A 1D thermodynamics model was built based on a single-stage turbocharged diesel engine. Exhaust boundary parameters, in-cylinder working characteristics and the braking power of the diesel engine were simulated and studied under different altitude of 0, 2 and 4 km with different supercharging systems. The results show that, before the compression top dead center, with the increasing of exhaust valve opening duration, IMEP360 (gross indicated mean effective pressure), brake mean effective pressure (BMEP) and the in-cylinder braking power firstly increase and then decrease slightly. With the delaying of exhaust valve opening time before the compression top dead center, the IMEP360, pumping mean effective pressure (PMEP) and BMEP firstly increase and then decrease slightly. Hence, there is an optimal exhaust valve opening time and duration to obtain the maximum braking power. In addition, compared to the single-stage turbocharging system, the two-stage turbocharging system at the rated engine speed increases the maximum IMEP by 65%, 74%, 55% and the maximum BMEP by 64%, 68%, 45% at the altitudes of 0, 2 and 4 km, respectively. Compared to the original engine with no incylinder braking, the single-stage turbocharger and the two-stage turbocharger increase the braking power at the rated engine speed by 112% and 249% at the altitude of 0 km, respectively. While at 4 km altitude, the braking power of the single-stage and two-stage turbochargers increases by 164% and 238% respectively. © 2021, Editorial Office of the Transaction of CSICE. All right reserved.
