Exhaust heat recovery device
AssigneeSanden Holdings Corporation
InventorsTomonori Haraguchi, Hiroyuki Nagai
Life of this patent
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Abstract
To effectively reduce a situation in which an over-rotation of an expander occurs or the expander becomes a load on an engine at the time of a stop of a Rankine cycle in an exhaust heat recovery device provided with the Rankine cycle that recovers exhaust heat of an engine. A pressure difference ΔP between a high-pressure side and a low-pressure side of the Rankine cycle is obtained when the Rankine cycle is stopped (S1), a waiting time Ta is set (calculated) based on the obtained pressure difference ΔP (S2). Then, a bypass valve is opened to allow a refrigerant to circulate while bypassing the expander (S3), and then an electromagnetic clutch is disengaged when the waiting time Ta has elapsed to block transmission of power between the expander and the engine (S4, S5).
Claims9
An exhaust heat recovery device comprising:
- a Rankine cycle that is provided with:
- a heater configured to heat and vaporize refrigerant by exhaust heat of an engine;
- an expander configured to expand the refrigerant passed through the heater to generate power;
- a condenser configured to condense the refrigerant passed through the expander;
- and a pump configured to send the refrigerant passed through the condenser to the heater, the heater, the expander, the condenser, and the pump being arranged in a refrigerant circulating passage;
- a bypass flow passage that allows the refrigerant to circulate while bypassing the expander;
- a bypass valve that opens and closes the bypass flow passage;
- a power transmission mechanism that has a clutch mechanism and is capable of transmitting power between the expander and the engine when the clutch mechanism is engaged;
- and
- a control unit that, at the time of stopping the Rankine cycle, executes control to open the bypass valve and then to disengage the clutch mechanism when a waiting time has elapsed, the waiting time being set depending on operation states or operation conditions of the Rankine cycle before the bypass valve is opened or at the point of time when the bypass valve is opened.
Dependencies are inferred from the claim text.