An Air Hybrid Engine With Higher Efficiency and Cam-Based Valvetrain System

In this paper, a new configuration for air hybrid engines is introduced which increases the energy storing capacity of the system during braking and simplifies significantly the valvetrain needed for the hybridized engine by relaxing the need for a fully flexible valvetrain system. The proposed configuration allows easy implementation of various air hybrid operational modes. Moreover, the specific configuration of the system avoids irreversible gas exchange in the cylinder during regenerative mode which results in the significant increase of the energy recovering efficiency. One of the most important advantages of the proposed system is that the engine torque in the regenerative braking mode is controlled by the same throttle system used in the conventional ICE mode. The performance and feasibility of the proposed configuration is shown through simulation and experimental work.