industrial park (Foton chassis) | Municipal cleaning & vacuum trucks in Sichuan (FAW chassis) From the perspective of Shenyang’s specific operational needs, the Dongfeng chassis emerged a