System for pressurizing a cooling circuit of an internal combustion engine equipped with a turbo compressor unit

Abstract

System for pressurizing a cooling circuit of an internal combustion engine (E) equipped with a turbo compressor unit (TC), wherein the turbo compressor (TC) comprises a turbine arranged on an exhaust gas line of the internal combustion engine (E), and a compressor (C) arranged on the inlet line (IL) of the internal combustion engine, wherein the internal combustion engine comprises a cooling circuit containing an expansion vessel (LAT) connected by a compressed air pipe (10) to a point on the inlet line (IL) downstream of the compressor (C), and wherein the compressed air pipe (10) comprises a mechanical valve (V) designed to open and close the compressed air pipe (10) with respect to a differential pressure between a point upstream and a point downstream of the mechanical valve (V) itself, wherein the mechanical valve (V) is of the three-way type.wherein a first port is directly connected to the inlet line (IL), a second port is connected to the expansion vessel (LAT), and a third port is connected to the second port to control the opening / closing of the mechanical valve, the mechanical valve comprising an air expansion reservoir (11) which is built into the body of the mechanical valve (V) itself to allow preventive expansion of the compressed air before and during its emission into the expansion vessel (LAT).

Description

Field of application of the invention

[0001] The present application relates to the field of cooling circuits of internal combustion engines and in particular to the field of controlling the internal pressure of the circuit by means of the compressed air generated by the turbo compressor, specifically by means of a mechanical valve without the use of pressure sensors and related control units. State of the art

[0002] Modern cooling systems for internal combustion engines are equipped with an expansion tank for the coolant. Part of the volume of such an expansion tank is filled with air, which usually contains a safety valve that allows gas / vapor to be released into the environment if a predetermined pressure value, measured within the expansion tank, is exceeded.

[0003] The circulation and pressurization of the coolant in the circuit is ensured by a hydraulic pump.

[0004] By using pumps with variable flow rates that are capable of self-adjustment based on the temperature of the coolant, it is possible that the cooling circuit has points where the pressure drops to the point that allows cavitation phenomena to occur.

[0005] Such phenomena cause rapid corrosion of the walls of the cooling circuit in the internal combustion engine, resulting in serious damage to the engine.

[0006] Such phenomena are related to the pressure of the circuit, but also to the temperature of the coolant.

[0007] Various solutions are known that are based on the emission of air into the circuit to increase the pressure in the circuit in order to avoid such cavitation problems.

[0008] JP19800169161 shows a solution in which piezoelectric sensors are arranged along the cooling circuit to detect cavitation phenomena. When these phenomena are detected, air is blown into the circuit by the cooling fan in a quantity proportional to the intensity of the detected cavitation phenomenon.

[0009] US2005061264 discloses a solution for pressurizing the cooling circuit by detecting the coolant level in the expansion vessel. Therefore, when the coolant level rises above a predetermined level, air is introduced into the vessel. A preferred embodiment further incorporates a pressure sensor located within the expansion vessel and processing means that control the emission of compressed air into the expansion vessel based on the pressure measured within the vessel. The compressed air can be drawn from the internal combustion engine's intake pipe, downstream of the compressor.

[0010] US6666175 shows another solution in which the cooling circuit is pressurized by the charging compressor and in which the pressurization is controlled by means of a spring valve or by means of a servo valve. Summary of the invention

[0011] The object of the present invention is to demonstrate a non-servo-controlled system for pressurizing a cooling circuit of an internal combustion engine operated by mechanical valves by taking compressed air from the inlet line of the internal combustion engine between the compressor and the inlet manifold.

[0012] The subject matter of the present invention is a system for pressurizing a cooling circuit of an internal combustion engine equipped with a turbo compressor unit, according to claim 1.

[0013] The attached claims describe preferred embodiments of the invention, thereby forming an essential part of the present invention. Brief description of the drawings

[0014] Further tasks and advantages of the present invention will become apparent from the detailed description below of one embodiment thereof (and two variants thereof) and from the accompanying drawings, which are given only as a non-limiting example, in which:

[0015] Fig. Figure 1 shows a schematic diagram of the system which is the object of the present invention,

[0016] Fig. It contains two examples of mechanical valves, which are part of the diagram in Fig. 1 are.

[0017] The same numbers and reference symbols in the figures denote the same elements or components. Detailed description of the embodiments

[0018] In Fig. Figure 1 shows an internal combustion engine E equipped with a turbo compressor unit TC, in which the turbine is arranged on the exhaust gas line of the internal combustion engine, while the compressor C is arranged on the inlet line IL of the internal combustion engine.

[0019] An intercooler IC is also arranged on the inlet line between the compressor C and the inlet manifold.

[0020] The internal combustion engine E has a cooling circuit (not shown) connected to a closed expansion vessel LAT, which is partly filled with coolant and partly filled with air.

[0021] A safety valve is generally connected to the upper part of the vessel LAT to release steam into the external environment when a predetermined pressure threshold is exceeded.

[0022] A compressed air pipe 10connects the inlet line IL to the upper part of the expansion vessel LAT and exactly one point on the line downstream of the compressor C.

[0023] Opening and closing such a pipe 10 is achieved by a mechanical valve V, preferably a spring valve, which has no electrical receiver.

[0024] Such a valve opens the pipe 10 , so that compressed air flows into the expansion vessel LAT when it detects a predetermined pressure difference between a point upstream and a point downstream of the valve itself, where upstream and downstream refer to the direction of circulation of the compressed air from the inlet line IL to the expansion vessel LAT.

[0025] Preferably, the mechanical valve V is adjusted based on the maximum boost pressure of the turbo compressor unit.

[0026] Therefore, every adjustment of the pressure coating of the vessel LAT is carried out mechanically, without the aid of control means.

[0027] System stability is significantly influenced by the fact that the compressed air is drawn downstream of the intercooler, i.e., between the intercooler and the intake manifold IC of the internal combustion engine E.

[0028] In fact, the emission of cooled air prevents the formation of vapors that would immediately harden upon opening the safety valve, which is generally located on the expansion vessel LAT.

[0029] Preferably, the mechanical valve is a three-way valve.

[0030] A more unusual feature is that, even if the valve appears from the outside to be a two-way valve, a third port is built into the valve and connected to one of the other ports to measure the pressure upstream or downstream of the valve. In other words, the third port controls the opening of the valve.

[0031] Preferably, the third port is connected to the outlet port of the valve, i.e., the port with the lower pressure, which is directly connected to the expansion vessel.

[0032] A small air expansion reservoir is preferred. 11 installed in the valve V to allow preventive expansion of the compressed air before and after its emission into the expansion vessel LAT.

[0033] Therefore, the reservoir 11 in compressed air communication with the compressed air pipe 10 .

[0034] Because of the design of the reservoir 11It is advantageously possible to control the opening and closing of valve V with greater precision, without risking exposing the expansion vessel to excessive pressure increases.

[0035] Additionally, the reservoir works 11 synergistically with the extraction of air downstream of the intercooler, because of the albeit modest expansion of the compressed air in the reservoir 11 This leads to a further reduction in the temperature of the compressed air introduced into the expansion vessel LAT. Preferably, the air expansion reservoir has 11 An internal volume of approximately 13 1. 1 / 5–1 / 10 of the (upper) part of the internal volume of the expansion vessel LAT is occupied by air.

[0036] According to a further preferred embodiment of the invention, the system comprises a valve 10, obviously a two-way valve in which the third port is connected to one of the other two ports, with an air expansion reservoir built directly into the valve body.

[0037] Fig. Figure 2 shows a purely indicative example of a Wabco ® -Valve, which is particularly suitable for the implementation of the present invention.

[0038] Such valves are equipped with two slides A and B, and both slides B integrate two slides, a control slide d and one for the passage of the compressed air.

[0039] The aforementioned air expansion reservoir 11is made in the valve body. In particular, such a reservoir is expandable by means of a diaphragm or a movable piston, which are loaded by a spiral spring f, which can be adjusted by means of a screw g, which is accessible outside the valve body and is arranged in an axial position with respect to the spiral spring.

[0040] Modifications to the embodiment of the described non-restrictive example are possible without, however, deviating from the scope of protection of the present invention.

[0041] A person skilled in the art can solve the problem of the invention based on the above description without introducing further design details. The elements and features disclosed in the various preferred embodiments can be combined with any other embodiment without deviating from the scope of protection of the present invention. Unless specifically excluded in the detailed description, what is described in the prior art description must be considered in combination with the features of the present invention, thereby forming an essential part of the present invention. QUOTES INCLUDED IN THE DESCRIPTION

[0042] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0043] JP 19800169161

[0008] US 2005061264

[0009] US 6666175

[0010]

Claims

[1] System for pressurizing a cooling circuit of an internal combustion engine (E) equipped with a turbo compressor unit (TC), wherein the turbo compressor (TC) comprises a turbine arranged on an exhaust gas line of the internal combustion engine (E) and a compressor (C) arranged on the inlet line (IL) of the internal combustion engine; wherein the internal combustion engine comprises a cooling circuit containing an expansion vessel (LAT) connected by a compressed air pipe ( 10 ) is connected to a point on the inlet line (IL) downstream of the compressor (C), and wherein the compressed air pipe ( 10 ) includes a mechanical valve (V) designed to control the compressed air pipe ( 10 ) to open and close with respect to a differential pressure between a point upstream and a point downstream of the mechanical valve (V) itself. [2] System according to claim 1, wherein the mechanical valve is set according to a maximum boost pressure of the turbo compressor unit (TC). [3] System according to claim 1, wherein the mechanical valve (V) is of the three-way type, wherein – a first connection is directly connected to the inlet line (IL), – a second connection is connected to the expansion vessel (LAT) and – a third port is connected to the first or second port to control the opening / closing of the mechanical valve. [4] System according to one of the preceding claims, wherein the mechanical valve is an air expansion reservoir ( 11 ) includes the component built into the body of the mechanical valve (V) itself. [5] System according to one of claims 1–4, wherein the inlet (IL) comprises an intercooler (IC) downstream of the compressor (C) and wherein the compressed air pipe ( 10) is connected downstream of the intercooler to the inlet line (IL). [6] Ground vehicle comprising an internal combustion engine cooled by means of a cooling circuit and equipped with a turbo compressor unit (TC), characterized by that it comprises a pressurization system of the cooling circuit according to one of claims 1–5.

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