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

In-line 4 engines have many merits when compared to engines with more cylinders, such as low cost, excellent gas mileage, low weight and compactness. 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 resin gears for the first time ever. Reliability was achieved by developing a high-strength resin optimal impact absorption characteristics. Cost, friction and weight of the balance shaft system were lowered 50% when compared to the Toyota 5S-FE engine. [Copyright &y& Elsevier]