DK168170B1 - Combustion engine with register pressure charge - Google Patents

Abstract

In this combustion engine with two-stage register supercharging, excess exhaust gas from an exhaust collector (2) in the engine (1) is utilised in a turbine (7) which can transmit its output to the output shaft (9) of the engine (1) via a clutch (8). One of the two exhaust turbochargers (3; 4; 28) is also fed at either full or restricted rate from the exhaust gas collector (2) depending on the partial load range. By switching the turbine (7) of the turbochargers (3; 4; 28) off or on, opening or closing a discharge duct (19) on the exhaust gas collector (2) and an overflow duct (17) between the charging air collector (16) and the exhaust gas collector (2) and by combinations of these measures the motor output can be adjusted to the particular requirements in a wider partial load range. <IMAGE>

Description

in DK 168170 B1

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion engine having a register pressure charge with a first exhaust gas turbocharger and a second exhaust gas turbocharger, the charging turbines of which are connected in parallel to an exhaust gas receiving vessel for the internal combustion engine adeluftoptagelsesbeholder.

Combustion engines with exhaust gas turbocharger in its simplest form, i.e. with a single one- or two-stage turbocharger, the operating characteristics of the turbine and compressor have physically determined operational deficiencies, namely to a relatively narrow range, limited performance and efficiency satisfactory operating characteristics and in conjunction therewith a fuel consumption which, seen over the full and 15 part! the asthma area, does not meet the current stringent requirements for economical engine operation.

The former deficiency can be satisfactorily remedied by the use of a register pressure charge according to known systems with at least two exhaust gas turbochargers or 20 exhaust gas turbocharger groups, which is to be understood as two-stage chargers. that too high fuel consumption, so far has not been optimally possible.

25 In order to reduce fuel consumption by a register pressure charge, it is proposed to use a portion of the engine exhaust gases to operate a utility turbine that can be coupled to the engine crankshaft or in the case of a geared motor can be coupled to the gearbox's shaft. Thus, as seen over the entire load range, a · 30 reduction in fuel consumption is achieved, since the extra exhaust gas flow that the main pressure charger turbine receives when the utility turbine is disconnected, extends the favorable operating range but fails to cover it practically important area where fuel consumption at part load cannot in all cases be reduced 35 near the best possible values.

From FR-U-2418864 there is known a register pressure charge with a first and a second exhaust gas turbocharger, whose charging turbines are connected in parallel to an exhaust gas recorder on the internal combustion engine to be charged, and whose compressors with their load air outlet parallel to a charging air collector, connects these charging air connectors to the engine's 1 noble air receiver. In the exhaust turbine exhaust gas line, a shut-off valve is mounted between the exhaust gas receiver and the second exhaust gas turbine charger turbine and in the charging air outlet between the other exhaust gas turbocharger and the 1 air intake manifold.

The combination of a utility turbine with an internal combustion engine with 10 exhaust gas turbines to improve the overall efficiency of the engine system is known, for example. from EP-A-0 091 139 and EP-A1-0199165. The former publication discloses an internal combustion engine with an exhaust gas turbocharger and a utility turbine which, directly or indirectly over a gear, is in communication with the engine and is either connected to the exhaust gas receptacle in parallel with the exhaust gas turbocharger or, as seen in the exhaust gas turbine series, in the flow direction of the exhaust gas turbine. . To obtain satisfactory partial load characteristics, the turbine area of the charging turbine, which means its exhaust gas cross-section, is dimensioned 20 according to the relevant important partial load range. By this, the utility turbine is stopped, whereby the charging turbine receives the entire exhaust gas flow and, as a result of the above-mentioned reduced load turbine area, provides the high charge pressure desired for the part load area. By the parallel coupling of the charging turbine 25 and the utility turbine, the exhaust gas supply to it is blocked and the exhaust gas flow is conducted in front of it in the event of a failure through an outlet from the exhaust gas line. Thus, in both cases, the charging turbine receives the full exhaust gas flow in the part load area.

30

Said second printing EP-A1-0 199 165 describes a ship engine plant with a pressurized diesel engine, whose charging turbine is also sized for maximum absorption capacity in a part load area and e.g. has an exhaust gas inflow cross section of 80% of a 35 to full load dimensioned cross section. The excess exhaust gas part current is fed directly from the exhaust gas acquisition tank to a utility turbine which, as a power generator, can be connected to and from the free end of an auxiliary diesel engine or a generator unit, and whose working performance relieves the auxiliary diesel engine and reduces fuel consumption.

DK 168170 B1 3

To achieve high charge pressures during Part 1 load operation, the exhaust gas flow to the utility turbine can be switched off and the utility turbine is disconnected from the power generator and shut down. The charging turbine then receives the full exhaust gas flow, whereby, because of its sub-dimensioning to the full-load dimensioning, it works with good efficiency, and the compressor delivers the high partial load efficiency required for the main diesel engine necessary charge.

10 If for some reason the utility turbine has nothing to do with the part 1 operation is to be stopped, its exhaust gas supply is blocked and the excess exhaust gas is passed over an exhaust pipe into the exhaust gas flow after the charging turbine. Thus, even in such a case, the charging turbine receives only a maximum of 15 the exhaust gas flow for which it is dimensioned.

At the two aforementioned plants, a sub-dimensioned charging turbine, which is sub-dimensioned to the full-load exhaust gas stream, achieves better part load characteristics than with a full-load dimensioned turbine with 20 non-adjustable inflow cross sections. The excess gas flow is processed in a utility turbine and increases the overall efficiency of the plant.

The improvement in the part load characteristics achieved in this way is significant, but to reduce the environmental impact caused by exhaust gases it is of course desirable to further expand the area for a favorable load operation and thereby obtain an extra reduction of fuel consumption. The object of the invention is to provide an internal combustion engine with these improved properties.

This is achieved according to the invention by an internal combustion engine with a register pressure charge of the aforementioned kind, which is characterized by the characteristic part of claim 1. Various coupling options for the register charging utility turbine and for the register pressure charging charging turbine for the engine exhaust gas take-off tank provide a good approximation of the engine's performance characteristics to its optimum performance over a wide range.

DK 168170 B1 4

The invention is explained in more detail below with reference to one. The embodiment illustrated in the drawing is illustrated. In the drawing:

FIG. 1 is a schematic view of a first embodiment of a motor according to the invention with its essential structural parts; FIG. 2 shows another embodiment, and FIG. 3 characteristics of the engine at different couplings of the utility turbine and the charging turbine.

In FIG. 1 is a six-cylinder internal combustion engine designated by 1. The engine exhaust gases are collected in an exhaust gas take-up container 2, 15 from which, depending on the instantaneous operation of the engine, they can be fed to one or more charging turbines 5 and 6, respectively, of two exhaust gas turbines. chargers 3 and 4 and / or to a utility turbine 7. This can be connected or separated from a power transmission shaft 9 via a coupling 8. In the present case, the PTO shaft is the crankshaft of the motor. The compressors 10 and 11 of the two turbochargers 3 and 4, respectively, deliver over their charge air connectors 12 and 13 and a common charge air conduit 14 charge air to a charge air cooler 15 and thence to a charge air collection vessel 16 at the engine suction side.

An overflow conduit 17 with an overflow damper 18 connects the charge air collection vessel 16 with the exhaust gas take-up container 2. An exhaust duct 19 with an exhaust damper 20 leads from the exhaust gas collection container 2 to the surroundings. In a first utility turbine exhaust gas line 21 between the exhaust gas receiving container 2 and the utility turbine 7, a shut-off damper 22 is arranged and two additional shut-off valves 24 and 25 are in the charge turbine exhaust. the gas conduit 23, respectively, between the charge air connectors 13 of the compressor 11 of the charger 4 and the 1 air conduit conduit 14.

A further second utility turbine exhaust gas line 26 with a shut-off valve 27 between the exhaust gas acquisition tank 2 and the input side of the utility turbine 7 suggests that this sector, preferably over two sectors, is supplied with exhaust gas. The input side may also have three or more sectors, which can preferably be blocked by means of DK168170 B1 5 shut-off dampers, which allows a finer stage division of the exhaust gas supply to the utility turbine. Instead of two one-stage exhaust gas turbochargers 3 and 4, one or both may also be two-stage or multi-stage turbocharger groups, which in connection with 5 suitably arranged dampers also allows for a finer adjustment of the charge air control according to the instantaneous engine load. The same also applies to known designs of turbochargers with variable · turbine geometry, e.g. for such as in the inlet coil has a displaceable plate or piston shaped wall element which at a reduced exhaust gas flow decreases its cross section and thus increases its speed or for those having more gas channels which can be opened and closed and by means of which a weaker exhaust gas flow can also be formed into a concentric jet efficient for the drive.

15

By means of various positions of the dampers described, and, if present, of the elements for changing the absorption capacity of the charging turbine, the charging pressure in a wide range can be adjusted to the immediate needs of the engine. Charging turbines with non-adjustable inlet cross section for the exhaust gas are sized to a part load area, in which the exhaust gas flow produces a sufficiently powerful driving impulse for the charging turbine to supply the required charging air. If the exhaust gas flow is not sufficient for both turbines 5 and 6, one, namely the turbine 6, can be stopped by closing the valves 24 and 25, thereby preventing the latter from delivering charge air supplied by the compressor 10 into the compressor 11 Using two-stage turbocharger groups, the same option exists to feed the currently available exhaust gas stream to the turbine group whose absorptive capacity provides the best charge air charge.

Another possibility of providing the charge air flow required for a particular part load area is to completely or partially block the exhaust gas flow to the utility turbine by means of the shut-off valves 22 35 and 27. The utility turbine is then completely disconnected from the engine 1. Further possibilities for adjusting the flows and the pressures of the exhaust gas and the charge air according to the common part 1 load condition are obtained by means of the exhaust and overflow device respectively.

6 DK 168170.B1

If the maximum permissible cylinder pressure is exceeded, the excess exhaust gas from the exhaust gas container 1 is discharged from the exhaust duct tank 1, under control, by means of a servo device not shown when opening the exhaust damper 20. The overflow channel 17 with the overflow damper 18 serves to prevent pumping of the compressors 10 and 11. If pumping occurs, the damper 18 is opened and the absorbent capacity of the charging device is increased.

10

A variant of the exhaust gas and charge air flow control shown by the turbocharger 4 is shown in FIG. 2. At this exhaust gas turbocharger 28, in the charge turbine exhaust gas line 31 leading to the charging turbine 29 and in the charging air-15 studs 32 of the charging turbine 32, each of the shut-off valves 33 and 34, respectively, is provided by which the turbine 29 can be driven. or shut down and compressor 30 can be shut down. If the turbine and compressor are stopped, this corresponds to that of FIG. 1, when turbine 29 is swirled by partially closing the shut-off damper 33 located in front of this 20, turbine 29 utilizes only a portion of the exhaust gas flow during which compressor 30 is short-circuited at idle without transporting charge air into 1 noble air conduit 14. This will then, by closed shut-off damper 34 and open overflow damper 35, which connect its pressure side with its suction side, circulate the air at idle. During normal charging operation, the dampers 33 and 34 are open in front of the turbine and after the compressor respectively, and the overflow damper 36 is closed.

This coupling can serve as a replacement for the exhaust device 19 30 and 20 or together with this further contribute to a pressure relief.

Depending on the purpose of use of the engine, the described disconnection or connection possibilities of the system are used for one or the other part of the required part load characteristic. The FIG. 3 illustrates, for example, for some part loads states of a ship diesel engine the dependence of the average effective pressure on the cylinders on the speed of rotation. The curves show the progress of the required engine performance when operating on different propeller curves. From point A

7 DK 168170 B1 for maximum performance, both turbochargers and utility turbine are kept in operation until point B and in area B-C the utility turbine is then fully or partially switched off, so that the two turbochargers operate at point C at the latest. Along the dashed line dot 5 with less fuel, you will continue from point D to point E with two turbochargers and, with variable absorption capacity turbines in the lower area, possibly run with narrow turbine inlet and along the left with fully drawn line shown and in the present case, practically usable curves from F to G and H 10 continue to run with only one turbocharger and possibly in the last section with reduced turbine inlet cross section. In the range from F to G, the pressure in the exhaust gas take-up container 2 for reducing the maximum cylinder pressure can be reduced over the exhaust duct 19 and the open exhaust valves 20, or for the same purpose 15 can be blown outside the other turbocharger 28's compressor 30 by throttle turbine 29.

The changes in the exhaust gas and charge pressure, rotational speed, and fuel supply sizes to be regulated are sensed by sensors of known design that trigger the regulating movements of the adjusting means for the turbines, compressors, and blow-outs of the turbines. and the overflow devices and for regulating the fuel supply. As control means, hydraulic, pneumatic, electrical and electrohydraulic, electropneumatic and electromechanical means such as diaphragm boxes, solenoid valves, hydraulic cylinders and the like can be used in known manner.

30 35

Claims (3)

1. A register pressure charge internal combustion engine having a first exhaust gas turbocharger (3) and a second exhaust gas turbocharger (4; 28), whose charging turbines (5; 6; 29) are connected in parallel to an exhaust gas take-up vessel (2) for the internal combustion engine (1), and whose compressors (10; 11; 30) with their charge air socket (12; 13; 32) open parallel to a charge air conduit (14) connecting these charge air sockets · 10 (12; 13; 32) to the engine (1) 1 noble air intake container. (16), characterized in that a utility turbine (7) can be coupled to this power transmission shaft (9) and parallel to said charging turbines (5; 6; 29). ) over a conduit (21 and 22; 26 and 27) that can be blocked is connected to the exhaust gas reservoir (2) that in the charging turbine exhaust gas line (23; 31) between the exhaust gas reservoir (2) and the second exhaust gas turbocharger (4; 28) charging turbine (6; 29) as well as in the charging air outlet (13; 32) The compressor (11; 30) of the second exhaust gas turbocharger (4; 28) and the charge air collector 20 (14) are arranged separately on each of the shut-off valves (24; 33 and 25; 34, respectively), and the inlet housing of the utility turbine (7) is divided into two sections independently of one another over each utility turbine exhaust gas line (21; 26) are connected to the exhaust gas acquisition tank (2) and each has a shut-off valve (22; 27). 25 Combustion engine according to claim 1, characterized in that at the second exhaust gas turbocharger (28), the pressure side of the compressor (30) communicates with the suction side of the compressor by means of an overflow line (35) in which is arranged an overflow damper (36). ). Combustion engine according to claim 1, characterized in that the exhaust gas receiving container (2) has an exhaust duct (19) with an exhaust damper (20) and that the charging air receiving container (16) 35 communicates with the exhaust gas receiving container (20) by means of an overflow (17). ) with an overflow damper (18).