FR3037616A1 - DEVICE FOR CONTROLLING AN AIR QUANTITY INTRODUCED TO THE ADMISSION OF AN INTERNAL COMBUSTION ENGINE WITH AT LEAST TWO SUPERCURRENT STAGE AND METHOD USING SUCH A DEVICE. - Google Patents

Abstract

The present invention relates to a device for controlling the quantity of air introduced at the intake of a supercharged internal combustion engine, said engine comprising two exhaust gas outlets (32, 36) each connected to a collector of exhaust (30, 34) of a group of at least one cylinder (121, 122, 123, 124), said device comprising a supercharging device (38) having at least two stages of high pressure (HP) supercharging and low pressure (BP), the high pressure boost stage comprising at least one double input HP turbine (TW) (46, 48) connected to said exhaust gas outlets by being connected to an HP air compressor (CW) , the low pressure boost stage comprising at least one LP turbine (T) connected to the HP turbine (TW) and connected to a compressor BP (C), and at least one partial transfer duct (64) of the air HP compressed air compressor HP to the HP turbine (TW) inlet. According to the invention, the device further comprises at least one partial transfer duct (102, 103, 104) of the compressed air leaving at least one compressor (CW, C) to the inlet of at least a turbine (TW, T) and in that said at least partial transfer conduit comprises valve means (V) for controlling the flow of the compressed air transferred.

Description

The present invention relates to a device for controlling the amount of air introduced to the intake of a supercharged internal combustion engine, in particular a stationary engine or for a motor vehicle or industrial vehicle, and a method of controlling the amount of air for such an engine.

In particular, the engine is here equipped with several turbochargers. As is widely known, the power delivered by an internal combustion engine is dependent on the amount of air introduced into the combustion chamber of the engine, amount of air which is itself proportional to the density of this air. Thus, it is usual to increase this amount of air by means of compression of the outside air before it is admitted into this combustion chamber. This operation, called supercharging, can be carried out by any means, such as a turbocharger or a driven compressor, which can be centrifugal or volumetric.

In the case of a supercharging by at least one turbocharger, the latter comprises a rotary turbine, single flow or double flow, connected by an axis to a rotary compressor. The exhaust gases from the engine pass through the turbine which is then rotated. This rotation is then transmitted to the compressor which, by its rotation, compresses the outside air before it is introduced into the combustion chamber. As is better described in the French patent application No. 2,478,736, it is provided, in order to significantly increase this amount of compressed air in the engine combustion chamber, to further increase the compression of the engine. outside air by the compressor. This is done more particularly by increasing the speed of rotation of the turbine and therefore of the compressor.

For this, a portion of the compressed air leaving the compressor is diverted to be admitted directly to the inlet of the turbine by mixing with the exhaust gas. This turbine is then traversed by a larger amount of fluid (mixture of compressed air and exhaust gas), which makes it possible to increase the speed of rotation of the turbine and consequently of the compressor. This increase in compressor speed thus makes it possible to increase the pressure of the outside air that will be compressed in this compressor and then introduced into the combustion chamber of the engine.

By this, the compressed air has a higher density which allows to increase the amount of air contained in the combustion chamber. This type of supercharged engine, although satisfactory, nevertheless has significant disadvantages.

Indeed, the flow rate of the compressed air that is admitted to the inlet of the turbine is not properly controlled, which can cause a malfunction of the engine. Thus, by way of example, in the event of too much compressed air being diverted to the inlet of the turbine, the exhaust gases entering the turbine are cooled too much by this air and causes a decrease overall performance of overfeeding. The present invention proposes to overcome the drawbacks mentioned above by means of a device for controlling the quantity of air introduced at the intake of a supercharged internal combustion engine which makes it possible to meet all the power demands of the engine. engine. In addition, the present invention relates to an internal combustion engine whose supercharging system comprises at least two turbochargers.

The invention presented here also makes it possible to transfer the compressed air from the intake to the exhaust even when the mean pressure of the compressed air at the intake is lower than that of the exhaust gases. It suffices only that there are phases during the operating cycle of the engine where the intake pressure is greater than that existing at the exhaust. For this purpose, the present invention relates to a device for controlling the quantity of air introduced at the intake of a supercharged internal combustion engine, said engine comprising two exhaust gas outlets each connected to a collector of exhaust of a group of at least one cylinder, said device comprising a supercharging device comprising at least two HP high pressure and low pressure BP booster stages, the high pressure booster stage comprising at least one HP double inlet turbine connected to said exhaust gas outlets by being connected to an air compressor HP, the low pressure booster stage comprising at least one LP turbine connected to the HP turbine and connected to a compressor BP, and at least one duct partial transfer of the compressed air HP from the air compressor HP to the inlet of the HP turbine, characterized in that it further comprises at least one conduit 15 trans partially filling the compressed air at the outlet of at least one compressor to at least one inlet of at least one turbine and in that the at least one partial transfer conduit comprises means for controlling the circulation of the compressed air transferred.

Said at least one partial transfer line may comprise a check valve. The device may comprise at least one partial transfer duct at the outlet of the HP compressor to the inlet of the LP turbine.

The device may comprise at least one partial transfer duct at the outlet of the LP compressor to the two inputs of the HP turbine. The device may comprise at least one partial transfer duct at the outlet of the compressor BP towards the inlet of the LP turbine. The valve means may comprise proportional valves.

The device may comprise means for controlling the proportional valves. The invention also relates to a method for controlling the amount of compressed air at the intake of a supercharged internal combustion engine, said engine comprising two exhaust gas outlets each connected to an exhaust manifold of a group of at least one cylinder, said device comprising a supercharging device comprising at least two HP high pressure and low pressure LP booster stages, the HP high pressure booster stage comprising at least one connected HP dual inlet turbine said exhaust gas outlets being linked to an air compressor HP, the low pressure boost stage BP comprising at least one LP turbine connected to the HP turbine and connected to a compressor BP, and at least one partial transfer of compressed air HP from the compressor to the inlet of the HP turbine, characterized in that it consists in further introducing compressed air at the outlet of a at least one compressor to at least one inlet of a turbine by a partial transfer conduit. The method may include introducing compressed air at the outlet of the HP compressor to the inlet of the LP turbine through a partial transfer conduit. The method may include introducing compressed air at the outlet of the compressor BP to the inlet of the HP turbine by a partial transfer conduit (103).

The method may include introducing compressed air at the outlet of the LP compressor to the inlet of the LP turbine through a partial transfer line (104).

The other features and advantages of the invention will become apparent on reading the description which will follow, given solely by way of illustration and without limitation, and to which are appended: FIG. 1 which shows an internal combustion engine equipped with a turbocharger supercharger to illustrate a schematic representation of the principle of a partial recycle loop of the compressed air upstream of the turbine, in particular of the "twin scroll" type, and FIG. 2 illustrates the present invention by describing, in the case of an internal combustion engine with a double stage supercharger, the various configurations of compressed air transfer ducts, according to the invention. In Figure 1, the internal combustion engine 10 comprises at least two cylinders, here four cylinders referenced 121 to 124 from the left of the figure.

Preferably, this engine is a direct injection internal combustion engine, especially diesel type, but this does not in any way discard any other type of internal combustion engine. Each cylinder comprises intake means 14 with at least one intake valve 16, here two intake valves each controlling an intake manifold 18. The intake manifolds 18 result in an intake manifold 20 supplied with fuel. by a supply duct 22 for intake air, such as compressed air.

This cylinder also comprises exhaust gas exhaust means 24 with at least one exhaust valve 26, here also two valves each controlling an exhaust manifold 28. In the example illustrated, the engine is designed to operate in accordance with a order of burning referred to as 1-3-4-2. Given this order of combustion, the exhaust pipes of the cylinder 121 and the cylinder 124, which form a first group of at least one cylinder, are connected to a first exhaust manifold 30 with a first gas outlet. The exhaust pipes of the cylinder 122 and the cylinder 123, which form a second group of at least one cylinder, are connected to a second exhaust manifold 34 which has a second exhaust gas outlet. 36.

303 7 6 1 6 6 The two exhaust gas outlets result in a turbocharger 38 for the compression of air and more particularly to the expansion turbine 40 of this turbocharger. As illustrated in FIG. 1, the turbocharger is a double-inlet turbocharger, better known as a "Twin Scroll" turbocharger. This type of turbocharger comprises the expansion turbine 40 which is swept by the exhaust gases and which is connected in rotation by a shaft 42 with a compressor 44.

At the turbine, the exhaust gas inlet is divided into two sections, a first inlet section 46 connected to the first exhaust gas outlet 32 of the first manifold 30 and a second inlet section. 48 The exhaust gas outlet 50 of the turbine 40 is connected conventionally to the exhaust line 52 of the engine.

The compressor 44 of the turbocharger 38 has an external air intake 54 supplied by a supply line 56. The compressed air outlet 58 of this compressor is connected to the feed duct 22 of the intake manifold 20 by means of a driving 60.

Advantageously, it can be provided to place a radiator for cooling the compressed air 62 on the pipe 60, between the compressor and the pipe 22. As best seen in FIG. 1, a transfer pipe 64 makes it possible to circulate a part of the compressed air leaving the compressor 44 to the inputs 46 30 and 48 of the turbine. According to FIG. 1, the partial transfer duct originates on the duct 60, at a point of intersection 66 between the compressor and the cooling radiator 62, and then separates, from a junction point 68, in two branches 70 and 72. The branch 70 leads to the inlet 46 of the turbine by its junction with the first exhaust outlet 32 and the branch 72 leads to the other inlet 48 of this turbine by its In each branch, there are valve means 74 and 76, such as a proportional valve, controlled by a control means 78, which can be common to both valve means. This valve thus makes it possible to control the circulation of the compressed air circulating in the branch. Advantageously, each branch also comprises a non-return valve 80 and 82 which prevents the flow of compressed air from the branch to the compressor while preventing the communication of the two branches. This configuration thus makes it possible, during operation of the engine, to take advantage of the zones of low exhaust pressure occurring occasionally in the exhaust manifolds to introduce compressed air into the turbine and thus to increase the flow rate of this turbine and consequently the compressor. This also allows for more efficient boosting for low revs. During operation, if there is a need for a large quantity of air in the cylinders, the valves 74 and 76 are controlled in opening to introduce compressed air from the compressor 44 into the turbine 40. The compressed air leaving the The compressor 44 circulates in the duct 64 and then in the branches 70 and 72 to reach the exhaust gas inlets 46 and 48 of the turbine 40 by bringing a surplus of fluid to the turbine. Thus, the turbine is traversed not only by the exhaust gas from the outlets 32 and 36, but also by compressed air which is added to these gases. As a result, the rotation of the turbine is increased, which causes an increase in the rotation of the compressor and, consequently, an increase in the pressure of the compressed air coming out of this compressor.

Of course, the valves 74 and 76 are controlled by the control means 78 so as to admit the amount of compressed air in the turbine that meets the engine's supercharging requirements.

FIG. 2 illustrates, according to the invention, a double supercharged internal combustion engine having a high pressure booster stage (HP) and a low pressure booster stage (LP). The supercharging stage HP comprises a compression stage CW HP driven by a turbine TW twin inlet or turbine "twin scroll" and the supercharging stage BP comprises a compression stage C BP driven by a turbine T BP. This booster stage BP is constituted, as conventionally, by a turbine T driven by the gases at the outlet of the turbine TW HP brought by a pipe 100 whereas the compressor C BP driven by the turbine T BP supplies compressed air to the compressor CW HP via a conduit 101. As already described in Figure 1, a partial transfer line 64 of compressed air HP is in communication with the two inputs 46 and 48 of the turbine TW of the HP supercharging stage.

In addition to the partial transfer duct 64 of compressed air HP to the turbine TW of the supercharging stage HP, the partial transfer of compressed air can also be achieved with: a partial transfer duct 102 to bring a portion of compressed air 25 HP upstream of the turbine T BP and / or - a partial transfer duct 103 of compressed air BP to direct a portion of compressed air BP to the two inlets 46 and 48 of the turbine TW HP and / or another conduit 104 for partial transfer of compressed air BP for directing a compressed air portion BP at the inlet of the turbine T BP. Of course, these configurations may be combined, partially or totally, with each other, for example one of the combinations may be the duct 64 which is in communication with the two inputs 46 and 48 of the turbine TW HP and the duct 104. which is connected to the turbine T BP. As described for the partial transfer duct 64, all the other partial compressed air transfer ducts comprise non-return means and means for controlling the flow rate of the transferred compressed air, such as valves. Proportional V and Ca check valves. Thus, depending on the operating conditions of the engine, including low load and / or low speed, the various partial transfer paths can optimize while controlling the boost level. In general, the present invention may be suitable for a supercharging system comprising more than two supercharging stages.

In this case, at the outlet (downstream) of each compressor, several partial compressed air transfer ducts communicate with the inlet (upstream) of each of the turbines. More precisely, according to FIG. 2 illustrating a two-stage supercharging, downstream of the compressor CW, two ducts 64 and 102 lead at the inlet (upstream) respectively of the turbine TW and of the turbine T. Also, downstream of the compressor C two ducts 103 and 104 lead at the inlet (upstream) respectively of the turbine TW and the turbine T. By generalizing, in the case of n stages of supercharging (with n greater than or equal to three), n ducts can be provided partial transfer downstream of each of the compressors to drive upstream (inlet) of each of the turbines.

Claims (11)

CLAIMS1) Device for controlling the amount of air introduced into the intake of a supercharged internal combustion engine, said engine comprising two exhaust gas outlets (32, 36) each connected to an exhaust manifold (30). , 34) of a group of at least one cylinder (121, 122, 123, 124), said device comprising a supercharging device (38) having at least two stages of high pressure (HP) supercharging and low pressure (BP) ), the high pressure boost stage comprising at least one double input HP turbine (TW) (46, 48) connected to said exhaust gas outlets by being connected to an air compressor (CW) HP, the low-pressure supercharging stage comprising at least one LP turbine (T) connected to the HP turbine (TW) and connected to an LP compressor (C), and at least one partial transfer duct (64) of the compressed air HP of HP air compressor to the inputs of the HP turbine (TW), characterized in that it further comprises at least one partial transfer duct (102, 103, 104) of compressed air leaving at least one compressor (CW, C) to at least one inlet of at least one turbine ( TW, T) and in that said at least partial transfer conduit comprises valve means (V) for controlling the flow of the compressed air transferred. 2) Device according to claim 1, characterized in that said at least one partial transfer conduit comprises a non-return valve (80, 82, Ca). 3) Device according to claim 1 or 2, characterized in that it comprises at least one partial transfer duct (102) at the output of the compressor HP (CW) to the inlet of the LP turbine (T). 4) Device according to one of the preceding claims, characterized in that it comprises at least one partial transfer duct (103) at the output of the compressor BP (C) to the two inputs of the HP turbine (TW). 5) Device according to one of the preceding claims, characterized in that it comprises at least one partial transfer duct (104) at the outlet of the compressor BP (C) to the inlet of the LP turbine (T). 303 7 6 1 6 11 6) Device according to one of the preceding claims, characterized in that the valve means comprise proportional valves (74, 76, V). 5 7) Device according to claim 6, characterized in that it comprises means for controlling the proportional valves. 8) A method of controlling the amount of compressed air at the intake of a supercharged internal combustion engine, said engine comprising two exhaust gas outlets (32, 36) each connected to an exhaust manifold ( 30, 34) of a group of at least one cylinder (121, 122, 123, 124), said device comprising a supercharging device (38) having at least two stages of high pressure (HP) supercharging and low pressure ( BP), the high pressure booster stage (HP) comprising at least one twin inlet turbine (TW) (46, 48) connected to said exhaust gas outlets by being connected to a compressor (CW) of HP air, the low pressure boost stage (BP) comprising at least one LP turbine (T) connected to the HP turbine and connected to a compressor BP (C), and at least one partial transfer duct (64) of the HP compressed air compressor to the inputs of the HP turbine (TW), characterized in that it consis to further introduce compressed air at the outlet of at least one compressor to at least one inlet of a turbine through a partial transfer conduit (102, 103, 104). 9) Process according to claim 8, characterized in that it consists in introducing 25 compressed air at the outlet of the HP compressor (CW) to the inlet of the LP turbine (T) by a partial transfer duct (102). ). 10) A method according to claim 8 or 9, characterized in that it consists in introducing compressed air at the outlet of the compressor BP (C) to the inlet of the HP turbine (T) by a partial transfer duct ( 103). 11) Method according to one of claims 8 or 10, characterized in that it consists in introducing compressed air output of the compressor BP (C) to the inlet of the LP turbine (T) by a conduit of partial transfer (104).