EP1965045A2 - Method and device for reheating crankcase emissions and gravity collector designed for crankcase emissions - Google Patents

Abstract

The method involves maintaining a temperature of a gravity collector (210) higher than the temperature i.e. zero degree Celsius, given by the heat exchange between the gravity collector and heat transfer fluid of an engine, where the heat transfer fluid is removed at an output of a heat exchanger (230) with the oil of a lubrication system of the engine. The heat exchange is obtained by circulation of the fluid on a wall of the gravity collector. An independent claim is also included for a device for reheating crankcase emissions in an engine of a motor vehicle.

Description

The present invention relates to a method and a device for heating crankcase gas in a motor vehicle engine. The invention also relates to a settling chamber contained in the crankcase circuit of a motor vehicle engine.

The invention finds a particularly advantageous application in the field of the automotive industry.

• ■ fuite au niveau des segments, depuis la chambre de combustion vers les volumes sous piston,
• ■ fuite au niveau des paliers du ou des turbo-compresseurs, depuis les corps de turbine et de compresseur vers le carter moteur par le retour d'huile,
• ■ fuite par les joints de queue de soupape, depuis les tubulures d'admission et d'échappement vers la culasse,
• ■ fuite des gaz de pompe à huile, depuis le circuit de freinage vers la culasse.

In an internal combustion engine, the crankcase gases, also called "blow-by" gases, come from different sources:

• ■ leakage at the segments, from the combustion chamber to the piston volumes,
• ■ leakage at the bearings of the turbo-compressor (s), from the turbine and compressor bodies to the crankcase by the oil return,
• ■ leakage through the valve stem seals from the intake and exhaust manifolds to the cylinder head,
• ■ oil pump gas leakage, from the braking circuit to the cylinder head.

These gases created in the crankcase of the engine must be evacuated to avoid the risks of escape to the outside and the discharge into the atmosphere of polluting hydrocarbons, as well as to keep the bottom of the crankcase in depression and to avoid a fire of the engine.

This is why it is provided in the heat engines to evacuate these crankcase gases by closed loop recovery circuits operating by suction to the intake of the engine gases for consumption in the combustion chamber.

• ■ Les gaz de carter sont composés :

• ■ de gaz de combustion, essentiellement de l'eau, du dioxyde de carbone et du diazote,
• ■ des gaz imbrûlés : air, carburant et diazote,
• ■ d'huile.

However, before being burned, they must be cleared of the oil they contain by passing through a settling chamber, this for reasons of fouling and pollution.

• ■ Crankcase gases are composed of:

• ■ flue gas, mainly water, carbon dioxide and nitrogen,
• ■ unburned gases: air, fuel and nitrogen,
• ■ oil.

During operation of the engine under cold climatic conditions, blow-by gases cool and some initially gaseous compounds can condense into liquid, or even solidify.

In particular, an amalgam may be formed, that is to say an emulsion obtained by stirring a mixture of water and oil in the liquid phase.

Similarly, under more severe conditions, the temperature of the crankcase gases can fall below 0 ° C, so as to freeze the water contained in these gases.

In any case, the formation of a plug of ice and / or amalgam causes a rise in pressure of the crankcase causing oil splashes under the hood and engine breakage by oil draining of the housing by the oil dipstick or by the seals. In some cases, a fire hazard of the vehicle is not excluded.

To remedy these difficulties, it is generally proposed to implement in the motors electric heating devices blow-by gas circulation pipes. These devices are most often made of a resistor under tension coming locally to heat the surface of the pipes.

These solutions are most often expensive energy, because of the consumption of electrical energy that the alternator must provide, and economically, because they affect the cost of the engine. In addition, there also arise implementation difficulties related to the size of the heating pipes and the electrical harness necessary to supply the heating resistors.

Also, an object of the invention is to provide a method and a device for heating "blow-by" gases which make it possible to avoid additional energy consumption, to limit the additional cost of reheating and not to increase engine clutter.

This object is achieved, in accordance with the invention, by a method of heating crankcase gas in a motor vehicle engine, said gases being circulated in a recovery circuit passing through an oil settling chamber contained in said crankcase gas, remarkable in that said method consists in maintaining in said settling chamber a temperature above a given temperature.

According to an advantageous embodiment, the temperature of the settling chamber is maintained higher than said temperature given by heat exchange between said settling chamber and a heat transfer fluid of the engine.

The invention provides in particular that said heat exchange is obtained by circulating said heat transfer liquid on at least one wall of the settling chamber.

It is also provided by the invention that said coolant liquid is taken at the outlet of a heat exchanger with the engine lubricating circuit oil.

Likewise, a device for heating crankcase gas in a motor vehicle engine, a circuit for recovering said gases passing through an oil settling chamber contained in said crankcase gases, is notably remarkable in that said device comprises means to maintain the temperature of said upper settling chamber at a given temperature.

According to one embodiment, said means are capable of creating a heat exchange between said settling chamber and a heat transfer fluid of the engine.

Advantageously, said means comprise at least one double wall arranged on the settling chamber and intended to achieve said heat exchange by circulation of the heat transfer fluid inside said double wall.

According to the invention, the double wall is provided with a heat transfer fluid inlet orifice in communication with a heat exchanger between said heat transfer fluid and the oil of the engine lubrication circuit.

The invention further relates to an oil settling chamber contained in the crankcase circuit of a motor vehicle engine, characterized in that said settling chamber comprises a double wall for the circulation of a coolant of the motor.

According to the invention, the double wall is provided with a coolant inlet for communicating with a heat exchanger between said heat transfer fluid and the engine lubrication circuit oil.

Thus, it is understood that the invention has the effect of avoiding the formation of ice plugs or amalgam due to the cooling of "blow-by" gases by preventing such cooling from occurring, or even favoring their warming.

The invention therefore makes it possible to use the heat-transfer fluid circuit of the engine, eg brine, of the cooling circuit, and in particular the heat it conveys, in order to heat the walls of the oil settling chamber. Thus, the heat exchange tending to cool the crankcase gases and to create the difficulties related to freeze "blow-by" and amalgam, are reversed. Indeed, by producing a double-walled settling chamber and introducing a hot water circulation between the two walls, the problems of gel and amalgam are minimized or even eliminated depending on the applications.

• ■ économie d'énergie en utilisant une source d'énergie disponible. En effet, l'eau du circuit de refroidissement est chauffée par la combustion dans le moteur. Cette énergie est ensuite perdue au travers du radiateur. Il s'agit donc d'utiliser une partie de cette énergie perdue pour éviter de refroidir les gaz de « blow-by » et leur permettre de s'échauffer plus rapidement,
• ■ déduction du prix de revient du moteur du coût des réchauffeurs électriques. En effet, le surcoût de développement et d'achat de la chambre de décantation reste bien inférieur à celui des réchauffeurs.
• ■ réduction de l'encombrement moteur. En effet, l'invention permet d'éviter l'installation d'un faisceau électrique et d'un connecteur encombrants.
• ■ temps de réponse très rapide.

The advantages of the invention are as follows:

• ■ saving energy using an available energy source. Indeed, the water of the cooling circuit is heated by combustion in the engine. This energy is then lost through the radiator. It is therefore a question of using part of this lost energy to avoid cooling the "blow-by" gases and allowing them to warm up more quickly,
• ■ deduction of the cost price of the motor from the cost of the electric heaters. Indeed, the additional cost of development and purchase of the settling chamber remains well below that of the heaters.
• ■ reduction of engine space. Indeed, the invention avoids the installation of a wiring harness and a bulky connector.
• ■ very fast response time.

• ■ La figure 1 est une vue de côté schématique d'un système de réchauffage de gaz de carter conforme à l'invention.
• ■ La figure 2 est une vue de côté de la chambre de décantation d'huile représentée sur la figure 1.

The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

• ■ The figure 1 is a schematic side view of a crankcase heating system according to the invention.
• ■ The figure 2 is a side view of the oil settling chamber shown on the figure 1 .

On the figure 1 is shown a crankcase heating device, or "blow-by", in a motor vehicle engine which is shown schematically on the figure 1 the cylinder head 10, the cylinder block 20 and the oil tank 30.

These gases circulate by suction between the bottom of the crankcase and the combustion chamber along a recovery circuit passing through a chamber 210 for decanting the oil contained in the "blow-by" gases.

The chamber 210 decantation is intended to decant the crankcase gases to separate them from the oil they are loaded. This is usually a baffle type settler that stops the oil droplets and returns them to the oil tank by means of an oil return pipe 215 from the decanter 210 to the oil tank 30.

As explained above, it can happen that under cold climatic conditions, water and oil blow-by gases create ice caps and / or amalgam, with all the damaging consequences that entails for the engine in terms of breakage or fire.

To prevent ice plugs from forming, due to the cooling of the crankcase gases through the recovery circuit, it is proposed to heat the gases by means of the heating device shown in FIG. figure 1 .

This is to at least partially heat the outer surface of the chamber 210 decantation so as to maintain its internal temperature above a given temperature, 0 ° C for example. The "blow-by" gases thus pass, between an inlet 211 and an outlet 212, a hot space inside the decanter 210 which protects them from possibly very cold temperatures that can be encountered outside, in particular in areas exposed to cold air under the hood.

In practice, the desired heating is obtained by equipping the chamber 210 with a double wall 216 decantation, as indicated by the figure 2 , and to circulate a coolant capable of constituting a heat shield for the crankcase gases that pass through the decanter 210. This fluid enters the double wall 216 through an inlet orifice 213 and out through a port 214 of exit.

In the embodiment of the figure 1 , the coolant introduced into the double wall 216 of the settling chamber 210 is, for example, the engine coolant, such as brine, which, leaving the water core of the cylinder block 20 through the manifold 231 enters a 230 water / oil exchanger to cool the oil of the engine lubrication circuit. This oil is removed from the oil tank 30 by the pipe 221, then is filtered by the oil filter 220 before passing through the heat exchanger 230 and continue its journey to supply the lubrication circuit.

At the passage in the heat exchanger 230, the water of the cooling circuit receives calories from the engine oil, enters the decanter 210 through the inlet orifice 213, circulates in the double wall 216 which it maintains at a constant temperature. temperature sufficient, spring decanter 20 through the outlet port 214 and continues its path to cool the cylinder head 10.

The double wall 216 may cover all the faces of the decantation chamber 210 or only some of them and, at least, the one most exposed to cold aeration under the hood.

Claims (6)

A method of heating crankcase gas in a motor vehicle engine, said gases being circulated in a recovery circuit passing through an oil settling chamber (210) contained in said crankcase gases, characterized in that said method consists of to maintain the temperature of the upper settling chamber at a given temperature by heat exchange between said settling chamber and a heat transfer fluid of the engine taken at the outlet of a heat exchanger (230) with the oil of the engine lubrication circuit The method of claim 1, wherein said given temperature is 0 ° C. Method according to claim 1 or 2, wherein said heat exchange is obtained by circulating said coolant on at least one wall of the chamber (210) of decantation. Method according to one of the preceding claims, wherein said heat transfer fluid is taken at the outlet of a heat exchanger (230) with the engine lubrication system oil. A crankcase heating device in a motor vehicle engine, a circuit for recovering said gases passing through an oil settling chamber (210) contained in said crankcase gases, characterized in that said device comprises means for maintaining the temperature of said upper settling chamber (210) at a given temperature, capable of creating a heat exchange between said settling chamber (210) and a heat transfer fluid of the engine, said means comprising at least one double wall (216) arranged on the chamber (210) of decantation and intended to carry out said heat exchange by circulation of the heat transfer fluid inside said double wall (216). Device according to claim 5, wherein the double wall (216) is provided with an orifice (213) for entering the coolant in communication with a heat exchanger (230) between said heat transfer fluid and the oil of the cooling circuit. engine lubrication.

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