Experimental and simulation-based investigation of power consumption of an electro-mechanical dual acting pulley continuously variable transmission for electric vehicle powertrain

• Experimental efficiency data of the prototype of electro-mechanical CVT (EMCVT). • Experimental work on dynamometer; the variable clamping forces applied on the CVT metal belt, resulting in 3 – 8% efficiency improvement of the EMCVT. • Analysis on the power consumption; EMCVT consumed 3.47 kWh (versus 4.60 kWh of a single speed transmission) for WLTC. • The single speed transmission performs better in terms of 0 to 100 km/h acceleration (22.6% faster) and top speed (3.7% faster) on 0-gradient, and it also outperforms the EMCVT in terms of gradient climbing capability. • Low vehicle speed is advantageous for the single speed transmission, while for high vehicle speeds, the EMCVT is more economical (less power consumed). This research investigates the potential of an electro-mechanical CVT (EMCVT) in reducing the power consumption of an EV powertrain, starting with the experimental phase to obtain the efficiency data of the EMCVT prototype. In the phase, the prototype is tested for the geometrical ratio ( r CVT_geo ) of 2.30, 1.60, 1.00 and 0.70, with the clamping forces of 8.5 kN, 10.5 kN and 11.0 kN applied on its secondary pulley. The results show the transmission efficiency can be improved by up to 10% with the properly reduced clamping force, depending on the ratio and loads. With the efficiency data, the simulation phase of the research is carried out, in which the power consumption of the EMCVT-based EV powertrain is compared to the single speed transmission. The results explain that for the combined low and medium phases of the Worldwide Harmonized Light Vehicles Test Cycle (WLTC), the EMCVT performs slightly worse; 0.04 kWh (4.1%) more power consumed that the single speed transmission. However, for the complete WLTC, it fares better, recorded 3.57 kWh compared to 4.60 kWh of the single speed transmission (22.4% efficiency improvement), highlighting the prototype's potential for implementation in an EV. These findings are useful for automotive industry to properly strategize the most effective implementation of EMCVT in an EV so that the maximum benefits in terms of driving mileage and cost can be realized.