ATKINSON CYCLE PDF
Atkinson cycle is an ideal cycle for Otto engine exhausting to a gas turbine. the isentropic expansion () of an Otto cycle () is further allowed to. The downside to the Atkinson cycle is that it has low torque output output of the Atkinson cycle can be supplemented by the high torque of. Keywords: Atkinson Cycle, Ultra-Downsizing, High Pressure Turbocharging, CO2 and Atkinson cycles have been used so far mostly with symmetrical crank.
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the British Gas Company built over Atkinson- cycle engines. Figure 1: The Atkinson Cycle engine patent: . Page 3. ® Operates on a four-stroke. PDF | On Aug 20, , Liyaquat Ali Shaikh and others published DEFERRED ATKINSON CYCLE AND SIMULTANEOUS HEAT EXTRACTION. PDF | Vehicle electrification has to be addressed to reduce dependence on fossil Experimental BSFC comparison between Otto and Atkinson cycle engines.
The U. Assuming daily production remains steady at It is particularly crucial to decrease the degree of vehicle dependence on fossil fuels. Developing new energy resources and significantly enhancing the energy efficiency of the conventional ICE are both effective paths and are also necessary to control GHGs and harmful emissions.
Demand for fuel savings and environmental protection is imposing a huge challenge on conventional ICEs.
More and more academic and government departments have transferred their focus to alternative automotive technology and fuels such as vehicle electrification, fuel cell, and hydrogen fuel. The conventional ICE technology is thought to be approaching its development limit [8,9].
However, the ICE technology is far from its development plateau. Much effort is being made to improve the fuel efficiency and reduce harmful emissions. The thermal efficiency of diesel engines is excellent, but they have a high noise level and an expensive post treatment system to handle a great deal of soot and PM production.
The TWC of gasoline engines is easy to resolve but gasoline engines have a lower mean fuel efficiency level. At present, popular gasoline engine technology mainly focuses on the turbocharged downsized GDI [10—12] and cooled EGR [13—15]. A problem in automotive ICE is that there is huge gap between the maximal power and the most frequent operating loads.
One feasible method is a turbocharged downsized engine that is more efficient with partial loads . Increased power output could be achieved through a turbocharger with GDI technology depressing the knock. Further emissions reductions can be achieved by combining with a cooled EGR [9,15]. However, a deeply downsized engine with extremely high intake boost is impeded by the increased exhaust temperature before turbine and knock tendency, especially in low speed ranges [16,18,19].
Greatly enhancing the fuel efficiency of a conventional gasoline engine is restricted. In the long term, the keys for conventional ICE sustainable development are: 1 accordance with emission regulations; 2 new fuels; 3 optimization of the combustion process; and 4 advanced energy saving concepts .
Two conflict problems exist when optimizing the combustion process: minimizing fuel consumption and reducing harmful emissions . For diesel engines, PM filter and NOx post-treatment equipment are not necessary. These challenges prevent the commercial development of an HCCI engine.
Research and application of over-expansion cycle (Atkinson and Miller) engines – A review
The target can be realized through advanced ICE technology while further targets must depend on vehicle electrification pure electric and hybrid vehicles . EV can draw electricity from the electric grid.
In regions where electricity is generated with low GHG intensity, EVs can contribute to a significant reduction of energy consumption and GHG emissions [24—26]. Moreover, if the upstream electricity generation and distribution are considered in the overall life cycle, the advantages of an EV, including energy savings and emissions reductions, will decrease [33—35]. In this situation, the ICE-based vehicles including a substantial portion of hybrid electric vehicles tend to be superior in terms of fuel consumption and GHG emissions.
Research in Ref. In countries such as China and India where electricity is produced dominantly from coal, total well-to-wheel emissions of the most efficient diesel engine are even lower than in EVs.
Therefore, the ICE still has significant potential for energy savings and emissions reduction. In , Toyota Company issued the first globally mass produced hybrid electric car, Prius, at the Tokyo Motor Show and brought it to market in .
In , Honda Company launched its hybrid car Honda Insight .
The Insight was rated as the most efficient gasoline car by the EPA. Ford Company also issued its own hybrid car called the Fusion Hybrid .
An ICE in a hybrid vehicle is so crucial that it considerably determines the vehicle fuel consumption and emissions [42—44]. As an example, study in Ref. However, a diesel engine is not the best for a hybrid vehicle compared to a gasoline engine because of the increased complexity, higher cost and weight. Received Mar 3; Accepted Jun 1. Gonca and B. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract This paper presents an ecological performance analysis and optimization for an air-standard irreversible Dual-Atkinson cycle DAC based on the ecological coefficient of performance ECOP criterion which includes internal irreversibilities, heat leak, and finite-rate of heat transfer.
A comprehensive numerical analysis has been realized so as to investigate the global and optimal performances of the cycle. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been attained introducing the compression ratio, cut-off ratio, pressure ratio, Atkinson cycle ratio, source temperature ratio, and internal irreversibility parameter.
The change of cycle performance with respect to these parameters is investigated and graphically presented. Introduction In the recent years, the studies related to engine research focused on reducing pollutant emissions, particularly NOx, released from internal combustion engines owing to environmental regulations and restrictions. The application of the Atkinson and Miller cycles to the internal combustion engines ICE may reduce NOx emissions with little cost of power [ 1 — 11 ].
In the literature, various optimization studies on the Miller and Atkinson cycles have been carried out. However, it should be noted that, at the same peak combustion temperatures and pressures, Atkinson cycle could become more efficient than the Miller cycle due to higher expansion ratio, as the amount of heat wasted with the exhaust gases may be reduced and transformed to power output by increasing expansion ratio.
There are various studies on the Miller and Atkinson cycles. Gonca et al. Wang et al.
Mikalsen et al. Thus, in each revolution, one piston provided a compression stroke and a power stroke, and then the other piston provided an exhaust stroke and a charging stroke. As the power piston remained withdrawn during exhaust and charging, it was practical to provide exhaust and charging using valves behind a port that was covered during the compression stroke and the power stroke, and so the valves did not need to resist high pressure and could be of the simpler sort used in many steam engines, or even reed valves.
Patent drawing of the Atkinson "Differential Engine", Animation of the Atkinson differential engine, Atkinson "Cycle Engine"[ edit ] The next engine designed by Atkinson in was named the "Cycle Engine" This engine used poppet valves, a cam, and an over-center arm to produce four piston strokes for every revolution of the crankshaft. The intake and compression strokes were significantly shorter than the expansion and exhaust strokes. The "Cycle" engines were produced and sold for several years by the British Engine Company.
Research and application of over-expansion cycle (Atkinson and Miller) engines – A review
Atkinson also licensed production to other manufacturers. Sizes ranged from a few up to horsepower.
Atkinson realized an improvement was needed to make his cycle more applicable as a higher-speed engine. With this new design, Atkinson was able to eliminate the linkages and make a more conventional, well balanced, engine capable of operating at speeds up to rpm and capable of producing power every revolution yet he preserved all of the efficiency of his "Cycle Engine" having a proportionally short compression stroke and a longer expansion stroke.Rate of heat transfer kW r: Sogut et al.
Challenges and recommendations on transient AFR control. It is clear that the process is an irreversible compression and internal irreversibilities were taken into account, whilst the process s is an isentropic compression.
Hou [ 33 ] compared the performances of the air-standard Otto and Atkinson cycles by taking into consideration the heat transfer impacts. The effective power, power density and effective efficiency increase up to an optimum value and then start to decrease with increasing compression ratio .
More space for ignition spark plugs, inlet ports and exhaust ports Although these advantages are inherent of every rotary engines, Kopelrot engine have also the advantage of a more efficient combustion due to the use of Miller cycle.