Adopting a fully closed-loop integrated process centered on environmentally friendly hydrocarbon/modified alcohol solvents + multi-frequency ultrasonic cleaning + vacuum drying + precision spray rinsing, this solution targets industry pain points including complex crankshaft oil passages, hard-to-remove carbon deposits in crank web gaps, vulnerability of precision surfaces to damage, and post-cleaning rust tendency. It delivers mass-production and maintenance-grade full-coverage cleaning with no corrosion, no sewage discharge, high cleanliness and strong compatibility. Suitable for gasoline and diesel engine crankshafts (cast iron, cast steel and aluminum alloy materials), it meets cleaning requirements for multiple scenarios such as original engine assembly, used part refurbishment and remanufacturing.

I. Core Difficulties in Crankshaft Cleaning

As the core component of an engine—the "heart", the crankshaft features a complex structure with multiple crank webs, multiple oil passages, and blind/angled oil passages. Operating under harsh working conditions, it is far more difficult to clean than ordinary parts, with four major core challenges:

• Stubborn oil contamination and carbon deposits: Long-term exposure to high temperature and pressure on the surfaces of crankshaft crank webs, connecting rod journals and main journals easily forms high-temperature cured sludge, carbon deposits and paint films. Carbon deposits especially in crank web gaps and inner oil passage walls are hard to strip, and cannot be completely removed by traditional cleaning methods.

• High difficulty in oil passage cleaning: Internal crankshaft oil passages (straight, angled and branch oil passages) are narrow and intricately routed. Residual metal debris and grinding powder from machining tend to block oil passages, resulting in poor lubrication and further causing journal scuffing, engine abnormal noise and other faults.

• Vulnerable precision surfaces: Crankshaft journals and thrust faces are high-frequency friction precision surfaces with extremely strict surface roughness requirements (typically Ra ≤ 0.8μm). They are prone to scratches, corrosion and material embrittlement during cleaning, impairing assembly accuracy and service life.

• High risk of rusting: For cast iron and cast steel crankshafts, incomplete drying after water-based cleaning leaves residual moisture that easily causes rust. In addition, some chlorine and sulfur-containing cleaning agents damage the surface metallographic structure of crankshafts and reduce component strength.