Honda: 

1. Honda has made an extended expansion cycle engine, in which the power and exhaust strokes have an extended stroke length that increases the efficiency.

2. It also uses a multi-link crank system as opposed to a conventional crank.

More about Honda Ex-Link Technology at Honda Global | Exlink - Picture Book 

The Kinematics of Honda Extended Expansion Technology 

Honda has proved that an engine can be operated with different stroke lengths in a cycle, and with a multi-link crank system.

 This start-up has also developed a multi-link crank system for high torque output and is venturing in a direction that Honda has not taken.