Power Flow and Efficiency Analysis of a Ravigneaux Hybrid Transmission

Abstract

In urban mobility, special attention must be paid to the energy requirements in vehicles, air quality and noise pollution. This can be achieved in two ways: the first is the use of low-emission hybrid vehicles, the second is the use of gear transmission system with improved efficiency. Both will reduce fuel consumption and provide more environmental protection. In the current work, a low-emission Ravigneaux hybrid transmission with thirteen operation modes is shown to be feasible. A fuel-efficient strategy is developed to control the fuel consumption of hybrid modes and reduce emissions. An efficiency analysis for all driving modes of the Ravigneaux hybrid transmission is conducted. The concept of potential power is used to determine the power ratios of any three links in the fixed reference frame (FRF) when the input link in the moving reference frame (MRF) is predictable. A single equation is developed that can be manipulated to determine all the powers flowing through the train. A numerical example is provided to give a complete view of the expected efficiency values. The proposed Ravigneaux hybrid transmission is found to be suitable for urban rather than external routes. The results can provide a theoretical bases for design works of hybrid transmissions with complex planetary gears.

Critical Analysis of Design of Ravigneaux Planetary Gear Trains

“…It can be done in two ways: the first one is use of low emission hybrid vehicles, and the second one is use of improved efficiency transmission systems. A. H. Juber and others [8] analyzed in their paper the application of Ravigneaux hybrid transmission that could be applied in cars that are driven in urban environments most of the time. It is extremely efficient in low and mid gears, and less so in high gears.…”