Effects of Exhaust Gas Recirculation on Fuel Consumption

Nakajima, Yasuo; Sugihara, Kunihiko; Takagi, Yasuo; Muranaka, Shigeo

doi:10.1243/pime_proc_1981_195_037_02

Cited by 10 publications

(2 citation statements)

References 4 publications

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“…This relationship has also been noted by other researchers using fragile, fine wire thermocouples [7]. For conventional spark ignition engines, increasing cyclic variability of combustion phasing is the underlying cause of increases in the COV of IMEP [8]. The correlation between cycle-by-cycle exhaust temperatures and the COV of IMEP exists because the changes in cycle-by-cycle exhaust temperatures reflect changes in the combustion phasing of the cycles, with slower burning cycles producing later combustion phasing and correspondingly high gas temperatures at the time of exhaust valve opening [5,7].…”

Section: Introductionsupporting

confidence: 73%

Real-Time Monitoring of Combustion Instability in a Homogeneous Charge Compression Ignition (HCCI) Engine Using Cycle-by-Cycle Exhaust Temperature Measurements

Gardiner

Neill

Chippior

2012

ASME 2012 Internal Combustion Engine Division Fall Technical Conference

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This paper describes an experimental study concerning the feasibility of monitoring the combustion instability levels of an HCCI engine based upon cycle-by-cycle exhaust temperature measurements. The test engine was a single cylinder, fourstroke, variable compression ratio Cooperative Fuel Research (CFR) engine coupled to an eddy current dynamometer. A rugged exhaust temperature sensor equipped with special signal processing circuitry was installed near the engine exhaust port. Reference measurements were provided by a laboratory grade, water-cooled cylinder pressure transducer. The cylinder pressure measurements were used to calculate the Coefficient of Variation of Indicated Mean Effective Pressure (COV of IMEP) for each operating condition tested.Experiments with the HCCI engine confirmed that cycle-bycycle variations in exhaust temperature were present, and were of sufficient magnitude to be captured for processing as high fidelity signal waveforms. There was a good correlation between the variability of the exhaust temperature signal and the COV of IMEP throughout the operating range that was evaluated. The correlation was particularly strong at the low levels of COV of IMEP (2-3%), where production engines would typically operate.A real-time combustion instability signal was obtained from cycle-by-cycle exhaust temperature measurements, and used to provide feedback to the fuel injection control system. Closed loop operation of the HCCI engine was achieved in which the engine was operated as lean as possible while maintaining the COV level at or near 2.5%.

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Section: Introductionsupporting

confidence: 73%

Real-Time Monitoring of Combustion Instability in a Homogeneous Charge Compression Ignition (HCCI) Engine Using Cycle-by-Cycle Exhaust Temperature Measurements

Gardiner

Neill

Chippior

2012

ASME 2012 Internal Combustion Engine Division Fall Technical Conference

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“…The improvement in fuel consumption at part load condition with increasing EGR gas at constant brake load is mainly due to the reduced pumping work. There are also other beneficial effects of EGR; reduced heat loss to the walls because burned gas temperature decreases remarkably, and the reduction in the degree of dissociation in the high-temperature burned gases [9,10].…”

Section: Engine Operating At High Level Of Charge Dilutionmentioning

confidence: 99%

Design and Demonstration of a Spark Ignition Engine Operating in a Stratified-EGR Mode

Han¹,

Cheng²

1998

SAE Technical Paper Series

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The use of substantial amount of exhaust gas recirculation (EGR) via the technique of flow stratification in-cylinder was investigated to improve the fuel economy of spark ignition engines under part load. The fuel economy gain is achieved by reducing the pumping loss with EGR while the stratification enables stable combustion at high levels of EGR. By doing so, the ability to control NOx emissions using the three-way catalytic converter is also retained. To realize this goal, a new method of supplying EGR to achieve in-cylinder stratification was incorporated and experiments were performed to demonstrate the concept.A new transparent engine facility was constructed to assist the development of the stratified EGR strategy. In order to minimize the mixing in intake port, to maintain the stratification in cylinder, and to obtain fast burn, an intake flow control system was realized by using solenoid valve-controlled EGR injection. Qualitative measurements of in-cylinder flow motion at motoring condition were carried out with visualization techniques such as planar laser-induced fluorescence (PLIF) and Mie scattering to obtain information on the mixing process during intake and compression. The engine was operated at firing condition to assess the engine performance operating in a stratified-EGR mode. Cylinder pressure measurements were used to gain information about the combustion process. A new combustion model incorporating mixing and flame stretch factor, which is believed to be significant, especially under the diluted mixture condition, was developed to examine flame propagation properties under the stratified condition.The visualization results of PLIF showed that the stratification between air/fuel mixture and EGR gas was relatively well established during the intake stroke. There was, however, significant mixing in the late part of the compression stroke. This process may be explained by that large scale tumble motion was introduced into the cylinder during the intake stroke, and that the organized motion broke into small eddies during the compression stroke and hence resulted in the substantial mixing then. Performance comparison between the engine operating with the homogeneous mixture and with the stratified mixture illustrated that the stratified mode had greatly improved fuel consumption and had provided stable combustion at high dilution ratio. The observed trend on the burning process could be reproduced reasonably well by the model. Thesis AdvisorWai K. Cheng Associate professor of Mechanical Engineering

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A new era in spark-ignition engines featuring high-pressure direct injection

Takagi

1998

Symposium (International) on Combustion

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Effects of Exhaust Gas Recirculation on Fuel Consumption

Cited by 10 publications

References 4 publications

Real-Time Monitoring of Combustion Instability in a Homogeneous Charge Compression Ignition (HCCI) Engine Using Cycle-by-Cycle Exhaust Temperature Measurements

Real-Time Monitoring of Combustion Instability in a Homogeneous Charge Compression Ignition (HCCI) Engine Using Cycle-by-Cycle Exhaust Temperature Measurements

Design and Demonstration of a Spark Ignition Engine Operating in a Stratified-EGR Mode

A new era in spark-ignition engines featuring high-pressure direct injection

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