Abstract
Research and/or Engineering Questions/Objective
In Auto transmission, oil pump and valve body are essential part, which is producing oil flow to lubrication and oil pressure with controlling clutch or brake members. In particularly, lubrication of traction motor is very important for the PHEV transmission, because traction motor and generator substitute the engine on large driving condition. So how to distribute lubrication to motor/generator and to gear, bearing, seal and etc. is the crucial point to designing and constructing hydraulic system. I suggest the way of getting optimal control and fuel efficiency in the methodology of placing pump system and of route to lubrication line
Methodology
There are many phev cars in the world market, but trendsetter is Toyota prius-III and Honda accord phev and GM Volt, that of transmission consist of high capacity motor and generator. The composition of oil pump is compared with each maker’s development strategy. In this study, an analysis of simulation by using AMEsim has been carried out in order to study the influence of flow rate to lubrication and control member on the performance of vehicle.
Results
In the paper, flow rate of motor lubrication line and frictional member lubrication line will be presented as function of distribution ratio of oil pump flow rate. The main focus is that constitution of oil pump (MOP+MOP, MOP+EOP, 1Motor 2Pump EOP, 2EOP, and etc.) and valve body flow route will verify the influential effect to distribution ratio defined in this study. New criteria for transmission structure by using high capacity motors in phev vehicle will be presented.
Limitations of this study
In accordance of motor size and driving cycle of fuel efficiency test mode, the effect to fuel efficiency gain will be varied. The car makers such as Toyota, Honda and GM have their own independent control logic and strategy, so the result of the effect may be different for each case of driving condition. Through the simulation of hydraulic system and vehicle model, we can suggest the control strategy of Motor driving condition and EOP’s operation timing, but it can be different from construction of transmission type and Motor’s performance. The new requirements are only valid for HMC’s new structure transmission.
What does the paper offer that is new in the field including in comparison to other work by the authors?
The analysis and comparison of pump composition and hydraulic circuit of phev transmission presented in this paper is new as well performance simulation data and requirements for control factor.
Conclusions
The Structures of hydraulic system including oil pump composition available to the investigated PHEV were examined. To design the capacity of the pump for transmission applied to PHEV, the required discharge flows and line pressures considering extreme and continuous driving conditions were defined and through the maximum motor power and torque are determined. Using the AMESim hydraulic system models of pump type respectively, the hydraulic performance simulation is conducted and the simulation results was validated by comparing with the test results.
Key Words : PHEV, Hydraulic control system, Electric oil pump(EOP), Mechanical oil pump(MOP), Lubrication, Fuel efficiency.