External characteristics and partial speed characteristics of speed characteristics

The rotational speed characteristics measured when the throttle valve of a gasoline engine is fully open (or when the fuel injection pump of a diesel engine is at the maximum fuel supply) are called the external characteristics of a gasoline engine. When the fuel regulating mechanism of diesel engine is fixed at the calibrated (rated) fuel supply position, the measured speed characteristic is the calibrated power speed characteristic, also known as the external characteristic, which represents the maximum power performance that the engine can obtain. From the external characteristic curve, we can see the maximum power and torque that the engine can output, as well as their corresponding speed and fuel consumption.

The speed characteristic measured when the throttle of gasoline engine is partially opened is called partial speed characteristic. When the oil quantity regulating mechanism of diesel engine is less than the calibrated oil supply of power cycle at each position, the measured speed characteristics are called partial speed characteristics.