Study of an EGR System for Downsizing Turbocharged Gasoline Engine to Improve Fuel Economy

Takaki, Daisuke; Tsuchida, Hirofumi; Kobara, Tetsuya; Akagi, Mitsuhiro; Tsuyuki, Takeshi; Nagamine, Morihiro

doi:10.4271/2014-01-1199

Cited by 66 publications

(29 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These previous investigations encourage further research efforts to gain knowledge on the real potential of cooled EGR for being standardized in future SI GTDI engines, and particularly, in its LP EGR loop configuration where the effects of the EGR can be maximized compared to the mixed and HP EGR loop configuration, as found by Takaki et al [18].…”

Section: Introductionmentioning

confidence: 62%

Influence of a low pressure EGR loop on a gasoline turbocharged direct injection engine

Luján

Climent

Novella

et al. 2015

Applied Thermal Engineering

View full text Add to dashboard Cite

This paper presents an experimental study of a low pressure EGR loop on a spark ignition (SI) Gasoline Turbocharged Direct Injection (GTDI) engine that will improve the understanding on the advantages and disadvantages of this strategy. Two steady engine operating conditions were investigated, 10 bar and 17 bar at 2000 rpm. At partial load conditions a combustion, performance, air management and exhaust gas emissions study was performed in order to analyses the EGR effect on the GTDI engine. The main advantages found were the reduction in fuel consumption due to the better combustion phasing, and the reduction in pumping losses and heat losses through the cylinder walls. A reduction on NOx, CO and soot was also observed when introducing EGR at these operating conditions. The main disadvantage found was the water condensation after the intercooler. At high load conditions similar analysis and conclusions to the partial load conditions are obtained. The EGR also allowed the combustion to be phased in a more efficient angle by reducing the risk of knocking, which helped reduce the exhaust gas temperature, despite the elimination of the fuel enrichment strategy. A reduction on CO and soot raw emissions was also observed when introducing EGR, as observed at partial load conditions, but a high reduction in NOx, CO, HC and soot emissions was observed after the catalyst since the fuel enrichment strategy is eliminated when cooled EGR is introduced. The main disadvantage found was the turbocharger limitation since higher compression ratio is required in order to keep the same air mass flow as the reference conditions without EGR. The original turbocharger is not designed to provide this higher compression ratio at low engine speed and high load. Results confirm how introducing EGR is a suitable strategy to control knocking and reduce simultaneously exhaust gas temperature and fuel consumption, but the disadvantages found in this investigation must be solved to assure its feasibility as a powerful technology to be implemented in future SI engines.

show abstract

Section: Introductionmentioning

confidence: 62%

Influence of a low pressure EGR loop on a gasoline turbocharged direct injection engine

Luján

Climent

Novella

et al. 2015

Applied Thermal Engineering

View full text Add to dashboard Cite

show abstract

“…Cooled, external Exhaust Gas Recirculation (EGR) can be effective for improving fuel economy and for suppressing knock in turbocharged, spark ignition engines [1]. One approach for delivering external EGR is Low-Pressure (LP-)EGR, where exhaust gas is extracted downstream of the turbine and reintroduced upstream of the compressor (e.g.…”

Section: Introductionmentioning

confidence: 99%

Modelling and Control of Engine Torque for Short-Circuit Flow and EGR Evacuation

Wiese

Stefanopoulou

Buckland

et al. 2017

SAE Technical Paper Series

View full text Add to dashboard Cite

Low-Pressure Exhaust Gas Recirculation (LP-EGR) has been shown to be an effective means of improving fuel economy and suppressing knock in downsized, boosted, spark ignition engines. LP-EGR is particularly beneficial at low-speed, high-load conditions, but can lead to combustion instability at lower loads. The transport delays inherent in LP-EGR systems slow the reduction of intake manifold EGR concentrations during tip-out events, which may lead to excessive EGR concentrations at low load. This paper explores leveraging Variable Valve Timing (VVT) as a means of improving the rate of reduction of intake manifold EGR concentration prior to tip-out. At higher boost levels, high valve overlap may result in intake manifold gas passing directly to the exhaust manifold. This short-circuiting behaviour could potentially improve EGR evacuation rates. However, introducing short-circuit flow may lead to lean exhaust flow through the catalyst, and/or necessitate rich in-cylinder conditions that could counteract the fuel economy benefits of increasing high load LP-EGR rates. Therefore, this paper seeks to quantify the improvement in EGR evacuation rate and duration of short circuiting that may be achieved while at boosted conditions with high valve overlap, in preparation for a tip out. To conduct this investigation, a controller is first proposed, capable of regulating torque at boosted operating conditions with high valve overlap and external EGR. This controller extends a published control architecture, by accounting for both short-circuit flow and external EGR. The developed controller is then applied to a GT-Power model to regulate torque during constant torque LP-EGR evacuations, where high valve overlap is shown to improve evacuation times by 15-25%.

show abstract

“…The use cooled EGR increase level of engine efficiency as cooled EGR act as diluent for combustion process resulting in reduced combustion temperature. Thus the addition of cooled EGR in SI engines result in higher compression ratios and production of more torque at low engine speed [18]. These advantages of cooled EGR enable to downsize the engine and improve fuel economy along with increased levels of thermal efficiency.…”

Section: Introductionmentioning

confidence: 99%

Influence of cooled exhaust gas recirculation on performance, emissions and combustion characteristics of LPG fuelled lean burn SI engine

Ravi

Bhasker

Alexander

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

View full text Add to dashboard Cite

Study of an EGR System for Downsizing Turbocharged Gasoline Engine to Improve Fuel Economy

Cited by 66 publications

References 7 publications

Influence of a low pressure EGR loop on a gasoline turbocharged direct injection engine

Influence of a low pressure EGR loop on a gasoline turbocharged direct injection engine

Modelling and Control of Engine Torque for Short-Circuit Flow and EGR Evacuation

Influence of cooled exhaust gas recirculation on performance, emissions and combustion characteristics of LPG fuelled lean burn SI engine

Contact Info

Product

Resources

About