in the gap in the ring lock by 6.28 mm. Total “allowable” increase in the gap in the compression ring lock will be 7.22 mm! This is without thermodynamic, i.e. thermal extensions [4].
It is difficult to imagine how such a “thin” seal, in the design of which, by definition, there should not be any gaps, or they should be reduced to an insignificant minimum. Unfortunately, it’s hard to argue with opponents who have disarming arguments. At first, the engines “work fine”, and secondly, the compression piston rings are made exactly in accordance with the instructions of the domestic standards [8] and [9].
In this case, the question arises, why the “modern” internal combustion engine is so “good”? The answer is obvious, if you give an example from everyday life, answering a similar question: can you take a bucket of water with a sieve? Of course you can. It needs to be done very quickly and for a long time, but… the efficiency is too small.
Is the engine has a high efficiency? No! Maybe he has a small rotation speed of the crankshaft? Also, no. On the latest models of VAZ engines, small-gas turns are already over 1000 min-1!
The engines of the Formula-1 maximum power reach over 22 000 min -1, while after each race there is a major repair of the engine.
So, what are the conclusions will be drawn?
Proceeding from a purpose of a working step “admission”, it is necessary to remember, the consolidation between the piston and the cylinder, the excluding, any suction from the crankcase is more reliable, the extent of discharge of space over the piston is more; the more actively there is a fence of an atmospheric air and implementation of rated data.
First of all, it is worth paying attention to the design of the cylinder-piston group and, first of all, the design, shapes and dimensions of the piston rings. It’s incomprehensible! With a complete change in the entourage of the car, the famous AvtoVAZ, which is quite competitive with foreign models, for decades the engines are equipped with permanent piston rings, performed at the will of the standards.
It is worth noting that the equipment and technology for the manufacture of piston rings not only for the AvtoVAZ engines but also for KAMAZ, YaMZ and other engines was used by the world famous German company Goetze, which is under the patronage of the equally famous Federal Mogul concern – “the advanced European manufacturer of the engine gaskets and piston rings”. That is, all claims to poor-quality piston engine compaction should be presented not to the main designers of these engines, but to world-famous specialists with whom the “main” are in solidarity.
To this we must add the following circumstance. From the advertisement of its latest achievement, the manufacturer of the elements of CPG the Kostroma-Motordetal presented “ncMDChr (nanochrome) – a new generation coating is applied to the working surface of the upper compression and oil-removable piston rings”! Especially shocking “… and oil-removable rings”, inefficient, performing a rough operation of removing oil from the cylinder wall, in a continuous oil environment.
It is unclear why to apply “nanochrome” on them, if the working surface of the oil-removable piston ring does not wear out and without “nano”. When it is necessary to change the piston rings, along with the compression rings, oil-removable rings also fall into disassembly, but not because they have a “worn working surface”, but because the waste oil is clogged, sometimes coked, by the spiral extension of the oil-removal ring. This is especially true of the diesel engines. The inefficient oil-removal piston ring becomes generally inoperable.
This is an example of the imperfection of the widely used oil-removable ring with useless “nanochrome”. Nevertheless, Kostroma is pleased, scientific and technological progress all that is needed for the buyer to “appreciate” these innovations.
The design of compression piston rings, subjected to rigid analysis by the author, continue to “live” and “improve.” The achieved results of the research and the proposed measures for the recognized authorities of the car industry are not so “obvious”, there may be other reasons that have nothing to do with science.
The low efficiency of consolidation between the piston and cylinder is one of the most important problems of the ICE. The negative consequences of this decision are obvious, the engine can “earn” and operate normally only at huge speeds of rotation of the crankshaft, boosting the engine work. What leads to “forcing” should be known even to the motorist.
The problem of gaps is only part of the general problem of the “cylinder-piston ring-piston” system. In this case, on a working step “admission”, in the absence of excessive pressure over the piston, the mechanical friction losses of the compression rings affecting the efficiency of the engine or compressor The magnitude of the mechanical losses at the “admission” step depends on the magnitude of the elastic forces of the piston seal ring and the friction coefficient of the two kinematic elements: “Piston ring-cylinder”, more specifically, the working surface of the piston ring and the cylinder wall.
The shape and dimensions of the piston seal ring at the “admission” step depend mainly on the design value of the minimum necessary elastic force of the ring. It is necessary to determine the magnitude of the elastic force of the piston ring and the necessary material from which the ring should be made.
In analysis of the reasons for the low efficiency of internal combustion engines, it was found that in calculating the sizes and permissible deviations in the manufacturing process, in domestic engines, especially in the cylinder-piston group, there is lacks precision; therefore, as one of the measures to increase the efficiency of internal combustion engines, in the system “cylinder – piston ring – piston “was held minimization of gaps [10].
The modern piston rings, depending on their size, are mainly made of steel and cast iron. The researches, the developed theory of designing of the piston rings provide an opportunity of manufacturing of rings from other metals and alloys, and also nonmetallic materials. For example, the domestic company LLC “Compressor Technologies” advertises bronze with various fillers, various plastics as a material for manufacturing sealing and oil-removable piston rings.
At the research stage, to define the shape and dimensions of the sealing (compression) piston rings, using the results of theoretical studies, to recommend various bronze alloys and copper alloys as a material for the preparation of the ring.
– Working step “compression” of a fresh charge of air, fuel-air mix and its ignition
The working step “compression” is fundamentally different from the previous step “admission” in that by obtaining a piston ring pressed against the upper flange of the piston groove and to the wall of the cylinder by the force of its own elasticity, at the beginning of the piston’s movement to the upper position, the piston ring is shifted downward. The forces of friction of the piston ring working surface against the cylinder wall, as well as the appearing overpressure P0 above the piston and in the piston groove, further enhance the contact of the piston ring with the lower flange of the piston groove and the cylinder wall.
It is important to note, the piston ring being in the lower dead point in rather free state, is fixed in this position, appearing changes and, above all, increasing pressure over the piston. This position of the sealing piston ring relative to the piston and cylinder will remain unchanged on the remaining steps of the engine motoring run.
So, with the beginning of the piston’s movement to the
