Fuel economy benefits of a new engine cooling pump based on sliding vane technology with variable eccentricity

Abstract

During a homologation cycle, engine cooling pump operates at off-design conditions that are characterized by low efficiency and, in turn, impacts on the vehicle fuel economy and emissions performances. Furthermore, the conventional centrifugal technology struggles with the need of implementing thermal management strategies. In order to address these issues, the current paper presents the development of an innovative engine cooling pump for automotive applications that is based on the sliding vane technology. The experimental performances of the novel pump were compared with the ones of a conventional centrifugal device through a test bench that reproduced the real operating conditions of a passenger car engine cooling circuit. Characteristic curves and efficiency maps were further used as input data for a comprehensive model that takes into account heat transfer and hydraulic phenomena of a real engine cooling circuit. The simulation platform was eventually used to assess the energy benefits of the sliding vane pump over a centrifugal machine along theWorldwide harmonized Light vehicles Test Cycle (WLTC) with respect to a fixed geometrical configuration and an optimized one achieved through a control on the eccentricity between stator and rotor that tuned up the flow rate on the cooling demand. A mechanical power reduction of 12% was estimated for a sliding vane pump mechanically linked to the engine crankshaft while the benefits reached 22% if the eccentricity actuation was considered. In terms of CO2 reduction, the benefits related to the introduction of the sliding vane pump are of about 0.5 g/km.