Optimal control strategy of the turbocharged direct-injection hydrogen engine to achieve near-zero emissions with large power and high brake thermal efficiency

•Lean combustion can reduce the cylinder temperature below 1400 K, reaching near-zero emissions (NOx less than 20 ppm) for turbocharged direct-injection hydrogen engines.•Delayed ignition is an effective measure to achieve near-zero emissions with low power loss.•An optimal control strategy of combining lean combustion and delayed ignition can enhance 20% output power compared to the single method with near-zero emissions.•The brake thermal efficiency of half of the working conditions can reach 40% with near-zero emissions.