Motor vehicles – Power – With means to guide and/or control air for power plant cooling
Reexamination Certificate
1999-08-23
2001-10-16
Mar, Michael (Department: 3619)
Motor vehicles
Power
With means to guide and/or control air for power plant cooling
C180S069200
Reexamination Certificate
active
06302228
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device and to a method for removing heat energy from a compartment which contains a heat engine.
BACKGROUND OF THE INVENTION
Heat engines generally, in order to run under optimum conditions, need to be cooled constantly while they are running. For a very long time, water- or air-cooling circuits have been developed, these being supposed to keep the immediate surroundings of the combustion chambers at a temperature which never exceeds the highest temperature compatible with the integrity of the static or moving mechanical parts present in the engine.
Frequently, at the present time, the search is on to improve the isolation of engine compartments, so as to limit the odours given off and the transmission of vibration and undesirable noises. These new requirements, coupled with the fact that the empty space within engine compartments has tended to decrease because of the development of compact, lightweight vehicles, are partly responsible for the net temperature rise in the environment of the engine within the compartment.
Something else which is responsible for this rise in temperature has been the tendency to incorporate, around modern engines, an increasing number of accessories, such as the air compressor or turbocharger which operate at very high temperatures and generate additional hot spots in the engine compartment.
The result of this is a danger of excessive heating of the environment in the engine compartment which conventional cooling circuits will not be able to limit completely.
It has therefore become desirable to supply means of cooling this environment in order not to harm the overall efficiency of the engine and not to endanger the mechanical performance of certain components and accessories in its immediate vicinity.
For example, it has been proposed that a duct be fitted in the compartment to convey the fresh air drawn in by the cooling circuit fan towards the rear of the engine compartment so as to better distribute the inrush of fresh air throughout the volume of the compartment (French patent application 2667549).
Japanese patent application JP-08/164756 describes a motor vehicle bonnet which, on its internal face, has a broad, flat duct conveying fresh air taken from the front face of the vehicle towards the rear part of a transverse engine.
These various systems do, however, have the drawback of cooling only one of the hot zones of the environment. Furthermore, the flow rate and, therefore, the cooling efficiency of such systems are still low because they are confined to introducing fresh air and do not directly remove the energy from the hottest spots of the environment in the compartment.
The object of the invention is therefore to provide a device which cools all of the hotter zones of the environment in an engine compartment, whether these be moving or static parts, with satisfactory efficiency and which makes it possible to use various materials from which to make the peripheral components and accessories of the engine.
SUMMARY OF THE INVENTION
To this end, the invention relates to a device for removing heat energy from a compartment containing a heat engine using at least one duct, one end of which is of the compartment, which passes through the upper part thereof towards at least one zone which opens to the outside and in which the pressure is lower than or equal to the pressure in the compartment, characterized in that the duct has at least one opening via which ambient air present in the compartment is drawn into the duct.
The term “compartment” is intended to mean an open or closed space bounded by one or more walls or faces. One wall or part of a wall is mobile and can be opened to allow access to the engine contained in the compartment.
The heat engine present in the compartment is an engine which converts calorific energy supplied by the burning of a fuel into mechanical energy. It may consist of any type of internal combustion engine, of the rotary or piston type, running on liquid fuel (such as petrol, diesel, alcohol, for example) or gaseous fuel (such as petroleum gas, natural gas, lean gas, hydrogen, methane, for example).
By extension, the term “heat engine” is also intended to mean one or more electric motors powered by at least one fuel cell or accumulator battery.
The duct is arranged in such a way as to pass through the upper part of the compartment containing the heat engine. It may be embodied in various forms and be mounted in the compartment in any way allowing easy access for engine maintenance and providing good cover of the hottest zones in the environment.
It may, in particular, be fixed to the engine itself, or be secured to the compartment. As an alternative, it may also be secured to the openable wall of the compartment.
One of the ends of the duct acts as an inlet for the external air. According to the invention, this end is located in a colder zone in close proximity to one face of the compartment. This zone is situated, for example, behind the air intakes pierced in one face of the compartment.
As an alternative, it is possible to install a fan in the colder zone in proximity to the end of the duct, so as to draw in the external air more effectively and force it, at least in part, to enter the end of the duct.
The duct passes through the upper part of the compartment towards at least one zone which opens to the outside. This zone may be located at various points in the compartment. It is generally located in a part at the opposite end to the face via which the outside air enters the compartment.
The pressure in the zone opening to the outside is lower than or equal to the ambient pressure in the compartment. Advantageously, the pressure in this zone is lower than the pressure of the environment. The means for achieving this reduction in pressure compared with the inside of the compartment may be of varying nature. It is possible, for example, to use a fan placed in the compartment to create a positive pressure difference between the inside of the compartment and the outside or, alternatively, in cases where the compartment forms part of a moving vehicle, it is possible to make use of the creation of aerodynamic disturbances caused by the motion of the moving vehicle through the ambient atmosphere outside the compartment, the duct outlet being directed towards the zone or zones outside the compartment in which a depression would be created locally under the layers of air disturbed in this way. Such turbulent zones are generally created near sharp edges present in the shape of the moving vehicle or in the layer of air separating the moving vehicle from the ground. Their precise location and intensity depend on the exact shape of the moving vehicle and the speed with which it travels through the atmosphere.
According to the invention, the duct has at least one opening for drawing ambient air from the compartment into the duct by an ejection effect under the impulse of the speed of the outside air flowing through the duct.
At least one opening could judiciously be located in line with a hotter zone of the environment in the compartment.
As a preference, the duct has a narrowing cross section in the region of the end located in a colder zone intended for air inlet. Air from the outside is thus advantageously accelerated through a venturi effect.
In a preferred embodiment, the compartment contains a fan and the duct is equipped with at least one opening connected to a suction nozzle directed towards a zone located behind the fan, at a raised pressure compared with the rest of the environment in the compartment. When the compartment is stationary or forms part of a moving vehicle which is at a standstill, this embodiment has the advantage of not interrupting the removal of heat energy even though there is no reduced pressure zone in its immediate vicinity.
According to this preferred embodiment, the fan may or may not be associated with a radiator acting as a heat exchanger through which the engine coolant flows.
In another embodiment of the invention, the duct may be
Cottereau Marc
Rhoumy Philippe
Larson & Taylor PLC
Mar Michael
Solvay ( Societe Anonyme)
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