Method of quick pneumatic braking of a diesel engine

A method of improving the effectiveness of the pneumatic braking of a reversible diesel engine operating in particular on a four-stroke cycle, the engine having intake and exhaust valve means controlled by an engine-driven camshaft with forward running cams and reverse running cams, said camshaft being axially displaceable between an engine forward running position and an engine reverse running position, an even number of at least ten working cylinders arranged in particular in two V-shaped rows of a same number of working cylinders, at least some of which in each row are respectively provided with individual starting valves automatically closed by spring means after having been vented and the openings of which are pneumatically controlled sequentially by at least one central engine-driven rotary distributor, said closing being delayed in time with respect to the moment at which the order to close is delivered by shutting off the compressed air and by venting said distributor as an increasing function of the length of feed piping of each starting valve from said distributor and of the instant rotary speed of said engine, said method including reducing through constructional design of said distributor the relative duration of admission, through said distributor, of compressed pilot air for opening said starting valves in at least one row of working cylinders with respect to the duration for the other row thereby advancing the delivery of the order to close in such a manner that each starting valve involved closes not later than about the time at which the corresponding exhaust valve opens on the associated working cylinder, wherein the improvement comprises the steps of optimizing through constructional design of said distributor at least approximately the thus shortened value of the actual relative duration or control of opening of the compressed air passage-way at the distributor for each starting valve of one row of working cylinders intended for braking purposes with a view to increasing the instantaneous decreasing value of the rotary speed of the engine from which the braking step is initiated thereby advancing the moment at which the braking begins and of optimizing the duration for each starting valve of the other row of working cylinders for performing the starting step.