JPS6346249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas energy recovery device for an engine.

Gasoline and diesel engines, which are internal combustion engines, burn a mixture of air and fuel in a cylinder and use the energy generated to push down a piston to generate power, and the exhaust gas generated by combustion in the cylinder is It is directly discharged from the exhaust manifold to the outside air. This exhaust gas is at high temperature and pressure and still retains considerable energy.

Recently, heat-insulating internal combustion engines have been developed in which ceramics are used in various parts of the engine, such as the outer wall of the exhaust manifold, the cylinder liner, the cylinder head insulation plate, the exhaust valve, and the piston. This internal combustion engine does not cool the internal combustion engine by dissipating the heat generated inside it, as in the past, but instead extracts hotter exhaust gas and returns this energy to the crankshaft. The aim is to improve operational efficiency,
To explain what has been done in the past, a turbine rotated by exhaust gas is placed near the exhaust port, and the surplus rotational power obtained from this turbine is reduced by speed conversion using multi-stage gears. The energy recovery device returns the energy to the crankshaft, but the structure of the entire energy recovery device is complex and the transmission efficiency is poor, which not only makes the overall price of the internal combustion engine expensive, but also does not provide very good operating efficiency. It also had the disadvantage that it could not be used under partial load, and was not very effective.

Furthermore, since the energy of the exhaust gas is effectively extracted using one turbine, the turbine has to have a large number of turbine blades, making it expensive.

Further, a generator includes a turbine rotationally driven by an exhaust gas flow discharged from the engine, a motor rotated by electric power generated by the generator, and a motor connected to the generator. , a controller that controls the rotation of the motor according to the engine rotation speed detected by the engine rotation speed detector; and a controller that is interposed between the motor and the engine and intermittently transmits the rotational force of the motor to the engine. An exhaust energy recovery device is disclosed in Utility Model Application Publication No. 58-30727, comprising: an electromagnetic clutch whose on/off is controlled by the controller;
It is stated in the No. This device differs from the conventional example described above in that a generator driven by an exhaust turbine drives a motor connected to the engine to assist the engine, but only one exhaust turbine is used. Therefore, it is difficult to completely recover the excess energy contained in the exhaust gas. In addition, by arranging two turbines, only the exhaust turbine 1 is used during normal operating conditions, and when the output increases, the exhaust turbine 1 is used.
A method of using 1' and 1' in series is also being considered, but to mechanically configure a two-stage recovery system,
To extract the sum of shaft outputs with less loss,
It was extremely difficult.

The present invention aims to improve these conventional drawbacks, and its purpose is to efficiently recover the energy held in the exhaust gas of an internal combustion engine and efficiently return it to the crankshaft. Another object of the present invention is to provide an exhaust gas energy recovery device that reduces costs by providing two turbines with simple structures as turbines.

Next, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a block diagram of the present invention, and numeral 1 in the figure is a ceramic liner. Reference numeral 2 denotes an exhaust port liner, the inner wall of which is made of ceramics or hollow stainless steel material having an air layer, and has a heat insulating structure. An exhaust manifold 13 provided with an exhaust manifold insulator 3 is connected to the tip of the exhaust port liner 2, and a turbine insulator 4 of a high-pressure exhaust turbine 6 is connected to the tip. The high-pressure exhaust turbine 6 is provided with an intake compressor on one side and a generator (DC) on the other side, and their rotating shafts are directly connected to the axis of the exhaust turbine 6. A low pressure exhaust turbine 7 is further connected to the exhaust side of the high pressure exhaust turbine 6 via piping. A generator (DC) is disposed in the low-pressure exhaust turbine 7, and the rotating shaft of the generator is directly connected to the axis of the exhaust turbine 7. In this case, the high-pressure exhaust turbine 6 and the low-pressure exhaust turbine 7 are of a simple structure with a small number of turbine blade stages and are easy to manufacture. 8 is an intake duct, one end of which is connected to an intake compressor, and the other end connected to an intake port of the engine. 9 is an exhaust valve, which is made of ceramics. 1
0 is a cylinder head, and a cylinder head heat insulating plate 5 is stretched over the combustion chamber forming part. 11
A piston is made of ceramic, and the above-described ceramic liner 1, cylinder head heat insulating plate 5, and exhaust valve 9 form a combustion chamber with a heat insulating structure. 14 is a crankshaft, which is connected to a DC motor 15 via gears. DC motor 1
5 is also driven by electric power generated by two generators driven by the above-mentioned high-pressure exhaust turbine 6 and low-pressure exhaust turbine 7.

FIG. 2 is a block configuration diagram showing an exhaust gas energy recovery device for an engine according to the present invention, and the engine E, high pressure exhaust turbine 6, low pressure exhaust turbine 7, and motor 15 have the configuration shown in FIG. ing. Reference numeral 61 denotes an intake compressor whose rotating shaft is directly connected to the shaft of the high-pressure exhaust turbine 6 as described above, and the intake compressor 61 has a commonly used structure. 62, 72
is a generator (direct current) whose rotating shaft is directly connected to the shafts of the high-pressure exhaust turbine 6 and the low-pressure exhaust turbine 7, respectively, as described above, and the generators 62 and 72 are for high-speed rotation. 1
Reference numeral 6 denotes an energy addition system that acts to superimpose voltages, and has a conventionally used configuration. A current control circuit 17 controls the current based on a control signal from the current detector 18. Current detector 18 detects signals from engine E and generators 62 and 72, and based on these signals, a signal to be controlled is transmitted to current control circuit 17. In addition, the current control circuit 1
7 also prevents current backflow during low speed rotation.

Next, the operation of the present invention will be explained.

When the engine E starts rotating and high-temperature exhaust gas is discharged from the engine E, the turbine blades of the high-pressure exhaust turbine 6 and then the low-pressure exhaust turbine 7 start rotating, driving the generators 62 and 72 to generate electricity. Start. generator 62,
An attempt is made to supply the electric power generated in 72 to the DC motor 15 to drive it, but since the rotational speed of the high-pressure exhaust turbine 6 and the low-pressure exhaust turbine 7 is low, the output voltage of the generators 62 and 72 is also small, and the DC motor 15 is The motor 15 cannot be driven.

On the other hand, the DC motor 15 is rotated by the engine E and acts as a generator to generate DC voltage, but the current control circuit 17 prevents reverse current, so the electric power generated by the DC motor 15 does not flow backward.

When the rotational speed of the engine E gradually increases, the amount of exhaust gas increases, and the temperature thereof also increases, the output voltages of the generators 62 and 72 also increase, and the DC motor 15 is finally driven. Since the DC motor 15 drives the crankshaft of the engine E in a direction that increases its output, the energy contained in the exhaust gas is recovered and fed back to the crankshaft of the engine E. Even if the engine speed changes, the current control circuit 17 controls the DC motor 15 so that it can always be driven under optimal load conditions in response to the control signal from the current detector.

Furthermore, if an excessive load is applied to the DC motor 15 for some reason and a current exceeding the rating is about to flow, the current detector 18 detects this, and this detection signal causes the current control circuit 17 to adjust to the optimum load condition. control so that it can be driven at the same time.

With this type of circuit configuration, the entire circuit can be configured with a high-voltage circuit system, resulting in less loss compared to the 12V or 24V circuit configurations normally used in automobiles.

As described in detail above, the present invention provides a generator that is operated at a pressure lower than the operating pressure of the first turbine, in addition to the generator rotationally driven by the first turbine, and downstream of the first turbine. A second turbine is provided, and a generator rotated by the second turbine is provided, and the electric energy generated from these generators is applied to a DC motor to drive it and recover the exhaust gas energy of the engine. Therefore, it is possible to provide an exhaust gas energy recovery device that can effectively recover energy emitted from an engine and dramatically improve combustion efficiency of the engine while reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a side view partially showing a main part of an embodiment of the invention in cross section, and FIG. 2 is a block diagram showing an embodiment of the invention. E... Engine, 6... Exhaust turbine (for high pressure), 7... Exhaust turbine (for low pressure), 13... Exhaust manifold, 14... Crankshaft, 15...
DC motor, 62, 72... Generator (DC).

Claims (1)

[Claims] 1. A first turbine in the exhaust system of the engine, a first generator that is directly connected to the turbine shaft and rotates, and further downstream of the first turbine, which is connected to the operating pressure of the first turbine. An exhaust gas energy recovery device for an engine that includes a second turbine that operates at a lower pressure and a second generator rotated by the second turbine, and extracts the energy of the exhaust gas as rotational force of the turbine. An engine exhaust gas comprising: an energy addition system that adds electric power output from a second generator; and a motor driven by the added electric power to return recovered energy to the engine. Gas energy recovery equipment.