FR2560406A1 - THERMOSTAT FOR THE ENGINE COOLING CIRCUIT OF A MOTOR VEHICLE - Google Patents

Abstract

A THERMOSTAT 1 FOR THE ENGINE COOLING CIRCUIT OF A MOTOR VEHICLE INCLUDES A HEAT SENSITIVE ELEMENT 16 LICKED BY THE FLUID THROUGH THE COOLING CIRCUIT AND CONTROLS THE POSITION OF A VALVE MEAN 20, 28 DEPENDING ON THE TEMPERATURE FLUID. THE MAIN CHARACTERISTIC OF THERMOSTAT 1 CONSISTS OF THE FACT THAT IT INCLUDES A MEANS 26 DESIGNED TO GENERATE A QUANTITY OF HEAT ACTING DIRECTLY ON THE HEAT SENSITIVE ELEMENT 16 IN ORDER TO INFLUENCE THE CONTROL OF THE POSITION OF THE VALVE MEAN 20 , 28. APPLICATION TO THE COOLING OF MOTORS OF MOTOR VEHICLES.

Description

The present invention relates to a thermostat for the circuit of

  cooling a motor vehicle engine, in particular a vehicle equipped with a small radiator on the cooling circuit for heating the passenger compartment. Thermostats are known in the art which

  carry an intake pipe, for the cooling fluid

  from the engine, and two exhaust pipes

  up to the line connected to the main radiator

  of cooling, which consequently amounts to

  through the fluid circulation pump

  of cooling, and the other directly fueling the

  Auxiliary diateur for heating the battery compartment

  sagers, which consequently returns to the motor via the pump.

  This type of thermostat contains a heat-sensitive element that includes a ball normally filled with wax

  and licked by the fluid circulating in the cooling circuit

  from the motor, which element actuates a control rod of the position of a valve means as a function of the temperature of the fluid licking the ball, for the purpose of regulating the passage of the input fluid as it moves

  to one or the other of the two outlet pipes of the

  mostat. Specifically, when the engine is running at a

  relatively low temperature, the totality of

  cooling from the engine is returned to the auxiliary radiator, while at a given temperature, for example 87 C, the passage leading to the main radiator begins to open and the direct passage to the auxiliary radiator begins to close until that, at a higher temperature, a direct flow to the auxiliary radiator

  completely cut off and the entire cooling fluid

  induced by the main radiator

  pal. However, such a constant operation, whatever

  the outside temperature, is far from being entirely satis-

  whereby a preferable arrangement is one in which the heat-sensitive element is actuated at different temperature thresholds, i.e. at a threshold

  higher in winter when, given the larger exchange of

  heat generation between the engine and the outside atmosphere,

  a higher operating temperature can be

  cooling fluid and, as a further advantage, a greater amount of heat can be

  applied to the auxiliary radiator for heating the com-

  passenger compartment, and a lower temperature of the coolant during the summer, for opposite reasons.

  Thermostats having valence means have already been proposed.

  ve operated at different temperatures, but these are bulky and involve manufacturing processes

complex, expensive.

  The object of the present invention is a thermostat for

  the cooling circuit of a self-propelled

  mobile phone of the type mentioned above, but which allows

  the position of the valve means to at least two times

  different ages and which, apart from the fact that his di-

  additional dimensions are negligible, can be manufactured

easily and cheaply.

  With this object in view, the present invention relates to a thermostat for the cooling circuit of a motor vehicle engine, this thermostat comprising a heat-sensitive element which is licked by the fluid circulating in the cooling circuit and controlling the position a valve means as a function of the temperature of the fluid,

  characterized in that it comprises means designed to pro-

  a quantity of heat acting directly on the element

  sensitive to heat in order to influence the

  DETAILED DESCRIPTION OF THE INVENTION The embodiment of the present invention will now be described, by way of nonlimiting example, in conjunction with the accompanying drawings, in which: FIG. 1 is a bottom view of a thermostat according to the present invention; FIG. 2 is a sectional view of the thermostat taken on

  along the line II-II of Figure 1.

  In FIG. 1, the reference 1 represents a thermostat according to the present invention which comprises, as is known,

  a connection flange 2, provided with a hole 3 intended to receive

  see the coolant from the engine, and two outlets, 4 and 5, for supplying the coolant to the main and auxiliary radiators,

  respectively. The thermostat is conveniently made of aluminum.

  silicon dioxide, in two parts (bottom 6 and top 7)

  linked together by means of bolts 8 (Figure 2). More specific

  3, the hole 3 communicates with a chamber 10 formed at the lower part 6 and having the same axis as a chamber 11 formed in the upper part 7 and which, in turn, communicates with the outlet pipe 4. The two chambers

  and 11 are separated by a set 12 responsive to the

  of an essentially known type, which has a structural

  A load-bearing member 13 having a circular edge 14 housed within a peripheral seal 15 enclosed between the portions 6 and 7. The assembly 12 also includes a heat-sensitive member 16 having an outer body 17.

  in the form of a ball filled with a substance, in the case

  wax, which expands rapidly to a given temperature threshold and acts on a rod 18 projecting axially on the body 17 and fixed to the top of the structure 13. Around the upper part of the outer body 17 is fixed a annular disk 20 which, by contact with the inner edge 21 of the structure 13, acts as a communication valve between the lower chamber 10 and the upper chamber 11. A spring

  22 is mounted between an annular projection 23 of the outer body

  17 and a lower annular edge 24 of the structure 13. According to the present invention, the lower part of the body

  17, conveniently made of brass, forms a cylinder

  hollow section 25, the end section of which has a hole

  a large diameter which contains an electrical resistance 26, in this case, of the shielded type, of cylindrical shape, having the same diameter as the upper inner hole of the cylinder and on which the resistive portion is concentrated at the top in contact with the lower part large section of

  the heat sensitive element 16 containing the wax.

  Around. the top of the cylinder 25 is mounted a spring 27 which rests, on one side, on the bottom of large section of the body 17 and, on the other side, on a ring plate 28 blocked

  axially by a ring 29 mounted at the bottom of the cylinder 25.

  The plate 28 is designed to cooperate with a recess 30 formed in the lower part 6, so as to form a communication valve between the chamber 10 and a lower chamber 31 containing the hollow cylinder 25 and communicating with the outlet pipe 5. The chamber 31 is defined by a cylindrical lower part 32 of part 6 and has an annular inner shoulder 33 which acts as a support for a bushing 34 mounted around the hollow cylinder 25. Below the bushing 34 is mounted an annular body 35, also conveniently made of plastic material such as bushing 34 and having two sealing rings 36 and 37 to seal the hollow inner surface of portion 32 and cylinder 25, respectively. The annular body 35 is locked at the bottom by a ring 38 fixed inside the hole in the cylindrical portion 32. The electrical resistance 26 is locked at the bottom by a washer 40 of plastic material which is mounted inside the hollow cylinder 25, whose inner end section is filled with an insulating material

  41, in this case an epoxy resin. From the cy-

  hollow liner 25 outputs a power supply cable 42,

  this cable comprising a first wire, connected to a terminal of a-

  positive power supply + V, via a switch 43, and a second

wire connected to the ground.

  The thermostat of the present invention operates from

  the following way: assuming, for example, conditions

  operating procedures that do not involve electrical resistance

  In FIG. 26, the heat-sensitive element 16 has been set so as not to be actuated when the temperature of the cooling fluid licking the outer body 17 is, for example, 87 C. Below this temperature, the passage entering the chamber 11 through the annular disc 20 remains closed, so that all of the coolant supplied to the hole 3 and the chamber

  out of the exit pipe 5 in the direction of

  additional dialer to heat the battery compartment

  swimmers, then return to the engine. When the temperature of the coolant exceeds 87 C, the rod 18 leaves the

  outer body 17 and, since the support structure

  load port 13 is fixed, the entire element 16 sen-

  As a result of the heat sink, the inlet passage to the chamber 11 and the outlet pipe 4 in the direction of the main radiator open and the inlet passage to the chamber 13 and the outlet pipe 5 gradually close. 'at

  when the annular plate 28 rests in the recess

  30, the second pass is cut and all the

  of cooling passes through the main radiator. For the operation of the heat sensitive element 16 at a lower temperature of the cooling fluid (for example

  example 80C) as may be necessary, for example

  ple, in summer, the switch 43 causes the power supply of

  the electrical resistance 26 which provides a sufficient quantity

  heat of heat to raise the temperature of the wax of

  the element 16 sensitive to heat of 7 C, so as to ac-

  tiver element 16, open the passage between chambers 10 and 11 and gradually close the entrance passage in the

  chamber 31 as previously described. In an identical way

  that the element 16 can be activated by two temperatures of

  cooling fluid, depending on whether the

  controller 43 has been activated or not. The latter can be a

  an ordinary switch mounted on the dashboard and actuated by the driver or, for example, a switch connected to a heat regulation control within the

  passenger compartment and designed to cut off the

  resistance 26 when the heating inside the compartment is closed. The advantages of the thermostat

  the present invention will become apparent in the drawings.

  previous description. In particular, it is relatively easy

  to manufacture, comprising only a few additional elements

  mentary; it is compact, requiring only the addition of the lower cylindrical portion 32 and is in a manner

  general low manufacturing cost.

  It will be apparent to those skilled in the art that modifications may be

  The described arrangement can be made without, however, departing from the scope of the present invention. For example, the switch 43 can be replaced by a sensitive element

  heat to get the order according to a time

  given reference temperature. Power control

  electrical resistance 26 can be performed proportionally

  in order to regulate the amount of heat

  denies heat sensitive element 16 and, therefore,

  the different temperature of the coolant at

  the element 12 sensitive to heat is actuated The resistor 26 can be connected to ground, for example

  using the mechanical contact between the body of the resistor

  26 and the hollow cylinder 25, and between the element 16 sen-

  heat-resistant and the load-bearing structure 13, and by connecting the latter to the part 6 or 7 of

  the assembly 1, for example by resting the circular edge

  14 of the structure 13 on the annular groove of the part 6 and therefore changing the shape of the seal 16. Around the outer upper part of the cylinder

  25, a cylindrical sealing bushing may be provided.

  end tee to form an air chamber in relation to the external fluid passage and some thermal insulation, so as to ensure that the maximum amount of

  heat developed by the electrical resistance 26 is either

  denies the wax of the element 16 sensitive to heat.

Claims (9)

  1. Thermostat (1) for the cooling circuit of a motor vehicle engine, this thermostat (1) comprising a member (16) sensitive to heat licked by the fluid flowing in the cooling circuit and controlling the position of a valve means (20, 28) as a function of the fluid temperature, characterized in that it comprises a   medium (26) designed to develop a quantity of heat a-   directly slipping on the heat sensitive element (16) to influence the position control of the valve means (20,28).   2. Thermostat according to claim 1, characterized in that   said means comprises an electrical resistance (26).   3. Thermostat according to claim 2, characterized in that   that the resistor (26) is shielded.   4. Thermostat according to claim 2 or claim 3, characterized in that the resistor (26) is housed in a hollow part (25) of the body (17) of the sensitive element. heat (16).   Thermostat according to any one of the claims   1 to 4, characterized in that it comprises a sealing means   auxfluides (34, 35, 36, 37) around the generating means of each   (26) to remove from the thermostat (1) a cable of electrical power supply (42).   Thermostat according to any one of the claims   1 to 5, characterized by comprising switching means   (43) to supply electrical power by means of heat generator (26).   7. Thermostat according to claim 6, characterized in that   that the switch means (43) is operated by the user tor.   8. Thermostat according to claim 7, characterized in that   that the switch means (43) is operable in   with a control for the regulation of the heat at inside the vehicle.   9. Thermostat according to any one of the claims 2 6040 6_   1 to 8, characterized in that it comprises means designed to   regulate the amount of heat generated.