cars with turbochargers

Abstract

The invention relates to a motor vehicle with an internal combustion engine (2) and a transmission (3) as well as a turbocharger (1) with a variable geometry for precompressing combustion air of the internal combustion engine (2). A turbocharger control unit (5) for changing the geometry of the turbocharger, wherein the turbocharger control unit (5) is configured to perform a downshift (t2) of the transmission (3) ; 13) Previously, the geometry of the turbocharger (1) was changed in the direction of reducing the rotation speed (ω) of the turbocharger (1).

Description

technical field [0001] The invention relates to a motor vehicle with a turbocharger with variable geometry and a device for controlling such a turbocharger. Background technique [0002] Variable geometry turbochargers, usually with adjustable guide vanes, make it possible to vary the relationship between the exhaust gas flow and the turbine speed and in this way provide good performance even at low engine speeds Compression power. In order to achieve the desired compression performance, it may be necessary to adjust the guide vanes in such a way that the turbine runs close to the permissible maximum rotational speed, although the exhaust gas flow has not yet reached its maximum value. A sudden increase in the exhaust gas flow, especially in combination with a sudden increase in the speed of the internal combustion engine when the vehicle's transmission is downshifted, can cause the turbine to exceed the maximum permissible speed and thus lead to damage to the turbocharger....

AI Technical Summary

Problems solved by technology

A sudden increase in the exhaust gas flow, especially in combination with a sudden increase in the speed of the internal combustion engine when the car's transmission is downshifted, can cause the turbine to exceed the maximum permissible speed and thus lead to damage to the turbocharger

Especially cars with automatic or automated transmissions allow very rapid downshifts, which can lead to exceeding the limit value

This problem is especially acute when the car is used in thinner air, that is, in higher mountainous areas, because the low air pressure in these places reduces the air mass sucked in by the compressor of the turbocharger per revolution and Correspondingly, the work per revolution compressed by the compressor onto the sucked-in air is reduced, so the turbocharger is harder to decelerate than it is when driving at high pressures in swales

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