Exhaust heat recovery system having a working fluid circuit and method for operating such an exhaust heat recovery system

Abstract

The invention relates to an exhaust heat recovery system having a working fluid circuit (1) carrying a working fluid, having a heat exchanger (2) which is connected in an exhaust line (3) of an internal combustion engine (5) and which is a part of the working fluid circuit (1) together with at least one expansion machine (11), a condenser (12), and a fluid pump (15). The aim of the invention is to provide an exhaust heat recovery system, which is improved with respect to known systems. This is achieved in that the exhaust heat recovery system has a device (27) for avoiding damage to the expansion machine (11) that is caused by liquid components of the working fluid. The device (11) is, for example, a container (21), a calming container (28, 28a), a line section (36) or a filter (26), or the device (11) has at least one such component.

Description

BACKGROUND OF THE INVENTION[0001]The present invention concerns an exhaust heat recovery system having a working fluid circuit carrying a working fluid, comprising at least one heat exchanger which is connected in an exhaust gas line of an internal combustion engine and which is a part of the working fluid circuit together with at least one expansion machine, a condenser and at least one fluid pump. The invention also concerns a method for operating such a working fluid circuit.[0002]Such an exhaust heat recovery system is disclosed in DE 10 2013 211 875. This exhaust heat recovery system comprises a working fluid circuit with two heat exchangers, wherein a first heat exchanger is connected in an exhaust gas line of the internal combustion engine, and a second heat exchanger is connected in an exhaust gas recirculation line of the internal combustion engine. The working fluid circuit furthermore comprises an expansion machine, a condenser and a fluid pump, wherein downstream of the ...

AI Technical Summary

Benefits of technology

This patent describes an exhaust heat recovery system that prevents damage to the expansion machine caused by liquid components in the working fluid. The system includes a device that separates or harmlzes liquid components from the working fluid to avoid damage. The benefits of this system include improved system regulation, increased energy yield, and higher overall efficiency. By bypassing the expansion machine less often, the system can operate for longer periods of time and with fewer maintenance issues. Additionally, the system is more robust and reliable.

Problems solved by technology

This is because a turbomachine is operated at very high rotation speeds, which leads to very high relative speeds at the turbine blades of the turbomachine.

If the turbomachine is not operated with a monophasic gaseous working fluid (as dry vapor), but rather with a vaporous working fluid which carries with it unvaporized working fluid in the liquid phase (liquid components in the working fluid, for example in the form of liquid droplets) in the form of wet vapor, erosion occurs at the turbine blades because of collision processes.

If the thermosensor is hit by a liquid droplet or if the liquid droplet is deposited on the thermosensor, an actual measurement value is falsified, which has a disadvantageous effect on the system regulation.

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