CN106285924B

CN106285924B - Device for improving energy utilization rate in tail gas of internal combustion engine

Info

Publication number: CN106285924B
Application number: CN201510357808.XA
Authority: CN
Inventors: 张建民
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-06-26
Filing date: 2015-06-26
Publication date: 2020-05-05
Anticipated expiration: 2035-06-26
Also published as: CN106285924A

Abstract

The invention provides a device for improving energy utilization rate in tail gas of an internal combustion engine. The device divides the exhaust pipe of the internal combustion engine into an expansion exhaust pipe and a push-out exhaust pipe, segments the expansion exhaust pipe, adopts a timely re-expansion technology in the expansion exhaust pipe, converts heat energy in tail gas into expansion energy on the premise of not increasing exhaust resistance, and pushes a tail gas turbine to do work after the expansion energy is superposed with original expansion energy in the tail gas. This device makes it possible to use a turbine to obtain more mechanical energy from the exhaust gases of an internal combustion engine. The main application directions of this technology are: the tail gas turbine drives the generator through the speed reducer to charge the storage battery of the oil-electricity hybrid electric vehicle, so that the oil-electricity hybrid electric vehicle can realize charging without additional energy consumption during running when an internal combustion engine driving mode is adopted.

Description

Device for improving energy utilization rate in tail gas of internal combustion engine

Technical Field

The invention relates to a device for improving the efficiency of an internal combustion engine, in particular to a device for improving the energy utilization rate in the tail gas of the internal combustion engine, belonging to the technical field of internal combustion engines.

Background

The exhaust loss is a large proportion of all losses of the internal combustion engine, which is almost equivalent to useful work, if the energy in the exhaust gas can be converted into the useful work, the efficiency of the internal combustion engine can be obviously improved, and the widely adopted exhaust gas turbocharging scheme is the research and practice on the aspect. With the application of the exhaust turbocharging solution, the power per liter of the internal combustion engine is significantly improved, but this solution cannot improve the thermal efficiency of the internal combustion engine, as the fuel consumption index of the supercharged internal combustion engine is not significantly reduced, mainly because the exhaust turbocharging solution has the following drawbacks: (1) the exhaust resistance is increased by pushing the exhaust gas turbocharger, so that the pushing-out loss work of the exhaust gas is increased; (2) the increase of the air inlet pressure increases the pressure in the cylinder in the compression stroke, so that the loss work of compression is increased; (3) since the pressure and temperature in the cylinder during the compression and power strokes are increased by a large amount due to the increase of the intake pressure, the magnitude of the boost pressure must be limited in order to avoid damaging the machine due to the high pressure and temperature, which makes the energy in the exhaust gas not fully utilized.

The utility model with patent number 201320008898.8 and the title "ventilator for improving thermal efficiency of internal combustion engine" discloses a method for reducing exhaust resistance by branch exhaust, converting expansion work in exhaust gas to useful work to the maximum extent by series pressurization, and limiting the pressure of cylinder in compression and power stroke by properly releasing the pressure in cylinder in the initial stage of compression, so as to convert the energy in exhaust gas to useful work to the maximum extent and improve the thermal efficiency of internal combustion engine. While this method has proven to be viable and effective, it suffers from two important drawbacks, (1) because it releases the pressure in the cylinder at the end of the intake stroke, making the amount of air actually involved in combustion in the cylinder difficult to measure and control, resulting in a fuel-air ratio that is also difficult to accurately control; (2) since a large part of the energy contained in the exhaust gas is heat energy, not expansion energy, the above-mentioned patent solution cannot utilize the heat energy in the exhaust gas. Therefore, in order to make the energy in the exhaust gas more fully utilized, further improvement of the above technical solution is necessary.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the device can not increase exhaust resistance, but also convert the heat energy in the tail gas into expansion energy, so that the expansion energy is superposed with the original expansion energy in the tail gas, and then the tail gas turbine is pushed to do work.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the device for improving the energy utilization rate of the tail gas of the internal combustion engine comprises a cylinder cover, an expansion exhaust pipe, a push-out exhaust pipe, an electromagnetic valve, a compressed air pipe, an engine control unit, an air storage tank, an air pump, an air inlet pipe, a turbine and a turbine connecting disc. The expansion exhaust pipe is divided into at least two sections according to the exhaust interval angle between each cylinder, each section of expansion exhaust pipe is converged in the tail gas turbine, each section of expansion exhaust pipe is connected with an air storage tank through a compressed air pipe by an electromagnetic valve, the air storage tank is connected with an air pump, the air inlet end of the air pump is connected with the air inlet pipe of the internal combustion engine, the air outlet end of the expansion exhaust pipe is communicated with a silencer after passing through the tail gas turbine, and the air outlet end of the push-out exhaust pipe is communicated with the silencer.

Exhaust passages are provided in the cylinder head corresponding to the expansion exhaust valve and the push-out exhaust valve, and are separated from each other.

The expansion exhaust pipe and the push-out exhaust pipe are located on the same side of the internal combustion engine.

The range of crank angles between the opening angle of the expansion exhaust valve and the closing angle of the pushout exhaust valve covers the entire exhaust stroke. After the shunt exhaust technology is adopted, the expansion exhaust process and the exhaust pushing process are respectively completed by two paths of exhaust, and the exhaust stroke can be completed only if the sum of the opening angle of the expansion exhaust valve and the closing angle of the exhaust pushing valve is equal to the opening lasting angle of the exhaust valve of the existing internal combustion engine.

The solenoid valve is supplied with control power by an Engine Control Unit (ECU).

The reason for arranging the expansion and push-out two exhaust branches of the invention is as follows: the tail gas exhausted from the two exhaust stages respectively passes through the two exhaust stages without mutual interference, and the expansion work carried in the tail gas exhausted from the expansion exhaust branch is used for pushing a tail gas turbine so as to utilize the energy in the tail gas; the exhaust gas discharged from the exhaust branch is exhausted to the atmosphere through the muffler while bypassing the turbine, so that the exhaust resistance in the exhaust stage is reduced. This measure creates conditions for making full use of the energy in the exhaust gases without increasing the exhaust resistance.

The reason for the invention using the expansion exhaust pipe segment is as follows: the expansion exhaust pipe is divided into at least two sections according to the exhaust interval angle between cylinders, the exhaust interval angle in each section of expansion exhaust pipe ensures that no overlapping angle exists between the exhaust valves connected with the expansion exhaust pipe, and each section of expansion exhaust pipe is converged at the air inlet end of the tail gas turbine, so that the adverse effect of pressure fluctuation in the exhaust pipe on the operation process of the internal combustion engine can be reduced while the expansion work in the tail gas is fully utilized as much as possible.

The reason for adopting the timely re-expansion in the expansion exhaust pipe is as follows: in order to convert the heat in the tail gas into useful work, compressed air is injected into each section of expansion exhaust pipe at proper time, the volume of the compressed air can expand after the compressed air contacts the high-temperature tail gas in the exhaust pipe, so that the heat energy in the tail gas is converted into expansion energy, and the expansion energy is superposed with the original expansion energy in the tail gas, so that more expansion energy can be obtained to drive a tail gas turbine.

The invention can convert the energy in the exhaust gas into usable mechanical energy to the utmost extent through the exhaust turbine, and the energy contained in the exhaust gas is almost equivalent to the useful work of the internal combustion engine, so the mechanical energy which can be obtained from the output shaft of the exhaust turbine is also considerable after the invention is implemented. According to the state of the art, the main directions of application of the mechanical energy obtained from the output shaft of the exhaust gas turbine after the implementation of the invention are: the tail gas turbine is utilized to drive the generator through the speed reducer to charge the storage battery of the oil-electricity hybrid electric vehicle, so that the oil-electricity hybrid electric vehicle realizes charging without additional energy consumption during running when adopting an internal combustion engine driving mode. After the invention is implemented, the utilization rate of the fuel of the internal combustion engine can be improved, and the aims of energy conservation and emission reduction are achieved.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of the present invention;

FIG. 2 is a schematic view of an expansion exhaust valve cam configuration;

FIG. 3 is a schematic view of a push-out exhaust valve cam configuration;

FIG. 4 is a schematic view showing the arrangement of air valves and air inlet and outlet pipes on the cylinder head;

FIG. 5 is a schematic view showing the arrangement of exhaust pipes on one side of the exhaust pipe on the cylinder head;

in fig. 1, a muffler, 2, a push-out exhaust pipe, 3, a turbine, 4, a connecting disc, 5, a first-stage expansion exhaust pipe, 6, a second-stage expansion exhaust pipe, 7, a cylinder head, 8, an expansion exhaust valve, 9, an intake valve, 10, a push-out exhaust valve, 11, an electromagnetic valve, 12, a compressed air pipe, 13, an Engine Control Unit (ECU), 14, an air storage tank, 15, an air pump, 16, an intake pipe 17, and an air cleaner;

the points marked by capital English letters in FIG. 2 correspond to: A. the method comprises the following steps of A, a lower dead point, B, an upper dead point, C, an expansion exhaust valve opening point (which corresponds to the existing internal combustion engine exhaust valve opening point), F, an expansion exhaust valve opening point to the maximum point, G, an expansion exhaust valve closing point, D, a push-out exhaust valve closing point (which corresponds to the existing internal combustion engine exhaust valve closing point);

the points marked by capital English letters in FIG. 3 correspond to: A. the method comprises the following steps of bottom dead center, B, top dead center, H, push-out exhaust valve opening point, I, push-out exhaust valve opening point to the maximum point, C, existing internal combustion engine push-out exhaust valve opening point (corresponding to existing internal combustion engine exhaust valve opening point), and D, push-out exhaust valve closing point (corresponding to existing internal combustion engine exhaust valve closing point).

The parts represented by the numbers in fig. 4 and 5 correspond to those in fig. 1.

Detailed Description

1) Branch exhaust: the method comprises the steps that exhaust passages which are mutually isolated are made on a cylinder cover of the existing internal combustion engine with the double overhead camshafts corresponding to each cylinder, corresponding modification is made on an exhaust cam, according to the time difference of an expansion exhaust stage and a push-out exhaust stage in an exhaust stroke, an exhaust path is divided into an expansion exhaust branch and a push-out exhaust branch, exhaust valves of the two exhaust branches are respectively controlled by utilizing a driving mechanism of an air valve, so that the expansion exhaust valve is opened in the expansion exhaust stage and is closed in the push-out exhaust stage; the push-out exhaust valve is opened in the push-out exhaust stage and closed when the exhaust is finished.

2) The expansion exhaust pipe is segmented: the connection mode of the expansion exhaust pipe and the tail gas turbine is similar to that of the exhaust pipe of the pressure-changing type exhaust gas turbocharging system of the existing internal combustion engine, the expansion exhaust pipe is divided into at least two sections, so that an exhaust valve in each section of the expansion exhaust pipe has no overlapping angle, and each section of the expansion exhaust pipe is connected with the air inlet of the tail gas turbine through a connecting disc.

3) Re-expansion at proper time: when the expansion exhaust valve corresponding to a certain section of the expansion exhaust pipe is completely closed, the electromagnetic valve is opened at proper time, compressed air is injected into the corresponding expansion exhaust pipe in proper amount, the volume of the compressed air is expanded after the compressed air absorbs the heat in the tail gas to generate expansion work, the heat energy in the tail gas is converted into expansion energy, and thus more expansion energy can be obtained to push the tail gas turbine.

Claims

1. A device for improving the energy utilization rate of tail gas of an internal combustion engine comprises a cylinder cover (7), an expansion exhaust pipe used for an expansion exhaust stage in an exhaust stroke, a push-out exhaust pipe (2) used for a push-out exhaust stage in an exhaust stroke, an electromagnetic valve (11), a compressed air pipe (12), an engine control unit (13), an air storage tank (14), an air pump (15), an air inlet pipe (16), a turbine (3) and a turbine connecting disc (4), wherein the expansion exhaust pipe is divided into at least two sections according to the exhaust interval angle between cylinders, so that the exhaust valve in each section of expansion exhaust pipe is free of an overlapping angle, and comprises a section of expansion exhaust pipe (5) and a section of expansion exhaust pipe (6); each section of expansion exhaust pipe is converged in a tail gas turbine (3), each section of expansion exhaust pipe is respectively connected with a gas storage tank (14) through a compressed air pipe (12) and an electromagnetic valve (11), the gas storage tank (14) is connected with a gas pump (15), the gas inlet end of the gas pump (15) is connected with a gas inlet pipe (16) of an internal combustion engine, the gas outlet end of each section of expansion exhaust pipe is communicated with a silencer (1) after passing through the tail gas turbine, and the gas outlet end of a push-out exhaust pipe (2) is communicated with the silencer (1); the first-section expansion exhaust pipe (5), the second-section expansion exhaust pipe (6) and the push-out exhaust pipe (2) are positioned on the same side of the internal combustion engine.

2. The apparatus for increasing energy utilization efficiency in the exhaust gas of an internal combustion engine according to claim 1, wherein: and exhaust passages which correspond to the expansion exhaust valve and the push-out exhaust valve and are mutually separated are arranged in the cylinder cover (7) corresponding to each cylinder.

3. The apparatus for increasing energy utilization efficiency in the exhaust gas of an internal combustion engine according to claim 1, wherein: the crank angle range between the opening angle of the expansion exhaust valve (8) and the closing angle of the push-out exhaust valve (10) covers the entire exhaust stroke.

4. The apparatus for increasing energy utilization efficiency in the exhaust gas of an internal combustion engine according to claim 1, wherein: the solenoid valve is supplied with control power by an engine control unit (13).