They will generate a technological complexity and the over-charge must be estimated. A physical model of the Rankine cycle was also developed, comprising a discretized 0D model of the heat exchanger. The synthesis, which consisted in finding out the required intake cam profile starting from an imposed intake valve law, is performed analytically. Abstract: In recent decades, the approach known as Finite-Time Thermodynamics has provided a fruitful theoretical framework for the optimization of heat engines operating between a heat source at temperature hs T and a heat sink at temperature cs T. It is shown with a local unsteady approach that a competition occurs between the thermodynamic expansion velocity and the heat propagation velocity during the expansion stroke. The ambient and mechanical losses as well as internal leakage were taken into account by the model. One of the most efficient ways to reduce the pollution and fuel consumption of an automotive engine is to downsize the engine, whilst maintaining a high level of power and torque.
The machine is divided into characteristic sub-blocks and resolution of thermomechanical flow equations is carried out using the necessary geometrical parameters. A better knowledge of these losses is required. The proposed analysis is based on the description of field working dynamics collected on an experimental tractor during a plowing operation. The recovery of this energy would enable a substantial reduction in fuel consumption. The compressor can be assumed to be adiabatic, and the power given to the air flow can be calculated using the first law of thermodynamics. In order to validate the model a comparison between estimated and real engine effective power was conducted at full load. Characteristic curves and envelope curves are plotted.
This approach reduces the fuel consumption and allows engines to meet future restrictions on carbon dioxide emissions. The trends of the modeling results thus obtained are compared with the performance measured on a micro gas turbine with and without insulation. This paper details the pros and cons of the Rankine and complexes cycles try to expose a concrete example of each application and finally briefly introduces the potential of the thermoacoustic heat for recovering waste heat and generating electricity. A novel turbocharger test bench equipped with a highly accurate torquemeter and a magnetic axial load device has been developed. The impact of those parameters has been studied in detail and presented in this paper.
This mechanism is self-regulated thanks to a hydro-mechanical system, which is the subject of a French patent and allows a continuously intake valve lift and opening variation. Dual fuel engines were found to be interesting for their small impact. Assuming the flow stationarity: the flow in a channel of a stator and a rotor; the law of moment of momentum for relative flows and the work exchanged between the fluid and the rotor will be presented. The object of this lecture is to present the procedure used to characterise the effect of different elements on the vehicle's acceleration : Firstly, set up of a specific test rig : the vehicle's inertia is simulated by a flywheel. Nevertheless, our study suggests that as long as torque at the shaft end is measured and mechanical power losses are known, the effective power provided to the air flow can be calculated. In reciprocating engines more than 60% of fuel energy is lost as heat.
Ce cogénérateur est animé par deux moteurs Stirling travaillant en opposition. Experiments conducted in our laboratory on a special test rig equipped with a high-precision torquemeter, demonstrate that compressor performances in this area cannot be deduced from adiabatic assumption. Pour tirer les conclusions, tous ses paramètres ont été analysés durant les phases de cranking, stabilisation et ralenti. In this context, the authors are about to develop a variable geometrical compression ratio engine, in order to overcome the main drawback of the spark ignition engine: the continuous variation of the real rate of compression, caused by the load control. .
Under the adiabatic assumption, the model results are overestimated. The paper presents some specific features regarding hinge position choice. Energy balance revealed a maximum engine efficiency of 42. A lot of these efforts leaded but to controversial results. In this sense the concept of thermal engine insulation has been for many years subject of intense researches dealing with the decrease of the heat transferred to the combustion chamber surroundings looking this way for thermal efficiency increasing.
The aim of this paper is to propose a more complete approach based on the association of Finite-Time Thermodynamics and the Bond-Graph approach for modeling endoreversible heat engines. One of the most efficient solutions to reduce fuel consumption is to downsize the engine and increase its specific power and torque by using turbochargers. Finally, acceleration tests : on 2. This is particularly important at idle and low part loads when low maximum lifts are to be used for improving the fuel economy or for achieving the required power. The Rankine cycle simulation was conducted over the engine operating map with water as the working fluid.
In order to improve the fin-and-tube heat exchanger performance, a model is developed to investigate the material and fin pitch on frosting carbon dioxide. The driving cycle, also named field working dynamics, is investigated by monitoring an experimental tractor throughout a whole year of field operations. The general concept of high-energy performance machines is analyzed from the energy and public health point of view and illustrated with typical examples of clean energy production and zero emissions. The evaporation process of temperature glide refrigerants is also modeled from Formula presented. This will also make it possible to calibrate the computation models of friction losses of the bearings separately.
Reducing fuel consumption is a prime objective in the automotive industry in order to meet regulatory and customer demands. On the other hand, frost layer thickness increases the external surface blockage, leading to higher pressure drop on the external side. They were subjected to diffuse field characterized by its white band frequency spectrum. The anaerobic digestion of farm waste could roughly cover these needs. Simulations performed with dedicated codes for thermodynamic engines analysis reveal the existing potentiality of energy recovery from the exhaust gases.
The aim of this work-in-progress communication is to bring a contribution to the understanding of these energy transfer phenomena between the exhaust and cooling systems of a reciprocating engine with energy recovery. The experimental set-up is illustrated, then the results are presented and discussed. Therefore, the engine research and development activities aiming to reduce the harmful effects on environment are currently divided into two main directions: the alternative fuel usage, and the reduction of fuel consumption by means of different techniques, the waste heat recovery being one of them. The bearing system performance is presented against the rotational speed at various oil inlet temperatures and pressures. The effects of the biogas velocity, fin material, tube material and frost layer thickness on the performance of the fin-and-tube heat exchanger are investigated. The test bench lay out is described. The article presents a numerical analysis of energy balance of an automotive diesel engine and exergy analysis of exhaust gas and cooling systems.