WO2016048184A1

WO2016048184A1 - Internal combustion engine and operating method

Info

Publication number: WO2016048184A1
Application number: PCT/RU2014/000720
Authority: WO
Inventors: Борис Львович ЕГОРОВ
Original assignee: Борис Львович ЕГОРОВ
Priority date: 2014-09-25
Filing date: 2014-09-25
Publication date: 2016-03-31

Abstract

An internal combustion engine and an operating method, characterized in that an ideal thermodynamic cycle of the engine comprises: isothermic compression, isochoric heat addition, isothermic or isobaric expansion, adiabatic expansion, and isobaric or isochoric heat rejection. Isothermic compression is carried out in a compressor (12) with internal cooling of the compressed air. The compressed air is admitted into a combustion chamber (1) and heated to a given temperature and pressure. The further process of adding heat energy is adjusted depending on the operating mode of the engine in order to produce the maximum torque in the current mode. The heated working fluid is admitted into an expansion device (17) via a valve (15). After the process of adding heat energy, adiabatic expansion of the working fluid is carried out. Following expansion, the working fluid is expelled by a piston (19) via an output valve (16).

Description

Internal combustion engine and slave method

Field of Invention

The invention relates to internal combustion engines.

BACKGROUND OF THE INVENTION

Two-stroke internal combustion engines are known from the history of engine building, in which a design with separate cylinders for compression and expansion of the working fluid and a separate combustion chamber in communication with

compressor and expansion cylinders through valves.

Known gas engine Barnett, patented in 1838 and containing separate cylinders for compression and expansion and a separate combustion chamber with intake and exhaust valves. ("The Gas and Oil Engines" by Dugald Clerk, John Wiley and Sons 1896). The compression process in this engine was close to

adiabatic, and the supply of thermal energy had to be carried out cyclically with a constant volume at the moment when the piston of the expansion cylinder reached top dead center.

Engine operating methods, which also use adiabatic compression and cyclic combustion of fuel in a separate chamber communicating with the compressor and expansion cylinders by valves, are described in US patents js> 708236, publication date September 2, 1902 and US 062999, publication date May 27, 1913 .

This method of operation of an internal combustion engine is noticeably inferior to

the efficiency and reliability of the operation of four-stroke engines operating on the Otto, Diesel or Trinkler-Sabate cycle, where the processes of compression, combustion and

SUBSTITUTE SHEET (RULE 26) extensions are carried out in one cylinder. The fact is that adiabatic compression is characterized by a significant increase in the temperature of the working fluid, and for its further expansion in order to obtain useful work, it is necessary

significantly increase the temperature at the time the valve opens and the start of the expansion stroke. The high difference between the temperature in the combustion chamber and atmospheric temperature at the time of supply of thermal energy with an increase in the surfaces heated by the working fluid due to a separate combustion chamber with a valve system causes a significant increase in thermal energy loss, i.e. decreased engine performance. There are also unavoidable problems with the manufacture and ensuring the reliability of parts operating at constant high temperatures, since with a push-pull operation and compression in a separate cylinder, the parts of the expansion cylinder are not cooled by a fresh charge.

As the closest prototype selected "Method of engine operation

of internal combustion ”, RF M ° 2066773 publication date 09/20/1996. This method also provides for adiabatic compression and combustion of fuel at a constant volume. In this case, combustion is carried out for a certain period of time before the piston of the expansion cylinder arrives at top dead center. Thus, it is expected to achieve a more complete combustion of the fuel and the effective response of thermal energy. This method has the same disadvantages as the above structures, namely: the need to heat the working fluid to high temperatures after adiabatic compression to perform useful work, increase the non-insulated surfaces heated by the working fluid due to a separate combustion chamber with a valve system, problems with manufacturing and provision reliability of heat-stressed parts.

Despite the various designs of the engine with separate cylinders for compression and expansion of the working fluid and a separate combustion chamber, all known analogues operate in thermodynamic cycles that use adiabatic compression.

SUBSTITUTE SHEET (RULE 26) SUMMARY OF THE INVENTION

To implement the idea of creating an effective heat engine based on a device with a separate combustion chamber that communicates with compression and expansion chambers by means of valves, it is necessary to significantly change the thermodynamic cycle used in known analogues and prototype of this method.

To solve the problem in the proposed method is used

thermodynamic cycle with heat removal in the process of compression of the working fluid and variable, depending on the rotation frequency and operating mode of the engine, the process of supplying thermal energy and initial expansion of the working fluid.

The technical result of this method is to reduce the temperature at the end of the compression process and the average temperature of the working fluid when expanded with

the ability to more efficiently realize the expansion energy of the working fluid with less heat and pressure losses during the descent. Reducing the maximum temperature of the working fluid can also reduce the heat load on the parts and reduce heat loss. Moreover, the effective implementation of this method and the achievement of thermal efficiency of 63-65% is possible even at a maximum temperature of the working fluid not exceeding 1200-1400 ° C and an average temperature of the parts of the combustion chamber not more than 600 ° C, which allows the use of thermal insulation of the combustion chamber to minimize heat loss .

A decrease in the process temperature with a simultaneous increase in the charge density is achieved by using isothermal compression in a cycle with heat removal during the compression process.

In practice, isothermal compression is carried out in a compressor with efficient internal cooling, such as in a liquid-cooled screw compressor with a compression polytropic close to 1.1. The most optimal are the degrees of pressure increase during isothermal compression from 14 and above.

SUBSTITUTE SHEET (RULE 26) In the process of isothermal compression, air without intermediate cooling is pumped through the separator into the combustion chamber, where thermal energy is supplied.

Compressed air is introduced into the combustion chamber after the process of inlet of the working fluid into the expansion unit and closing of the intake valve

expansion installation.

In vehicle engines, to improve fuel efficiency, use a regenerative braking system with a pneumatic accumulator,

representing the heatisolated additional receiver for compressed air with a pressure regulator. When the vehicle brakes, the intake of the working fluid into the expansion unit is stopped, and the compressor continues to pump compressed air through the bypass valve into the pneumatic accumulator until the vehicle is completely stopped. Compressor performance

adjustable by pressing the brake pedal. During acceleration, the compressor is switched to idle mode or to the mode of minimum performance, and compressed air from the pneumatic accumulator is let through the pressure regulator into the combustion chamber. When the vehicle is moving at the same speed, the pneumatic accumulator is closed by means of a shut-off valve.

The supply of thermal energy is carried out inside the combustion chamber after the intake of compressed air and closing the inlet valve of the combustion chamber by continuously or periodically interrupted fuel supply with an excess of oxygen.

Ignition of the fuel is carried out from glow plugs or ignition and from the surfaces of the parts of the chamber.

Improving fuel efficiency compared to internal combustion engines used can be realized, first of all, due to a significant improvement in torque characteristics in the entire range of operation. Improving the torque characteristics is achieved by using a thermodynamic cycle with variable, depending on the operating mode and engine speed, the processes of supplying thermal energy and the initial expansion of the working fluid.

SUBSTITUTE SHEET (RULE 26) It is known that gasoline engines with external mixture formation, operating according to the Otto cycle, have maximum torque at high speeds (over 3000 rpm). Diesel engines operating on the Trinkler-Sabate cycle have a maximum torque at medium speeds (from 1700 to 3000 rpm).

Steam reciprocating engines had the highest torque at the lowest revs. Also, the first diesel engines operating on the Diesel cycle had a nominal speed of 100-200 rpm. By analogy with the well-known heat engines, the process of supplying thermal energy and

the initial expansion of the working fluid of the proposed engine is approximate depending on the speed: to the Otto cycle at high speeds, to the cycle

Trinklera-Sabate at medium speeds, to the cycle of steam piston engines or to the Diesel cycle at the lowest speeds.

The initial fuel injection is carried out at any operating conditions with a constant volume in the amount necessary to raise the temperature to 500-700 ° C.

When operating at the lowest speeds (from 50 rpm), further supply of thermal energy is carried out immediately after the piston reaches TDC at a constant pressure or constant temperature, depending on the load and power used. With an increase in speed, the amount of thermal energy supplied after TDC is reduced, and the amount of energy supplied at a constant volume to TDC is increased.

When operating at medium speeds (from 1500 to 3000 rpm), heat energy is supplied at a constant volume until a temperature of 1000-1300 ° C is reached, and then heat is supplied at a constant pressure or constant temperature depending on the load and the power used.

When operating at high speeds (over 3000 rpm), heat energy is supplied at a constant volume until a temperature of 1300 ° C or more is reached. At the maximum speed, almost all thermal energy is supplied to the TDC, or until the piston reaches 10-15 ° after the TDC, by analogy with the gasoline engine operating according to the Otto cycle.

SUBSTITUTE SHEET (RULE 26) b

The expansion process takes place first at constant pressure or constant temperature and then adiabatically without supply of heat.

At the end of the adiabatic expansion process, an exhaust valve opens

expansion machine, and the spent working fluid is pushed into the atmosphere. In the ideal case, the working fluid should expand completely to the moment of release and the process of heat removal to the atmosphere should be isobaric, but in some cases, for reasons of expediency, for example, to reduce the size of the expansion cylinders, it can be changed to isochoric. At the same time, at small and medium capacities, the heat removal process will still remain isobaric.

Environmental safety of engine operation is achieved more fully and

efficient combustion of fuel with an excess of oxygen and a lower combustion temperature with the formation of a significantly smaller amount of harmful substances.

Description of drawings

FIG. 1 TS diagram (temperature-entropy diagram) of the theoretical engine cycle at the lowest revolutions

FIG. la PV- diagram (pressure-volume diagram) of the theoretical engine cycle at the lowest speeds

FIG. 2 TS diagram (temperature-entropy diagram) of the average engine theoretical cycle

FIG. 2a PV-diagram (pressure-volume diagram) of the theoretical engine cycle at medium speed

FIG. 3 TS-diagram (temperature-entropy diagram) of the theoretical engine cycle at maximum speed

FIG. Behind the PV diagram (pressure-volume diagram) of the theoretical engine cycle at maximum speed

SUBSTITUTE SHEET (RULE 26) FIG. 4 Scheme of a device operating according to the specified method

DESCRIPTION OF EMBODIMENTS OF THE INVENTION Implementation of the indicated method of operation can be carried out in the device shown in FIG. one.

The device contains the following main elements: a piston expansion unit 17 with an inlet valve 15, an exhaust valve 16 and an anti-vacuum valve 24, a combustion chamber 1, a screw compressor 12, an air accumulator 10, a radiator of a cooling system 14, a fan 13, a fuel pump 22, a fuel tank 23, electric starter 21.

The implementation of the proposed method in the specified device is as follows:

Starting and operating the engine Open the shutoff valve 5 of the main receiver 6. Turn on the electric.

starter 21. Scroll the crankshaft 18 and drive the compressor 12. At the beginning of the movement of the piston 19 of the expansion unit 17 up, the valve 15 is closed, and the valve 4 is opened and the combustion chamber 1 is filled with compressed air. After filling the combustion chamber with a fresh charge, valve 4 is closed and fuel is injected through the nozzle 2. Using the spark plug 3, the fuel is ignited and the fuel is burned. Until piston reaches 19 TDC

close valve 16 in order to create the necessary pressure in the "dead"

space "to facilitate the opening of the valve 15 and reduce the negative impact of" dead space ". As soon as the piston 19 reaches TDC, the inlet valve 15 is opened and the working fluid is inlet from the combustion chamber 1. The electric starter 21 is turned off. Once the piston 19 reaches the BDC, open the exhaust

SUBSTITUTE SHEET (RULE 26) valve 16 and exhaust gases are pushed by the piston into the atmosphere. Next, the cycle is repeated without turning on the starter with valve 5 open.

Acceleration and braking for vehicle engines

Vehicle engines are equipped with a pneumatic brake energy recovery system consisting of a receiver 10 (pneumatic accumulator), a pressure regulator 8 and a bypass valve 9.

When the vehicle is braking, the shutoff valve 5 is closed, the non-return (anti-vacuum) valve 24 is forcibly opened and the fuel supply is stopped. Expansion unit 17 is put into idle mode. Compressor 12 continues to pump air. Using the bypass valve 9, the compressed flow is directed to the pneumatic accumulator 10. The compressor capacity is controlled by a valve 11 controlled by the vehicle’s brake pedal.

When accelerating the vehicle, the compressor 12 is transferred. to idle or low power. The pressure regulator 8 open and maintain in the main receiver 6 a predetermined pressure until the end of the acceleration mode.

An example of an idealized theoretical calculation of an engine

The calculation below is made with certain assumptions and its purpose is only to determine the theoretical potential of the proposed device operating at maximum power with maximum rotation speed in the following thermodynamic cycle: isothermal compression - isochoric heat supply - isothermal expansion - adiabatic expansion - isobaric heat removal.

Initial data

Theoretical power: 104 kW (maximum power at 5000 rpm) Rotation speed: 5000 rpm (83 rpm.)

SUBSTITUTE SHEET (RULE 26) Volume of expansion unit: 0.0023 m3 (2300 cm3)

Max. Intake air volume per cycle (revolution): 0.001 m3 (1000 cm3)

Intake air mass per cycle: 0.0012 kg

Inlet air temperature: 293K (20 ° C)

Isothermal Compression Pressure Increase: 15.2

Polytropic isothermal compression: 1.1

Volume of the combustion chamber: 0.000087 m3

Isothermal compression

Carried out in a screw compressor

V _x = 0.001m3 (intake air volume per cycle)

m = 0.0012kg (intake air mass per cycle)

R ₀ = 287; T _g = 293K; n = 1.1 (polytropic); g _p = 15.2 (degree of increase in pressure)

Work per cycle: W r p ^p - 1

W = - ^ - 0.0012-287-293 15.2 1.1 = 310.3 J

¹ 1,1-1 '

Total compression work per second (at 5000 rpm): W = 310.3 x 83 = 25755 J

Output Pressure: P = 1.52MPa

Outlet temperature: Т = 375К (102 ° С)

Gas mixing

V = 0.000087m3 (combustion chamber volume)

SUBSTITUTE SHEET (RULE 26) T _± = 693K (420 ° C) (temperature of the residual gases in the combustion chamber) P = 101000 Pa (pressure of the residual gases in the combustion chamber)

PV

^{W = ~} t ⁼ 0> 000044 kg (mass of residual gases in the combustion chamber)

T ₂ = 375K (102 ° C) (temperature of the fresh charge of compressed air)

P ₂ = 1.52MPa (compressed air pressure)

mp ₂ = 0.0012 kg (mass of fresh charge of compressed air)

„_ 0.000044-693 + 0.0012-375„ yyyy t.t

The temperature of the mixed gases: T = 386 (113 C)

^ ^JV 0.000044 + 0.0012

Mixed gas pressure: P = 1.52MPa

Heat supply

Q-Cm (T ₂ - 7)

C = 0.785 (average heat capacity of air with a constant volume of 100-1600 ° C)

PV 1525300 0.000087 _{L LL 1 1 P} , s - m = - R ₀ T = 287-386 0,> 00119 kg (Vmax, mass p ^{f of the} working body in the chamber

combustion)

T _x = 386K (113 ° C) (initial temperature of the working fluid during heat supply) G ₂ = 1930K (1657 ° C) (final temperature of the working fluid)

1930

Final pressure: P = 1.52 — Zo — b = 7.6 MPa

Q _x = 0.785-0.00119 · (1930 - 386) = 1.44503 kJ = 1445.03 J

Qz ⁼ ^ ι ⁼ 507.71J (the amount of heat required for isothermal expansion is equal to the work of isothermal expansion)

Total heat per second (at 5000 rpm):

Q = (1445.03 + 507.71); 83 = 162077.7 J

SUBSTITUTE SHEET (RULE 26) Expansion

The expansion process is divided into 2 stages:

1. Isothermal expansion with the supply of additional thermal energy

2. Adiabatic expansion

1. Isothermal expansion

Vi = 0.000087m3 (volume of the combustion chamber)

U ₂ = 0.000187mZ (the total volume of the expander and the combustion chamber at the time of the end of the heat supply, when the mass of the working fluid in the expander is 0.0012kg)

R _Q = 287; 7Ί = 1930K (1657 ° C); m = 0.00119kg

W = mRoTln ^

"l

IL ¹ = 0, '00119-287- 1930 · / p (4 ° 0', ° 0 ° 0 ° 00 "8P7 / = 507.71 J

The work of isothermal expansion - 507.71 J 2. Adiabatic expansion -L = 0.000187m3 (volume of the working fluid at the beginning of adiabatic expansion) V ₂ = 0.002387m3 (volume of the working fluid at the end of adiabatic expansion) R ₀ = 287; T _x = 1930K (1657 ° C); n = 1.4 (adiabat); m = 0.0012kg

Adiabatic expansion work

SUBSTITUTE SHEET (RULE 26) Total expansion work per second (at 5000 rpm): W = (1061.72 + 507.71) 83 = 130263 J

Efficiency

Useful work of the engine: W =, _extensions - W _{C3lcamu! L}

^ extensions - 130263 J squeeze = 25755J

W = 130263 - 25755 = 104508J (effective engine operation per second) Q = 162077J (amount of heat per second)

Theoretical power (W) = Net work per second (J) = 104508W (104 kW)

W 104 508 _L ,, „„ _{Τ Ϊτγτ h}

η = - - ₁₆₂₀₇₇ ⁼ 0.645 (theoretical thermal efficiency of the model)

findings

This calculation shows that at a maximum temperature of the working fluid of not more than 1700 "C, the thermal efficiency of the engine operating in the maximum power mode can be about 65%.

Similar calculations of the cycle for the maximum temperature of the working fluid of about 1350 ° C, presumably corresponding to the engine at medium speed, show a decrease in efficiency of no more than 1%, i.e. about 64%

With a further decrease in the maximum temperature of the working fluid, the drop in efficiency is more significant. The drop in efficiency when operating at the lowest speeds can be compensated by a decrease in heat loss and an increase in torque.

SUBSTITUTE SHEET (RULE 26)

Claims

Claim

1. An internal combustion engine, which is repelled by the fact that it contains a separate combustion chamber in communication with expansion and compression chambers by means of valves, a compressor unit with a compressible air cooling system, and a method characterized in that the ideal thermodynamic cycle of the engine includes isothermal compression, isochoric heat input energy, isothermal or isobaric expansion, adiabatic

expansion, isobaric or isochoric heat energy removal, and heat removal is carried out both in the exhaust process and in the process of isothermal compression, and the heat energy supply process is changed depending on the engine operating mode to obtain maximum torque in the current mode so that when low rotational speed, most of the thermal energy is supplied immediately after the piston reaches the expansion set top dead center, and when the rotational speed increases, the amount of thermal energy reduced after the top dead center is reduced, and summed up to the top dead center is increased so that at maximum speed almost all thermal energy is brought to the top dead center, or until the piston reaches 10-15 ° after the top dead center, reaching maximum torque at all operating modes.

2. The engine according to claim 1, characterized in that it comprises a pneumatic regenerative braking system for vehicles, consisting mainly of a pneumatic accumulator, a pressure regulator, a bypass valve and characterized in that when the vehicle is braking, the compressor pumps compressed air through the bypass valve into

the pneumatic accumulator until the car is completely stopped, while regulating the compressor performance by pressing the brake pedal, and during acceleration, compressed air from the pneumatic accumulator is let through the pressure regulator into the combustion chamber.

SUBSTITUTE SHEET (RULE 26)