Catégorie

Moteur à combustion interne

An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons (piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle (jet engine). This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known as the Otto engine, was created in 1876 by Nicolaus Otto. The term internal combustion engine usually refers to an engine in which combustion is intermittent, such as the more familiar two-stroke and four-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine. A second class of internal combustion engines use continuous combustion: gas turbines, jet engines and most rocket engines, each of which are internal combustion engines on the same principle as previously described. Firearms are also a form of internal combustion engine, though of a type so specialized that they are commonly treated as a separate category, along with weaponry such as mortars and anti-aircraft cannons. In contrast, in external combustion engines, such as steam or Stirling engines, energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids for external combustion engines include air, hot water, pressurized water or even boiler-heated liquid sodium. While there are many stationary applications, most ICEs are used in mobile applications and are the primary power supply for vehicles such as cars, aircraft and boats.

Ontologie

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Exercices associés (13)

Zoologie du mouvement uniformément accéléré

The numbered squares in the figure below represent the position of two blocs at 0.20 s intervals. The blocs are moving in the left to right direction. Compare their acceleration.
A spaceship drifts sideways in space between point P and Q. It is not subject to any external force. At point Q, the spaceship’s engine is turned on and produces a constant acceleration perpendicular to PQ. This acceleration is maintained until the spaceship reaches a point R. Which of the followin

A package falling from a truck

xa0 A truck starts at null velocity and uniformly accelerates to reach the velocity v₀ in a time t₀. A package of mass m lays on the trailer without being attached. It is situated at a distance D from the edge of the trailer. When the truck starts, the package starts to slip towards the back of the trailer with a dry and dynamic friction coefficient μ_(d).

Make a sketch in a coordinate system bound to the ground of the different forces applied on the package.
Calculate the horizontal acceler

James Bond en chute libre

James Bond escaped from a helicopter in stationary flight. He vertically falls in free fall, without friction. His friend must save his with her motorcycle. She starts from a ramp that points towards the direction of James Bond, hanging from the helicopter. She leaves the ramp with a velocity v₀ and at the same time James drops from the helicopter. Will Bond manage to land on the motorcycle? As it is James Bond, we guess that yes! Show that it is the case. We set the origin of the coordinate system at the

La Fusée

A rocket contains a fuel mixture that is ejected with a relative speed u with respect to the nozzle. We assume that the fuel escapes vertically towards the bottom of the nozzle. We neglect the air friction and the variation of the gravitational field with height (i.e. we treat g as a constant). The fuel mass is m, and the total mass of the rest of the rocket (tanks, accessories, etc...) is M.

Show that the rocket can only take off if the flow of burned fuel (i.e. the variation of fuel mass per unit

Excitation d un oscillateur harmonique vertical

A mass m is suspended on a spring of natural length l₀ and of elastic constant k. The spring is attached to a piston. The vertical motion of the piston is described by the equation s(t)u2004=u2004s₀cosu2006(ωt)xa0.

Give explicit expressions for the external forces and determine the equation of motion.
Show that the equation of motion can be recast as, $\ddot{x}\left(t\right) + c_1\,x\left(t\right) = c_1\,s\left(t\right)\ ,$ where x(t)u2004=u2004z(t)u2005+u2005c₂ with z(t) the vertica

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