Abstract: An internal combustion engine includes a port injection valve, a direct injection valve, and a forced-induction device. A ratio of an amount of fuel injected from the port injection valve with respect to a total amount of fuel supplied for one fuel combustion in the cylinder is defined as a port injection ratio. The internal combustion engine is controlled such that, in a case in which a condition is satisfied that the forced-induction device is in an operation of performing forced induction and the internal combustion engine is in an engine operation region in which a valve overlap period is greater than zero, the port injection ratio is set to be small and a start timing of fuel injection from the port injection valve is delayed as compared with a case in which the condition is not satisfied.

Abstract: A 7-acylamino (or 7-amino)-3-(substituted thiomethyl)cephalosporin derivative or a carboxyl derivative thereof is prepared by heating the corresponding 7-acylamino (or 7-amino)-3-carbamoyloxymethylcephalosporanic acid or a carboxyl derivative thereof with a thiol corresponding to the group which it is desired to introduce at the 3-position under conditions in which the water present is minimized, specifically, either no water is present or the amount of water is limited to less than 5 times the weight of the 7-acylamino (or 7-amino)-3-carbamoyloxymethylcephalosporanic acid or carboxyl derivative thereof. The compounds thus prepared are useful as pharmaceuticals or as intermediates in the production of pharmaceuticals. One of the compounds thus prepared, namely 7.alpha.-methoxy-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-7.beta.-(O-5-p-ni trobenzoylamino-5-carboxyvaleramido-3-cephem-4-carboxylic acid, is a new compound and it and its salts and esters also form part of the present invention.