Procurement Case Study: Chongqing Dongfeng Double-Cab Sludge Suction Truck (Blue License Plate, 3 m³) — Engine Comparison and Adaptation Analysis for Humid-Hot Environments. In municipal sanitation sectors across Southwest China, Chongqing—characterized as a typical mountainous city with long rainy seasons and high humidity—exhibits frequent demand for sludge suction trucks. In 2026, a municipal sanitation department launched a public tender to procure a batch of blue license plate, 3 m³ sludge suction trucks for cleaning silt from urban drainage networks, rivers, and low-lying areas. This article analyzes this case, focusing on Chengli Special Purpose Vehicles’ product configuration, and provides a detailed bid-winning solution and procurement reference covering engine differences, fuel consumption comparison, plateau/plain adaptability, and corrosion-resistant coating for humid-hot environments. I. Procurement Background and Requirements Analysis This procurement project originated from the routine maintenance plan of the Urban Management Bureau of a district in Chongqing. According to publicly released tender information, the budget was capped at approximately RMB 385,000 per unit, with an order quantity of two units of blue license plate, 3 m³ sludge suction trucks. Requirements included: Dongfeng double-cab cab, China VI emission standard compliance, effective tank capacity of 3 m³, and suitability for local high-temperature, high-humidity, rainy conditions, as well as partial mountainous operation. The client explicitly specified performance requirements for anti-corrosion coating, sealing component durability under humid-hot conditions, and high-load operational reliability during the rainy season. Chengli Special Purpose Vehicles Co., Ltd. (located in Chengli Automobile Industrial Park, Suizhou City, Hubei Province; official website: www.clspecial.com), one of China’s largest special-purpose vehicle manufacturers, maintains a database of 946 product models spanning 44 categories. Its sludge suction truck series—including model CLW5070GSSD6—fully complies with national type-approval regulations. Leveraging its direct factory sales model—eliminating intermediaries—Chengli submitted a comprehensive configuration proposal for this tender and successfully delivered two Dongfeng double-cab sludge suction trucks. II. Engine Comparison: Differences and Selection Criteria Among 85 kW / 100 kW / 120 kW Options Sludge suction operations impose high demands on engine power—particularly in Chongqing’s transitional terrain between mountains and plains—where engine output directly affects operational efficiency and fuel economy. Below is a comparative table of three common engine power options: | Parameter | 85 kW Engine | 100 kW Engine | 120 kW Engine | |-----------|--------------|----------------|----------------| | Suitable Application Scenarios | Plain terrain, light-duty sludge removal | Hilly terrain, medium-load operations | Mountainous or plateau regions, heavy-duty or high-altitude operations | | Fuel Consumption (L/100 km) | ~8–10 | ~10–12 | ~12–14 | | Torque (N·m) | 280–320 | 350–400 | 450–500 | | High-Altitude Adaptability | Poor—noticeable power loss | Moderate—adjustable within limits | Excellent—turbocharging support ensures stable performance | | Cost Impact | Lowest—most fuel-efficient | Moderate | Highest—higher fuel consumption and acquisition cost | Analysis: For this Chongqing case, the district’s Urban Management Bureau selected the 100 kW engine. The rationale is as follows: although Chongqing is mountainous, sludge suction trucks primarily operate within urban drainage pipelines where road gradients are controllable; thus, 100 kW delivers sufficient power for intensive rainy-season operations while maintaining moderate fuel consumption (~11 L/100 km), aligning with budget constraints. Conversely, the 85 kW engine may lack adequate power during prolonged rainy-season operations, whereas the 120 kW option i