Wyniki wyszukiwania - BazTech

1

Improving the effective efficiency of a spark ignition engine through the use of a fully independent valve control system

Żmudka Zbigniew, Postrzednik Stefan

Combustion Engines

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2021

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R. 60, nr 4

30--35

EN

The article presents theoretical research of the proposed system of fully independent valve control (FIVC) of the SI engine. The analysis included controlling the movement of the intake valves, which results in adjusting the mass of the fresh charge to the current engine load, as well as the movement of the exhaust valves, where the main aim is to keep the rest of the exhaust gas in the cylinder, i.e. implementation of internal EGR. The open theoretical Seiliger-Sabathe cycle with the classic throttle regulation of load is the reference cycle for assessment of benefits and study of the effectiveness of obtaining work as a result of application of the FIVC system. A comparative analysis of the effectiveness of application of the proposed system was carried out based on the selected quantities: fuel dose, cycle work, relative work of charge exchange and cycle efficiency. The use of the FIVC to regulate the SI engine load makes it possible to eliminate the throttle and thus reduce the charge exchange work, especially in the partial load range. And this then leads to an increase in internal and effective work, which in turn results in an increase in the effective energy efficiency of an engine operation.

2

New teoretical cycle for active combustion chamber engine

Głogowski Michal Piotr, Kubiak Przemysław, Šarić Željko, Barta Dalibor

Archiwum Motoryzacji

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2019

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Vol. 83, nr 1

23--42

EN

This paper presents calculations of the theoretical cycle of engines with an active combustion chamber depending on energy delivery and dissipation. In the case of ACC engines, a different calculation approach is required to account for the possibility of additional volume change, independent of the piston-crank system. The introduction presents a schematic diagram of volume change, accomplished by two independent piston-crank systems and an active combustion chamber, as proposed by the authors. Moreover, the diagram, which is the basis for analysis in this paper, illustrates characteristic points of the cycle. In existing theoretical cycles of combustion, this issue does not present any difficulties, since the solution is exact and based on known equations. In the case of theoretical ACC engines, however, the situation is different, since this engine can perform not only in typical cycles, but also in new ones. To explain the challenges of these new cycles, authors present a few of the most probable calculation variants, taking into account the new kinematic capabilities of ACC engines. Each comment justifying the choice of a certain calculation variant is illustrated with a theoretical cycle figure and closest approximation of induced pressure course of the ACC engine. At the same time, however, the authors show that this problem can have many interpretations. It has been concluded that the solution depends on the assumptions made about the active combustion chamber, namely its principle of operation.

3

High compression spark ignition engine with variable compression ratio using Active Combustion Chamber

Kubiak Przemysław, Glogowski Michal, Soghabatyan Tigran, Mrowicki Adam, D'Errico Gianluca

Archiwum Motoryzacji

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2019

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Vol. 86, nr 4

5--26

EN

Abstract In this article Authors present the continuation of the calculations for theoretical ACC engine cycle, considering additionally “VCR function” – changeable compression level. For this purpose the self-acting volume change, realized by ACC system, was used. The ACC system was adjusted appropriately to control the compression level. The analysis is based on three cases, representing delayed, premature and optimal reaction of ACC system. Reactions are presented in form of plots with indicated pressure in the combustion chamber. As the result of the conducted analysis and interpretation of obtained graphs, the calculation approach of compression ratio for ACC presented in previous article is being challenged. For the optimal reaction of ACC system, the theoretical operation schematics are devised and presented in the key points of the work. Based on the schematics, the values of theoretical efficiency were calculated for different cycles of theoretical ACC engine, in which regulation of compression ratio takes place. Moreover, the presented analysis includes graphs with optimal courses of indicated pressure for significantly different work parameters of ACC engine, showing its regulation possibilities. Also the time scaled graphs (with millisecond as basic time unit) are presented to show the possibilities of dynamic ACC systems, which are comparable with the combustion time (from 3 to 0,5 ms). In this paper the general discussion is started about the compression ratio in more complex kinematic systems including ACC.

4

Throttleless control of SI engine load by fully flexible inlet valve actuation system

Żmudka Z., Postrzednik S., Przybyła G.

Combustion Engines

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2016

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R. 55, nr 1

44--48

EN

A system with independent, early inlet valve closure (EIVC) has been analysed. The open, theoretical cycle has been assumed as a model of processes proceeding in the engine with variable inlet valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle which is theoretical cycle for the classic throttle governing of engine load. The influence of EIVC on fuel economy, cycle work, relative charge exchange work and cycle efficiency has been theoretically investigated. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine.