Lean burn: Seven detailed aspects

The lean combustion concept has several advantages for the thermal efficiency enhancement of internal combustion (IC) engines: (1) the reduction of pumping loss resulting from throttle opening, (2) the reduction of heat-transfer losses, led by a lower combustion temperature than the stoichiometric condition, and (3) the increase in the specific heat ratio, enhancing thermal efficiency.

Nakata et al. reported that lean combustion led to achieving more than 10% improving rate of brake thermal efficiency. They achieved the maximum efficiency of 45.7% with a combination of lean combustion and EGR (exhaust gas recirculation) while it was 36.7% in the stoichiometric condition. [ Koichi, N. , Shinichiro, N. , Daishi, T. , Yasushi, Y. , Atsunori, K. , & Tetsushi, S. . (2015). Engine technologies for achieving 45% thermal efficiency of s.i. engine. SAE International Journal of Engines,9(1), 2015-01-1896. ]

What is the difference between lean burn and rich burn?

What does lean engine mean?

What is rich and lean air/fuel mixture?

Does a lean mixture burn faster?

What is a lean fuel condition?

Why lean burn engines produce small amounts of nitrogen oxides?

Can lean fuel mixture cause overheating?