Numerical and thermodynamic study on effects of high and low pressure exhaust gas recirculation on turbocharged marine low-speed engine

•Effects of high and low pressure EGR on marine low-speed engine are studied.•Control strategy of cylinder bypass for high pressure EGR is originally proposed.•Demand of high and low pressure EGR is firstly obtained by thermodynamic model.•Guidance for turbine re-match of high and low pressure EGR is first presented.•Detailed comparisons between high and low pressure EGR are conducted.