HYC - A Hybrid Concept with Small Lean Burn Engine, Electrically Heated Catalyst and Asynchronous Motor for Enhanced Performance and ULEV Level Emissions

A new hybrid concept is applied to a small carburetted lean burn 2-stroke engine where, according to the underlying patent, the asynchronous motor is mounted on the ICE crankshaft, to provide increased torque during acceleration, lower and stabilise idle speed, replace the electric starter, act as a speed limiter, recover energy during deceleration and to provide the power for the electrically heated catalyst. The paper describes the mechanical development, the redesign of the thermodynamic parts of the donor engine, the light-off optimisation of the electrically heated catalyst, the electric and electronic development including ECU, power electronics, sensors, battery management, mapped ignition system and control strategies. The results show acceleration performance at par of a 50% bigger engine, ULEV level emissions including cold start, and no visible smoke or smell and very low particulate emissions very short after the cold start.