DEVELOPMENT OF BOOST SYSTEMS FOR FORCED DIESEL ENGINES

Abstract

The paper analyzes the world experience in boosting diesel engines by improving the air supply system, i.e. the installation of drive superchargers and (turbochargers) TKR. Two main types of mechanical superchargers, rotary and centrifugal, are considered. The most common models of rotatory superchargers, Roots, Eaton and Lysholm, the scheme and principle of operation of centrifugal superchargers are analyzed. The main disadvantage of mechanical supercharging is that all the power needed to compress the air is taken from the engine crankshaft. Therefore, gas turbine supercharging is considered the most promising. Single-stage boost systems are analyzed using the example of well-known car manufacturers such as Pegaso and Volkswagen. It has been established that the use of turbocharging increases engine efficiency, which leads to a decrease in specific effective fuel consumption. The further development is aimed at improving single-stage turbocharging systems, reducing the size of turbochargers, reducing inertia, using turbine controls and using two-stage boost systems. In addition, an analysis is made of the work of well-known companies developing boost systems (ABB Turbo Systems, MTU, MAN, Borg Warner Turbo System), which showed that for diesel engines with a liter capacity of more than 60 kW / l it is rational to use a two-stage boost system with intermediate cooling of the charge air. The advantages of using a two-stage boost system are: high torque at low engine speeds; increase in rated power; increase in boost pressure; reduction in fuel consumption; smoke reduction; high potential to reduce NOx emissions; improved transient characteristics. The use of a two-stage controlled turbocharging with cooling of the charge air type R2S achieves a high average effective pressure. Depending on the setting, the system can be implemented both at low and high engine speeds.