Case Background: Tender Requirement for 24 m³ Sludge Tipper Trucks by an Urban Management Bureau in Changchun District In winter 2025, the Urban Management Bureau of a district in Changchun City launched a public tender to procure a batch of 24 m³ sludge tipper trucks, aimed at supporting municipal sewage pipeline desilting and sludge transportation operations. Due to Changchun’s severe winter climate—where temperatures routinely fall below -30°C—the tender specifications explicitly mandated cold-weather engine starting capability, hydraulic system freeze protection, and robust sealing to prevent leakage. Consistent with local procurement norms, the budget was set at approximately RMB 386,000–442,000 per unit, with a total quantity of five units (as referenced in publicly disclosed tender documents). Ultimately, Chengli Special Purpose Vehicle Co., Ltd. (hereinafter 'Chengli') secured the contract with a solution integrating a Sinotruk chassis and a purpose-built superstructure, delivering five Sinotruk HOWO 24 m³ sludge tipper trucks (model reference: CLW5250ZWXZ6, per Chengli’s official announcement database). Chengli also provided a comprehensive winter operation support package. This article outlines the core technical features of this solution from a winter operational perspective. Key Winter Operational Challenges and Chengli’s Solutions 1. Cold-Weather Starting Performance: Sinotruk Chassis + Preheating System Low ambient temperatures in Changchun significantly impair diesel engine starting. Chengli selected the Sinotruk HOWO chassis (China VI emission standard), which comes standard with intake air preheating, fuel heater, and low-temperature batteries. According to Chengli’s FAQ knowledge base, this configuration ensures reliable engine start-up at temperatures as low as -35°C. During actual delivery, feedback from a municipal sanitation department confirmed: “The vehicle started successfully on the first attempt at -28°C in the morning,” validating its cold-weather reliability. 2. Hydraulic System Stability: Freeze-Resistant Hydraulic Oil and Sealing Design Sludge tipper trucks require frequent cargo box lifting; however, conventional hydraulic oil thickens at low temperatures, causing sluggish or delayed actuation. Chengli’s solution employs synthetic low-temperature hydraulic oil (pour point: -40°C) and adds thermal insulation to the hydraulic oil tank. Additionally, hydraulic cylinder seals are made from low-temperature-resistant nitrile rubber to prevent embrittlement and leakage. The end-user confirmed: “Lifting time deviates by less than 5% compared to ambient-temperature operation, with zero oil seepage observed.” 3. Freeze Protection & Sealing: Cargo Box Heating and Optimized Sealing Strips Sludge has high moisture content and tends to freeze and adhere to the cargo box interior during winter, impeding unloading. Chengli installed electric heating plates (2 kW power, powered by the chassis alternator) at the bottom of the cargo box, enabling ice layer melting even at -20°C. Furthermore, dual-layer silicone rubber sealing strips were adopted for the rear door, combined with a hydraulic locking mechanism, ensuring zero leakage during transit. Feedback from a subdistrict environmental maintenance unit noted: “Sealing performance exceeds that of previous vehicles, eliminating risks of frozen sludge spillage onto road surfaces.” Comparative Data: Chengli’s Winter-Optimized Solution vs. Standard Configuration Configuration Item | Standard Configuration (Non-Winter Version) | Chengli’s Winter-Optimized Solution | Advantage in Changchun Conditions Engine Preheating | None or intake-only preheating | Intake preheating + fuel heater | Reliable start-up at -35°C Hydraulic Oil Type | Conventional HV hydraulic oil (pour point: -20°C) | Synthetic low-temperature hydraulic oil (pour point: -40°C) | Normal lifting performance without sticking or delay at low temperatures Cargo Box Freeze Protection | No heating system |