Taking a 6EX340EF low-speed marine diesel engine as the research object

the issue of the combustion imbalance between the cylinders and working cycles of low-speed marine diesel engines was studied using the in-cylinder pressure feedback control technology. A simulation model with pressure fluctuations between the cylinders and working cycles was developed using the AVL Cruise M software to meet accuracy and real-time requirements

and a rapid control prototype was also developed based on the NI CompactRIO hardware and NI LabVIEW software. The closed-loop adjustment of the in-cylinder pressure was accomplished by using combustion characteristic parameters as feedback variables

such as indicated mean effective pressure and 50% combustion heat release phase extracted from the pressure in cylinder through position management module and cylinder pressure acquisition analysis processing module

and injection timing and injection pulse width as control variables. Then the real-time simulation model

hardware-in-loop simulation system and control prototype were integrated to form a closed-loop system. The test results show that the proposed in-cylinder pressure feedback control strategy can reduce the pressure fluctuation by about 50%

and it has an improvement effect on the reduction of the combustion imbalance between the cylinders and working cycles.