Power transmission system for free-piston engines

Abstract

The present application relates to a hydraulic transmission system for use with free-piston engines coupled to hydraulic pumps, wherein multiple such engines are coupled to a single power transmission and output system. The system according to the present application aims to overcome the limitation of using a single free-piston engine, especially considering that in the prior art, this type of engine is used in isolation and that the power of the system, in these cases, is a function of the power of the free-piston engine itself, which makes it unsuitable for applications in which greater or variable power is required, whereas the system according to the present application can be used to power complex systems, such as isolated electrical power systems, mining, construction and road construction machinery, large agricultural machinery, forklift trucks, hydraulic booms and the like.

Description

[0001] POWER TRANSMISSION SYSTEM FOR FREE PISTON ENGINES

[0002] FIELD OF THE INVENTION

[0003]

[0001] This application relates to a hydraulic transmission system for use with free piston motors coupled to hydraulic pumps wherein multiple such motors are coupled in a single transmission and power output system.

[0004] BACKGROUND OF THE INVENTION

[0005]

[0002] The free piston engine was invented in the 1920s by Pescara, and saw limited use over the years as the main engine for gas compressors, as gas generators for early gas turbine engines. This type of engine is still used, in very small numbers, as the main engine for silent electric generators in diesel-powered submarines. However, except for its extremely limited use in submarines, its use has almost disappeared since the 1950s.

[0006]

[0003] It is worth highlighting document US7845317, which discloses a power converter system that includes a combustion system, including at least one piston, at least one combustion chamber having at least one inlet and at least one outlet with inlet and outlet valves. Also present are at least one controllable inlet valve and at least one outlet valve. A fuel supply is disclosed to provide fuel and a medium containing oxygen is provided for induction in the combustion chamber. An electrical device is arranged to interact directly or indirectly with the piston, in an electromagnetic manner, so that it produces electrical energy from the piston's movements, as well as uses electrical energy to affect the piston's movement. A control unit controls the combustion system and the electrical machine. The power converter is arranged to adapt its power depending on the required load of the power converter.

[0004] Document US8337359 discloses a hybrid engine and coupling system for use with a vehicle, or other load, that makes use of a motor / generator unit connected via controllable couplers to a kinetic energy storage device and to one or more internal combustion engine modules in a programmed manner. Various embodiments have varying configurations to meet various design, power demand and sizing requirements.

[0007]

[0005] Document US20240052924 also discloses a transmission system that includes an input shaft coupled to a main motor, a countershaft, a main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably engaging the gears between the countershaft and the main shaft. The shift actuator is mounted on an outer wall of a housing that includes the countershaft and the main shaft.

[0008]

[0006] Finally, US document 6957632 discloses a free-piston engine configured with a pair of opposed engine cylinders located on opposite sides of a fluid pumping assembly. An internal piston assembly includes a pair of internal pistons, each operationally located in a respective of the engine cylinders, with a push rod connected between the internal pistons. The push rod extends through an internal pumping chamber in the fluid pumping assembly and forms a fluid plunger within this chamber. An external piston assembly includes a pair of pistons, each operationally located in a respective of the engine cylinders, with at least one pull rod connected between the external pistons. The pull rod extends through an external pumping chamber in the fluid pumping assembly and forms a fluid plunger within this chamber.Each outer piston works with an integrated scavenging pump to compress intake air, significantly increasing the air charge density in the engine cylinders for each engine stroke.

[0009]

[0007] In summary, the state of the art provides examples of use in the field of the present invention, mainly focusing on the use of the free piston motor as a driver for linear electric generators and also as the main motor for hybrid cars. Furthermore, there has been research into the use of the free piston motor as a driver for hydraulic pumps that can transfer hydraulic energy for other uses. The limitation of this technology, however, is that the system power is a function of the power of the free piston motor itself, which makes it unsuitable for applications where higher or variable power is required.

[0010] SUMMARY OF THE INVENTION

[0011]

[0008] The present application consists of a hydraulic transmission system for use with free piston motors coupled to hydraulic pumps in which multiple of these motors are coupled in a single transmission and power output system. The system incorporates the advantage that a free piston motor, developed without rotating parts and having a single mechanical motion that is linear, is a quiet motor with little vibration.

[0012]

[0009] The system in accordance with this application is suitable for:

[0013] ■ To accumulate the combined power of the connected motors into a single power source through the installation of a large-volume hydraulic pressure accumulator,

[0014] ■ Dampen harmful harmonic frequencies created by individual motors by using this same accumulator as a hydraulic damper, as well as individual motor hydraulic dampers as needed. ■ Utilize the energy stored in the accumulator to serve as an output stabilizer for transporting loads throughout an entire power system.

[0015] ■ Utilize the energy stored in the accumulator for auxiliary power functions, such as individual engine starting pumps, lubricating oil and cooling pumps, etc.

[0016] ■ Utilize multiple free-piston motors to power complex systems, such as isolated electrical power systems, mining, construction and road building machinery, large agricultural machines, forklifts, hydraulic arms, etc.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018]

[0010] Figure 1 corresponds to a flowchart of the free piston motor system in series according to the present application.

[0019]

[0011] Figure 2 illustrates the arrangement with a single piston.

[0020]

[0012] Figure 3 illustrates the arrangement with an opposed piston.

[0021]

[0013] Figure 4 illustrates the arrangement with a double piston.

[0022]

[0014] Figure 5 illustrates a piston arrangement that is a varied configuration.

[0023]

[0015] Figure 6 illustrates the configuration with a free piston engine.

[0024] DETAILED DESCRIPTION OF THE INVENTION

[0025]

[0016] The present application consists of a hydraulic transmission system for use with free piston motors coupled to hydraulic pumps in which multiple of these motors are coupled in a single transmission and power output system. It is a system that is easy to maintain and very simple in concept.

[0026]

[0017] The system according to the present application aims to overcome the limitation of using a free piston engine, especially considering that in the state of the art the use of this type of engine occurs in isolation and that the power of the system, in these cases, is a function of the power of the free piston engine itself, which makes it unsuitable for applications where greater or variable power is required. Here, the number of pistons is variable and depends on the energy demand, being limited only by a possible restriction in terms of the size of the assembly.

[0027]

[0018] The hydraulic transmission system for use with free-piston motors coupled to hydraulic pumps according to the present application solves this limitation by coupling multiple of these motors into a single transmission and power output system that serves to:

[0028] ■ To accumulate the combined power of the connected motors into a single power source through the installation of a large-volume hydraulic pressure accumulator,

[0029] ■ Dampen the harmful harmonic frequencies created by the individual motors by using this same accumulator as a hydraulic damper, as well as individual motor hydraulic dampers, as needed.

[0030] ■ Use the energy stored in the battery to serve as an output stabilizer for transporting loads throughout the power system.

[0031] ■ Use the energy stored in the accumulator for auxiliary power functions, such as individual engine starting pumps, lubricating oil and cooling pumps, etc.

[0032] ■ Using multiple free-piston motors to power complex systems, such as isolated electrical power systems, mining, construction and road building machinery, large agricultural machines, forklifts, hydraulic arms, etc.

[0033]

[0019] In the system according to the present application, the transmission of the generated force is transmitted by hydraulic pumps and the transmitted force moves the alternators. It is also worth noting that the cylinder (piston) volume can be easily modified and, thus, the assembly can adapt to consume virtually any fuel, a very interesting aspect for isolated and small systems, where a micro-production of fuel is sufficient to power the assembly.

[0034]

[0020] As illustrated in Figure 1, the system according to the present application comprises a plurality of free piston motors (1a - 1n) which are connected to a hydraulic pressure accumulator (2) (the term “accumulator” being an illustrative description and does not reflect a single accumulator, but rather an unlimited plurality of accumulators) which, in turn, is connected to a series of hydraulic motors (3a - 3n) (hydraulic motors being preferred, but the system is not limited to these, hydraulic pistons may be employed, among others), which are powered by load (electric alternators, connected to the piston) and in which a crankcase (4) is positioned in sequence to the hydraulic motors (3a - 3n). The crankcase (4), being connected to the set of free piston motors (1a - 1n), serves the system as a whole.Here, the high-pressure oil discharge from each engine goes to the crankcase independently, resulting in an individual discharge. It's worth noting that the oil enters at high pressure and exits to the crankcase at low pressure. In a system like the one described here, the starter motor is the pressure of the system itself.

[0035]

[0021] The system according to the present application is robust, inexpensive and simple because it uses free piston engines. A diesel engine, for example, comprises 80% more parts than the assembly according to the present application.

[0036]

[0022] In a preferred embodiment, the plurality of free piston motors (1 - n) corresponds to a motor set with n = 20 and, in this way, the series of hydraulic motors corresponds to a versatile plurality that, even in this large number, is configured with very easy connection, also providing variable torque. With the configuration according to the present application, the same functionality as a corresponding conventional motor is obtained, with the advantage of absence of vibration, reduction in mass and a reduced number of parts (20% of the parts of a corresponding conventional motor).

[0037]

[0023] Important features of the power system according to the present application, constructed with multiple free-piston engines, include the fact that it allows:

[0038] ■ Simple maintenance procedures and simultaneous costs, since the power component of this engine consists of a single main moving mechanical part (with the piston and drive rods connected), instead of the hundreds associated with a modern internal combustion engine.

[0039] ■ Capable of using various fuels such as diesel, biodiesel, ethanol, gas, biogas, vegetable oil, gasoline, kerosene, aviation fuel, etc., since the cylinder volume can be varied by adjusting the power stroke.

[0040]

[0024] Figures 2 to 6 illustrate arrangements with a single piston, with an opposed piston, with a double piston, with a piston arrangement called a varied configuration, and in a configuration with a free piston motor, highlighting the absence of rotary motion where a single mechanical movement is observed which is linear, resulting in a quiet motor with little vibration.

[0041]

[0025] Although the present application has been described with respect to preferred embodiments, it will be understood that many variations, modifications, equivalent structural elements, combinations, sub-combinations and other applications of the present system may be made and do not depart from the scope of protection of the present application.

Claims

CLAIMS 1. Hydraulic transmission system for use with free piston motors coupled to hydraulic pumps, characterized in that it comprises a plurality of free piston motors (1 - n) that are connected to a hydraulic pressure accumulator (2) which, in turn, is connected to a series of hydraulic motors (3 - n), and wherein a crankcase (4) is positioned in sequence with the hydraulic motors (3 - n); the crankcase (4) being connected to the set of free piston motors (1 - n) and serving the system as a whole.

2. System according to claim 1, characterized in that the plurality of free piston engines corresponds to 20 engines present (n = 20).

3. A system according to any one of claims 1 or 2, characterized in that the hydraulic transmission system uses free-piston motors coupled to hydraulic pumps, and in that multiple such motors are coupled in a single power transmission and output system.

4. System according to any one of claims 1 to 3 characterized in that the transmission system is capable of being powered by fuel such as diesel, biodiesel, ethanol, gas, biogas, vegetable oil, gasoline, kerosene, aviation fuel, and the like.

5. Use of a system as defined in any one of claims 1 to 4, characterized in that it is for powering complex systems, such as isolated electrical power systems, mining, construction and road building machinery, large agricultural machinery, forklifts, hydraulic arms, and the like.

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