JPS62258108A - Waste heat recovery device for engine - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of an engine, by rotating an exhaust gas turbine with the exhaust gas, at the same time, rotating a ranking turbine furnished coaxially to the exhaust gas turbine, and driving a generator by the power of both turbines. CONSTITUTION:An exhaust gas turbine 14 rotated and driven by the exhaust gas from an engine 11 is prepared, and the exhaust gas which has finished the work there is exhausted through a heat exchanger 15. To this exhaust gas turbine 14 is linked a ranking turbine 16 coaxially, and the ranking turbine 16 is rotated and driven by the flow of a ranking medium. By the rotations of both turbines 14 and 16, a generator 17 is rotated and driven. The ranking medium is led through a capacitor 18 to a liquid pump 19, where its pressure is raised, then it is led to the heat exchanger 15 to be heated and gasified, and fed to the ranking turbine 16 again. The generated power at the generator 17 is fed to the motor 22 to drive a crank shaft 12 and returned to the engine power.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention effectively utilizes thermal energy contained in exhaust gas generated from, for example, an automobile engine.
The present invention relates to an engine exhaust heat recovery device that allows the engine to generate output more efficiently and improve thermal efficiency.

[Prior Art] Turbocharger systems have been known as a means of utilizing engine exhaust energy. That is, the exhaust gas from the engine drives the turbocharger to increase the supercharging pressure of the carrot.

Furthermore, in order to improve the thermal efficiency of the engine, it has been considered to make the engine thermally insulated by, for example, configuring the engine with ceramic or the like. When the engine is insulated in this way, the exhaust heat energy from the engine increases further, and there is a need to effectively utilize this large amount of heat energy. It is desired to utilize the above thermal energy to improve engine output.

[Problems to be Solved by the Invention] This invention has been made in view of the above-mentioned points, and aims to more effectively utilize the energy contained in the exhaust gas generated by the engine to increase the engine output. The purpose of this project is to provide an engine exhaust heat recovery device that can be used for return.

[Means for solving the problem] That is, the engine exhaust heat recovery device according to the present invention has the following features:
The exhaust turbine is rotationally driven by exhaust gas from the engine, and a Rankine turbine is coaxially connected to the exhaust turbine, so that the exhaust turbine and the Rankine turbine drive a generator. In addition, the power generated by this generator is used to circulate and cool the Rankine medium, and the circulated Rankine medium undergoes heat exchange with the exhaust gas that has passed through the exhaust turbine and evaporates. It is designed to be supplied to the Rankine turbine.

[Operation] In the above-described exhaust heat recovery device, first, the Rankine turbine is rotationally driven by the exhaust gas from the engine, and the generator is driven to generate electric power. This electric power circulates and cools the Rankine medium, and at the same time exchanges heat with the exhaust gas, driving the Rankine turbine coaxial with the exhaust turbine, and the generator generates a large amount of electric power. It becomes like this.

Therefore, the electric power generated by the second generator drives, for example, an electric motor, and the rotational force generated by this electric motor is feedback-coupled to the rotational power of the engine, thereby effectively increasing the thermal efficiency of this engine. This is something that will be improved.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows its configuration. Reference numeral 11 is, for example, a normal gasoline engine, and the operation of this engine 11 drives a crankshaft 12 to rotate.

The exhaust gas from this engine 11 is transmitted through the exhaust gas vibe 1.
3 to the exhaust turbine 14. This exhaust turbine 14 has a similar configuration to a normal gas turbine, and is driven to rotate at high speed by being supplied with exhaust gas. The exhaust gas that has passed through the exhaust turbine 14 is then discharged via the heat exchanger 15.

A Rankine turbine 1B is coaxially coupled to the exhaust turbine 14. This Rankine Turbine 1G is
It is constructed in the same manner as the exhaust turbine 14, and is rotationally driven by the flow of a Rankine medium such as fluorocarbon gas, and the generator 17 is rotationally driven by this Rankine turbine 16 and the exhaust turbine 14. It has become.

A Rankine medium such as chlorofluorocarbons, which is supplied to the Rankine turbine 1B, is led to a liquid pump 19 via a condenser 18, and the Rankine medium, which has been suctioned and pressurized by this pump 19, is heated exchanger 1
5, is evaporated by exhaust gas heat, and is circulated and supplied to the Rankine turbine lft. Here, cooling air is supplied to the condenser 18 from a cooling fan 20.
Furthermore, the liquid pump 19 is driven by a motor 21 to which electric power generated by the generator 17 is supplied.

The electric power generated by the generator 17 is used to drive the motor 21 as described above, and is also used as a power source for peripheral electronic devices, etc., but most of it is used as a power source for the output of the engine 11. Return to be used. For example, a motor 22 is driven by electric power from a generator 17, and the rotational force of the motor 22 is coupled to the crankshaft 12 via a clutch mechanism or the like.

That is, high-temperature and high-pressure exhaust gas from the engine 11 is adiabatically expanded in the exhaust turbine 14, and its energy is converted into rotational power.

This rotational energy, together with the rotational force of the Rankine turbine 16 coaxial with the exhaust turbine 14, drives the generator 17 and is converted into electrical energy. Further, the exhaust gas exiting the exhaust turbine 14 is transferred to a heat exchanger 15.
The evaporation tube through which the Rankine medium passes is heated, and the Rankine medium is evaporated. This Rankine medium, which has become high-temperature and high-pressure steam, is supplied to the Rankine turbine 16 to rotationally drive the turbine 1B. The low-pressure steam Rankine medium that exits the Rankine turbine 16 is led to the condenser 18, cooled by the airflow generated by the cooling fan 20, condensed and liquefied, and then sucked and pressurized by the liquid pump 19 to be heated again. It comes to be circulated to the exchanger 15.

In this way, the energy of the exhaust gas from the engine 11 is efficiently recovered as electricity,
This recovered energy can be returned to the output of the engine 11.

Particularly, when the engine 11 is used for automobiles and has significant load fluctuations, the change in exhaust energy is also large. Therefore, in such cases, the fluctuations in recovered energy are large, but since this energy is efficiently converted into electrical energy, its controllability is good and it can be regenerated in a stable manner. This allows it to be reduced to rotational power.

Here, it is possible to recover the rotational power of the exhaust turbine or the Rankine turbine as power via an inefficient reduction gear, but as described above, it is possible to make the exhaust turbine 14 and the Rankine turbine 16 coaxial. Since both the turbines 14 and 16 are connected to each other and the generator 21 is driven by the turbines 14 and 16, the transmission efficiency of exhaust energy can be effectively improved.

In the embodiment described above, exhaust gas from the engine 11 is directly supplied to the exhaust turbine 14, and the generator 21 is driven by the exhaust turbine 14. However, the above exhaust gas can also be used for other purposes as appropriate. For example, as shown in FIG. 2, exhaust gas from the engine 11 is supplied to a turbocharger 23, which sucks air, increases the pressure, and supplies it to the engine 11 via an intercooler 24. .

Then, the combustion efficiency of the engine 12 is improved so that its output is increased. The exhaust gas discharged from the turbocharger 23 is then supplied to the exhaust turbine 14. Other components that are the same as those in Figure 1 are given the same reference numerals and their explanations will be omitted.

That is, conventionally known turbocharger mechanisms can be effectively used in combination, and engine exhaust energy can be efficiently recovered as engine output.

[Effects of the Invention] As described above, according to the exhaust heat recovery device for an engine according to the present invention, it is possible to effectively set the Rankine cycle in which the exhaust gas drives the Rankine turbine together with the exhaust turbine, and the above-mentioned two turbines can effectively set up the Rankine cycle. A driven generator can convert it into a sufficiently large amount of electrical energy. Therefore, this electrical energy can not only be used as a driving power source for various electrical devices, but also can be converted into rotational power.For example, it can be used as rotational power for the engine crankshaft, and as a result, the thermal efficiency of the engine can be improved. will be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an engine exhaust heat recovery device according to one embodiment of the present invention, and FIG. 2 is a block diagram illustrating another embodiment of the present invention. 11...Engine, 12...Crankshaft, 14...
- Exhaust turbine, 15... Heat exchanger, 1B... Rankine turbine, 17... Generator, 18... Capacitor, 199.・Liquid pump, 20...Cooling fan, 2L
22...Motor. Applicant's representative Patent attorney Takehiko Suzue Engraving on page 12 (no changes in content) Fig. 2 0chi.6.z4yo Commissioner of the Patent Office Michibe Uga 1, Indication of case Patent application No. 102467/1986 2. Name of the invention Engine exhaust heat recovery device 3. Person making the amendment Relationship to the case Patent applicant (426) Nippondenso Co., Ltd. 4. Agent 6. Subject of the amendment 7. Contents of the amendment (1) In the drawings In addition, the figure number “Figure 1” is not provided in the attached sheet.
and "Figure 2" are added.

Claims (1)

[Scope of Claims] An exhaust turbine supplied with exhaust gas from an engine and rotationally driven by the exhaust gas, and a Rankine turbine provided coaxially coupled to the exhaust turbine, the above-mentioned exhaust turbine and the Rankine turbine. a generator rotationally driven by a generator, a means for cooling and circulating a Rankine medium using the electric power generated by the generator, and a means for evaporating and vaporizing the circulated Rankine medium by the heat of the exhaust gas that has passed through the exhaust turbine. and a heat exchanger, the Rankine medium expanded by the heat exchanger is supplied to the Rankine turbine, and the electric power generated by the generator can be returned to the engine output. Engine exhaust heat recovery device.