Early vacuum pumps were typically used only in diesel engines, primarily serving as a vacuum source for the vacuum booster pump in the braking system. Due to their single function and relatively low requirements for vacuum pumping speed and vacuum level, engine vacuum pumps did not prioritize high rotational speed or pumping speed.
In recent years, with advancements in modern automotive technology, the standards for vacuum sources in vehicles have become increasingly stringent. Direct-drive vacuum pumps connected to the camshaft have gradually replaced those connected to the alternator shaft, offering higher vacuum levels and faster pumping speeds. This paper investigates the working principle, structure, and performance metrics such as vacuum level of direct-drive camshaft vacuum pumps used in automotive engines. The performance characteristics of engine rotary vane vacuum pumps employing a spiral-shaped pump chamber are theoretically validated, with theoretical calculation methods provided for all performance metrics of this pump type. An innovative approach is proposed to address the low intake efficiency in domestic engine vacuum pump intake chambers: designing intake and exhaust guide channels and optimizing their parameters.
Based on theoretical calculations, a three-dimensional model was established to conduct theoretical analysis of the mechanical and kinematic properties of the vacuum pump's main components. Addressing the difficulty of simulating engine operating conditions on conventional rotary vane vacuum pump test platforms, a novel engine vacuum pump test platform was designed, with a preliminary design proposal provided. Utilizing existing CNC machining equipment, a machining process specification for the vacuum pump housing was developed, followed by simulation and final machining of the housing. This research provides feasible design methodologies and machining experimental protocols for the further development and production of automotive rotary vane mechanical vacuum pumps.
