Case Study and Bid-Winning Solution Analysis of the Dongfeng D6 Sewage Treatment Vehicle (Blue License Plate) for Mianyang’s Government Procurement — Amid increasingly stringent environmental policies, municipal sanitation departments’ demand for sewage treatment vehicles continues to rise. A district urban management bureau in Mianyang recently procured a batch of blue license plate sewage treatment vehicles to handle operations at small urban sewage stations and temporary street drainage tasks. After multiple rounds of technical evaluation and price comparison, Chengli Special Purpose Vehicle’s Dongfeng D6 chassis-based modification solution was selected. This article provides an in-depth analysis of this government procurement case from perspectives including engine comparison, fuel consumption performance, and adaptability to plateau vs. plain terrain. I. Case Background and Procurement Requirements In 2025, a district urban management bureau in Mianyang planned to procure five blue license plate sewage treatment vehicles to support urban drainage network maintenance and temporary sewage cleanup tasks. The total budget was capped at approximately RMB 512,000, with an average unit price of around RMB 90,000 (based on publicly available tender information). Key procurement requirements included: blue license plate eligibility (drivable with Class C driver’s license), China VI emission standard compliance, independent power supply for the superstructure, and suitability for the Sichuan Basin topography and surrounding hilly areas. Following rigorous screening, Chengli Special Purpose Vehicle’s Dongfeng D6-based solution stood out, resulting in the delivery of five CLW5070GSSD6 model sewage treatment vehicles (modified on the Dongfeng D6 chassis). Customer feedback indicates that these vehicles are performing well in actual operation—particularly playing a critical role in handling seepage during rainy seasons. Chengli’s service team provided full-cycle technical support, ensuring rapid commissioning and deployment. II. Engine Comparison: Analysis of Power Output Differences (85 kW / 100 kW / 120 kW) In government procurement, engine power is a core factor influencing vehicle performance. The Dongfeng D6 chassis typically offers three engine options: 85 kW (~115 hp), 100 kW (~136 hp), and 120 kW (~163 hp). Below is a comparative analysis based on real-world operating conditions: | Parameter | 85 kW Engine | 100 kW Engine | 120 kW Engine | |-----------|--------------|----------------|----------------| | Suitable Application Scenarios | Urban flat roads, light-load operations | Urban roads, moderate gradients, standard payload | Hilly/mountainous areas, heavy-load or rapid-response missions | | Maximum Torque (N·m) | ~300 | ~380 | ~450 | | Fuel Consumption per 100 km (L) | ~12–14 | ~14–16 | ~16–18 | | High-Altitude Adaptability | Moderate; noticeable power loss above 3,000 m elevation | Good; suitable for elevations between 2,000–4,000 m | Excellent; suitable for elevations above 4,000 m | | Plain Adaptability | Excellent: low fuel consumption, low noise | Good: balanced power and economy | Higher fuel consumption; suited for special operational needs | | Maintenance Cost | Low | Medium | High | In the Mianyang case, given the local geography—situated in the Sichuan Basin at approximately 500 m elevation—and the predominance of light-load urban operations, the 85 kW engine option was ultimately selected. This choice fully satisfies routine sewage discharge requirements while significantly reducing fuel consumption and overall operating costs. Customer feedback confirms stable performance of the 85 kW engine in plain terrain, with average fuel consumption of ~13 L/100 km—approximately 15% lower than the 100 kW variant, translating into notable fuel cost savings. III. Fuel Consumption Comparison and Operating Cost Analysis According to publicly released tender information, the Dongfeng D6 sewage treatment vehicle supplied by