I. Case Background: Winter Sewer Cleaning Challenges Faced by a Municipal Sanitation Department in Harbin At the end of 2024, a municipal sanitation department in Harbin procured a batch of blue license plate Dongfeng double-cab sewer cleaning trucks (3-cubic-meter capacity) for urban drainage pipe cleaning operations. Winter temperatures in this region frequently drop to -30°C, imposing extremely high requirements on vehicle cold-start performance and hydraulic system stability. After comprehensive evaluation, Chengli Special Purpose Vehicle delivered 10 units of the CLW5040TQYD6 sewer cleaning truck model. These vehicles have now operated successfully for over one winter season, and driver feedback forms the core reference for this case study. II. Driver’s Perspective: From 'Afraid to Drive' to 'Used Daily' 1. Real-World Driving Experience: Blue License Plate, C-Class Driving License — Effortless Urban Maneuverability Master Zhang, the driver assigned to these vehicles, brings 15 years of experience operating sanitation vehicles. He remarked: 'This truck qualifies for a blue license plate and can be driven with a Class C license. Its overall length is under 6 meters, and its small turning radius makes U-turns exceptionally convenient on narrow streets and alleys in Harbin’s historic urban districts. Previously, with yellow-plate trucks, we couldn’t even enter certain narrow lanes; now, a single trip with this truck completes the entire sewer cleaning task for an entire residential community.' Master Zhang especially emphasized that the Dongfeng double-cab offers generous interior space—drivers remain comfortable even wearing thick winter parkas. The seat features shock-absorbing functionality, delivering noticeably superior lumbar support on bumpy roads compared to similar models. 2. Operational Convenience: One-Touch Hydraulic Control — Easy for Novice Operators The core functionality of a sewer cleaning truck lies in its hydraulic lifting and vacuum suction systems. Master Zhang demonstrated the operation sequence: simply press the 'Power Take-Off (PTO)' switch inside the cab; the hydraulic pump automatically activates, and two control levers enable full operation—including tank lifting, rear lid opening, and suction hose deployment/retraction. 'I trained new crew members — they mastered it within 15 minutes. Compared to older mechanical systems, this truck saves effort and enhances safety.' According to Chengli after-sales technicians, the vehicle’s hydraulic system employs a multi-way valve control unit with built-in overload protection, effectively preventing hydraulic cylinder damage caused by operational errors. 3. Low-Temperature Winter Performance: Successful Cold Start at -30°C This is the top concern for users in Northeast China. Master Zhang recalled: 'Last December, ambient temperature dropped below -30°C overnight, with the vehicle parked outdoors. In the morning, following standard preheating procedures (power-on self-check, depressing the clutch twice, then ignition), the engine started instantly—no gear grinding or starting difficulties occurred.' Technical support staff from Chengli’s Northeast regional after-sales service center explained: The vehicle comes standard with a fuel heater and low-temperature start assist system; hydraulic oil meets -35°C low-temperature specifications; and all hydraulic lines are insulated to ensure optimal oil fluidity under extreme cold conditions. According to the official announcement parameters for model CLW5040TQYD6 in the knowledge base, the truck is equipped with a 95-horsepower Quanchai engine featuring electronic high-pressure common-rail technology, enabling more complete combustion in sub-zero conditions. III. Comparative Data: Blue License Plate 3-cubic-meter Sewer Cleaning Truck vs. Comparable Competitors Based on publicly available tender documents, the department’s procurement budget was capped at approximately RMB 204,000 per unit. Below is a parameter com