I. Project Background and Management Perspective: From 'Fear of Freezing' to 'Confidence in Operation' In winter 2025, a municipal sanitation department in Hohhot launched a procurement initiative for 24 m³ sludge tipper trucks to meet sludge transportation demands generated by the city’s wastewater treatment plants and pipeline desilting operations. When reflecting on this procurement, Mr. Wang, the department’s fleet management director, stated frankly: 'In northern China, where temperatures can drop to -30°C in winter, whether the vehicle can start reliably and whether its hydraulic system operates normally are the top criteria in vehicle selection.' Previously, the department had used sludge trucks from other brands, but frequently encountered issues in winter—including hydraulic oil solidification, difficult cold starts, and aging/cracking of sealing components—resulting in over 30% reduction in operational efficiency. Therefore, this procurement explicitly required vehicles capable of operating reliably at -35°C, featuring freeze-resistant starting capability, stable hydraulic performance under low temperatures, and a comprehensive winter maintenance plan. Following an open tender process, Chengli Special Purpose Vehicle Co., Ltd. delivered five 24 m³ sludge tipper trucks built on SINOTRUK chassis. In line with local procurement practices, the unit price was approximately RMB 450,000, keeping the total budget within RMB 2.634 million. II. Dispatch Flexibility: 'On-Demand Availability' in Cold Conditions Mr. Wang noted that dispatch pressure peaks during winter, as failure of a vehicle to start during sub-zero early-morning hours would disrupt the entire sludge removal chain. The vehicles delivered by Chengli feature SINOTRUK chassis and Chengli-developed sealed sludge tipper bodies with a 24 m³ capacity. Technically, they are equipped as standard with a -35# cold-start assistance system (including preheating devices) and full-vehicle low-temperature-resistant rubber sealing components—ensuring engine start time of no more than 10 seconds even at -35°C. 'We conducted real-world testing: after parking overnight for 8 hours in ambient temperatures of -28°C, the vehicle started successfully with one button press, and the hydraulic system reached operational pressure within 15 seconds—a feat previously unattainable,' emphasized Mr. Wang. Additionally, hydraulic lines are double-insulated, and low-temperature hydraulic oil (with pour point of -45°C) is used to prevent sluggish actuation caused by excessive oil viscosity. Dispatchers can assign vehicles on demand without preheating delays, significantly enhancing emergency response capability during winter. III. Fuel Consumption Monitoring Data: Real-World Performance Under Low-Temperature Conditions Regarding energy consumption, Mr. Wang provided fuel consumption monitoring data collected over three months of operation. Vehicles primarily travel between urban roads and suburban wastewater treatment plants, covering ~25 km per trip and completing 6–8 trips daily. To assess the impact of low temperatures on fuel consumption, the department recorded data from November 2025 to January 2026 (ambient temperature range: -15°C to -35°C): Table 1: Winter Fuel Consumption Data for Chengli-SINOTRUK 24 m³ Sludge Tipper Trucks (Reference: Public Tender Information) Month | Avg. Temp. (°C) | Avg. Fuel Consumption per Trip (L/trip) | Daily Total Fuel Consumption (L) | Notes ---|---|---|---|--- Nov. 2025 | -10 | 8.5 | 68 | Auxiliary preheating not activated Dec. 2025 | -22 | 9.2 | 73.6 | Auxiliary preheating activated 3 times Jan. 2026 | -32 | 9.8 | 78.4 | Auxiliary preheating used throughout As shown in the table, even in the coldest month (January), fuel consumption per trip remained at 9.8 L.