DE102006011422A1 - Supercharged internal combustion engine for motor vehicle has exhaust gas system connected to induction system by connecting line - Google Patents

Abstract

The engine has an exhaust gas system (4) and an induction system (6), which are connected by a connecting line (100), so that exhaust gas from the exhaust gas system can flow into the induction system. A branch of the connecting line upstream of the turbine (3) and an input of the connecting line itself are in a blade region of the compressor (2).

Description

The The invention relates to an internal combustion engine with an exhaust gas turbocharger according to the preamble of claim 1.

since At the beginning of the year 2000, the topic "speed-steady turbocharging" will be pursued.

• • ATL-Verdichter in Turbinenbetriebsweise: DE 199 55 508 A1
• • Ölfreier Turbolader, Luftlagerung: DE 100 11 419 A1 ,
• • Ölfreier Turbolader, Magnetlagerung: DE 100 05 64 A1 ,
• • Axial-Radial-Beaufschlagung Verdichterrad: DE 100 49 198 A1 ,
• • Variabler Abgasturbolader: DE 102 13 897 ,
• • Abgasturbolader drehzahlstationäres Turboaufladen: DE 102 21 014 A1 ,
• • variable Verdichtergeometrie, Verdichter als Kaltluftturbine: DE 102 33 042 A1 ,
• • Drehzahlstationäres Aufladen mit Abgasrückführung: DE 102 44 535 A1 ,
• • Zweistromaggregat mit Hilfskompressor: DE 102 44 356 A1 ,
• • Zweistrom-Maschine mit integrierter Drosseleinrichtung: DE 102 52 767 A1 .

In the meantime, several patent applications have been made in this connection, which are summarized below.

• • ATL compressor in turbine mode: DE 199 55 508 A1
• • Oil-free turbocharger, air bearing: DE 100 11 419 A1 .
• • Oil-free turbocharger, magnetic bearing: DE 100 05 64 A1 .
• • Axial-Radial impingement of compressor wheel: DE 100 49 198 A1 .
• • Variable turbocharger: DE 102 13 897 .
• • Turbocharger, turbocharger DE 102 21 014 A1 .
• • variable compressor geometry, compressor as cold air turbine: DE 102 33 042 A1 .
• • Speed-stationary charging with exhaust gas recirculation: DE 102 44 535 A1 .
• • Dual-flow unit with auxiliary compressor: DE 102 44 356 A1 .
• • Dual-flow machine with integrated throttle device: DE 102 52 767 A1 ,

Problem:

Around To achieve the goal of a nearly "turbocharger-speed stationary turbocharging", must the power balance on the rotor of the exhaust gas turbocharger through the Influencing the turbomachinery be satisfied that the speed fluctuations on the high speed level in the desired Can run limits. In the low-exergy engine map area of the turbocharger turbine (Hot gas turbine), as it usually does in the naturally aspirated engine map area of the engine shows a significant proportion of turbine power from the cold air turbine on the air side and possibly an additional auxiliary drive (eg Low-power electric motor) are provided for the storage losses compensated at the desired high exhaust gas turbocharger speed level become.

The power balance in the uncharged engine operating range is: P Cold air turbine + P Hot gas turbine (if necessary + P auxiliary power unit ) = P Bearing power loss

A fundamental problem exists in the low load range and the aspired high exhaust gas turbocharger speeds, a larger amount of power from the hot turbine 3 (please refer 1 ) to get. The hot gas turbine runs in this operating range at high exhaust gas turbocharger speeds usually with very low efficiencies or even in the complete ventilation range with a non-negligible power consumption.

Solutions:

To get a significant increase in output by the cold air turbine, it is proposed from the exhaust side 4 a feedback line 100 to the air side 6 in the area of the compressor 2 or the cold air turbine (s. 1 ).

This Suggested solution is for Diesel, but especially for Otto engines for drastically improving the transient engine behavior very easy and advantageous to implement.

at Gasoline engines arise in the partial load area up to the idling point pressure conditions from the environment to the suction pipe over 3 to a maximum of 5, whereby the desired strong increase in the Cold air turbine power is accomplished and the high Can set exhaust gas turbocharger speeds at low load.

In addition to the base pressure ratio for fixed geometry turbines, the feedback pressure ratio π _back from the exhaust side can be found in the Vario turbines, which are now widely used in the supercharged passenger car diesel engines 4 towards the air side 6 by closing the Vario guide screen 9 be increased again.

The inventive feedback of the exhaust side with the air side allows hereby, the pumping action of the engine 1 for relieving the compressor by high Mitdrall- intensities of the compressor inflow or even to increase the cold air turbine power to use.

In the small turbocharger turbines with wastegate 150 is the regulation of the feedback pressure _ratio π _{back influenced} by the wastegate control (s. 2 ). The evolved form, the turbocharger turbine with Vario-turbines are a very sensitive device for adjusting the desired feedback pressure ratios π _back or to Mitregelung the cold air turbine power.

is the compressor in its normal operation, so not in the range of Kaltluftturbinenbetriebsweise, so the Mitdrallintensität by the recycle stream from the exhaust side to the air side through the cross section adjustment the hot ones Vario turbine over the feedback according to the invention authoritative influenced with. In the concrete supply of the exhaust gas in the outer inlet region the compressor wheel in mitdrallrichtung can also be the surge limit to smaller throughputs shift, causing higher stationary Engine torques can be realized.

wobei

c_p

der Wärmekapazität des Abgases,

T_(tot)

der Totaltemperatur des Abgases,

κ

dem Isentropenexponenten des Abgases und

π_(tot,s)rück

dem Rückkopplungsdruckverhältnis total, statisch entsprechen.

All concrete devices with the flow feedback from the exhaust side to the air side have the following in common:
The feedback pressure _ratio π _back is converted with a certain efficiency η in flow velocity c _u , according to the equation

in which

c _p

the heat capacity of the exhaust gas,

T _(dead)

the total temperature of the exhaust gas,

κ

the isentropic exponent of the exhaust gas and

π _{(dead, s) back}

totally correspond to the feedback pressure ratio statically.

The achieved flow velocity c _u is then largely directed in a circumferential direction of the compressor wheel. According to the Euler turbine equation, this peripheral speed is converted into a discharge of the compressor or in cold air turbine operation into an increase of the turbine power of the cold side.

The 3 shows the supply of Rückführabgasgas via the line 100 , The administration 100 flows into another line 5 leading to an annular collecting space 106 leads. The collection room 106 has nozzles 108 on, which aligned in the circumferential direction, above the compressor wheel 7 are arranged. The recirculation mass flow flows out of the nozzle orifice at the speed c _u 108 and hits the wheel blading of the compressor wheel 7 on. In order to make the feedback pressure _ratio π _return effective, the valve becomes 107 (S. 1 ) open.

To the over the further line 5 supplied exhaust gas mass flows in this example adapted combustion air through the known device 9 . 12 the twin-stream machine. The blade height of the Leitgitters 190 is opened according to the air requirement, in this example, a very low load and engine speed, in this case a gasoline engine, is indicated. The adjusting device 9 . 180 . 190 assumes the function of a throttle valve in the two-stream machine.

The 2 . 4 and 5 show the main features of a device in which the feedback pressure ratio π _back in a nozzle is translated into velocity in the vane ring 190 is represented by hollow blades (s. 5 ). The narrowest cross-section 200 for the air is the narrowest cross-section 201 upstream of the exhaust gas. A mixture of exhaust gas and air takes place at the Radeinströmung or in the Radkanal of the compressor.

The 4 shows the twin-stream machine with the feed port for the channel 100 and the annular plenum 106 , From the annular collecting space, the exhaust gas is in the hollow blades 190 directed where it leaves the moving matrix 180 uncovered nozzle area 201 will flow into the Verdichterradbereich. Like from the 2 to see, with this proposed solution no additional valve is needed. The obstruction for the air and the exhaust duct is with the axially displaceable die 180 carried out simultaneously.

There at the future Engines almost all engines with exhaust gas recirculation systems for NOx reduction equipped, is the simultaneously introduced to the air side Partial exhaust gas flow in the part load area not undesirable.

Because in principle the matrix 180 and the plunger 9 can be independently adjustable for the axial inlet, the required modes of operation for the transient and steady-state behavior of the engine, even in the high load ranges are in most cases good to satisfy.

Claims (1)

Internal combustion engine with an exhaust gas turbocharger, with an intake system ( 6 ) and an exhaust system ( 4 ), with charge air sucked in for compression ( 2 ) of the exhaust gas turbocharger in the intake system ( 6 ) and for expansion of exhaust gas of the internal combustion engine, a turbine ( 3 ) of the exhaust gas turbocharger in the exhaust system ( 4 ) are arranged, wherein the compressor ( 2 ) is operable in such a way in a cold air turbine operation that sucked charge air in the compressor ( 2 ), characterized in that the exhaust system ( 4 ) with the intake system ( 6 ) via a connecting line ( 100 ), so that exhaust from the exhaust system ( 4 ) into the intake system ( 6 ), wherein a branch of the connecting line ( 100 ) upstream of the turbine ( 3 ) and an opening of the connecting line ( 100 ) in a blade area of the compressor ( 2 ) are arranged.