Turbochargers with variable turbine geometry change the output
of the turbine as a function of engine load. In this way the
optimum boost pressure can be maintained and optimum use can be
made of the energy in the exhaust gas. Cross-sectional changes
are made by resetting the turbine blades (smaller contact
surface at low speeds, larger contact surface at high speeds).
VTG turbochargers are particularly efficient at partial load and
eliminate “turbo lag”. They increase engine power, increase
throttle response and can also have a beneficial effect on
particulate emissions. In addition, they open new perspectives
regarding the control of exhaust gas recirculation.