RU77358U1 - CONTROLLED INITIAL PRESSURE DIESEL FUEL SUPPLY SYSTEM - Google Patents

Abstract

The utility model relates to engine building, in particular to the design of fuel-supplying equipment for diesel engines.

The technical result is aimed at improving the efficiency of the diesel engine, as well as reducing the toxicity of exhaust gases by controlling the initial injection pressure depending on the speed and load conditions of the diesel engine and reducing the discharge period of the discharge line by organizing the recharge of the accumulator from the additional section of the high pressure fuel pump.

The technical result is achieved by the fact that the diesel fuel supply system with a controlled initial pressure, comprising a double-acting pressure valve, a low-pressure fuel line, a hydraulic accumulator connected through a double-acting valve to a low-pressure pipe and through a feed pipe and a double-acting pressure valve with a high-pressure pipe, pump high pressure, which is connected to the low pressure fuel line and connected through a double-acting discharge valve and a pipe high-pressure wire with nozzle, the plug of the pump plunger has a suction and shut-off hole, the shut-off hole has the shape of a triangle, with the base inclined relative to

the vertical axis by an angle equal to the angle of inclination of the cut-off edge of the plunger and is connected with the cut-off channel made in the pump housing, and the plunger has a regulating edge made in the form of a small chamfer with an angle of inclination a, and the inclination of the helical groove is reduced by the same amount, while the shut-off channel is connected to the low-pressure line, the accumulator is fed with an additional section of the high-pressure fuel pump, and the double-acting valve of the accumulator is made electromagnetic and controlled by an electronic block a control window that processes signals received from the speed sensor, the position sensor of the rail of the high-pressure fuel pump, and the fuel pressure sensor in front of the nozzle.

Description

The utility model relates to engine building, in particular to the design of fuel-supplying equipment for diesel engines.

A known system for supplying fuel to a diesel engine comprising a high-pressure pump, a discharge valve, a feed line, an additional channel and a non-return valve, the pump being connected to a feed line and connected through a pressure valve and a high pressure pipe to a nozzle, and a non-return valve is placed in an additional channel, which at one end is connected to the high-pressure pipeline, and at the other end to the feed line, while the plug of the pump plunger has a suction and shut-off holes and the pump has a fuel channel connected to this hole, characterized in that the shut-off hole has the shape of a rectangle rotated relative to the vertical axis by an angle equal to the angle of inclination of the cut-off edge of the plunger, while the fuel drain channel connected to the shut-off channel is made in the pump casing hole (RF patent N 2151904, F02M 55/00, 09/25/98).

The disadvantages of the known technical solutions that affect the efficiency of the diesel engine and the toxicity of the exhaust gases are: the law of increasing the effective passage section of the rectangular cut-off hole that does not provide a sufficiently intense start of cutoff,

affecting the appearance of the injection characteristics at the pressure drop section and the delaying period of the discharge of the high pressure line; lack of adjustment of the angle of advance of fuel injection (UOVT) depending on the load. This solution allows you to increase the initial pressure only to a limited value. This is due to the fact that the creation of initial pressure by a fuel priming pump (TPN) depends on the high-speed mode of operation of the diesel engine. Even at nominal speeds, the values of the maximum pressure generated by the WBC in the feed line will be significantly less than the recommended initial pressure in the high pressure pipelines. In addition, the use of an adapter and a holder complicates the design and increases the volume of the discharge line.

A known diesel fuel supply system adopted for the prototype (RF patent No. 64430, F02M 55/00, 09/10/07), comprising a high pressure pump, a double-acting pressure valve (NKDD), a low pressure fuel pipe, the high pressure pump being connected to the low pressure fuel pipe and connected through NKDD and a high-pressure pipeline to the nozzle, the pump plunger sleeve has a suction and shut-off hole, while the shut-off hole has the shape of a triangle, with the base inclined relative to the vertical axis by an angle equal to the angle Pull shutoff plunger edges and the plunger has a regulating edge formed into a shallow depth with a chamfer angle a, a slope of the helical groove is reduced by the same amount; in pump housing

made shut-off channel associated with the shut-off hole on one side and with a hydraulic accumulator through the shut-off pipe and non-return valve on the other hand; the hydraulic accumulator, in turn, is connected through a double-acting valve to the low-pressure pipeline and through the feed line and NKDD to the high-pressure pipeline.

The disadvantages of the prototype are: an increase in pressure in the shut-off line when the initial pressure in the accumulator increases, due to their direct structural relationship, which reduces the amount of fuel flowing into the shut-off line from the discharge line during shut-off due to a decrease in the pressure difference (Ragn-Rots) ” , ultimately, leads to an increase in the discharge period of the discharge pipeline; the inability to automatically control the initial pressure depending on the speed and load modes of the diesel engine, which negatively affects the coordination of the development of the fuel flame in the cylinder of the diesel engine with the movement of the air charge, thereby not ensuring the optimal flow of the processes of mixture formation and combustion

The technical result is aimed at improving the efficiency of the diesel engine, as well as reducing the toxicity of exhaust gases by controlling the initial injection pressure depending on the speed and load conditions of the diesel engine and reducing the discharge period of the discharge line by organizing recharge

accumulator from the additional section of the high pressure fuel pump.

The technical result is achieved by the fact that the diesel fuel supply system with a controlled initial pressure, comprising NKDD, a low pressure fuel pipe, a hydraulic accumulator connected through a double-acting valve to a low pressure pipe and through a feed pipe and a NKDD to a high pressure pipe, which is connected with a low pressure fuel line and connected through NKDD and a high pressure pipe to the nozzle, the pump plunger sleeve has a suction and shut-off hole, cut-off e hole has the shape of a triangle, with the base inclined relative to the vertical axis by an angle equal to the angle of inclination of the cut-off edge of the plunger and connected to the cut-off channel made in the pump housing, and the plunger has a regulating edge made in the form of a small chamfer with an angle of inclination a, and the inclination of the helical groove is reduced by the same amount, while the shut-off channel is connected to the low-pressure line, the accumulator is fed with an additional section of the injection pump, and the double-acting valve of the accumulator is made electromagnetic and is controlled by an electronic control unit that processes signals received from the speed sensor, the fuel rail position sensor and the fuel pressure sensor in front of the nozzle.

A distinctive feature of the prototype is that the shut-off channel is connected to the low-pressure line, the accumulator is fed with an additional section of the injection pump, and the double-acting valve of the accumulator is electromagnetic and controlled by an electronic control unit (ECU) that processes signals received from the speed sensor, position sensor high pressure fuel rail and fuel pressure sensor in front of the nozzle.

Figure 1 shows a diagram of a fuel supply system of a diesel engine with a controlled initial pressure;

figure 2 - diagram of the operation of the electromagnetic valve of double action (ECD);

figure 3 - scheme of the NKDD.

The fuel supply system of a diesel engine with a controlled initial pressure (FIG. 1) contains a high-pressure switch 1 connected through a low pressure pipe 2 to the suction hole 3 of the sleeve 4 of the plunger 7 of the injection pump, which also has a triangular-shaped cut-off hole 5 diametrically located to the suction hole 3 with a base parallel to the cut-off edge 6 of the plunger 7. The plunger 7, in turn, contains a Central hole 8, a diametrical channel 9, an upper end edge 10 and a regulating edge 11, made in the form of a chamfer of small depth with an angle of inclination a, and the inclination in intova grooves 12 reduced by the same amount; while the plunger space 13 is communicated through NKDD 14 through the high pressure pipe 15 with the nozzle 16, and the shut-off

the hole 5 through the shut-off pipe 17 is connected to the low pressure pipe 2. The hydraulic accumulator 18 is fed through the non-return valve 19 and the pipe 20 from the additional section of the high pressure fuel pump 21 and is communicated, in turn, from one side through the EDC 22 and the pipe 23 with the low pressure pipe 2, and on the other hand, through the feed pipe 24 and NKDD 14 with the high pressure pipe 15. The EKDD 22 is connected through electric wires 25 to the ECU 26, which receives and processes the signals of the speed sensor of the drive shaft of the high-pressure fuel pump 27, an indication of the position of the rail of the high pressure fuel pump 28 and the pressure sensor 29, which acts as a controller for the operation of the initial pressure control system (RND).

EKDD 22 (FIG. 2) contains a solenoid 30, a controlled valve 31, a controlled valve spring 32, a controlled valve limiter 33 with an adjustment screw 34, a non-return valve 35, a non-adjustable valve limiter 36 with an adjustment screw 37 and a non-return valve spring 38 in case 39.

NKDD 14 (Figure 3) consists of a housing 40 in which a working channel 41 and a feed channel 42 are made, and a valve 43 and a valve spring 44 are located.

The system operates as follows.

With the active stroke of the plunger 7 (Figure 1) after the upper end edge 10 overlaps the suction hole 3 of the plunger sleeve 4, the flow of fuel into the plunger space 13 stops and

part of the fuel from the above-plunger space 13 is displaced through the cut-off hole 5 until it is blocked by the regulating edge 11, made in the form of a small chamfer with an inclination angle a. As a result of this, the moment of overlapping of the shut-off hole 5 varies depending on the position of the high pressure fuel rail, adjusting the geometric UWT. In the above-plunger space 13, the fuel pressure increases, under the influence of which the NKDD 14 opens (Fig. 3), and the fuel is forced out through the high pressure pipe 15 to the nozzle 16. In this case, when opening, the NKDD 14 disconnects the accumulator 18 and the high pressure pipe 15. When further movement of the plunger 7 upward, the cut-off edge 6 of the screw groove 12 opens the shut-off hole 5 and fuel from the above-plunger space 13 begins to flow respectively through the central hole 8, the diametrical channel 9, the helical groove 12 of the plunger 7, from The bore hole 5 of the plug of the plunger 4 and the shut-off pipe 17 to the low-pressure pipe 2. In this case, the fuel pressure drops in the supra-plunger space 13, and the NKDD 14 closes under the influence of the fuel pressure differential in the high-pressure pipe 15 and the super-plunger space 13, a sharp cutoff of the fuel and a pressure drop in the high pressure pipe 15, as a result of which the fuel supply through the nozzle 16 is stopped.

When landing NKDD 14 in the valve seat, the accumulator 18 through the feed pipe 24 communicates with the high pressure pipe 15, resulting in a high pressure pipe 15

pressure is formed, which is the initial one before the next fuel injection cycle. In this case, the initial pressure should be insufficient for accidental re-raising of the nozzle needle. When lowering the plunger 7 after opening the suction hole 3, the supraplunger space 13 is filled with fuel, which is supplied from the discharge pipe 1 through a low pressure pipe 2 connected to the suction hole 3.

The hydraulic accumulator 18 has a volume many times greater than the maximum cyclic supply, therefore, the wave phenomena created when fuel enters the hydraulic accumulator through the non-return valve 19 and the pipeline 20 from the additional section of the injection pump 21 are attenuated. EKDD 22, connected through a pipe 23 to a low pressure pipe 2, limits the pressure in the accumulator 18 to a value equal to the required initial fuel pressure in the high pressure pipe 15 depending on the loading and high-speed diesel operation modes. In the event of a leak in the pipeline 20 or the failure of the additional section of the injection pump 21, when the pressure in the accumulator 18 decreases below the pressure of the created ТПН 1, the back pressure valve 32 of the ECD 22 acts in the opposite direction and the fuel from the low pressure pipe 2 starts to flow into the accumulator 18, protecting it and the discharge line from overload (Figure 2).

The ECU 26 receives signals from the speed sensor of the drive shaft of the injection pump 27 and the position sensor of the rail of the injection pump 28, processes

data and feeds through electric wires 25 to the solenoid 30 EKDD 22 current, the value of which corresponds to the speed and load mode of operation of the diesel engine. At the same time, a constant electromagnetic field arises in the solenoid 30 of the EKDD 22, which attracts the valve 31 with a force P _sol , _{_} which is determined by the formula:

P _sol = P _ha -P _spring ;

where R _ha - the force acting on the valve 31 is optimal for a given speed and load operation of the diesel engine pressure in the accumulator, N;

P _spring - compression force of the spring 32 EKDD 22, N.

If the real pressure P _ha ′ in the accumulator 18 turns out to be larger than the calculated optimal value P _ha , then the sum of the pressures (P _sol + P _spring ) becomes less than P _ha ′, the ECD 22 opens and the fuel flows through the pipe 23 into the low pressure pipe 2 until until the pressure R _ha ′ in the accumulator 18 becomes equal to the calculated optimal value of R _ha , after which the ECD 22 closes. Pressure sensors 29 installed in front of the nozzles 16 record the initial pressure at the moment corresponding to the beginning of the rise of the plunger 7 in the corresponding sections of the injection pump. The signals from the pressure sensors 29 enter the ECU 26, where they are averaged over the last N injection strokes (where N is the number of nozzles) to a value of P _cf , which is compared with the calculated optimal value of P _ha for a given high-speed and load operating mode of the diesel engine, after which the current coming in

the solenoid EKDD 22 increases or decreases accordingly, increasing or decreasing the pressure in the accumulator 18, i.e. adjusting the initial pressure in the high pressure pipe 15.

The need to increase the fuel injection energy in a diesel engine, which is especially important in a high-speed engine, when a short-term supply of a large portion of fuel is required, has been proved and substantiated in the work of many scientists.

There are two ways to increase the fuel injection energy: by increasing the maximum injection pressure P _vp.max and increase to the maximum possible value of the average pressure Ppv.sr at a fixed P _vp.max . Due to restrictions on the load of the drive, an increase in the maximum pressure is advisable only after the reserves for increasing P _{forwards are exhausted} . In addition, it is the value of the average pressure per cycle that determines the efficiency of the fuel supply system.

To increase the average injection pressure P _forwards, it is necessary to increase the rate of rise and fall of pressure in the initial and final phases of the process and expand the main section of the curve at the maximum fuel supply pressure. In the limit, the law of variation of the injection pressure should be as close as possible to the U-shaped.

From the point of view of improving the performance of traditional fuel supply systems, methods that allow

to regulate the initial conditions in the discharge line in the inter-cycle period.

In traditional systems, the residual pressure Growth after the next cycle becomes the initial P _beginning for the subsequent. At the same time, the requirements for the values of Growth and P _beginning are contradictory. On the one hand, at the end of the feed cycle, it is advisable to carry out a deep discharge of the discharge line to ensure a quick fit of the nozzle needle, i.e. reduce the duration of the final phase of the process and eliminate the likelihood of re-raising the needle. At the same time, the intensity of the initial injection phase substantially depends on the value of P _beg , which determines the actual moment of the beginning of the feed.

This contradiction can be eliminated if the process is organized in such a way that the value of the initial pressure, when it plays the role of the residual, is minimal, and when the role of the initial pressure is, on the contrary, increased [1].

The accumulator recharge from the additional injection pump section makes it possible to increase both the steepness of pressure increase in the fuel supply characteristics due to the creation of high initial pressures in the discharge line, and the steepness of the pressure drop during unloading due to a decrease in pressure in the shut-off line.

The control of the initial pressure in the discharge pipe of the EDC using the ECU allows you to increase the injection pressure and

to increase stability at the beginning of fuel supply and cycle feeding at low speed and load operating modes of the diesel engine.

The implementation of the RND system according to the proposed scheme will optimize the fuel supply process and, as a result, increase power, improve diesel efficiency and reduce exhaust emissions by:

- increasing the initial pressure and controlling it depending on the load and speed modes of the diesel engine, which is especially true for small and medium loads and crankshaft speeds, at which the diesel engine runs most of the time;

- adjusting the initial pressure according to the average readings of the pressure sensors installed in front of the nozzles;

- reducing the amount of fuel supplied to the combustion chamber of the diesel engine after the cut-off has begun by intensifying the discharge of the high pressure pipeline by reducing the pressure in the shut-off line;

- improving the stability of fuel supply in cycles and uniformity in cylinders.

Information sources:

1. Savelyev M.A. The influence of the formation of the initial conditions in the discharge line of the high-pressure fuel equipment on the injection characteristics [Text] / M.A. Saveliev // Sat. scientific tr No. 10. Production. Technology. Ecology. Volume 1. / - M .: 2007, p. 109-113.

Claims (1)

A fuel supply system for a diesel engine with a controlled initial pressure, comprising a double-acting discharge valve, a low-pressure fuel line, a hydraulic accumulator connected through a double-acting valve to a low-pressure pipeline and through a feed line and a double-acting discharge valve to a high-pressure pipe, a high-pressure pump, which is connected to low-pressure fuel line and is connected through a double-acting discharge valve and a high-pressure pipe to the nozzle, sleeve the pump plunger has a suction and shut-off holes, the shut-off hole has a triangle shape with a base inclined relative to the vertical axis by an angle equal to the angle of inclination of the cut-off edge of the plunger, and is connected with a cut-off channel made in the pump housing, and the plunger has a regulating edge made in the form small chamfers with an inclination angle α, and the inclination of the helical groove is reduced by the same amount, characterized in that the cut-off channel is connected to the low-pressure line, the accumulator is fed up to avochnoy section of the high pressure fuel pump and the valve double-acting electromagnetic accumulator configured and controlled by an electronic control unit processing signals received from the speed sensor, position sensor rail high-pressure fuel pump and the fuel pressure sensor before the nozzle.