Search Results

An integrated starter and generator (ISG) is a type of electric machine which is mechanically connected to an internal combustion engine (ICE). The ISG is intended to conduct important roles in the hybrid electric vehicle (HEV) such as engine start and stop. Since the HEV has frequent electric vehicle (EV)/HEV mode transition, rapid engine cranking and vibration-free engine stop controls are necessary. In the case of the engine stop, the ISG provides the negative torque output to the ICE which can rapidly escape from its resonance speed. However, the ISG torque is determined by engineering intuition, the amount of energy recovery is hardly considered. Dynamic programming (DP) is an effective solution to find optimal ISG control strategy to maximize energy recovery during engine stop transition. Even though DP is an offline algorithm, the result can be used as a reference to evaluate and improve an existing on-line algorithm.

Transient control for EV/HEV mode change takes an important role in the system of the parallel HEV, which consists of internal combustion engine (ICE), electric motor (EM), integrated starter & generator (ISG), battery, automatic transmission and clutch (that replaces the torque converter), not only ICE/EM control but also clutch engagement control are the key of it. To improve the mode change performance, this study proposes clutch slip control methods. Method 1. focuses on the open loop clutch pressure control so as to adjust target clutch transfer torque. The main idea of Method 2. is to control the clutch pressure in order to achieve the desired speed difference(Method 2-1) from each side of clutch when motor speed is faster than engine idle speed and keep target engine speed(Method 2-2) when motor speed is slower than engine idle speed. This paper defines control sequence which is scheduling the behavior of powertrain components as well.