Known in the art are rotary vane machines with planetary trains designed for the above-mentioned applications, e.g., by E. Kauertz, U.S. Pat. No. 3,144,007 for Rotary Radial-Piston Machine, issued 1967 (appl. Aug. 11, 1964); U.S. Pat. No. 6,886,527 ICT for Rotary Vane Motor.
Such machines are also disclosed in German Patent No. 142119 issued 1903; German Patent No. 271552 issued 1914, cl. 46 a6 5/10; French Patent No. 844 351 issued 1938, cl. 46 a5; U.S. Pat. No. 3,244,156 issued 1966, cl. 12-8.47 and others. Mechanisms and machines for similar applications are disclosed in Russian Patent No. 2 013 597, Int. cl.5 F02B 53/00; Russian Patent No. 2 003 818, Int. cl.5 F02B 53/00; Russian Patent No. 2 141 043, Int. cl.6 F02B 53/00, F04C 15/04, 29/10, issued 1998; Ukrainian Patent No. 18 546, Int. cl. F02B 53/00, F02G 1/045, issued 1997.
Similar structure is disclosed in U.S. Pat. No. 6,739,307, US Cl. 123/245, issued May 25, 2004 for Internal Combustion Engine and Method to Ralph Gordon Morgado.
Planetary trains used in the prior-art machines provide for mutual and relative rotationally-oscillatory movement of their compression members such as rotary pistons. However, in prior-art rotary-piston machines, all thermodynamic processes occur between the positive displacement members, fuel combustion included. This results in losses of heat into the walls with lesser temperature and in a high heat load within the working chamber of the casing and the positive displacement members. As a result, dependability of rotary-piston machines becomes worse and their useful life decreases. Also, it is difficult to ensure optimal—close to spheroidal—compact shape of the combustion chamber in such rotary-piston machines structurally. Furthermore, it is practically impossible to optimally arrange the spark plug within the combustion chamber to minimize the time of flame front spread. The spark plug has to be placed at the edge of the combustion chamber near the wall of the working chamber.
The prior-art rotary-piston machines with positive displacement members have the following common structural features:
a casing having an annular chamber and an intake port and exhaust port;
at least two pairs of rotary pistons fixed on two drive shafts coaxial with the annular surface defining the chamber, and at least one of the drive shafts having a crank;
an output shaft coaxial with the drive shafts and having a carrier,
at least one external planetary gear meshed with a stationary central gear coaxial with the surface defining the chamber and with the drive shafts;
crankshaft(s) coaxial with the planetary gear;
connecting rods pivotally linking the arms of the drive shafts and crankshafts of the planetary gears.
A disadvantage of such engines resides in the fact that the chamber defined by rotary pistons is of a final volume and hot burnt gases remain there after the exhaust stroke is completed. This impairs usage of the working chamber capacity for clean air and/or the next air-fuel mixture and worsens power characteristics of the engine.
A further disadvantage resides in the fact that additional equipment is required to initiate the cyclic ignition of the air-fuel mixture at each running cycle to be strictly synchronized with the phases of the work of the kinematic mechanism of the rotary-piston machine. This is a factor that complicates the engine and decreases its operational reliability.
Known in the art are gasoline engines with precombustion chambers to ensure a combination of precombustion chamber ignition and torch ignition of very thin mixtures [1]. In this case the precombustion chamber communicates with the cylinder via a channel. Use of precombustion chambers provides for complete combustion of the fuel and enhancement of the engine efficiency at lower peak temperatures in the cylinder, the major drawback being a complicated fuel-supply system.
Also known in the art are diesel engines having separate combustion chambers—precombustion chambers and swirl combustion chambers [2]. These chambers communicate with the cylinder through one or several channels to provide for a bidirectional flow of working fluid. In such engines, the air-fuel mixture is highly turbulized to form a thoroughly mixed charge and get a complete combustion of the fuel even under moderate pressures of the fuel injection. However, due to an increase in heat losses, the efficiency of the engines with separate combustion chambers is rather low compared with the engines where combustion chambers are not separated.
The closest prior art is disclosed in WO/2009/072994 published Nov. 6, 2009; (Int. Appl.: No. PCT/UA2007\000080; F01C 1/063, F02B 53/00, F04C 2/063; POSITIVE EXPANSION ROTARY PISTON MACHINE, inventor DRACHKO, Yevgeniy Fedorovich, UA).
This is a rotary-piston machine with a planetary mechanism capable of various gear ratio transmissions, namely, i=n/(n+1), where n=1, 2, 3, 4 and so on, for various uses (for example, as engines and compressors).
This machine, in particular, comprises a casing having an annular working chamber and an intake port and exhaust port, as well as:
at least two drive shafts coaxial with the annular surface defining the working chamber and provided with pistons on one end thereof and with arms on the other end thereof,
at least one stationary central gear coaxial with the surface defining the working chamber and with the drive shafts,
an output shaft concentric with the drive shafts and having a carrier,
crankshafts connected to the arms of the carrier of the output shaft and carrying planetary gears meshed with the stationary central gear,
connecting rods linking the arms of the drive shafts and crankshafts, and
the output shaft having an offset portion carrying the carrier and a planetary gear,
the planetary gear being in mesh with the stationary central gear on the internal teeth thereof,
the carrier is pivotally connected to the arms of both drive shafts through the connecting rods.
Engines built on the concept of such rotary-piston machine suffer from a number of drawbacks.
First, to keep cyclically igniting the fuel, additional equipment is required, such as a fuel pump and high-pressure nozzles where there are the diesel cycle or spark-plug ignition in a gasoline engine implemented. The necessity of ideal synchronization of operation of the system components with kinematics of the engine is peculiar to both the diesel fuel-supply system and ignition systems of a gasoline engine. Even small deviations in the operation of synchronization systems from optimum conditions (for some reason or other) substantially impair operational characteristics of the engines. In many cases of running engines, synchronization disturbances are the cause of a malfunction.
Second, combustion takes a long time compared to maximum compression phase when the fuel is ignited cyclically. This phenomenon mostly shows up at maximum revolutions. To overcome the phenomenon, use is made of conventional methods of intensifying combustion in piston engines (e.g., turbulization of the air-fuel mixture). The point is that at high revolutions, the fuel has no time to fully combust between the rotary pistons under maximum compression. This reduces the engine efficiency and environmental safety.
Third, the fuel ignition and combustion (at a temperature about 2000° C.) takes place in the working chamber having “cold” walls (with a temperature about 300° C.) and the working chamber having walls and rotary pistons undergo a high thermal load due to a big difference between the temperatures. For this reason a large amount of heat energy is lost and the engine would require intensive heat removal (i.e., a cumbersome and complicated cooling system would be required). This complicates the engine and impairs its efficiency.
From the aforesaid it will be obvious that the drawbacks of the prior-art engine stem from its design features and the nature of its operation, notably
cyclic ignition from a high-temperature point source of heat (0.6-0.8 mm interelectrode space of a spark plug) for a gasoline engine;
cyclic ignition from a low-temperature spatial source of heat (compression ignition of diesel fuel) for an internal mixture formation;
fuel ignition and combustion in the engine working chamber between the sides of the rotary pistons.