1D modelling and PID control of helicopter Diesel engine rotational speed in torque changes

Abstract

The article discusses the results of simulation tests concerning the operation of a diesel engine for a light helicopter. The tests were carried out in the AVL Boost software which is used to analyze dynamic phenomena in internal combustion engines. The research object was a newly designed diesel engine of a V8 structure and a power of 330 kW. This engine was designed to be used in the construction of a light class helicopter. The created one-dimensional simulation model included all the main engine components as well as the connection to the helicopter main transmission and the helicopter rotor. The tests consisted in selecting the P value in the PID controller used to control the amount of fuel injected into the engine. The change in the P value indirectly influenced the reaction of the engine to a change in power and torque during horizontal flight of a helicopter. These changes were introduced by changing thrust torque in the helicopter rotor. The fuel injection regulator was designed to maintain a constant engine rotational speed. The maximum speed deviations from the nominal speed of the engine operation due to both increasing and decreasing speed were analyzed. Additionally, the sum of the deviation values was analyzed until the rotational speed of the tested object stabilized. The results showed that the change of the P parameter affects all the analyzed parameters of the engine operation; however, the minimum deviation values for each parameter occur at non-equal PID settings, which makes it difficult to clearly indicate the appropriate value of the P element.