Patent ID: 9217362
Filing Date: 2015-12-22
Classification: F02B,F02D,F02M,Y02T

Abstract:
1. A method for controlling a two-stage turbocharger system having a low-pressure turbocharger and a high-pressure turbocharger sequentially in line with an engine, wherein the low-pressure turbocharger has a low-pressure turbine (LP turbine) and a low-pressure compressor (LP compressor) and the high-pressure turbocharger has a high-pressure turbine (HP turbine) and a high-pressure compressor (HP compressor), wherein the LP compressor is operatively connected to the HP compressor, which is operatively connected to an intake of the engine, and the LP turbine is operatively connected to the HP turbine, which is operatively connected to an exhaust of the engine, the method comprising: determining a total boost pressure for the two-stage turbocharger system, wherein the total boost pressure provides sufficient combustion reactant for the engine and determining the total boost pressure includes: calculating an LP compressor power from the determined total boost pressure, and calculating an LP turbine flow from the calculated LP compressor power; commanding the low-pressure turbocharger to operate at the calculated LP turbine flow; calculating an HP compressor power from the determined total boost pressure, and calculating an HP turbine flow from the calculated HP compressor power; commanding the high-pressure turbocharger to operate at the calculated HP turbine flow; monitoring an atmospheric pressure; determining a total pressure ratio, wherein the total pressure ratio is equal to the total boost pressure divided by the atmospheric pressure; determining an LP pressure ratio and an HP pressure ratio, wherein the LP pressure ratio is equal to a mid-stage pressure, between the LP compressor and the HP compressor, divided by the atmospheric pressure and the HP pressure ratio is equal to the total boost pressure divided by the mid-stage pressure, and wherein the LP pressure ratio multiplied by the HP pressure ratio equals the total pressure ratio; and wherein the LP compressor power is calculated from the determined LP pressure ratio, and the HP compressor power is calculated from the determined HP pressure ratio.