RU2525766C1 - Circulation of exhaust gases into external combustion chamber of free-piston power module with external combustion chamber - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: engine with common external combustion chamber and linear electrical generator converts exothermal energy of motor fuel into electric power and/or high-temperature high-pressure working gas power. It comprises one or several expansion machines with their pistons connected with linear electrical generator armatures, control system and exhaust gas bypass valve communicating expansion machine intake and discharge manifolds. Control system defines time interval of bypass valve open position in compliance with load set for said engine. At displacement of piston set said control system changes said bypass valve into open position for time interval in compliance with load set for said engine. Portion of exhaust gases flow from exhaust manifold into intake manifold and therefrom into piston set compression chamber and thereafter if flows together with compressed air into external combustion chamber.

EFFECT: lower toxicity of exhaust gases at partial loads mode.

1 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the field of power engineering.

BACKGROUND

The closest prototype of the claimed invention is "Free-piston twin-cylinder with a common external combustion chamber and a linear electric generator dual-purpose power module", patent 2468224.

A two-cylinder free piston with a common external combustion chamber and a linear electric generator, a dual-purpose energy module (hereinafter referred to as the energy module) converts the exothermic energy of motor fuel into electricity and / or energy of a gaseous working fluid of high pressure and temperature. It consists of two expansion machines, the pistons of which are connected to the anchors of a linear electric generator, a linear electric generator (hereinafter referred to as the generator), a common external combustion chamber and an energy module control system. It acts as follows.

Before starting the energy module (see the figure) in its combustion chamber 1. Before starting the energy module in its combustion chamber 1 there is always a certain amount of air. If the piston group (pistons 2, 3, rod 4 and generator armature 5) is in the right, figure, extreme position, the nozzle control system 6 delivers a dose of fuel to the combustion chamber 1 and ignites it with a spark plug 7. The fuel burns, resulting in temperature and pressure of combustion products increase. The products of combustion from the combustion chamber 1 through the pipe 8 through the open gas distribution valve 9 enter the right cavity of the piston 3. Under their influence, the piston group begins to move from right to left. Since the area of the right surface of the piston 3 is greater than the area of its left surface by the difference in the cross-sections of the rods on the left and right side of the piston 3, the pressure of the air compressed in the left cavity of the piston 3 is greater than the pressure of the combustion products in its right cavity. Therefore, compressed air in the left cavity of the piston 3 through the check valve 10 through the pipe 11 is supplied to the combustion chamber 1, providing combustion of the fuel injected into it by the nozzle 5. At the same time, air from the atmosphere is sucked into the right cavity of the piston 2 through the non-return valve 12, and air is released into the atmosphere from its left cavity through the open valve 13. Upon arrival of the piston group at the left extreme point of movement, the control system closes the gas distribution valves 9 and 13 and opens the gas distribution valves 14 and 15.

Under the action of the combustion products coming from the external combustion chamber 1 through the open gas distribution valve 14 into the left piston cavity 2, the piston group starts to move from left to right. Now compressed in the right cavity of the piston 2, air through the check valve 16 through the pipe 11 enters the combustion chamber 1, maintaining continuous combustion of fuel. From the right cavity of the piston 3, the exhaust gases through the open gas distribution valve 15 are released into the atmosphere, and air is sucked into the left cavity through the check valve 17 from the atmosphere. If the duty cycle proceeds according to the start-up scenario, the conversion of the energy of the expanding combustion products into the kinetic energy of the piston group will be ineffective due to the fact that the pressure of the combustion products in the left cavity of the piston 2 is practically equal to that in the combustion chamber. The expansion of the combustion products in this case occurs only when they are ejected from the cylinder at the end of the piston group path, without performing any useful work - at the moment in question through the gas distribution valve 13. Therefore, to increase the efficiency energy conversion organizes the expansion of combustion products directly in the cylinder. By analogy with an internal combustion engine (ICE), the cylinder of an energy module can be conventionally divided into two volumes. The first corresponds to the combustion chamber of the internal combustion engine - a virtual combustion chamber. The remaining volume of the cylinder, in fact, as in the internal combustion engine, is the virtual working volume.

Since the processes of energy conversion in the cylinders of both expansion machines are similar, to simplify the presentation, these processes are considered only in relation to the left expansion machine. Two scenarios of the expansion of combustion products are considered.

First option. At the beginning of the cycle, when the piston group is at the left extreme point of movement, the control system opens the intake valve 14 and the combustion products from the combustion chamber 1 enter the virtual combustion chamber of the cylinder (left piston cavity 2). As soon as the piston group begins to move under their influence, the control system closes valve 14 and the actual process of expansion of the combustion products begins, that is, in both volumes of the cylinder — in the virtual volume of the combustion chamber and the virtual working volume.

The second option. It is possible that when the expansion of the combustion products in a certain section of the movement even before the piston group reaches the extreme point of movement, the resistance to movement will be equal to the sum of the pressure forces of the combustion products and the inertia of the piston group, which will stop the piston group. Therefore, the control system based on the speed of the piston group and its mass determines the closing moment of the valve 14 already after the start of its movement in such a way that the expansion of the combustion products upon its arrival at the extreme point of movement is most effective.

In both cases, the air compressed in the right cavity of the piston 2 continues to flow into the combustion chamber 1 until the gas pressure and temperature in it reaches the level that was before the valve 14 was opened. In addition, the control system monitors the current speed and acceleration of the piston group, the pressure of the combustion products in the combustion chamber 1, the pressure of the combustion products in the left working cavity of the piston 2 and the pressure compressed in its right compressor air cavity. In accordance with these values, the control system generates an algorithm for determining the time of opening of the bypass valve 18, which ensures maximum expansion of the combustion products in the working cavity of the piston 2 by the time of arrival of the piston group at the opposite extreme point of movement, and commands the opening of the bypass valve 18.

As a result, the compressed air in the right cavity of the piston 2 flows into the left cavity of the piston 3. The counteraction of air to the movement of the piston group decreases sharply, contributing to the expansion of the combustion products in the virtual combustion chamber and in the virtual cylinder’s working volume. At this point, a certain amount of air from the atmosphere has already entered the left compressor cavity of the piston 3. The air coming in through the valve 18 to a certain degree in the right cavity of the piston 2 additionally charges the left compressor cavity of the piston 3, and air suction from the atmosphere through the valve 17 is stopped. In this case, the energy expended in compressing the air at a given phase of the cycle also is transferred there together with the air. The incoming compressed air, expanding, gives an additional impulse of kinetic energy to the piston group. The energy to overcome the dynamic resistance of air in the valve 17 is transferred to the valve 18. That is, the timing of the opening and closing of the gas distribution valve 14 and the bypass valve 18 is determined by the control system in such a way as to ensure maximum efficiency of the expansion process when the piston group moves in the virtual combustion chamber and virtual cylinder capacity.

The second expansion machine is shown on the right side of the figure. It simultaneously proceeds the same processes as in the left expansion machine. The peculiarity is that the movement of its piston group is organized in antiphase relative to the piston group of the left expansion machine. The oppositional movement of the piston groups of the energy module allows you to compensate for the reaction from their movements to eliminate vibration of the housing of the energy module and at the same time ensure the action of the generator. The stator magnet of the generator 19 may be a permanent magnet (in this embodiment) or an electromagnet magnetized by a magnetizing coil mounted on it (not shown in the figure). The magnetic flux closes along the contour: the stator magnet 19, the anchor 5, the anchor 20, and again the stator magnet 19. When the piston groups of the expansion machines converge and diverge, the magnetic lines of force of the anchors 5 and 20 intersect, the magnetic flux in the circuit increases or decreases, resulting in the stator coil 21 alternately generated pulses of electricity of one and the other sign. The valve 22 is used to operate the energy module in the generator mode of a gaseous working fluid to drive expansion machines for various purposes - expansion machines of engines for driving wheels of vehicles, jackhammers, etc.

OBJECT OF THE INVENTION

The purpose of the invention is to reduce the toxicity of the exhaust gases of the energy module (the content of nitrogen oxides NOx: NO and NO2) in the mode of partial loads on the energy module.

SUMMARY OF THE INVENTION

Known exhaust gas recirculation systems in internal combustion engines. Material from Wikipedia - the free encyclopedia.

The exhaust gas recirculation system is used on gasoline, diesel and gas engines. Designed to reduce exhaust toxicity in partial load mode. Some of the conditionally inert exhaust gases enter the cylinders as ballast, which causes a decrease in the maximum combustion temperature and, as a result, a decrease in emissions of nitrogen oxides formed at high temperatures and which are one of the most toxic substances. The simplest mechanical system is a valve connecting the intake and exhaust manifolds, which opens under the action of vacuum in the intake manifold.

In the power module, the same effect is achieved by equipping it with an additional exhaust gas bypass valve 23. To recycle the exhaust gases to the external combustion chamber, the energy module control system determines the time interval of the open position of the exhaust gas bypass valve in accordance with the specified load on the energy module. When the piston group of the energy module moves, the control system puts the bypass valve in the open position for a time interval in accordance with the specified load on the energy module. Part of the exhaust gases from the exhaust manifold flow into the intake manifold and from there into the compressor cavity of the piston, and then together with compressible air into the external combustion chamber.

SUMMARY OF THE INVENTION

A method of recirculating exhaust gases into an external combustion chamber of a free-piston energy module with an external combustion chamber, including an external combustion chamber, one or two expansion machines, the pistons of which are connected to the armature of a linear electric generator, a linear electric generator, an exhaust gas bypass valve of the expansion machine and an energy module control system, characterized in that for the exhaust gas recirculation to the external combustion chamber of the energy module, the energy module control system determines in accordance with a given load on the energy module, the time interval of the open position of the exhaust gas bypass valve of the expansion machine, puts the exhaust gas bypass valve of the gas expansion machine in the open position and keeps the exhaust gas bypass valve of the expansion machine in the open position in accordance with a certain time interval of the open position of the exhaust gas bypass valve expansion machine in the open position, resulting in a portion of the exhaust gas from the exhaust manifold torus flows into the intake manifold, is sucked through the intake manifold cavity to the compressor piston expansion machines and in compression in the compressor air cavity expansion piston machine with compressible air supplied into the outer chamber of the combustion power module.

TECHNICAL APPLICABILITY OF THE INVENTION

The costs of research and development and the production of the claimed invention cannot differ significantly from those in the design and development of classic engines. Requirements for materials and technologies do not go beyond the scope of modern capabilities.

GRAPHIC MATERIAL

Figure. Schematic diagram of a free piston with an external combustion chamber of a dual-purpose power module.

1 - combustion chamber; 2, 3 - the piston; 4 - stock; 5, 20 - anchor; 6 - nozzle; 7 - a spark plug; 8, 11 - channel; 9, 13, 14, 15 - gas distribution valve; 10, 12, 16, 17 - check valve; 18 - bypass valve; 19 - stator magnet; 21 - stator coil; 22 - valve; 23 - exhaust bypass valve.

Claims (1)

A method of recirculating exhaust gases into an external combustion chamber of a free-piston energy module with an external combustion chamber, including an external combustion chamber, one or two expansion machines, the pistons of which are connected to the armature of a linear electric generator, a linear electric generator, an exhaust gas bypass valve of the expansion machine and an energy module control system, characterized in that for the exhaust gas recirculation to the external combustion chamber of the energy module, the energy module control system determines in accordance with a given load on the energy module, the time interval of the open position of the exhaust gas bypass valve of the expansion machine, puts the exhaust gas bypass valve of the gas expansion machine in the open position and keeps the exhaust gas bypass valve of the expansion machine in the open position in accordance with a certain time interval of the open position of the exhaust gas bypass valve expansion machine in the open position, resulting in a portion of the exhaust gas from the exhaust manifold torus flows into the intake manifold, is sucked through the intake manifold cavity to the compressor piston expansion machines and in compression in the compressor air cavity expansion piston machine with compressible air supplied into the outer chamber of the combustion power module.

Images