WO2000079104A1

WO2000079104A1 - A system for compressing and ejecting of piston engines

Info

Publication number: WO2000079104A1
Application number: PCT/BG2000/000015
Authority: WO
Inventors: Jordan Borislavov Kolev
Original assignee: Jordan Borislavov Kolev
Priority date: 1999-06-18
Filing date: 2000-05-25
Publication date: 2000-12-28
Also published as: CA2340638A1; IL141237A0; BG103504A; CN1313928A; ZA200102199B; BR0006871A; CZ2001995A3; JP2003502567A; AU4902100A; PL346056A1; EP1108118A1; MXPA01001835A; BG63668B1

Abstract

The system is designed for compressing and ejecting of piston engines, with a field of application in the transport, in the power engineering and in any field of engineering where engines are used. Unlike the steam, gas and gas-steam thermodynamic cycles used up to now, it is an object of the proposed invention to create a system for compressing and ejecting of piston engines which to realize an air-steam thermodynamic cycle. The invention creates a possibility to increase the thermal efficiency of the piston engine up to 80-85 % taking into consideration that the steam is used to compensate the energy loss in the cycle reversibility only (mass flow about 20-30 %) but not in the full working volume of the engine as it is in the steam engine and the steam turbine. The system for compressing and ejecting consists of a steam generator (SG), an ejector (E), a piston engine (PE), a steam-air turbine (T), an air compressor (K), a thermo exchanger (TE), a condenser (C), a piston condensate pump (PC), a sweat-reservoir (SR) and control valves (CV).

Description

A SYSTEM FOR COMPRESSING AND EJECTING OF

PISTON ENGINES

Technical Field

The invention relates to the system for compressing and ejecting of piston engines, with a field of application in the transport, in the power engineering and in any field of engineering where engines are used.

Background of Art

It is known in the thermodynamics that the perfect cycle of a steam plant is the Carnot cycle realized at set temperatures and having the highest thermal efficiency among all possible thermodynamic cycles, but the modified cycle proposed by Rankine has found application in the steam plants.

Also known are gas-steam cycles combining the combustion gas and the water steam in gas-turbine plants but the thermal efficiency cannot be higher than the efficiency of each of the component cycles. In certain cases, after the pattern of the binary mercury-water plant, the gas-steam cycle has a gas-turbine stage in the high-temperature range and a steam-turbine stage in the low-temperature range. In this case the thermal efficiency is higher than the efficiency of each of the separate component cycles (the gas and steam ones) but this considerably complicates the power plant.

A gas-steam engine is known, patent RU 2054563 Cl , having a forward- flow steam generator whose outlet is connected to the active nozzle of a mixing camera, and the directing apparatus is placed on the outlet of a Laval nozzle whose inlet is coaxial with the active nozzle located in the mixing camera where the steam mixes with the combustion gas driving the blades of the inward-flow turbine which are fixed to a heat-conducting disk, etc.

Also known is a regenerative gas-turbine cycle disclosed in the patent EP 0619417 Al where the gas turbine unit includes a compressor for compressing air, a combustor for burning fuel and a turbine driven by the combustion gas, for driving the compressor. A steam-driven mixer boosts the air and mixes the steam and the air. A heat exchanger is arranged downstream of the turbine for heating the mixed gas from the mixer with heat from the turbine exhaust gas. An air line is provided for introducing a first portion of the compressed air from the compressor to the combustor and for introducing a second portion of the compressed air to the mixer. The mixed gas from the mixer is introduced to the combustor via the heat exchanger. The mixer can include either a steam turbine-driven compressor or an ejector.

Also known is a vapour-air steam engine, patent US 07/967,289 (WO 94/10427) which utilizes a working fluid consisting of a mixture of compressed uncombusted air components, fuel combustion products, and steam. In the new cycle described, the working fluid is provided at constant temperature and pressure. The combustion air is supplied adiabatically by one or more stages of compression. At least 40% of all of compressed air is burned. The inert components are injected at high pressure to produce steam and thus provide a vapour required for internal cooling of a turbine or another type system.

The main defect of the above patents is that the utilization of the air is realized by passing through the combustion camera of the engines and there is no condenser in the scheme which practically do not increase the thermal efficiency, as well as that the gas-turbine engines do not operate effectively at low rotational speed and low pressure of the working fluid.

The other defects of the steam plants are well-known: large steam boiler, large condensation devices owing to the high enthalpy of the exhaust steam, low thermal efficiency, considerable weight and volume owing to the inevitable steam lines, all this determining their use mainly in the thermoelectric power stations for burning of coal. By reason of that, their applicability in the transport is limited.

Summary of the Invention

It is an object of the present invention to create a system for compressing and ejecting of piston engines which to realize an air-steam thermodynamic cycle, unlike the steam, gas and gas-steam thermodynamic cycles used up to now.

The problem is solved by connecting in a particular way a steam generator (SG), an ejector (E), a piston engine (PE), a steam-air turbine (T), an air compressor (K), a thermo exchanger (TE), a condenser (C), a piston condensate pump (PC), a sweat-reservoir (SR) and control valves (CV), all this forming the system for compressing and ejecting of piston engines. A simple scheme is shown on Fig. 2.

If the operation of piston engine is traced on the p-v diagram (Fig. 1 ), the following processes could be described: the steam with high pressure comes from the steam generator with a pressure p] (p. l ) and flows out of the ejector nozzle with high velocity expanding in the diffuser to a pressure p2, entraining the compressed air with pressure p to pressure p2 in the cylinders of the piston engine. From (p.2) to (p.3) the air-steam mixture expand isobarically in the engine, performing work to overcome the external resistances. At the end of the working stroke of the piston, the outflow opening opens and the air-steam mixture with pressure p3 (p.3) expands adiabatically in the working wheel of the turbine-driven compressor to the atmospheric pressure p_ (p.4). From (p.4) to (p.5) the air-steam mixture passes through the condenser cooled by the air sucked from the compressor. The exhaust steam cools in the condenser to its condensing, and the air leaves the condenser with a temperature of 70-80°C. The compressed heated air from (p.5) to (p.6) mixes in the mixing camera of the ejector with the coming steam and increases its pressure to p2 (p.2) at the cylinders of the piston engine. One can see from the diagram that the closing of the cycle along the circuit 2-3-4-5-2 is impossible in the part of the compressing adiabat 6-2 owing to a loss of energy in the turbine-driven compressor. Therefore, it is necessary to increase the pressure of compressing in order to be able to utilize the energy of the compressed air for work in the piston engine. This is realized by means of a steam- jet ejector which is in its essence a jet compressor and has a simple structure.

The described path of work of the piston engine with a system for compressing and ejecting shows that a very compact use of the steam enthalpy through a cascade way, namely the path 1-2-3-4 consisting of two adiabats and one isobar. The use of a mixed air-steam cycle allows a sharp decrease in the use of steam in the engine in its full volume, thus increasing considerably the thermal efficiency of the engine, decreasing to a minimum the size of the steam generator and the condenser increasing its mobility.

An advantage of the system with compressing and ejecting is that instead of exhaust gas it uses the atmospheric air which cools the condenser and returns back to the engine the heat released at the steam condensation and at the air cooling by the air-steam mixture. This contributes to the sharp increase of the reversibility of the cycle and from there to an increase of the thermal efficiency, taking into account that the steam is used only to compensate the loss of energy in the cycle reversibility (mass flow about 20-30%) but not in the full working volume of the engine as in the steam engine and the steam turbine. It permits to reach a thermal efficiency of 80-85% which would diminish the fuel consumption from 2 to 3 times compared to the actual operational values.

Despite the low values of the operational pressure and temperature, the power of the engines with compressing and ejecting is comparable to that of the corresponding with respect to the displacement gasoline or Diesel engine owing to the fact that the operational pressure is equivalent to the effective pressure p_e of the internal combustion engines, and the working process is a two-stroke one. In addition, the engine cooling and the need of a mechanical transmission for transmit the moment of rotation to the wheels are avoided. Other important advantages are the high wear resistance of the engines with a system for compressing and ejecting as well as the noiseless operation.

Brief Description of Drawings

A realization of the invention is shown as an example on the enclosed figures, of which:

Fig. 1 shows the thermodynamic process of compressing and ejecting in a p- v diagram.

Fig. 2 is a schematic representation of the system for compressing and ejecting.

Fig. 3 is a detailed representation of the system for compressing and ejecting. Description of the Preferred Embodiments

The invention could be explained with more details using Fig. 3.

According to the invention, the system for compressing and ejecting consists of: a condenser 22 on the core of which the air draught hoods 31 are mounted, the rear ones are firmly fixed and the front ones are mounted by means of flat-wire bimetal springs 29, a lever 30 and a spring 28 (see view C). In the upper part on the condenser, a thermoexchange serpentine 23 is fixed and the lower part is shaped as a condensate reservoir 25 into which a float 26 and a needle float 27 is mounted, and is connected via a tube to the sweat-reservoir 3 in which a condensing serpentine 2 is mounted on which outlet a control valve 7 is mounted. The steam generator 14 is connected to the high-pressure part of the ejector 12 whose outlet is connected to the inlet port of the piston engine 24 whose exhaust port is connected to the air-steam turbine 5. On the condenser 22, the air compressor 4 and the air-steam turbine 5 are mounted forming a turbine-driven compressor and are connected via openings to the condenser 22, the opening of the compressor being closed by a valve 1 connected by means of the air draught hoods 31. The compressor 4 is connected via the thermo exchanger 6 with the low- pressure diffuser 10 of the ejector 12 and this low-pressure diffuser is pressed by the precision spring 8 and is enveloped by the casing ring 9, and in it the low- pressure profile rollers 17 are located having on their cylindrical surface semicylindrical channels with variable section and rugged pins 18 mounted into them. Smaller-size high-pressure profile rollers 16 are mounted into the high- pressure diffuser 11 in which the pushing pins 15 are placed and the diffuser 1 1 is pressed by a spring 13. On the crankshaft axle of the piston engine 24, the cam disk 35 is fitted which contacts with the piston condensate pump 32 fixed on a carrier 21 mounted on the axle 20. The piston condensate pump 32 is connected to the drive mechanism 33 coupled to a screw with right-hand thread 40 placed into a nut with right-hand thread 39 and connected with a screw with left-hand thread 44 placed into a nut with left-hand thread 42 by means of a clutch sleeve 41. The nuts 39 and 42 are mounted together into a cutout in the body of regulator 43 and into two oblique cutouts in the triangular plates 45 connected to the pressure regulator 34 via a tube for the steam generator 14 and the four-bar mechanism 19 which is mounted together with the pusher of four-bar mechanism 36, the weight 37 and the V-shaped feet 38. The inlet of the piston condensate pump 32 is connected to the condensate reservoir 25, and the outlet is connected in series with the thermoexchange serpentine 23, the thermo exchanger 6 and the steam generator 14.

In order to prove the advantages that can be obtained using the present invention, the theoretical cycle of a piston engine with compressing and ejecting is described below.

The thermodynamic cycle (fig. 1) consists of the following processes: 1-2 - adiabatic expansion of the steam in the ejector; 2-3 - isobaric expansion of the air- steam mixture in the piston engine; 3-4 - adiabatic expansion of the air-steam mixture in the turbine; 4-5 - isobaric condensation of the steam; 5-6 - adiabatic compression of the air in the compressor.

If one traces the processes according to the p-v diagram (Fig. 1 ), one can see that the piston engine operates with a steam, an air and three mixed air-steam cycles. The thermodynamic processes in the piston engine with a system for compressing and ejecting are described below.

The work of the piston engine is equal to the sum of the works of the compressor and ejector

L_pe = L_e+L_k = m_s Cp^S ( T ι -T2 ) +m_ac_pa ( T2 -T_at_m ) , J/ s where Cp^s - the specific heat of the steam at constant pressure Cp^a - the specific heat of the air at constant pressure

or L_pe = P2N_S , J/ s where V_s - the second volume of the engine which is equal to the sum the partial volumes of the steam and the air in the air-steam mixture

V_s = V_s s+v_sa , or

nVi V_s = , _m

60 where V]_ - the engine displacement m^>_ and n - the engine revolutions per minute

The power of the engine could be determined by the formula:

^Lpe N_pe = , kW

1000 The law of conservation of energy serves as a base to work out the energy balance. For an open thermodynamic system it reads: the sum of the inflows is equal to the sum of the outflows:

^∑win = ^Σwout

For the relation between the work of deformation and the absolute work, one can write:

Id ⁼ l s or le+l = lpe . J kg

After multiplying the left side of the equation by the mass flow of the steam and air, m_s and m_a respectively, one obtains: m_s e+m_al k = Lpe . ( D Le+^k ⁼ Lp_e, J/s

In order to determine the two unknowns - the steam mass flow in the engine m_s and the air mass flow m_a, one has to work out a second equation, namely for the relation of the adiabatic work in the turbine-driven compressor, from where the relation between m_s and m_a is found and substituted in Equation

(1)

m_alk = ηtk(m_al^at+m_sl^St) (2) or L_k = ηtkLt

From the cycling process of the piston engine with compressing and ejecting realized in this way, one can see the heat introduced in the engine comes from the heat introduced by the steam into the ejector and the heat introduced by the air compressor which utilizes the heat of the waste air-steam mixture.

Thus, one obtains for the introduced heat: q_s = i"-i', J/kg

Q_s = m_s(i"-i') , J/s where i " - enthalpy of the dry saturated steam i ' - enthalpy of the water injected in the steam generator

For the heat returned back to engine, one obtains:

q = c^a _p (T₆-T_atm) , J/kg

Qa = m_ac^ap (T₆-T_atm) , J/s

The thermal efficiency (η^) is used to evaluate the thermal cycle

Q-Qo η_t =

Q where Q - the introduced heat equal to Q_s - the heat introduced with the steam from the steam generator

Q₀ - the heat abstracted from the engine equal to Q_s- (L_e+Lk) , i.e. equal to the difference between the introduced heat and the work performed in the ejector plus the compressor work.

After substituting into the formula for the thermal efficiency, one obtains:

Q_s-{Q_s-( _e+L_k) } L_e+L_k L_pe η_t = = = =

Q_s Qs Qs m _sc_p ^s ( T₁-T₂ ) +m_ac_pa ( T₂-T atm'

TCL_ ; i ' ' -i

Analyzing the formula for the thermal efficiency of the piston engine with compressing and ejecting, one can see that the efficiency increases with the increase of the efficiency of the turbine-driven compressor and with the decrease of the evaporation heat r = i " -i ' , which depends, on the other hand, on the nature of the working fluid (water, alcohol, ammonia, freon, etc.) as well as on the degree of heating of the working fluid to be injected in the steam generator,

In the present case, a new reversibility factor of the cycle could be introduced, i.e. the ration of the heat returned back from the compressor and the condenser into the engine to the heat introduced with the steam:

la ¥ I c m_ac_p ^{a (} T₆-T₅ ⁾ +m_ac_p ^{a (} T₅-T_atm ⁾ η

Q_ rt

m_ac_p ^a ( T₆-T_atm)

m_s ( i ' ' -i '

Comparing the efficiencies and the thermodynamic parameters of the engine with a system for compressing and ejecting to the gasoline and Diesel engines, one can see that ηt is at least two times greater than that of the internal combustion engines, the maximum pressure is 5 to 10 times smaller, the maximum temperature is also up to 10-15 times smaller, and the rotational speed is 4-16 times smaller than that of the gasoline and Diesel engines.

Industrial Applicability

The system for compressing and ejecting operates as follows: Through the medium of the drive mechanism 33 put into motion by the accelerator pedal of the piston engine 24, the screw with right-hand thread 40 starts turning and by means of the clutch sleeve 41 and the screw with left-hand thread 44 which, by turning the nuts 39 and 42, brings nearer the carriers 21 on which the piston condensate pumps 32 are fixed, and by means of the cam disk 35, a sucking of condensate from the condensate reservoir 25 is performed and it is supplied under pressure via the thermoexchange serpentine 23 an the thermo exchanger 6 into the steam generator 14. The steam obtained in the steam generator flows into the high-pressure area of the ejector 12 where operates the pushing pins 15 and pushes them under the action of the pressure to the low-pressure diffuser 10 creating a clearance δ (see B-B) through which passes the low-pressure air flow from the air compressor 4. The motion of the pushing pins 15 is strictly determined depending on the precision spring 8. When the pushing pins 15 move, the high- pressure profile rollers 16 start turning through the medium of the rugged part, and these rollers ensure, by changing the section of the opening formed at their turning, a high-speed steam flow from the diffuser 1 1 into the diffuser 10. In the same way operate the rugged pins 18 which, propped on the wall of the ejector 12 when the diffuser 10 moves, turn the low-pressure profile rollers 17 by which at each moment, depending on the engine load, the optimum operational parameters of the ejector are automatically ensured. The air-steam mixture thus obtained with precisely determined parameters of the pressure, temperature and volume flows during the whole working cycle into the engine and provides a power exactly corresponding to the external resistances.

During the intake stroke of the piston, the exhaust port is open; this port is connected via a tube to the air-steam turbine 5 which drives the compressor 4. The waste air-steam mixture passes through the condenser 22 where the steam condenses is collected in the condensate reservoir 25 in which by means of the float 26 and the needle float 27, a constant level is maintained. The humid air from the condenser passes through the condensing serpentine 2 into the sweat-reservoir 3 where a further condensation of the air moisture takes place. The air thus dried leaves the system or flows via the control valve 7 into steam generator 14 to be burned.

The air in the system for compressing and ejecting is sucked in to the air compressor 4 through the air draught hoods 31 which are automatically driven by a flat-wire bimetal spring 29 heated by the air-steam mixture in the condenser 22, a lever 30 and a spring 28. At the start of the operation, the movable air draught hoods 31 are in the lower position (see view C). As it is, the cooling air enters through one only cooling sector into the condenser 22. When heated, the flat-wire bimetal spring 29 bends and shifts upwards the lever 30 and the spring 28 fixes tightly the hood to the condenser wall. As it is, the cooling air enters through three cooling sectors into the condenser 22. And the last position is when the second bimetal spring 29 also heats to the corresponding temperature and the second air draught hood 31 shifts upwards. Then the cooling air passes through all the five cooling sectors of the condenser 22 (see section A-A). The valve 1 serves to switch the compressor 4 to suction not only of atmospheric air but also of air- steam mixture from the condenser at a determined operation mode of the engine as in the case of an fully capsulated system for compressing and ejecting using the engine in vacuum.

The four-bar mechanism 19 and the pressure regulator 34 serve to limit the rotational speed and the pressure in the engine. They operate either separately or together, depending on the operational mode of the engine. For example, at low rotational speed and high load, only the pressure regulator operates, and at high rotational speed and load, both of them operate together. Both of them are connected with the triangular plates 45 which have two oblique cutouts where the guides of the nuts 39 and 42 enter. When the pressure into the steam generator 14 exceeds the specified value, it acts through a tube of the pressure regulator 34 and pushes the plate 45 upwards, thus drawing apart the nuts 39 and 42 which move in a cutout into the body of regulator 43 and the nuts, on their part, push the screws 40 and 44 that are fixed to the carriers 21. Thus, the stroke of the piston condensate pumps 32 diminishes, as well as the water amounts injected into the steam generator 14. When the rotational speed exceed the admissible, the centrifugal force created by the weights 37 acts on the V-shaped feet 38 and, on their part, shift the pusher of four-bar mechanism 36 and by so doing the four-bar mechanism 19 draws the triangular plate 45 upwards thus drawing apart the nuts 39 and 42 as well as the piston pumps 32 from the cam disk 35, thus reducing the amount of the injected condensate.

Claims

C L A I M S

1. A system for compressing and ejecting of piston engines including a steam generator (14), an ejector (12), a piston engine (24), an air-steam turbine (5), an air compressor (4), a thermo exchanger (6), a condenser (22), a piston condensate pump (32), a sweat-reservoir (3) and control valves (1 ) and (7), characterized in that the steam generator (14) is connected to the high-pressure part of the ejector (12) whose outlet is connected to the inlet port of the piston engine (24) whose exhaust port is connected to the air-steam turbine (5) which is mounted to one and the same shaft with the compressor (4), and both of them are placed on the condenser (22), the outlet of the turbine (5) is connected to the interior of the condenser (22), the inlet of the compressor (4) is connected to the air draught hoods (31) and to the interior of the condenser (22) by a valve (1 ), the lower end of the condenser (22) is connected via a tube to the sweat-reservoir (3) in which a condensing serpentine (2) is mounted on which outlet a control valve (7) is mounted, the outlet of the compressor (4) is connected in a series with the thermo exchanger (6) and the low-pressure part of the ejector ( 12); the inlet of the piston pump (32) is connected to the condensate reservoir (25), and the outlet is connected in series with the thermoexchange serpentine (23), the thermo exchanger (6) and the steam generator (14).

2. A system for compressing and ejecting of piston engines according to claim 1 , characterized in that the ejector (12) consists of a low-pressure diffuser (10) with mounted into it low-pressure profile rollers (17) connected with rugged pins (18), pressed by a precision spring (8) and enveloped by a casing ring (9); and of a high- pressure diffuser (1 1) with mounted in it high-pressure profile rollers (16) connected with pushing pins (15), pressed by a spring (13).

3. A system for compressing and ejecting of piston engines according to claim 1 , characterized in that an air draught hoods (31 ) are mounted on the condenser (22), the rear ones firmly fixed and the front ones connected by flat-wire bimetal springs (29), a lever (30) and a spring (28), in its upper part a thermoexchange serpentine (23) is manufactured, and the lower part is shaped as a condensate reservoir (25) in which a float (26) and a needle float (27) are mounted.

4. A system for compressing and ejecting of piston engines according to claim 1 , characterized in that on the axle of the piston engine (24), a cam disk (35) is mounted on which a piston condensate pump (32) is propped, fixed on a carrier (21) mounted on an axle (20) connected with a drive mechanism (33) fixed by a screw with right-hand thread (40) fitted into a nut with right-hand thread (39) and connected with a screw with left-hand thread (44) fitted in a nut with left-hand thread (42) by means of a clutch sleeve (41 ); the nuts (39) and (42) are placed into a cutout in the body of the regulator (43) and into two oblique cutouts of the triangular plates (45) which are connected to the pressure regulator (34) which, on its part, is connected by means of a tube to the steam generator (14) and by means of the triangular plates (45) to the four-bar mechanism (19) which is mounted together with the pusher of four-bar mechanism (36), the weight (37) and the V- shaped feet (38).