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Troubleshooting On Exhaust Turbocharger: Introduction

For charged engines, exhaust turbochargers are of significant importance to the power development. The turbochargers deliver the charging pressure that is required by the engines. Depending on the system (one-phase or multi-phase), one or more turbochargers are installed. However, the function of the turbocharger greatly depends on the proper function of other components in the periphery.

This article describes the sources of fault on the actual exhaust turbocharger as well as the factors influencing and causing faults in the periphery.

The following pictures show examples for the schematic structure of one-phase or multi-phase systems with the subsequently required actuators.

Fig 1: Turbochargers Operation Diagram (One-Phase System)
G09841675Courtesy of BMW OF NORTH AMERICA, INC.

One-phase system 

1 Compressor
2 Turbine
3 Exhaust gas
4 Fresh air
Fig 2: Turbochargers Operation Diagram (Two-Phase System)
G09841676Courtesy of BMW OF NORTH AMERICA, INC.

Two-phase system 

1 Compressor bypass plate
2 Compressor high-pressure stage
3 Turbine high-pressure stage
4 Turbine control flap
5 Wastegate valve
6 Exhaust gas
7 Turbine low-pressure stage
8 Compressor low-pressure stage
9 Fresh air
10 Low pressure compressor bypass flap
Fig 3: Identifying Turbocharger Components
G09841677Courtesy of BMW OF NORTH AMERICA, INC.

Sectional view of turbocharger 

1 Turbine housing
2 Turbine wheel
3 Variable blades
4 Adjusting ring
5 Oil inlet journal
6 Adjusting lever
7 Electrical turbocharger pressure adjuster
8 Compressor housing
9 Compressor
10 Thrust bearing
11 Shaft
12 Radial bearing
13 Oil supply