The specific meanings of the two are as follows:

1. sy: sy is the abbreviation of Japan Yanmar Engine Co., Ltd., a manufacturer specializing in the production of agricultural machinery engines. The engine power it produces Ranging from 1 horsepower to 90 horsepower, the main products include diesel engines and gasoline engines for agricultural machinery such as tractors and combine harvesters.

2. cy: cy is the abbreviation of Changchai. Changchai is a manufacturer specializing in the production of diesel engines. Its products include single-cylinder and multi-cylinder diesel engines with power ranging from 10 horsepower to 200 horsepower. Changchai's single-cylinder diesel engines have a high market share and are widely used in agricultural machinery such as tractors and harvesters.