Turbocharger (design description)

General View Drawing Description of Turbocharger Structure Sheet 2 shows a longitudinal section of a turbocharger on which: a turbine impeller 8 is attached to the shaft 10, to the right, by means of a welded joint, and to the left with interference, the compressor impeller 16 is fitted and fixed using a nut 17. The shaft rotates in bearings 2, which in turn are in the housing 1. Turbine impeller is located in housing (snail) 6, which is fixed to housing of nozzle unit 5 by means of screw 3 and clamp 4, in which blades of nozzle unit 9 are located. The compressor impeller, as well as the turbine impeller, is located in the housing (snail) 21 and is attached by a bracket and screw to the housing of the blade diffuser 15, between them is the sealing ring of the snail 22. In the housing of the vane diffuser there are vanes of the diffuser 20. Sealing sleeve 19 is arranged between bearing housing and compressor impeller to receive sealing ring 14 to prevent oil ingress into compressor impeller housing. The sealing sleeve presses the washer 13 and also rests on the thrust bearing 12. Turbocompressor is attached to outlet pipeline by means of flange (7). Air inlet is provided by means of branch pipe 18. Oil is supplied to bearing housing by means of union 23, which is fixed by screw 24, and outlet by means of drain branch pipe 11. Pressure Control The need for effective pressure regulators in the turbocharging system is due to the fact that, in accordance with the characteristics of the turbocharger, its air flow increases faster than the ability of the engine to receive this air. If not discouraged by this, the turbocharger can quickly create too high a pressurization pressure, which is not permissible for engines operating on light fuels, as this leads to detonation. The methods and devices by which the pressurization pressure can be controlled are one of the most important components of the turbocharging system. Note that in order to extend the possible range of change in crankshaft speed (KB) at constant pressurization pressure, the most effective control method is to bypass part of the exhaust gases (GG) bypassing the turbine. In this method, the pressurization pressure control is based on the control of the OG flow through the turbine. The control value can be pK or pT pressures, as well as pK/p0, pT/p0 pressure ratios. Bypass valve is installed in outlet pipeline between outlet channels of engine cylinder head and turbine inlet or is mounted directly into turbocompressor housing. Depending on the value of the control value used, the valve opens and bypasses part of the VG bypassing the turbine directly into the exhaust system. When the engine is fully loaded, depending on the design parameters of the valve, 20... 40% of the total gas flow is sent to bypass the turbine. The remaining 60... 80% go to the turbine rotor drive and provide the necessary pressurization pressure. This control method, depending on the selection for the control valve of the control value, allows individual adjustment of the nature of the pressure change. Turbocharged engines having a supercharging pressure control by OG bypass usually have a good torque characteristic and satisfactory acceptance. The advantage of this control method is that by bypassing a portion of the exhaust gas bypassing the turbine, it is possible to use a turbine and a compressor of substantially smaller dimensions. As a result, even at a relatively low KB speed, a sufficiently high pressurization pressure is achieved, which allows improving engine acceptance. In this course design, I select the pressurization pressure pK as the control value. The actuator of this system includes a bypass valve resembling cylinder head valves.Valve rod end is secured to diaphragm pressed by calibrated spring. The membrane is tightly clamped along the entire perimeter by a metal cover in the form of a cap. The bypass valve is closed due to spring compression. Between the membrane and the cover there is a cavity into which control pressure is supplied. When a certain pressure pK adjusted for each engine is reached, this pressure, acting on the membrane, creates a sufficient force to compress the calibrated spring to prevent opening of the bypass valve. The valve opens and bypasses the OG bypassing the turbine. By means of the force of the calibrated spring, the supercharging pressure can be adjusted, that is, the greater the spring force, the greater the supercharging pressure can be created.