KR101015696B1 - Air inlet system for a turbocharger-equipped heat engine - Google Patents

Abstract

The present invention relates to an air inlet system for a heat engine (10), which cools the main air duct (16) connecting the turbocharger (18) to the intake portion (12) of the heat engine, and charge air delivered to the intake portion of the heat engine. It comprises a main cooler 20 mounted to the main air duct to. The system of the present invention also includes a bypass duct 32 upstream of the main cooler 20, which directly connects the main air duct 16 to the intake 12 of the heat engine; First selection means (34) used to deliver the charge air to the main cooler (20) or directly to the intake portion (12) of the heat engine; And a second selection means 36 used to isolate the main cooler 20 from other parts of the system. The present invention is suitable for use in automotive diesel engines.

Description

Intake system for heat engine with turbocharger {AIR INLET SYSTEM FOR A TURBOCHARGER-EQUIPPED HEAT ENGINE}

TECHNICAL FIELD The present invention relates to a heat engine for automobiles, in particular, equipped with a turbocharger.

More specifically, the invention includes a main air duct connecting the turbocharger to the intake of the engine and a main cooler mounted on the main air duct for cooling the turbocharged air delivered to the intake of the engine. It relates to a heat engine equipped with a charger.

Heat engines used in automobiles, especially diesel engines, are usually equipped with turbochargers to improve engine performance.

The turbocharger, driven by engine exhaust gas, generates compressed air, also called "turbocharge air," which is delivered to the intake of the engine. Therefore, the heat engine provided with a turbocharger is supplied with compressed air, unlike a normal heat engine supplied with air at atmospheric pressure.

However, since the air from the turbocharger is hot, it is necessary to cool the turbocharged air before it is delivered to the intake portion of the engine in order for the engine to operate at optimum conditions.

This is why a turbocharged air cooler (abbreviated as TAC) is placed at the outlet of the turbocharger and used to lower the temperature of the turbocharged air.

For this purpose, it is known to use an air / air type main cooler that cools the turbocharged air by heat exchange with external airflow.

Also known in the art is a water-cooled auxiliary cooler located upstream of the main cooler of the air / air type, which is also referred to as a "precooler".

It is also known that diesel engines are usually equipped with particulate traps for limiting the release of harmful particulates to the atmosphere. Engine coolant is supplied and by reheating the intake air by another exchanger, also referred to as "Intake Air Reheater (IAR)", to reduce noise due to combustion and to promote the regeneration of these particulate traps. Known.

The presence of these various exchangers obviously has an advantageous effect on the operation of the engine, but has the disadvantage that additional volumes of air contained in the exchanger and in the air ducts occur. This volume of air directly affects the engine's response time to acceleration.

Summary of the Invention

The present invention aims, in particular, to overcome these disadvantages.

It aims in particular to optimize the operation of the intake system of a turbocharged engine equipped with a turbocharged air cooler.

Accordingly, the present invention provides an intake system of the type defined in the introduction.

A bypass duct upstream of the turbocharged air main cooler, which connects the main air duct directly to the intake of the engine,

First selection means mounted to the intersection of the main air duct and the bypass duct, for delivering turbocharged air to the main cooler or directly to the intake of the engine,

A second selection means for connecting the main cooler to the intake of the engine downstream of the main cooler and for isolating the main cooler from other parts of the system.

Thus, with this bypass duct, it is possible to deliver turbocharged air from the turbocharger directly to the intake of the engine and thus bypass the main cooler. This advantage improves the response time of the engine, especially during acceleration of the engine, by reducing the volume of air contained between the turbocharger and the engine inlet, ie the inlet of the cylinder.

In order to further reduce the volume of air contained between the turbocharger and the inlet of the engine, the second selecting means makes it possible to isolate the main cooler from other parts of the circuit.

On the other hand, in the normal operating mode, the first selecting means directs the turbocharged air to the main cooler, thereby forming a stream of cooled air delivered to the intake of the engine.

As used herein, the term "intake" generally refers to an intake manifold that receives turbocharged air and directs it to the cylinder of the engine.

In an engine of the type described above, a part of the exhaust gas is delivered to the intake manifold to be recycled, to burn again in the cylinder of the engine, and to reduce the emission of harmful gases.

According to another feature of the invention, the main air duct comprises a control valve which serves to regulate the engine exhaust gas recirculation flow rate.

In another embodiment of the invention, the intake system further comprises an auxiliary cooler for turbocharged air, disposed upstream of the turbocharged air main cooler.

In a first variant, the bypass duct is connected to the outlet of the auxiliary cooler.

In another variant, the bypass duct is connected to the inlet of the auxiliary cooler.

In a preferred embodiment of the invention, the selecting means comprises an upstream valve disposed on the main air duct upstream of the turbocharged air main cooler, optionally providing turbo charge air to the main cooler or via the bypass duct to the engine. Direct it directly to the intake section.

Advantageously, the main air duct also comprises a downstream valve disposed downstream of the turbocharged air main cooler, which connects the main cooler to the intake of the engine and prevents the turbocharged air from flowing back towards the main cooler. can do.

The present invention makes it possible to form various layouts of the turbocharged air main cooler.

In particular, this main cooler may be located next to the engine, while connected to the intake by suitable ducts.

However, in certain advantageous embodiments, the turbocharged air main cooler is installed in an intake chamber (also referred to as an intake plenum) contained within the intake air distributor.

This solution is particularly advantageous because it makes it possible to exclude the connecting duct and thus limit the overall size.

In this embodiment, a blocking gate may be provided installed in the plenum downstream of the turbocharged air main cooler to isolate the air volume contained upstream of the main cooler, between the cooler and the intake of the engine. Therefore, the volume of air contained between the turbocharger and the intake portion of the engine can be isolated, and the turbocharged air can be prevented from flowing back toward the main cooler.

1a and 1b show two different modes of operation of an intake system according to a first embodiment of the invention,

2a and 2b show two different modes of operation of an intake system according to a second embodiment of the invention,

3a and 3b show two different modes of operation of an intake system according to a third embodiment of the invention,

4A and 4B show two different modes of operation of an intake system according to a fourth embodiment of the invention.

The following description will refer to the accompanying drawings for purposes of illustration only.

Referring first to FIGS. 1A and 1B, there is shown a heat engine 10, such as a diesel engine 10, in particular for a motor vehicle such as a private vehicle.

The engine 10 refers to an intake manifold 12 (hereinafter referred to simply as an "intake") and an exhaust manifold 14 (hereinafter referred to simply as an "exhaust"). Include.

The engine 10 is provided with an intake system comprising a main air duct 16 connecting the turbocharger 18 to the intake 12 of the engine. The turbocharger 18 is driven by engine exhaust gas and supplied with outside air. The turbocharger 18 forms a compressed air stream, referred to as "turbocharge air," which is delivered to the intake 12 of the engine. On the main air duct 16 a turbocharged air main cooler 20 (referred to as "TAC") is interposed in a known manner.

The function of such a cooler is to cool the turbocharged air by heat exchange with external cold air. It is therefore an air / air type heat exchanger. It is also possible to consider cooling the turbocharged air with a cooling liquid. In that case, this is an air / water type heat exchanger.

In a known manner, the exhaust 14 of the engine is connected to an exhaust duct 22, which in turn allows a part of the exhaust gas to be recirculated to the engine by the duct 26. Is connected. In order to increase the amount of gas recycled, the pressure in the main air system is reduced by the proportional valve 28.

Downstream of the valve 24 is mounted a heat exchanger 30, also referred to as an "exhaust gas recirculation cooler", whose function is to cool the recycled exhaust gas delivered to the engine. The exhaust gas so recycled is burned again at the same time as the intake air in the cylinder of the engine in order to improve combustion and reduce harmful gases emitted to the atmosphere.

As described so far, the engine 10 with an intake system and an exhaust system is of known construction.

As mentioned above, a disadvantage of this is that the volume of air present in the intake system between the turbocharger 18 and the intake 12 increases, which in particular increases the engine's response time to acceleration.

To avoid this drawback, the intake system of the present invention further comprises a bypass duct 32 which connects the main air duct 16 directly to the intake 12 of the engine at a point located upstream of the main cooler 20. do. To this end, a selector valve 34 is arranged upstream of the cooler 20 at the intersection of the main air duct 16 and the bypass duct 32. This selector valve has the function of directing turbocharged air directly to the main cooler 20 or via the bypass duct 32 to the intake 12 of the engine.

In the latter position, a "full on or full off" type selection valve ("downstream valve") arranged downstream of the cooler 20 and connecting the main cooler 20 to the intake 12. 36) prevents turbocharged air from flowing back toward the main cooler.

The selection valve 34 is advantageously a three-way type valve, which is operated by a micromotor and is commanded by an appropriate control circuit which takes into account operating parameters of the heat engine.

The apparatus of the present invention operates in the following manner. In the operating mode of FIG. 1A, the selector valve 34 directs turbocharged air directly to the intake of the engine 10 bypassing the main cooler 20. This turbocharged air is directed directly to the intake of the engine 10 through the control valve 24 at the same time as part of the recycled exhaust gas. The valve 36 is then shut off and the volume of air contained upstream of the main cooler 20, between the cooler 20 and the intake 12, is isolated by the valves 34, 36. In this mode of operation, the volume of air contained between the turbocharger 18 and the inlet of the cylinder of the engine is reduced, thus making it possible to improve the response time of the engine, especially during acceleration.

On the other hand, in the normal operating mode as shown in FIG. 1B, the selector valve 34 directs the turbocharged air to the main cooler 20.

The main air duct 16 is connected to the intake 12 via a valve 36, which is then opened. In this normal operating mode, the stream of turbocharged air is cooled by the main cooler 20 before being delivered to the intake of the engine.

Referring now to FIGS. 2A and 2B, another embodiment similar to FIGS. 1A and 1B is shown. Common elements are denoted by the same reference numerals. In this embodiment, the air system further comprises an auxiliary cooler 38 for turbocharged air, which is arranged upstream of the main cooler 20. This secondary cooler is also referred to as a “precooler” and has the function of precooling the turbo charge air before cooling the turbo charge air by the main cooler 20. The main cooler 20 is an air / air type exchanger, but the auxiliary cooler 38 is typically an air / water type exchanger. It typically passes through the engine cooling liquid. Such exchangers also serve to reheat intake air to reduce noise and promote regeneration of particulate traps (not shown).

In the embodiment of FIGS. 2A and 2B, the selector valve 34 is disposed between the coolers 20, 38. Thus, the bypass duct 32 is connected to the outlet of the auxiliary cooler 38. 2A and 2B correspond to the operating modes of FIGS. 1A and 1B, respectively. The main difference lies in the fact that in both modes, the turbocharged air is precooled at the outlet of the turbocharger. Thus, in the case of FIG. 1A, the turbocharged air is precooled before being delivered directly to the intake of the engine. In the case of FIG. 2B, the turbocharged air is cooled in the main cooler 20 and precooled before being delivered to the intake of the engine.

The embodiment of FIGS. 3A and 3B is similar to that of FIGS. 2A and 2B. The main difference is that the bypass duct 32 is connected to the inlet of the auxiliary cooler 38.

The selection means comprise two valves. That is, one is an upstream valve 34 similar to the valve 34 of the two embodiments described above, which is arranged upstream of the auxiliary cooler 38 here. The other is a valve 40 disposed downstream, thus at the outlet of the auxiliary cooler 38.

In the operating mode of FIG. 3A, the valve 34 directs turbocharged air to the bypass duct 32 and thus to the intake 12 of the engine. Thus, the turbocharged air is delivered directly to the intake section of the engine without being precooled, as opposed to in the embodiment described above.

The valves 40 and 36 isolate the turbocharged air from other parts of the system to prevent the turbocharged air from reaching the main cooler 20.

In the operating mode of FIG. 3B, valve 34 delivers turbocharged air to auxiliary cooler 38, and valve 40 delivers precooled turbocharged air to main cooler 20.

Thus, the turbocharged air is in turn precooled and cooled before being delivered to the intake of the engine.

Referring now to FIGS. 4A and 4B, another embodiment of the present invention similar to the embodiment of FIGS. 1A and 1B is shown.

In this embodiment, the main cooler 20 is installed on the engine 10, in particular in an intake plenum (also referred to as an intake chamber) 42 contained in an intake distributor (not shown). This embodiment repeats the main elements of the embodiment of FIGS. 1A and 1B, with the common elements being denoted by the same reference numerals. On the main air duct 16 is mounted a selector valve (or “upstream valve”) 34, which has two outlets. One of the outlets of the valve 34 is connected to the bypass duct 32 which is directed to the intake 12 of the engine. The other of the outlets of the valve 34 faces the inlet of the main cooler 20.

As in the embodiment of FIGS. 1A and 1B, the control valve 24 is connected to a duct 26 for recycling the exhaust gas.

The plenum 42 is provided with a blocking gate 46 downstream of the main cooler 20 to isolate the volume of air contained upstream of the main cooler 20 and between the cooler 20 and the intake 12. do. This blocking gate 46 corresponds to the downstream valve 36 described in the above embodiment. This gate may for example be of the flap type, so that it is possible to limit its overall size and be controlled by the actuator 45.

In the mode of operation of FIG. 4A, gate 46 is blocked. The turbocharged air is delivered directly to the intake 12 of the engine by the bypass duct 32. The engine is supplied with turbocharged air and recirculated exhaust gas, the toxic speed adjustment of the turbocharged air is performed by the control valve 28, and the flow rate control of the recycled gas is performed by the valve 24.

In the operating mode of FIG. 4B, the gate 46 is open. The valve 34 directs turbocharged air to the main cooler 20 installed in the plenum 42. At the exit from the main cooler 20, the turbocharged air passes through the open gate 46 to reach the intake 12 of the engine in a manner similar to the operating mode of FIG. 1B.

Thus, the intake system of the present invention allows the turbocharged air to pass directly through the main cooler and directly through the secondary cooler or directly to the intake of the engine. The first mode of operation makes it possible to limit the volume of air contained in the exchanger and the air duct and in particular to improve the engine's response time to acceleration.

In various embodiments of the invention, the control element and in particular the selection means are commanded by a suitable control circuit (not shown). These circuits take into account operating parameters of the heat engine, in particular parameters related to injection, engine load and the flow rate of the recycled gas.

The present invention is particularly used for automobile engines such as private vehicles.

Claims (8)

A main air duct 16 connecting the turbocharger to the intake 12 of the heat engine, and a main cooler 20 mounted on the main air duct for cooling the turbocharged air delivered to the intake of the heat engine. In the intake system for a heat engine equipped with a turbocharger, A bypass duct 32 directly connecting the main air duct 16 to the intake portion 12 of the heat engine upstream of the turbocharged air main cooler 20; First choice mounted at the intersection of the main air duct 16 and the bypass duct 32 for delivering turbocharged air to the main cooler 20 or directly to the intake 12 of the heat engine. Means 34 and 40, Second selection means downstream of the main cooler 20 to connect the main cooler 20 to the intake 12 of the heat engine and to isolate the main cooler 20 from other parts of the intake system (36; 46), The main air duct 16 comprises a control valve 24 which serves to regulate the engine exhaust gas recirculation flow rate. Intake system for heat engine with turbocharger. delete The method of claim 1, An auxiliary cooler 38 for turbocharged air is arranged upstream of the turbocharged air main cooler 20 and the bypass duct 32 is connected to the outlet of the auxiliary cooler 38. Intake system for heat engine with turbocharger. The method of claim 1, An auxiliary cooler 38 for turbocharged air is arranged upstream of the turbocharged air main cooler 20 and the bypass duct 32 is connected to an inlet of the auxiliary cooler 38. Intake system for heat engine with turbocharger. The method of claim 1, The first selection means includes an upstream valve 34 disposed on the main air duct 16 upstream of the turbocharged air main cooler 20 to selectively receive turbocharged air from the main cooler 20. Furnace or directly to the intake portion 12 of the heat engine via the bypass duct 32. Intake system for heat engine with turbocharger. The method of claim 1, The main air duct 16 includes a downstream valve 36 disposed downstream of the turbocharged air main cooler 20, the downstream valve which passes the main cooler 20 to the intake 12 of the heat engine. And prevent the turbocharged air from flowing back toward the main cooler 20. Intake system for heat engine with turbocharger. The method of claim 1, The turbocharged air main cooler 20 is installed in the intake plenum 42 included in the intake air distributor. Intake system for heat engine with turbocharger. The method of claim 7, wherein The intake pleats downstream of the turbocharged air main cooler 20 to isolate the volume of air contained upstream of the main cooler 20 and between the cooler 20 and the intake portion 12 of the heat engine. Characterized in that it comprises a blocking gate 46 provided in the overflow 42. Intake system for heat engine with turbocharger.

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