RU45468U1 - SYSTEM OF CLEANING AND RECIRCULATION OF EXHAUST GASES OF THE DIESEL ENGINE - Google Patents

Abstract

The utility model is aimed at increasing the engine resource by reducing the deposition of products of incomplete combustion of fuel and oil on engine parts by forced controlled removal of exhaust gases and increasing the rate of intake of recirculated exhaust gases into the intake pipe. The indicated technical result is achieved in that the diesel engine exhaust gas purification and recirculation system includes an inlet pipe, an exhaust pipe, a recirculation pipe equipped with a cooler, an adjustable valve, a filtration device, an exhaust gas pressure sensor, and a suction-discharge device. In this case, the exhaust gas pressure sensor, the filtration device, the suction-discharge device are arranged sequentially along the exhaust gas flow in the exhaust pipe. The recirculation pipe is, on the one hand, connected to the exhaust pipe after the suction-pumping device or through the suction-pumping device, and on the other hand is connected to the inlet pipe through an adjustable valve. The suction-pumping device is equipped with an electric drive configured to control the speed.

The suction-pumping device can be made in the form of a rotor with blades mounted in a cylindrical housing with end walls, forming a flow chamber equipped with inlet, outlet and recirculation pipes. The inlet pipe of the device is in communication with the exhaust pipe. The recirculation pipe is in communication with the recirculation pipe.

Description

The utility model relates to engine building, and in particular, to devices for adding exhaust gases to the intake air before it enters the diesel engine and can be used, in particular, in the development of diesel engines of automotive vehicles to reduce exhaust toxicity.

Known internal combustion engine [A.S. SU No. 1028863, IPC F 02 M 25/06, publ. 07/15/83, Bull. No. 26], comprising a cylinder, inlet and outlet pipelines, communicated by a recirculation channel in which the heat exchanger is installed, and a pipe switching organ, moreover, a catalytic converter is placed in the exhaust pipe to the recirculation channel along the exhaust gas flow, the recirculation channel is equipped with a bypass pipe and after the heat exchanger, and the pipe switching body is installed in the recirculation channel at the point where the bypass pipe is connected to the heat exchanger.

The device allows for the purification of exhaust gases using a catalytic converter, including at idle and low loads of the internal combustion engine with compression ignition. The presence of a heat exchanger in the device makes it possible to cool the recirculated exhaust gases and thereby reduce the formation of nitrogen oxides in the engine cylinders.

The disadvantage of this device is that the catalytic converter for cleaning exhaust gases installed in the exhaust pipe creates increased aerodynamic resistance to the flow of exhaust gases and reduces its speed. The result is

coking of the piston group, which reduces the engine life. The passage of exhaust gases through the catalytic converter and the heat exchanger significantly reduces the flow rate of gases recirculated to the intake manifold. This leads to heterogeneity of the mixture of air with recirculated exhaust gases entering the engine, which worsens the combustion process and increases the amount of unburned particles deposited on the inner surface of the combustion chamber of the engine.

A known exhaust system of an internal combustion engine [A.S. SU No. 1165809, publ. 07.07.85, bull. No. 25], comprising an exhaust pipe connected by an exhaust gas recirculation pipeline to the intake manifold, and a filter and an exhaust gas composition sensor connected to the mixture formation control unit of the engine power system in series with the exhaust gas recirculation pipe.

The use of a filter in the device provides the necessary degree of purification of recirculated exhaust gases from soot, tar and other aggressive solid and liquid products, stabilizes the gas flow, dampens flame processes in the sensor zone, eliminating abrasive wear and its pollution, increasing the reliability of its sensitive elements. The regulation of mixture formation is carried out by the control unit for the composition of the exhaust gases.

However, the rate of recirculated gases in the filter decreases, which worsens the combustion process due to the heterogeneity of the intake charge.

This device does not provide for the purification of exhaust gases discharged into the atmosphere. The lack of cooling of the recirculated exhaust gas increases the formation of nitrogen oxides in the combustion chamber of the engine and leads to an increase in environmental pollution.

The closest technical solution to the claimed utility model is a device for recirculating part of the exhaust gases from the exhaust pipe of a diesel engine to the engine inlet [Patent RU No. 2230212, IPC F 02 M 25/07, F 16 K 11/052, F 16 K 11/14 publ. 06/10/2004], including an exhaust pipe, a recirculation pipe, a controlled valve device located between the engine and the air intake for supplying air / recirculated exhaust gases in the required ratio to the engine combustion chamber. The valve device contains flaps located in the inlet channels for recirculated exhaust gases and air, and at least one of the flaps is kept open, there is a drive motor for closing the second flap. The recirculation pipe is connected to the exhaust pipe of the engine after the catalyst and particle filter. A cooler is located in the recirculation pipe.

The system allows for controlled recirculation through a controlled valve and the necessary exhaust gas cleaning using a catalytic converter and a particle filter.

However, the catalytic converter and particle filter create increased hydraulic resistance to the flow of exhaust gases. This leads to a decrease in the rate of their exit from the combustion chamber and the deposition of the products of incomplete combustion contained in them on the engine parts. As a result, engine wear increases and its service life decreases.

The decrease in the flow rate of exhaust gases occurring both in the catalyst and particle filter, and in the cooler leads to a decrease in the rate of supply of recirculated gas to the valve to form a mixture with air, which significantly worsens the process of mixture formation. The resulting inhomogeneous mixture of intake air and exhaust gases during combustion increases the amount of unburned particles deposited on the inner walls of the combustion chamber of the engine.

The task to which the claimed utility model is directed is to develop an effective system for cleaning and recirculating diesel exhaust gases, which allows to increase the engine resource by reducing the deposition of products of incomplete combustion of fuel and oil on engine parts by forced controlled removal of exhaust gases and increasing the rate of intake of recirculated exhaust gases in the intake manifold.

The essence of the claimed utility model lies in the fact that the diesel engine exhaust gas purification and recirculation system includes, similarly to the prototype, an exhaust pipe, a recirculation pipe, an adjustable valve, an inlet pipe, a filtration device located in the exhaust pipe, a cooler placed in the recirculation pipe, the recirculation pipe connected to the exhaust pipe after the filtration device.

Unlike the prototype, the system further comprises an exhaust pressure sensor located in the exhaust pipe in front of the filtration device, a suction-discharge device installed in the exhaust pipe behind the filter device. The recirculation pipe is connected to the exhaust pipe after or through the suction-delivery device. The recirculation pipe is connected to the inlet pipe through an adjustable valve. The suction-pumping device is equipped with an electric drive configured to control the speed.

The suction-pumping device can be made in the form of a rotor with blades mounted in a cylindrical body with end walls forming a flow chamber equipped with an inlet, outlet and recirculation pipes, the inlet pipe communicating with the exhaust pipe and the recirculation pipe in communication with the recirculation pipe.

Thanks to this set of features, when the system is running, the gas flow through the filtering device increases, the process of removing exhaust gases and unburned particles is accelerated, preventing them from being deposited on engine parts. An increase in the rate of exit of exhaust gases from the recirculation pipe to the inlet pipe increases turbulence and improves the degree of homogeneity of the mixture of air and exhaust gases at the inlet. When a more homogeneous mixture is admitted into the engine cylinder, more complete combustion of the fuel occurs, the formation of unburned particles decreases, which leads to an increase in the engine operating life.

The suction-discharge device draws all exhaust gases through a filtration device and injects part of the exhaust gases intended for recirculation into the recirculation pipe. For this, the recirculation pipe is connected to the exhaust pipe after the suction-discharge device

The implementation of the suction-discharge device in the form of a flowing cylindrical chamber with inlet, outlet and recirculation pipes allows you to divide the stream of purified exhaust gases into two parts: recirculated and sent to the atmosphere. In this case, the connection of the recirculation pipe with the exhaust pipe is carried out through the suction-discharge device.

The rotor with blades mounted coaxially in the housing can be driven by a DC motor that changes the speed depending on the pressure of the exhaust gases in the exhaust pipe. For this, the output of the pressure sensor is electrically connected to the input of the control unit, the output of which is connected to the electric motor. If the actual pressure exceeds the atmospheric pressure in the exhaust pipe, the sensor transmits a signal to the unit

control, which converts the current signal into a control signal for the electric motor of the suction-discharge device.

The control signal of the control unit increases the speed of the electric motor of the suction-discharge device, increasing the speed of rotation of the rotor. This reduces the pressure in the exhaust pipe after the filtering device in front of the suction-discharge device, increasing the pressure difference before and after the filtering device. As a result, the speed and flow rate of exhaust gas passing through the filtration device increases. The electric motor of the suction-discharge device works until the pressure sensor in the exhaust pipe again registers the atmospheric pressure in front of the filtration device.

As a result, the speed of passage of exhaust gases through the filtering device is controlled in the event of a change in the pressure of the exhaust gases caused by a change in the number of revolutions of the diesel engine, and, therefore, the complete removal of unburned particles from the engine, which increases its service life.

The filtration device may be a ceramic particulate filter or a ceramic particulate filter with a catalytic layer deposited on its inner surface, or consist of a catalyst and a particulate filter mounted in series in the exhaust pipe.

As a pressure sensor, thick-film or semiconductor pressure sensors can be used that change the control signal depending on the pressure [Automobile reference book. Per. from English - M .: ZAO KZhI “Behind the Wheel”, 2002. - p.113-114].

The essence of the claimed utility model is illustrated by graphic images on which are presented:

- figure 1 - diagram of a system for cleaning and recycling exhaust gases of a diesel engine;

- figure 2 is a diagram of a suction-discharge device.

The exhaust gas purification and recirculation system of the diesel engine 1 (Fig. 1) comprises an inlet pipe 2, an exhaust pipe 3, in which an exhaust gas pressure sensor 4, a filtration device 5, a suction-discharge device 6 are arranged sequentially along the exhaust gas stream. 3 is connected to the recirculation pipe 7 through a suction-pumping device 6 (FIG. 2), consisting of a cylindrical body 8 having end walls 9, 10. In the end wall 9 there is an inlet pipe 11 connected outlet pipe 3. In the cylindrical wall 12 of the housing 8 there is an exhaust pipe 13 and a recirculation pipe 14 connected to the recirculation pipe 7. A rotor 15 with blades 16 is installed in the housing 8. The suction-pumping device 6 is equipped with an electric drive consisting of an electric motor 17, electrically connected to the control unit 18 and the sensor 4. The recirculation pipe 7 is equipped with a cooler 19 and is in communication with the inlet pipe 2 through an adjustable valve 20.

The system for purification and exhaust gas recirculation of a diesel engine operates as follows.

When starting engine 1, air charge enters through the intake pipe 2 into engine 1, where it mixes with fuel and burns. Exhaust gases under pressure are fed into the exhaust pipe 3, enter the device 5, where they are cleaned of products of incomplete combustion of fuel. As gases pass through device 5, their speed

reduced due to the occurrence of hydraulic friction. As a result, there is an increase in gas pressure in the exhaust pipe 3 in front of the device 5. The pressure increase in the exhaust pipe 3 is detected by the sensor 4, the signal of which is supplied to the control unit 18. At a pressure above atmospheric, the control unit 18 converts the sensor signal into the control current of the electric motor 17, which starts the rotor 15 of the suction-pumping device 6. When the rotor 15 is operating, the pressure in the area of the exhaust pipe 3 after the device 5 drops, the flow rate of exhaust gases increases as in the exhaust pipe 3 due to the absorption of gases, and in the recirculation pipe 7 due to the injection of gases. As a result, products of incomplete combustion of fuel do not have time to be deposited on engine parts.

In the suction-pumping device 6, the stream of purified exhaust gases is divided into two parts. Most are emitted through the exhaust pipe 13 of the suction-discharge device 6 into the atmosphere. A smaller part of the cleaned exhaust gases, having received an increase in speed due to the rotation of the rotor 15, is sent through the pipe 14 to the recirculation pipe 7, where it is cooled in the cooler 19 and enters the intake pipe 2 through an adjustable valve 20 for mixing with the intake air to form an intake charge that provides minimal toxicity of exhaust gases. At the same time, at idle and a load corresponding to 75% of the nominal or more, to ensure effective gas pressure in the cylinder, the adjustable valve 20 cuts off the supply of recirculated gases. An increase in the rate of passage of the recirculated exhaust gases through the pipeline 7 causes a greater turbulization of the recirculated gases, and, consequently, the degree of homogeneity of the intake charge, improving the combustion process of the fuel-air mixture and increasing the engine resource.

When the engine 1 is in transient conditions (acceleration, braking), the pressure in the exhaust pipe 3 is constantly changing and

registered by the sensor 4. The control unit 18 constantly converts the signal of the sensor 4 into the control current of the motor 17, adjusting the rotational speed of the rotor 15 of the suction-discharge device 6.

Thus, the introduction of a suction-discharge device with an electric drive and a pressure sensor into the exhaust gas purification and recirculation system will increase the speed of passage of exhaust gases both through the filtration device and in the recirculation pipeline, which will lead to an improvement in the process of mixture formation, reduction in the formation of unburned particles and more their complete removal from the combustion chamber, which will increase the life of the engine.

Claims (2)

1. A system for cleaning and recirculating exhaust gases of a diesel engine, including an inlet pipe, an exhaust pipe, a recirculation pipe provided with a cooler, an adjustable valve, a filtration device, characterized in that it further comprises an exhaust pressure sensor, an intake-discharge device, and a pressure sensor exhaust gases, a filtration device, a suction-discharge device are arranged sequentially along the exhaust gas flow in the exhaust pipe, recirculation pipe kulyatsii one side connected to the outlet conduit after the suction-blowing apparatus or the suction through the pressurizing device, on the other hand communicates with the inlet conduit through an adjustable valve, suction-blowing apparatus provided with electrically operable to regulate the speed. 2. The cleaning system according to claim 1, characterized in that the suction-pumping device is made in the form of a rotor with blades mounted in a cylindrical body with end walls forming a flow chamber equipped with an inlet, outlet and recirculation pipes, and the inlet pipe of the device is in communication with exhaust pipe, the recirculation pipe is in communication with the recirculation pipe.