Development of polymer gear balance shaft system for 2 AZ-FE engine

摘要

In-line 4 engines have many merits when compared to higher cylinder engines. For instance, low cost, excellent gas mileage, low weight and compactness are a few. However, one disadvantage is a vibration at 2nd order frequency. This vibration can be canceled by applying a 2nd order balance shaft. For the 2AZ-FE engine, a world class balance shaft system was achieved using polymer gears for the first time ever. Reliability was achieved by developing a high-intensity polymer with optimal impact absorption characteristics. Cost, friction and weight were lowered 50% when compared to the Toyota 5S-FE engine.