Abstract
Modern automobiles should be more optimal and more costeffective, should execute more tasks for one fuel unit in a broad range of road and climatic conditions. At the present time the world production of lorries and trucks takes place on the path of evolution. One of its the basic features is the differentiation of models line. It allows customers to select an optimal lorry or truck for the required operation conditions.
In this case a mechanical engineer of power distribution mechanisms should guideline to the buyer the rational gear ratio of an interaxle differential for its all-wheel drive (AWD) vehicle, which ensure the least costs of engine power and fuel consumption to overcome a road resistance while automobile is moving.
The practice demonstrates, that at the series production there is no possibility for long simulating and detail researching the lorry efficiency for every customer after he defined engine, gearbox, tires, wheelbase, axle loads etc. for AWD automobile. As well known modifications for above mentioned units characteristics and parameters influence significantly on the AWD vehicle efficiency. Therefore it is necessary to find such combinations of gear ratios for an interaxle differential at given transmission gear ratios for most typical operation conditions, that both to supply an automobile passability and also to do not worsen its general efficiency without applying lock devices for an interaxle differential.
In the given paper the authors offer a computation method of a gear ratios selection for an AWD automobile interaxle differential using simple energy indexes. It allows to reduce time for looking up the design solutions and to improve an energy performance of vehicle. The matching with other known methods confirms its efficiency. The outcomes of our research were analyzed concerning AWD automobile MAZ-4373 produced by the Minsk automobile plant (MAZ, Belarus). They show, that for increasing of the running efficiency of the automobile it is expediently to use differentials in the interaxle drive with gear ratios depending on the suspected operation conditions. We recommend such numerical values.
For an estimation of influencing of the advisable solutions on the automobiles efficiency the comparative computational motion studies were carried out for automobiles with obtained gear ratios of interaxle differentials on given roads. As base for matching the motion of automobile with similar characteristics and only with rear driving axle was modeled.
Keywords:interaxle differential, transfer case, driving axle, traction force, passability