Machine external apparatus for maintaining multi-cylinder engine high-efficiency operation

The invention provides an off-machine device for maintaining efficient operation of multi-cylinder engines, which belongs to the engine field and is used for overcoming the defect that the multi-cylinder engines are low in working mechanical efficiency in low power state. The off-machine device consists of a fuel or gas control mechanism, an air pressure control mechanism, as well as a fixing frame which carries the fuel or gas control mechanism and the air pressure control mechanism. After the off-machine device is arranged on a corresponding multi-cylinder engine, the operation of increasing or decreasing the number of working cylinders can be accomplished during the operation of the engine, so as to allow the engine to operate with high mechanical efficiency, thereby achieving the aimsof saving energy and reducing emission. Moreover, as the off-machine device does not need to change an internal structure and parameters of the corresponding engine, the off-machine device not only can be applied to produce n