HUP0200634A2 - Dynamically balanced engine - Google Patents

Abstract

Dynamically balanced mass engine arrangement, the cylinders of which rotate the common crankshaft have axes perpendicular to the centerline of the crankshaft rotation and the moving mass of the engine is evenly distributed along the mentioned perpendicular axes between the two sides. its dynamic mass and strength are twice that of single-sided ones. In the case of a four-cylinder version, the two extremes are located on one side of the cylinder, and the two inner ones are located on the other side. HE

Description

figures-

PUBLICATION) : COPY

Dynamically balanced mass engine layout

The invention relates to a dynamically balanced mass engine arrangement, the cylinders of which, rotating a common crankshaft in a sliding manner, have axes perpendicular to the rotational centerline of the crankshaft, and the moving mass of the engines is evenly distributed between the two sides along said perpendicular axes, and the engines are controlled synchronously.

It is a known fact that in the case of internal combustion engines, the operation is accompanied by strong dynamic effects (vibrations). The operating principle of internal combustion engines implies that the explosion occurs during a short period of the entire cycle, and work is also done during this period. In classic four-stroke engines, the power stroke in each cylinder does not occur simultaneously, which makes the work more uniform in time, but is not more favorable in terms of dynamic effects. Dynamic effects are understood as the force exerted on the crankshaft by the moving piston and its associated assemblies perpendicular to the axis and the torque acting on the axis.

Dynamic effects are primarily manifested in the vibration of the engine arrangement. In the case of motor vehicles, the strengthening of the engine and the available dead mass together alleviate the problems arising from shaking and the vibration energy is absorbed by suitable damping elements.

However, there are motor applications where, due to weight or space constraints, the motors must be made in a minimized design. Typically, such applications include all motor-operated hand tools, such as chainsaws, motorized sprayers, lawn mowers, edgers, etc. In these machines, the motor comes into direct contact with the hands or body, and the vibrations resulting from operation can be harmful to health after prolonged use.

There are many solutions to reduce engine vibrations, which are summarized, among others, in Bernhard Krause's book "Modellmotoren Technik" (Neckar-Verlag VillingenSchwenningen, 1996). Figure 3.66 of the book shows a four-cylinder boxer engine. In boxer engines, cylinders of identical design and dynamic mass are located opposite each other on opposite sides of the crankshaft, and their operation is carried out simultaneously (synchronously). The resultant of the forces exerted by boxer engines with respect to the crankshaft is zero, which is why such engines are much more favorable from a dynamic point of view than traditional engine arrangements. However, due to the mechanical arrangement, a certain distance is necessarily formed between the axes of the opposite cylinders along the crankshaft, and the two forces acting in opposite directions are transmitted across this distance as a torque arm.

-2 The crankshaft is loaded with dynamically varying torques, which results in vibration of the arrangement.

Opposite piston engines that work perfectly against each other are already known, for example, as shown in Figure 3.6 of the aforementioned book, but such an engine is also described in the Technical Lexicon under the heading “opposed piston engines”. Although such engines appear balanced at first glance in terms of both force and torque, the conversion of the opposing motion of the two pistons into rotary motion requires a complex and large structure that makes the use of such engines uneconomical. The applications with minimized engine sizes listed above simply rule out the use of such systems.

The aim of the invention is to further develop the principle of boxer engines in a way that, in addition to balancing force effects, can also ensure balancing torques, and whose dimensions are not larger than those of conventional engines with standard power and number of cylinders.

With the invention, I have created a dynamically balanced mass engine arrangement, the cylinders of which, rotating a common crankshaft in a sliding manner, have axes perpendicular to the centerline of rotation of the crankshaft, and the moving mass of the engines is evenly distributed between the two sides along the said perpendicular axes, and the engines are controlled synchronously, and according to the invention, the resultant of the torques created by the engines and referred to the centerline of rotation of the crankshaft is zero.

In a preferred embodiment, the arrangement consists of three engines, two outer engines along the crankshaft are of the same size and mass, and between them, in the middle, in opposite directions, is an engine whose cylinder and piston exert twice the force of the two outer engines, its moving mass is twice the moving mass of the outer engines, and the pistons of all engines have the same stroke length.

In this case, the diameter of the center cylinder and piston is around 1.41 times the diameter of the outer cylinders and pistons.

An alternative arrangement consists of four identical engines arranged along a common crankshaft, the two outermost ones being located on one side of said perpendicular axes and the two innermost ones being located on the opposite side of the perpendicular axes.

It is advisable to have the same distance between adjacent motors, which corresponds to the minimum distance achievable with the technology used.

-3The motor arrangement according to the invention ensures perfect dynamic balancing and, despite its small dimensions, significantly reduces the vibration affecting the body in the case of the handheld applications mentioned in the introduction.

The solution according to the invention will be described in more detail below with reference to exemplary embodiments, based on the drawings.

The drawing shows:

Figure 1 is a kinematic diagram of a first embodiment of the engine arrangement;

Figure 2 is a simplified longitudinal section of the arrangement according to Figure 1;

Figure 3 is a simplified top view in section of the arrangement according to Figure 1;

Figure 4 is a kinematic diagram of the second embodiment of the engine arrangement;

Figure 5 is a simplified longitudinal section of the arrangement according to Figure 4; and

Figure 6 is a simplified top view in section of the arrangement according to Figure 4.

The engine arrangement according to the invention is a three-cylinder engine as depicted in Figure 1, the axes of the pistons of the cylinders 1, 2 and 3 of which are parallel, the direction of movement of the two outermost cylinders 1 and 3 is the same, and that of the middle cylinder 2 is opposite. In the arrangement, the engine cylinders operate synchronously and assume one of the extreme positions depicted in Figure 1 at the same time.

The piston shafts are connected to a common crankshaft 4 with a rotation axis perpendicular to the piston shafts via bearings 5, 6 and 7, and there is the same distance x between adjacent bearings 5, 6 and 6, 7 in the direction of the crankshaft 4. The distance x must be dimensioned to the minimum that is structurally feasible.

Of the cylinders 1, 2 and 3, the two outermost cylinders 1 and 3 are of identical design, each of them has the same moving mass m, and during operation they establish the same force F along the piston axis. The magnitude of the force F varies during the cyclic operation of the cylinder, but is the same at all times for cylinders 1 and 3. The force F outlined in Figure 1 should be interpreted at the moment of explosion.

The middle cylinder 2 has a moving mass of 2m compared to the outer cylinders 1 and 3 and creates a force of 2F. This condition can be realized if the diameter of the piston in cylinder 2 is approximately 1.41 times that in the other two cylinders 1, 3, and the displacement length of the pistons is the same.

Figures 2 and 3 show front and top sectional views of the engine arrangement outlined in Figure 1. Cylinders 1, 2 and 3 contain pistons 9, 10, 11, the ends of whose shafts 13, 14 and 15 connected to the crankshaft 4 are at the same distance 1 from the center of the crankshaft 4 in the extreme position outlined in Figure 3.

-4 During the operation of the engine arrangement, not only the forces resulting from the explosion balance each other out, as in the case of traditional boxer engines, but also the torques acting on the crankshaft 4. This is easy to see if we consider that the shaft 14 of the piston 10 of cylinder 2 is connected to the crankshaft 4 at the bearing 6. If we examine the torque Fx of the force F originating from cylinder 1 at this connection point, then the torque exerted by cylinder 3 at the same point is -Fx, so the resultant of the two torques is zero. In the case of boxer engines, in accordance with the fluctuation of the force F, nothing compensates for the constant thrust Fx, and significant dynamic effects occur during the operation of the engine.

The arrangement outlined in Figures 1-3 can be repeated along the length of the 4-stroke crankshaft or in a V arrangement, each balanced unit being formed by the engine trio outlined here. In terms of operation, the individual engines can be two-stroke or four-stroke. In the two-stroke version, one explosion cycle occurs for every revolution of the 4-stroke crankshaft, while in the four-stroke version, the explosions occur once every two revolutions, therefore a flywheel with adequate inertia is required.

A four-cylinder arrangement suitable for four-stroke engines can be seen in Figures 4-6. In the kinematic diagram shown in Figure 4, four cylinders 20, 21, 22 and 23 of identical design and construction, i.e. mass, are arranged in pairs opposite and behind each other. The difference compared to the classic boxer design is that on the opposite side of cylinder 21 to the opposite cylinder 20, cylinder 22 is also on the same side and not in an opposite position, and only the outermost cylinder 23 is in this opposite position. This arrangement results in the torque generated by cylinders 20-21 with respect to the crankshaft 24 being of the same magnitude but in the opposite direction compared to the torque generated by cylinders 22, 24. The arrangement is therefore balanced in terms of both force and torque. In this case, all the cylinders and pistons are of the same size and weight, but the arrangement is one unit larger along the crankshaft 24. Figures 5 and 6 illustrate the construction of the arrangement in more detail and are similar to Figures 2 and 3.

The engine arrangement according to the invention, due to its dynamic balance, vibrates significantly less and is quieter than conventional engine arrangements. This property makes it excellently suitable for all kinds of hand-held or direct contact applications with the hand or body. Among these, we can mention chainsaws, backpack sprayers, wind and edge trimmers, lawn mowers. The generators of backup power sources are also typically vibration-sensitive systems, and the primary limitation of their use is the high level of noise generated. In addition to special engines, in the case of conventional automobile engines, serious

-5balance is an advantage. For example, the weight of the components involved in vibration damping and sound attenuation accounts for a significant portion of the vehicle's weight, and some of the engine's energy is lost in the form of excess vibration energy. Dynamic balance of the engine layout reduces the number of components listed here, thereby significantly improving the vehicle's efficiency.

Balance is of particular importance in the case of piloted and robotic helicopters, where high vibration levels limit the performance of certain tasks. Balance results in a significant reduction in vibration levels.

Claims (5)

-6Patent claims 1. A dynamically balanced mass engine arrangement, the cylinders of which, rotating a common crankshaft in a sliding manner, have axes perpendicular to the centerline of rotation of the crankshaft and the moving mass of the engines is evenly distributed between the two sides along said perpendicular axes and the engines are controlled synchronously, characterized in that the resultant of the torques generated by the engines and referred to the centerline of rotation of the crankshaft (4, 24) is zero. 2. The arrangement according to claim 1, characterized in that it consists of three engines, two outer engines along the crankshaft (4) are of the same size and mass, and between them, in the middle, in opposite directions, is an engine whose cylinder (2) and piston (10) exert twice the force compared to the two outer engines, and its moving mass is twice the moving mass of the outer engines, and the pistons (9, 10, 11) of all engines have the same stroke length. 3. Arrangement according to claim 2, characterized in that the diameter of the central cylinder (2) and piston (10) is approximately 1.41 times the diameter of the outer cylinders (1, 3) and pistons (9, 11). 4. An arrangement according to claim 1, characterized in that it consists of four identical motors arranged along a common crankshaft (24), the two outermost ones being located on one side of said perpendicular axes and the two innermost ones being located on the other side opposite the perpendicular axes. 5. Arrangement according to any one of claims 1-4, characterized in that there is an identical distance (x) between adjacent motors, which corresponds to the minimum distance achievable with the applied technology. * Authorized by: