Introduction: Background of Sludge Transport Vehicle Procurement by a Municipal Environmental Sanitation Department in a District of Hangzhou City. In summer 2025, a municipal environmental sanitation department in a district of Hangzhou City initiated a procurement process for blue license plate, 3-cubic-meter sludge tipper trucks to replace aging vehicles. The department is responsible for transporting sludge from multiple domestic wastewater treatment plants within its jurisdiction to centralized processing facilities, with an average daily transport distance of approximately 80 km. Operating conditions primarily involve urban roads and industrial park roads, with occasional short uphill sections. The procurement budget was capped at around RMB 137,000 (based on publicly available tender information), requiring compliance with China VI emission standards, operability under a Class C driver’s license (blue plate), and suitability for Hangzhou’s high-humidity, frequently rainy, hot-and-humid plum-rain season. Following open tendering and evaluation, the proposal submitted by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as “Chengli”) — featuring a Dongfeng D6 chassis-based, blue license plate, 3-cubic-meter sludge tipper truck — was selected. A total of four units were ultimately delivered. This article provides an in-depth analysis of the technical rationale and procurement considerations behind this winning solution, focusing on key dimensions including engine power comparison, fuel consumption performance, and adaptability to hot-and-humid environments. I. Engine Power Comparison: Differences and Selection Among 85 kW / 100 kW / 120 kW Options. Sludge tipper trucks used for short-distance urban transportation must balance full-load starting capability, hill-climbing performance, and fuel economy under urban speed limits (60 km/h). For this procurement, three Dongfeng D6 chassis-compatible engines were evaluated: 85 kW (~115 hp), 100 kW (~136 hp), and 120 kW (~163 hp), all compliant with China VI emission standards. Key parameters are compared below: Engine Model (Reference) | Rated Power (kW) | Max Torque (N·m) | Displacement (L) | Recommended Operating Conditions | Reference Fuel Consumption (L/100 km) ---|---|---|---|--- 85 kW Engine | 85 | 280 | 2.3 | Flat urban roads | 10–12 100 kW Engine | 100 | 320 | 2.8 | Urban roads + short inclines | 11–13 120 kW Engine | 120 | 360 | 3.0 | Mountainous/high-altitude/heavy-duty applications | 13–15 85 kW Engine: Suitable for flat urban roads in Hangzhou; delivers smooth full-load (3 m³ sludge ≈ 4.5 tons) take-off, but requires engine speeds above 2,500 rpm when negotiating short steep grades (e.g., access ramps into treatment plants), resulting in higher fuel consumption. Due to insufficient power reserve, this model was eliminated during procurement evaluation. 100 kW Engine: Serves as the core configuration of the winning solution. Delivering peak torque of 320 N·m at just 2,000 rpm, it strikes an optimal balance between urban-speed fuel economy and hill-climbing capability. According to official Dongfeng D6 chassis specifications provided by Chengli (e.g., CLW5070GSSD6 series), the 100 kW engine achieves an average fuel consumption of ~11.5 L/100 km under typical Hangzhou road conditions — approximately 15% more fuel-efficient than the 120 kW variant. 120 kW Engine: Though highly powerful, it is primarily intended for heavy-duty or high-altitude applications (e.g., projects in Sichuan or Yunnan provinces). In Hangzhou’s flat terrain, its larger displacement leads to elevated fuel consumption under no-load conditions (~13.5 L/100 km), and increases procurement cost by approximately RMB 3,000–5,000.