An exhaust gas heat recovery system for an internal combustion engine has a pump for conveying an operating fluid, an evaporator for converting the operating fluid from the liquid state to the gaseous state, and a condenser for liquefaction of the operating fluid, and having an expansion engine through which the gaseous operating fluid can flow. A sensor is arranged on the expansion engine with which a function of the expansion engine can be monitored. An exhaust system may have such an exhaust gas heat recovery system, and a method for the diagnosis of such an exhaust heat recovery system.

A Stirling refrigerator serves as a reciprocating motion engine and has: a casing; a cylinder arranged within the casing; a piston capable of being reciprocated within the cylinder in a reciprocating direction as being uniaxial; a control circuit electrically controlling movement of the piston; a damping unit provided at one end side of the casing in the reciprocating direction via a first connection part and a second connection part serving as connection parts; and a vibration detection board arranged via an attachment body on the second connection part, said vibration detection board serving as a vibration detector to detect a vibration in the reciprocating direction, caused by the reciprocating movement of the piston, to transmit it to the control circuit.

The disclosure provides a vibration isolation structure for linear oscillating motor and Stirling engine, wherein the said vibration isolation structure comprises a first vibration isolation device and a second vibration isolation device. The first vibration isolation device is set between the fixed hood and the housing of the linear oscillating motor to attenuate the high-frequency and small-amplitude vibrations from the linear oscillating motor. The first vibration isolation device comprises a first set of tension springs and a second set of tension springs, and a lateral gap is formed between the fixed hood and the linear oscillating motor. The second vibration isolation device is set in the said lateral gap to attenuate the low-frequency and large-amplitude vibrations from the linear oscillating motor. The second vibration isolation device comprises at least two sets of position-limiting protrusions and position-limiting blocks, and the position-limiting protrusion and position-limiting block are set in a match at the linear oscillating motor and the fixed hood respectively or reversely. Also disclosed is a Stirling engine assembled with a linear oscillating motor that comprising with an aforementioned vibration isolation structure. The vibration isolation structure improves the stability of the reciprocating linear oscillating motor and the Stirling engine, and reduces mechanical vibrations and noises.

A Stirling refrigerator serves as a reciprocating motion engine and has: a casing; a cylinder arranged within the casing; a piston capable of being reciprocated within the cylinder in a reciprocating direction as being uniaxial; a control circuit electrically controlling movement of the piston; a damping unit provided at one end side of the casing in the reciprocating direction via a first connection part and a second connection part serving as connection parts; and a vibration detection board arranged via an attachment body on the second connection part, said vibration detection board serving as a vibration detector to detect a vibration in the reciprocating direction, caused by the reciprocating movement of the piston, to transmit it to the control circuit.

The disclosure provides a vibration isolation structure for linear oscillating motor and Stirling engine, wherein the said vibration isolation structure comprises a first vibration isolation device and a second vibration isolation device. The first vibration isolation device is set between the fixed hood and the housing of the linear oscillating motor to attenuate the high-frequency and small-amplitude vibrations from the linear oscillating motor. The first vibration isolation device comprises a first set of tension springs and a second set of tension springs, and a lateral gap is formed between the fixed hood and the linear oscillating motor. The second vibration isolation device is set in the said lateral gap to attenuate the low-frequency and large-amplitude vibrations from the linear oscillating motor. The second vibration isolation device comprises at least two sets of position-limiting protrusions and position-limiting blocks, and the position-limiting protrusion and position-limiting block are set in a match at the linear oscillating motor and the fixed hood respectively or reversely. Also disclosed is a Stirling engine assembled with a linear oscillating motor that comprising with an aforementioned vibration isolation structure. The vibration isolation structure improves the stability of the reciprocating linear oscillating motor and the Stirling engine, and reduces mechanical vibrations and noises.

An exhaust gas heat recovery system for an internal combustion engine has a pump for conveying an operating fluid, an evaporator for converting the operating fluid from the liquid state to the gaseous state, and a condenser for liquefaction of the operating fluid, and having an expansion engine through which the gaseous operating fluid can flow. A sensor is arranged on the expansion engine with which a function of the expansion engine can be monitored. An exhaust system may have such an exhaust gas heat recovery system, and a method for the diagnosis of such an exhaust heat recovery system.