Two-stage supercharging device

Abstract

The invention relates to a two-stage supercharging device (1) for an internal combustion engine comprising a high-pressure turbine (2) and a low-pressure turbine (4), wherein the high-pressure turbine (2) is formed as a radial turbine with a spiral housing (6) and the low-pressure turbine (4) is formed as an axial turbine. The spiral housing (6) has an exhaust-gas inlet connecting piece (9) which is connected to an exhaust line (10) and via which an exhaust-gas flow flows from the internal combustion engine to the high-pressure turbine (2). A partial flow of the exhaust-gas flow can flow past the high-pressure turbine (2) in a bypass unit (13) and can be adjusted by means of a shut-off valve (22). The bypass unit (13) comprises a branch line (15) and an annular duct housing (17) which are both integrally formed on the spiral housing (6) such that they together form a single-piece component. The branch line (15) branches off from the exhaust-gas inlet connecting piece (9) at a branching point (14) and issues into an annular duct (18) formed by the annular duct housing (17). The shut-off valve (22) is arranged, in the form of a flap (23) which adjusts the partial exhaust-gas flow, at the branching point (14). Said partial exhaust-gas flow flows through the branch line (15) into the annular duct (18) and from there through an axially arranged annular gap (19) into an exhaust-gas duct (20). There, the partial exhaust-gas flow merges with a main exhaust-gas flow emerging from the high-pressure turbine (2), in order to flow together therewith into the low-pressure turbine (4).

Description

technical field [0001] The invention relates to a two-stage supercharging device with a high-pressure turbine and a low-pressure turbine for an internal combustion engine according to the preamble of claim 1 . Background technique [0002] Modern internal combustion engines are usually equipped with a two-stage supercharging device. The first stage of the supercharging device is a high pressure stage, and the second stage is a low pressure stage. Here, the high-pressure stage includes a high-pressure turbine and a high-pressure compressor. The low pressure stage includes a low pressure turbine and a low pressure compressor. The high-pressure and low-pressure stages of the supercharging device are each equipped with impellers, which comprise a high-pressure turbine rotor or a low-pressure turbine rotor, a corresponding shaft and a high-pressure compressor rotor or a low-pressure compressor rotor. In operation, the exhaust gas flow flows from the internal combustion engine ...

AI Technical Summary

Problems solved by technology

Here, the disadvantage is that the main exhaust flow and the sub-exhaust flow cannot be combined before the low-pressure turbine

This results in a radially uneven inflow of the low pressure turbine rotor

In combination with the swirl of the partial exhaust gas flow due to the helical shape of the annular channel, this leads to poorer efficiency of the low-pressure turbine

A further disadvantage is the high installation space and component requirements of the bypass device for the line guides and shut-off valves of the branch lines as well as for the ring channel with separate coupling flanges

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