The main reason that at part loads Otto internal combustion engine has higher specific fuel consumption than diesel engine is higher pumping losses, which are increasing by shutting the engine's throttle valve. Opening the throttle valve as wide as possible can decrease these losses and this can be done in stratified charged Otto engines. Using results of developed from us thermodynamically cycle calculation model, theoretical minimum specific fuel consumption characteristics of a stratified charged Otto engine with 'two-stage combustion' mechanism are determined. Minimum specific fuel consumption characteristics at two compression ratios and characteristics of classical Otto engine at stoichiometric composition with 'homogeneous charge combustion' were compared. As a result the lowest effective specific fuel consumption and exhaust gas emission values has the stratified charged engine at high compression ratio (without detonation) with 'two-stage combustion' mechanism. Minimum fuel consumption, volumetric efficiency and excess air ratio that allow this consumption were determined according to the change of the engine load $(b_e = f(p_{me}), eta_v = f(p_{me}), lambda=f(p_{me}))$- With use of these characteristics in real engine calibration it can be saved time and money. As a conclusion it can be said that this paper suggests one theoretical solution to the problem of combining the advantages of both Otto and diesel engines.