RU2519128C1 - Supercharged internal combustion engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed engine comprises cylinder with piston and displacement compressor. Said piston is engaged via two co-rods with two parallel crankshafts timed by two gears. Said compressor is composed of toothed compressor discs fitted on crankshafts of diameter 2r of teeth pitch circle equal to diameter DC of timing gear pitch circle. Compressor disc tooth length b is set subject to engine piston cylinder working volume, supercharge degree e and diameter DC at the following ratio $$b=e^{1/n}*R_X^2*X/\left(m*{\eta }_V*D_C\right),$$

where n is polytropic exponent of air compression in compressor, RX is the piston outer circle radius, X is piston stroke, m is the compressor disc tooth pitch, ηV is the compressor volume efficiency.

EFFECT: simplified and compact design, higher mechanical efficiency.

2 cl, 1 tbl, 6 dwg

Description

The invention relates to the field of mechanical engineering, more specifically to reciprocating internal combustion engines, and is intended for diesel locomotives, track machines, automobiles, tractors, power plants and other power plants of carburetor, ejector, diesel.

A conventional internal combustion engine is known, comprising a block head with a gas distribution mechanism located therein; a piston cylinder with a piston that is kinematically connected by one connecting rod to the connecting rod neck of one crankshaft [1, С.14, Fig.1.1]. The advantage of the engine is the greatest simplicity of its design and acceptable efficiency in its manufacture and operation. A traditional engine has the following disadvantages.

1. When the engine is running, lateral pressure of the piston is formed on the cylinder mirror, causing its uneven wear and loss of mechanical energy to overcome friction forces, which reduces the engine resource, its mechanical efficiency, eliminates engine forcing by the crankshaft rotation speed [2].

2. The engine is subject to vibration periodically resulting from the action of vertical and horizontal forces from rotation of the crankshaft crankshaft [3].

Known piston engine without lateral pressure of the piston on the mirror of the cylinder, which has the best balance of the crank mechanism [4]. The engine contains a single-row cylinder block; a pair of crankshafts parallel to the crankcase, synchronized with a corresponding pair of gears and a pair of connecting rods for each piston. The engine is equipped with a turbocharger, the turbine of which can have several stages and be connected by transmission with one of the crankshafts to transfer excess load to the flywheel. In turbocharging, the energy of the exhaust gases is used to rotate the turbine, which rotates a centrifugal compressor that provides air to the engine. The increased mass of air entering the engine from the compressor under excessive pressure increases the specific power of the engine, reduces fuel consumption and allows to obtain a high indicator engine efficiency. The advantages of turbocharging are so great that at present the turbocharger is the main, most common unit of pressurization in internal combustion engines [5, P.71, 104]. Turbocharging has the following disadvantages.

1. When the engine is changing, there is a significant lag in the acceleration of the turbocharger due to its inertia from the acceleration of the crankshaft, which leads to an increase in exhaust smoke and a sharp loss in engine throttle response [2, C.106].

2. The use of a turbocompressor in an engine with a small displacement has a number of difficulties associated with the need to obtain the same pressures as in a high-power engine, but with a low air flow rate. Therefore, small diameter wheels are used, with a high speed of up to 240,000 rpm. For the manufacture and balancing of this design, special materials, bearings, and high-precision equipment are required [6, C.173], which greatly complicates and increases the cost of mass production of transport engines.

Known internal combustion engine with supercharging, which is equipped with a centrifugal compressor driven by the crankshaft of the engine using a boost gear transmission [7, C.260, 8]. The centrifugal compressor operates at high peripheral speed to provide the required level of pressure increase. The rotor of such a compressor rotates at a frequency of (15000 ... 200000) rpm. The advantages of a centrifugal compressor include: low weight and small dimensions, no lag in the supply of air to the engine at its partial loads, extreme compactness due to its high speed. However, the unreliability of the drive and the increased noise of the unit during operation reduce its advantages [1, P.407]. Drive centrifugal compressors are used to boost four-stroke engines. In two-stroke engines, the most common are Ruth type superchargers. Centrifugal gas blowers have the worst performance in transport installations operating at a very variable speed of rotation of the crankshaft compared to volumetric rotary gear superchargers. Such small-sized blowers have low economic indicators, and to increase the speed of rotation, a bulky step-up gearbox is required [9, P.67]. It should be noted that with the successful design of the centrifugal supercharger it provides a good flow of the working process of the transport engine, but the advantage still remains with the volumetric rotary gear supercharger [10, P.536].

A known internal combustion engine, which is equipped with a rotary gear supercharger [11, C.51]. An engine with such a supercharger provides rotation of the rotor of the supercharger of air in strict proportion to the speed of rotation of the crankshaft, which virtually eliminates the lag in the supply of air to the engine during intensive acceleration and increasing load. Thanks to the mechanical drive of the supercharger from the crankshaft, the contact of the supercharger parts with the exhaust gases with a high temperature is excluded, which occurs during turbocharging. The supercharger parts do not heat up, so there are no lubrication or cooling problems. Such superchargers are characterized by high reliability, durability and ease of manufacture in mass production. Volumetric rotary-gear with a mechanical drive from the crankshaft are preferred for boosting gasoline automobile engines, due to the high acceleration rates that they provide to the engine and the car [5, P.94]. The known engine with a positive displacement has the following disadvantages.

1. The geometric dimensions of the supercharger with a mechanical drive are assigned without taking into account the geometric dimensions of the engine design, which excludes the placement of the supercharger in the dimensions of the engine without pressurization. Such a supercharger is made in the form of a separate engine of an independent structural unit and is connected to the engine using individual fasteners, which increases the overall dimensions of the power plant.

2. The placement of a volumetric supercharger on the engine, taking into account its dimensions and the need for mechanical fastening to the engine, is also a difficult problem and, accordingly, a drawback of such an engine [5, P.95].

The main prototype is an internal combustion engine with a volume compressor, which is driven from the crankshaft of the engine using two gear pulleys or two bevel gears, a gear chain or shaft with a pair of bevel gears and a pair of synchronizing gears for mating rotors [12]. The principle of operation of such a compressor does not differ from the principle of operation of a gear pump [9, P.69, Fig.51]. Compared to a compressor having an evolute rotor profile, a gear involute rotor is manufactured in a simpler and more precise way to break-in. When the rotors rotate, the gaseous working fluid enters the cavities formed by the cavities between the teeth and is transferred without compression to the side of the injection cavity. External compression of the gaseous body occurs when the depressions communicate with the volume of the injection cavity. The main prototype has the following disadvantages.

1. The geometric dimensions of the gear rotors are made without taking into account the geometric dimensions of the piston engine, which eliminates the compact placement of the supercharger on the piston engine and reduces its overall mass indicators.

2. The compressor of the prototype includes a long chain of sequentially connected intermediary parts: pulleys or bevel gears of the crankshaft, a gear chain or a connecting gear shaft, a pair of synchronizing gears. Such a compressor reduces the mechanical efficiency of the engine, worsens the quality of the transmitted movement at the output in the form of slippage and the presence of additional unrecoverable pulsations of the injected air, and adds complexity and cumbersomeness to the engine design.

An auxiliary prototype is a twin-shaft de-axial piston engine containing a housing with a crankcase; pistons placed in the cylinders, which are connected by crescent rods to a pair of parallel crankshafts in compliance with the principle of “right with right and left with left” [13, 14]. In the known engine, the synchronization of the rotational speed of a pair of crankshafts is provided by a pair of gears mounted on their shanks. The disadvantage of this engine is that its layout is made without taking into account the geometric dimensions of the volumetric gear compressor, which eliminates the effective placement of the compressor in the dimensions of the engine, for example, without pressurization.

The task of the new development involves the creation of boost for a piston engine with a pair of synchronized crankshafts while simplifying the design of the engine and improving its compactness.

The problem is solved in that in order to synchronize the speed of rotation of a pair of compressor gear rotors, a pair of synchronized crankshafts of a piston engine is used, which eliminates the use of additional synchronization gears for compressor rotors.

The technical result of the invention is to simplify the design of the engine, improve its compactness and increase mechanical efficiency by reducing the number of parts in the design of the gear compressor and determining its geometric dimensions, taking into account the parameters and dimensions of the piston engine.

The specified technical result is achieved in that the internal combustion engine, comprising a housing block with one at least a piston cylinder and with one piston in it, connected by a pair of connecting rods with a pair of parallel crankshafts, synchronized by a pair of gears; the compressor is made in the form of a pair of synchronized crankshafts coaxially mounted on a pair of synchronized shafts, for example, on their shanks, gear compressor disks with a diameter 2r of the initial circumference of their teeth equal to the diameter D _{C of the} initial circumference of the synchronizing gears, and with the tooth length b of such disks, set from the displacement of the engine, the degree of e boost and diameter D _C in the following ratio

$$b=e^{\mathrm{one}/n}*R_X^2*X/\left(m*{\eta }_V*D_C\right),\left(\text{one}\right)$$

where n is the indicator of the polytropic compression of air in the compressor,

R _X is the radius of the outer circumference of the piston,

X is the piston stroke

m is the tooth module of the compressor discs,

η _V - volumetric efficiency of the compressor.

To reduce the imbalance of the mass of the gear discs, their teeth are made hollow.

At 2r <D _C, the required mating of the compressor disks is violated, the gaps between their mating surfaces increase, which leads to an unacceptable decrease in the volumetric efficiency of the compressor. At 2r> D _C , it is not possible to place compressor disks on synchronized crankshafts while maintaining engine dimensions.

Distinctive features of the proposed engine allow the compressor part to be made in the form of four structural elements: a pair of shanks of crankshafts and a pair of gear compressor disks. The compressor part according to the prototype [12, Fig.1a] is made in the form of 12 structural elements: a shank and a pulley 11 of the crankshaft, a pulley 10a of the driving rotor 10, a pair of synchronizing gears of the compressor, a pair of compressor disks 6, a driven shaft and at least three bearings and one assembly 12.

The compressor of the proposed engine, unlike the prototype compressor [12], works without an overdrive, which increases the reliability of the drive, its mechanical efficiency and reduces the noise of the boost.

The signs mentioned above are necessary and sufficient to achieve the specified result, that is, they are significant. The presence of distinctive features in relation to the selected prototype indicates the compliance of the claimed technical solution with the criterion of "novelty" according to current legislation.

The possibility of implementing the invention with obtaining the above technical result is illustrated by drawings.

Figure 1 shows a vertical front view in section along the piston and crankshaft; figure 2 is a section aa in figure 1; figure 3, 4, 5 - section bB in figure 1 at different angles of rotation of the compressor discs; figure 6 is an isometric General view of the proposed internal combustion engine.

The engine comprises a housing block 1 with at least one sleeve 2 and one piston 3 in it, connected by a pair of connecting rods 4,5 with a pair of crankshafts 6 and 7, synchronized by a pair of gears 8, 9 with the diameter of the initial circle D _C and a known head 10 block 1, for example, according to the patent [15]. A pair of gear compressor disks 11, 12 with an initial circle diameter of 2r = D _{C is} coaxially mounted on a pair of synchronized crankshafts 6 and 7, for example, on their shanks, using, for example, a spline connection. The design is supplemented by a suction cavity 13 with a suction pipe 14 and a discharge cavity 15 with a discharge pipe 16 and with an intake manifold 17 of the head 10. With this design, there is no need to use synchronizing gears, with their shafts, pulleys and bearings.

The engine operates in accordance with traditional push-pull or four-stroke cycles. When fuel is combusted above the piston 3, the combustion products, acting on it, drive the rods 4 and 5, which, acting on the cranks of the crankshafts 6 and 7, provide their rotation, the synchronization of rotation of which is supported by a pair of gears 8, 9. Together with the rotation of the synchronized 6.7 crankshafts rotate synchronously gear compressor disks 11, 12 in opposite directions. When the tooth leaves the cavity in the cavity 13, a reduced pressure is created and atmospheric air enters from the suction pipe 14. For example, Figures 3, 4, 5 show the position of the compressor disks 11 and 12 with a module m = 16 mm, with radii of the main circle r _o = 50 mm, the initial circumference r = 66 mm and the circumference of the tooth head r _e = 82 mm at various angles of rotation of the crankshaft of the engine. Figure 3 shows the position of the compressor disks at which the angle of rotation of the crankshaft is conventionally assumed to be zero. At an angle al = 0, the suction cavity 13 is separated from the injection cavity 15 by the lateral surfaces of the mating teeth of the compressor disks 11, 12. As the angle al increases, the cavity S _{V1 is} filled with atmospheric air while moving to the injection cavity 15. At al ~ 111 ° (Figure 4 ) the full working volume of one compressor disk is fixed. At such an angle, the suction zone 13 is separated from the discharge zone 15 by the surface of the main circle of the disk 12 and the circumference of the head of the disk 11. At al> 111 °, the tooth of the disk 12 enters the cavity S _{V1 of the} disk 11, displacing atmospheric air from it, which enters the discharge pipe 16 and into the intake manifold 17. At al> 291 ° (FIG. 5), air is displaced from the cavity S _{V1 of the} disk 11 and air is displaced from the cavity S _{V2 of the} disk 12. The processes of suction and discharge occur continuously during the rotation of the gear disks 11, 12. Located in about cavities, the teeth are a movable seal separating the suction and discharge cavities of the compressor. The gaps between the lateral surfaces of the teeth and between them and the housing are insignificant and the transported air flows from the injection cavity 15 into the suction 13 in small volumes, the value of which is determined by the volumetric efficiency of the compressor η _V.

The working volume V _K (productivity) of the compressor per revolution of the crankshaft is determined by the expression [16, C.73]

$$V_K=2{\eta }_V*\pi *{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">m</figure-callout>}}^2*z*b,\left(\text{one}\right)$$

where z is the number of teeth equal to 1. Given m * z = 2r = D _C from (1) follows.

$$V_K=2{\eta }_V*\pi *m*D_C*b.\left(\text{2}\right)$$

The working volume V _{D of a} four-stroke engine with four pistons per revolution of the crankshaft is determined by the expression

$$V_D=2\pi *{\mathrm{<figure-callout\; id="2"\; label="R\; X"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">R\; </figure-callout>}}_X^{}*X.\left(\text{3}\right)$$

It is traditionally accepted that gas compression in a compressor occurs according to a polytropic with its constant index n [1, P.71]. In this embodiment, the equation of polytropic air compression takes the form [17, S.139]

$$P_K*{\left(V_D\right)}^n=P_O*{\left(V_K\right)}^n{\text{or <figure-callout id="1" label="e" filenames="00000010.png,00000011.png" state="{{state}}">e</figure-callout>}}^{\text{1 / n}}*V_D=V_K,\left(\text{four}\right)$$

where P _K - low boost pressure, P _O - atmospheric air pressure; e = P _K / P _O. From the joint solution of equations (2, 3, 4) follows the expression for determining the length b of the tooth of the compressor discs

$$b=e^{\mathrm{one}/n}*{\mathrm{<figure-callout\; id="2"\; label="R\; X"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">R\; </figure-callout>}}_X^{}*X/{\eta }_V*m*D_C.\left(\text{5}\right)$$

As an example, the table shows the values of b calculated by formula (5) for an automobile engine with constant values of polytropes n = 1.6 [1, P.65]; radius R _X = 45 mm; piston stroke X = 70 mm; volumetric efficiency η _V = 0.85 [18, C.63] of the compressor; diameter D _C = 132 mm.

The table No. p / p S _V mm ² r _o mm 2r mm re mm z m mm Tooth length mm e = 1.3 e = 1,5 e = 1.7 one 4586 55 132 77 one eleven 135 148 160 2 6760 fifty 132 82 one 16 93 102 110 3 9475 44 132 88 one 22 68 74 80 four 10920 41 132 91 one 25 59 65 70

In the table, the area S _{V of the} depression of the compressor disks is determined using the computer-aided design system "KOMPAS - 3D".

The table shows that a pair of compressor disks, for example No. 3, can effectively replace the bulky and bulky known compressors for low boost.

Thus, a supercharged piston engine with an improved design with the best mechanical efficiency of the compressor, with increased reliability of its drive and lower noise of the boost is proposed, which is especially important for modern automobile transport, including passenger cars.

From the above it follows that the claimed invention is aimed at solving the problem with the achievement of a qualitatively new technical result and meets the requirements of patentability under the current legislation.

Information sources

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Claims (2)

1. A supercharged internal combustion engine comprising a housing block with at least one piston cylinder and one piston in it, kinematically coupled by a pair of connecting rods and a pair of parallel crankshafts synchronized by a pair of gears; characterized in that the compressor is made in the form of a pair of synchronized crankshafts coaxially mounted on a pair of synchronized shafts, for example, on their shanks, gear compressor disks with a diameter 2r of the initial circumference of their teeth equal to the diameter D _{C of the} initial circumference of the synchronizing gears, and with the tooth length b of such disks , established depending on the working volume of the piston cylinder of the engine, the degree of e boost and diameter D _C in the following ratio
$$b=e^{\mathrm{one}/n}*R_X^2*X/\left(m*{\eta }_V*D_C\right),\left(\text{one}\right)$$

where n is the indicator of the polytropic compression of air in the compressor,
R _X is the radius of the outer circumference of the piston,
X is the piston stroke
m is the tooth module of the compressor discs,
η _V - volumetric efficiency of the compressor. 2. The supercharged internal combustion engine according to claim 1, characterized in that the teeth of the compressor disks are hollow.

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