Skip cycle method with a valve-control mechanism for spark ignition engines

The main problem in near future is to increase the eciency of internal combustion engines, which is the most important cause of air pollution in cities and the reduction of exhaust emissions from these engines. When operating conditions are examined in passenger cars, which are the main users of internal combustion engines, it has been seen that high fuel consumption occurs in the partial load area. A new working method for internal combustion engines, skip cycle strategy, which were revealed by Kutlar in 1999 has similarities with the cylinder deactivation systems, but it also has advantages especially in the application to single cylinder engines. The skip cycle strategy is a method of reducing the power taken by the engine, in other words, reducing the pumping losses in the partial load area. In this work, the control process has been provided according to cycle conditions and depending on skip cycle system needs, besides the mechanical valve control. The created mechanism consists of two groups: lock system and control system. In this study, the kinematic analysis of the engine has been carried out and the loads acting on the system have been determined. Finally, mechanism has been manufactured and experiments have been carried out at di erent speeds according to the NS (Normal cycle-Skip cycle) method, which is one of the several skip cycle strategies.

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“…which can be expanded depending on load condition, applied strategy and design of mechanism. [13] p me = 1bar p me = 2bar p me = 3bar…”

Section: Figure 15: Experiments Resultsmentioning

confidence: 99%

Design and Experimental Investigation of a Novel Skip Cycle Mechanism

Günkan

Baykara

Kutlar

2020

Preprint

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“…The intermittent changes in the pressure pulses and the reduction in the firing frequency (increased firing intervals) generate oscillations in the crankshaft speed. Peak-to-peak pressure amplitudes rise, which leads to greater torsional force and speed fluctuations [38]. All methods lead to greater linear and torsional vibrations, which means higher amplitudes and lower resonance frequencies.…”

Section: Negative Effectsmentioning

confidence: 99%

“…A similar idea was used in a research engine with a skip cycle mechanism [38]. The mechanism block for the CDA mode was mounted on the front cover of the engine.…”

Section: Fig 9 Movable Cam Sectionsmentioning

confidence: 99%

“…This is caused by the fact that, in part-load operation, proportionally more fuel is used for running the engine itself, compared to vehicle propulsion, than in full-load operation. In the most frequently used partload regimes, the efficiency of engine decreases to 10-15% [38]. By deactivating some of the cylinders, the load on the active cylinders increases and the engine works with higher efficiency and lower BSFC [39].…”

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Overview of the potential and limitations of cylinder deactivation

Fridrichová

Drápal

Vopařil

et al. 2021

Renewable and Sustainable Energy Reviews

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“…In another study, Kurtlar et al 11 carried out a study that they worked on cycle skipping methods with positive ignited engine and spark ignited engine. In another study, Baykara et al 12 carried out an experimental study that they worked on cycle skipping methods on one cylindered, positive ignited engine by valve control mechanism which they developed. They indicated that specific fuel consumption reduced as 14% at low partial loads and as 26% at higher partial loads, HC emissions increased in seriously.…”

Section: Introductionmentioning

confidence: 99%

Investigation of cycle skipping methods in an engine converted to positive ignition natural gas engine

Tunçer

Sandalcı

Karagöz

2021

Advances in Mechanical Engineering

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In this study, a single cylinder of 1.16 L, naturally aspirated engine was converted to a spark ignition engine, which was a diesel engine operating with natural gas as fuel. By placing electronic throttle, electronic ignition module, gas fuel injectors and proximity sensors on the test engine, the engine has been turned into a positive ignition engine that can work with natural gas as fuel, thanks to the electronic control unit developed by our project team. Then, in the study performed, different cycle skipping strategies were experimentally investigated at a constant engine speed of 1565 rpm, in accordance with the generator operating conditions. Engine performance, emissions (CO, HC, and NOx), and combustion characteristics (cylinder pressure, rate of heat release, etc.) of cycle skipping strategies were experimentally investigated with natural gas as fuel in Normal, 3N1S, 2N1S, and 1N1S engine operating modes. According to the results obtained, specific fuel consumption, CO and HC values improved in all cycle skipping operating conditions, except for NOx, but the best results were obtained in 2N1S operating conditions; it was concluded that the specific fuel consumption, CO and HC values improved by 11.19%, 61.89%, and 65.60%, respectively.

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Skip cycle method with a valve-control mechanism for spark ignition engines

Cited by 13 publications

References 25 publications

Design and Experimental Investigation of a Novel Skip Cycle Mechanism

Design and Experimental Investigation of a Novel Skip Cycle Mechanism

Overview of the potential and limitations of cylinder deactivation

Investigation of cycle skipping methods in an engine converted to positive ignition natural gas engine

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