Realization of the Atkinson-Miller cycle in spark-ignition engine by means of the fully variable inlet valve control system

Abstract

The theoretical analysis of the charge exchange process in a spark ignition engine has been presented. This process has significant impact on the effectiveness of engine operation because it is related to the necessity of overcoming the flow resistance, followed by the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by the throttling valve is especially high during the part load operation. The open Atkinson-Miller cycle has been assumed as a model of processes taking place in the engine. Using fully variable inlet valve timing the A-M cycle can be realized according to two systems: system with late inlet valve closing and system with early inlet valve closing. The systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle which is a theoretical cycle for the classical throttle governing of the engine load. Benefits resulting from application of the systems with independent inlet valve control have been assessed on the basis of the selected parameters: fuel dose, cycle work, charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from the system inlet and reduce the charge exchange work, especially within the range of part load operation.

Energy Aspects of the Si Engine Load Adjustment by Early Closing of Inlet or Exhaust Valve

“…Presented systems with early inlet valve closing (EIVC) and early exhaust valve closing (EEVC) are two of several possibilities of application of the fully independent valve control [11,15,16,17,18,20]. Generally, the use of the fully variable valve actuation systems to governing of engine load enables to eliminate a throttling valve from intake system of spark ignition engine and reduce the charge exchange work, especially within the range of partial load.…”

A three-way catalyst system for a five-stroke engine

“…Due to the described inconsistency in the nomenclature, the term "Atkinson-Miller cycle" can also be found in the literature. This term is mainly used in theoretical works [49]. It should be mentioned here that while both Atkinson and Miller aimed to realise an increased expansion ratio of the charge, Atkinson's original idea did not adopt the use of a non-standard opening of the intake valve, which was a fundamental assumption of Ralph Miller [32].…”

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

“…The open Seiliger-Sabathe cycle (presented in Fig. 1) is the reference cycle for an assessment of advantages and effectiveness of work gaining in consequence of application of the early inlet valve closure [4,5].…”

“…Increasing the energy efficiency of an internal combustion engine with spark ignition is possible by eliminating the throttle. This may be accomplished by using fully independent control of intake or/and exhaust valves [3][4][5]. The most flexible solution for independent control of the valves is to use electromagnetic actuators but they are still under construction and are not in mass production because of electro-mechanical problems [6,7].…”

“…Fully independent valve drive enables engine load control according to different, the following strategies [2,3] -late inlet valve closure (the open Atkinson-Miller cycle) [4,[11][12][13], -early inlet valve closure [5], -early exhaust valve closure , -fully-independent both valves control.…”