Exhaust Heat Recovery Apparatus

• US 20090094980A1
• Filed: 02/28/2007
• Published: 04/16/2009
• Est. Priority Date: 03/01/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Mitani, Shinichi, Sawada, Daisaku, Yaguchi, Hiroshi
• Granted Patent: US 8,250,869 B2
• Time in Patent Office: Days
• US Class Current: 60/615
• CPC Class Codes: F02B 41/00 Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power
• CPC Class Codes: F02G 1/043 the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
• CPC Class Codes: F02G 2254/15 by exhaust gas
• CPC Class Codes: F02G 5/02 Profiting from waste heat of exhaust gases
• CPC Class Codes: Y02E 20/30 Technologies for a more efficient combustion or heat usage
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An exhaust heat recovery apparatus includes a Stirling engine and a clutch. The Stirling engine produces motive power by recovering thermal energy from exhaust gas discharged from an internal combustion engine from which exhaust heat is recovered. The motive power produced by the Stirling engine is transmitted to an internal combustion engine transmission through the clutch and an exhaust heat recovery device transmission, and combined with the motive power produced by the internal combustion engine through the internal combustion engine transmission, and is output from an output shaft. If rapid acceleration is required, and the increase in the rotation speed of the Stirling engine therefore lags behind the increase in the rotation speed of the internal combustion engine, the clutch is released. With this configuration, reduction in the power output from the heat engine, from which exhaust heat is recovered, is restricted, and the degradation of the acceleration performance is minimized.

Claims

1. An exhaust heat recovery apparatus, characterized by comprising:

exhaust heat recovery means (100) that produces motive power by recovering thermal energy from exhaust gas from a heat engine (1), wherein the produced motive power is output together with motive power produced by the heat engine (1); and

rotation speed ratio-changing means (6, 7, 8) that transmits the motive power produced by the exhaust heat recovery means (100), and changes a ratio (Ns/Ne) of a rotation speed (Ns) of the exhaust heat recovery means (100) to a rotation speed (Ne) of the heat engine (1).

2. The exhaust heat recovery means according to claim 1, characterized in that,

when increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind increase in the rotation speed (Ne) of the heat engine (1), the rotation speed ratio-changing means (8) sets the ratio (Ns/Ne) of the rotation speed (Ns) of the exhaust heat recovery means (100) to the rotation speed (Ne) of the heat engine (1) smaller than that when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) follows the increase in the rotation speed (Ne) of the heat engine (1).

4. The exhaust heat recovery apparatus according to any one of claims 1 through 3, characterized in that

the rotation speed ratio-changing means is a clutch (6) that is provided between the heat engine (1) and the exhaust heat recovery means (100), wherein, when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind the increase in the rotation speed (Ne) of the heat engine (1), the clutch (6) is released.

5. The exhaust heat recovery apparatus according to claim 4, characterized by further comprising a one-way clutch (7), provided between the exhaust heat recovery means (100) and the heat engine (1), for transmitting motive power from the exhaust heat recovery means (100) to the heat engine (1).

6. The exhaust heat recovery apparatus according to any one of claims 1 through 3, characterized in that

the rotation speed ratio-changing means is speed-changing means (5, 5b, 6, 7, 8) provided between the heat engine (1) and the exhaust heat recovery means (100), wherein the rotation speed ratio (Ns/Ne) is changed by changing the speed ratio of the speed-changing means (5, 5b, 6, 7, 8).

7. The exhaust heat recovery apparatus according to claim 6, characterized in that,

when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind the increase in the rotation speed (Ne) of the heat engine (1), the rotation speed ratio-changing means sets the rotation speed ratio (Ns/Ne) so that the rotation speed (Ns) of the exhaust heat recovery means (100) becomes a rotation speed less than that when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) follows the increase in the rotation speed (Ne) of the heat engine (1).

8. The exhaust heat recovery apparatus according to claim 7, characterized in that,

when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind the increase in the rotation speed (Ne) of the heat engine (1), the rotation speed ratio-changing means sets the rotation speed of the exhaust heat recovery means (100) to a minimum rotation speed (NS₂) at which the exhaust heat recovery means (100) can operate.

9. The exhaust heat recovery apparatus according to claim 6, characterized in that

when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind the increase in the rotation speed (Ne) of the heat engine (1), the rotation speed ratio-changing means sets the rotation speed ratio (Ns/Ne) so that the rotation speed (Ns) of the exhaust heat recovery means (100) becomes a rotation speed at which the exhaust heat recovery means (100) produces the maximum motive power.

10. The exhaust heat recovery apparatus according to claim 9, characterized in that,

when a time period (t_1) for which rapid acceleration has not been required of the heat engine (1) exceeds a predetermined time period (t_d), the rotation speed ratio-changing means sets the rotation speed ratio (Ns/Ne) so that the exhaust heat recovery means (100) produces the maximum motive power.

11. The exhaust heat recovery apparatus according to any one of claims 2 through 10, characterized in that

when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind the increase in the rotation speed (Ne) of the heat engine (1) is when the heat engine (1) is rapidly accelerated.

12. The exhaust heat recovery apparatus according to claim 11, characterized in that,

when an accelerator pedal operation amount-differential value (dAccp/dt) is greater than an accelerator pedal operation amount-threshold value (Accp_sud), it is determined that the heat engine (1) is rapidly accelerated.

13. The exhaust heat recovery apparatus according to claim 11, characterized in that,

when a required driving force-differential value (dF/dt) is greater than a required driving force-threshold value (F_sud), it is determined that the heat engine (1) is rapidly accelerated.

3. An exhaust heat recovery apparatus, characterized by comprising:

exhaust heat recovery means (100) that produces motive power by recovering thermal energy from exhaust gas from a heat engine (1), wherein the produced motive power is output together with motive power produced by the heat engine (1); and

rotation speed ratio-changing means (8) that, when increase in the rotation speed (Ns) of the exhaust heat recovery means (100) lags behind increase in the rotation speed (Ne) of the heat engine (1), sets the ratio (Ns/Ne) of the rotation speed (Ns) of the exhaust heat recovery means (100) to the rotation speed (Ne) of the heat engine (1) smaller than that when the increase in the rotation speed (Ns) of the exhaust heat recovery means (100) follows the increase in the rotation speed (Ne) of the heat engine (1).