Abstract
KEY WORDS - MRF, Coupling Technology, Multimode-Transmission, Plug-in-Hybrid, PHEV
ABSTRACT - Objective of the German Federal Government funded advanced “PHEVplus”-project is the development of a multimode transmission for Plug-in Hybrid Electric Vehicles (PHEV). Special feature of this optimised transmission is the implementation of Magneto Rheological Fluid (MRF)-based clutch technologies and an adapted operating strategy.
GKN Driveline as specialist in the field of powertrain development and worldwide supplier for most of the world renown Automotive OEMs is responsible for the transmission development. University of Applied Sciences (“Hochschule Ostwestfalen-Lippe” HS-OWL) on the one hand has its expertise in the field of MRF-technologies and is responsible for the development of the MRF-clutch system. On the other hand HS-OWL is also specialized in real time simulation of automotive systems including the whole vehicle and its drivetrain.
The transmission concept provides the following features: 2 “CVT”-modes (high efficiency, start up and drive up to a certain speed even with empty batteries), (Internal Combustion Engine) “ICE”-Mode with 2 gears, “EV”-mode with 2 (optional up to 4) gears, 2 “Parallel”-modes and overall recuperation functionalities.
An excellent feature of MRF is the high control quality combined with its very fast response times. Due to the given requirements on torque capacities, packaging, weight, temperature and contamination within a transmission-environment the optimal place for the usage of MRF-clutch technologies had to be determined in the available shielded place between the ICE and the actual transmission housing. Locating the MRF coupling between ICE and transmission allows furthermore the active damping of the torsional vibration exited by the ICE. This allows the reduction of the ICE operation speed which results in lower fuel consumption.
The described transmission shall serve in front wheel driven mid-size cars (vehicle category D) according to common OEM-specifications. Project-target is the development of a gearbox prototype which will be tested on a test rig in combination with the development of an associated operating strategy. After completion GKN plans to build up a test vehicle to work out results in real driving scenarios.