From the wide variety of car engine’s working regime two extreme situations have the biggest importance: intense city traffic with low speed and load and highway traffic with high speed and load. The purpose of this paper is to show that the adaptive thermal engine operates with lower consumption and pollution with respect to actual engine for the first situation and it can also give high power output for small displacement in the second situation,

In a century of car engine development, only two processes were subject to automatization: air-fuel mixture ratio and spark advance angle. Therefore, it is obvious that going even further with automatization of another two engine parameters, such as compression ratio and intake valve(s) lift, will lead to improved performances. Many thermal engine designers have tried, so far, to achieve variable compression ratio and variable valve(s) lift, especially

The paper outlines the fact that the overall efficiency of a spark ignition engine can only be improved through the maximization of the thermal efficiency on the high frequency working regimes, i.e. the low part loads. One way of doing this is by getting rid of inefficiencies that for the past hundred years have largely been accepted as inevitable. Thus, the authors are about to develop a variable volumetric compression ratio engine, in order to

The response of the engine in the transient working regimes influences the vehicle’s behaviour in terms of dynamic and comfort performances but also in terms of toxic emissions. The study of the transient phenomenon of the automotive engines is very difficult due to the important variation of working regimes (load and speed of rotation). In order to perform a theoretical estimation of the dynamic performances during these transient regimes, mechanical,

Often a turbocharger is led to run at low speeds. A better knowledge of turbocharger characteristics at low speeds is needed in order to improve the engine running in this area. As regard friction losses at the turbocharger’s shaft, although these are generally small, they have a greater importance in this case of lower speeds. So, in order to have more information on the mechanical efficiency of the turbocharger, a special torquemeter has been

The inefficient running of the spark ignition engine at part loads due to the load control method, but mostly, their major weighting in vehicle’s operation time justifies the interest for the technical solutions, which act in this particular operating range. These drawbacks encountered at low part loads are even more amplified when talking about bigger engines. For instance, it is well known the fact that at the same engine load, a bigger engine

When talking about diesel engine, it cannot be considered as a true competitor of the gasoline engine without the turbocharging. The most obvious drawback of the engine-turbocharger assembly is the operation of these two machines with highly different laws. This calls for a tuning of their characteristics. Running at low speeds, which is often encountered in automotive applications, is generally not an optimum range for the turbocharger. Moreover,

The inefficient running of the spark ignition engine at part loads due to the load control method, but mostly, their major weighting in vehicle’s operation time justifies the interest for the technical solutions, which act in this particular operating range. These drawbacks encountered at low part loads are even more amplified when talking about bigger engines. For instance, it is well known the fact that at the same engine load, a bigger engine

Une des particularités essentielle du moteur d'automobile est sa grande plage de fonctionnement en termes de régimes et de charges. La pleine charge "pied au plancher" est rare, l'utilisation du moteur s'effectue principalement en charges partielles. Le rendement maximum du moteur à allumage commandé qui est d'environ 30%, ne dépasse pas 10 à 15% aux faibles charges partielles. C'est ce dernier cas qui est principalement rencontré, 80 à 90