Effects of Exhaust Gas Recirculation on Fuel Consumption

1981 ◽  
Vol 195 (1) ◽  
pp. 369-376 ◽  
Author(s):  
Y Nakajima ◽  
K Sugihara ◽  
Y Takagi ◽  
S Muranaka
Keyword(s):  
Fuel Consumption ◽  
Fuel Economy ◽  
Load Condition ◽  
Dissociation Rate ◽  
Gas Temperature ◽  
Specific Heats ◽  
Light Load ◽  
Combustion Duration ◽  
Gas Recirculation ◽  
Burn Through

The effects of EGR on fuel consumption were analysed quantitatively in terms of factors improving and deteriorating fuel economy through experiments as well as thermodynamic calculations. To examine the effects of combustion duration on fuel economy under heavy EGR, experiments were performed with three engine variations. In calculation models, changes in specific heats, heat transfer rate, and dissociation rate caused by changes in gas temperature were considered. In conclusion, it may be stated that reductions of pumping loss, cooling loss, and dissociation were found to be improving factors, where the contribution ratio was approximately 4.5:4.0:1.5. The sum of calculated fuel economy gain increased steadily as the EGR increased, and reached more than 10 per cent at a 20 per cent EGR under light load condition. On the other hand, a major deteriorating factor was found to be a combustion fluctuation. This combustion fluctuation could be significantly reduced by achieving a ‘fast burn’ through increased turbulence and/or dual point ignition.

scholarly journals Effects of Specific Fuel Consumption and Exhaust Emissions of Four Stroke Diesel Engine with CuO/Water Nanofluid as Coolant

2017 ◽  
Vol 64 (1) ◽  
pp. 111-121 ◽  
Author(s):  
S. Senthilraja ◽  
KCK. Vijayakumar ◽  
R. Gangadevi
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Load Condition ◽  
Exhaust Emissions ◽  
Cuo Nanoparticles ◽  
Specific Fuel Consumption ◽  
Gas Temperature ◽  
Step Method ◽  
Series Of Experiments ◽  
Exhaust Gas Temperature

Abstract This article reports the effects of CuO/water based coolant on specific fuel consumption and exhaust emissions of four stroke single cylinder diesel engine. The CuO nanoparticles of 27 nm were used to prepare the nanofluid-based engine coolant. Three different volume concentrations (i.e 0.05%, 0.1%, and 0.2%) of CuO/water nanofluids were prepared by using two-step method. The purpose of this study is to investigate the exhaust emissions (NOx), exhaust gas temperature and specific fuel consumption under different load conditions with CuO/water nanofluid. After a series of experiments, it was observed that the CuO/water nanofluids, even at low volume concentrations, have a significant influence on exhaust emissions. The experimental results revealed that, at full load condition, the specific fuel consumption was reduced by 8.6%, 15.1% and 21.1% for the addition of 0.05%, 0.1% and 0.2% CuO nanoparticles with water, respectively. Also, the emission tests were concluded that 881 ppm, 853 ppm and 833 ppm of NOx emissions were observed at high load with 0.05%, 0.1% and 0.2% volume concentrations of CuO/water nanofluids, respectively.

Combining Diesel Generators With Ultracapacitors to Enhance Stability and Reliability

2014 ◽  
Author(s):  
M. Averbukh ◽  
A. Kuperman ◽  
G. Geula ◽  
S. Gadelovitch ◽  
V. Yuhimenko
Keyword(s):  
Control System ◽  
Fuel Consumption ◽  
Fuel Economy ◽  
Fuel Efficiency ◽  
Diesel Generator ◽  
Load Power ◽  
Light Load ◽  
Wide Range ◽  
Auxiliary Power Units ◽  
Diesel Generators

Diesel generator based auxiliary power units (DG-APU) are widely used in different civil and military applications. Fuel economy and service life are probably the most important issues concerning their operation. Controlling engine throttle position in accordance with the load power allows regulating fuel supply to the engine to optimize fuel consumption. Despite the advantage of the method, control stability is sacrificed in case of light load operation as follows. When the DG-APU is running with a light load, engine throttle position should be nearly closed in order to minimize fuel consumption. If a load step is applied in such situation, engine velocity may drop sharply until complete stop because of insufficient control system bandwidth. This is why velocity and throttle position of a DG-APU should not be decreased below some level even if load power is low to maintain reliability at the expense of increased specific fuel consumption. Moreover, for small diesel-generators the throttle position is usually fixed. Thereby, relatively wide range load power variations (typical for many of diesel-generator applications) cause excessive fuel consumption. The situation may be sufficiently improved by connecting ultracapacitors (UC) on the DG-APU output terminals, introducing additional inertia allowing smoothing engine velocity decrease during a sudden load increase thus providing more time to the control system to regulate throttle position. As a result, DG-APU would be operated much more efficiently at light loads without sacrificing stability. Moreover, the UC may be used at as starter motor power source, removing starting stress from electrochemical batteries. Present work investigates the improvements in UC-supported DG-APU fuel efficiency and stability compared to conventional technical solutions. The research is based on mathematical modeling of the entire system, verified by experiments. The results support the presented ideas and quantitatively demonstrate the improved fuel economy and reliability of small DG-APUs.

Investigation on the Combustion and Emission Characteristic of Diesel Engine with EGR

2011 ◽  
Vol 464 ◽  
pp. 668-671 ◽  
Author(s):  
Bi Feng Yin ◽  
Zhen Wei Xu ◽  
Jiang Guang He ◽  
Yi Xu ◽  
Yong Qiang Li
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Inflection Point ◽  
Load Condition ◽  
Pressure Rise ◽  
Emission Characteristic ◽  
Common Rail System ◽  
Instantaneous Rate ◽  
Light Load ◽  
Load Rate

Based on a diesel engine with common rail system, influence of EGR on combustion and emission characteristic were investigated. The test results show that EGR can cut down both cylinder pressure and the rate of pressure rise, which leads to the depression of instantaneous rate of heat release and combustion temperature and the extension of the whole combustion period.EGR make effective improvements on reducing NOx emissions in all the operating modes. In light load condition CO and HC emissions take a favorable turn with larger EGR rate, SOOT and fuel consumption are well maintained. In moderate and heavy load condition, the curve of HC ,CO emissions assume “hook-like”, which is get down first and then steep rise. SOOT is well maintained before the inflection point but get deteriorate after the point. As the working load rate of the engine become heavier, the rate of EGR whose inflection point located becomes smaller and the fuel consumption turn out to be worse.

Research of EGR On Commercial Turbocharged GDI Engine with Intense Tumble Flow

2021 ◽  
Author(s):  
Congbo Yin ◽  
Quanwei Chen ◽  
Zhendong Zhang ◽  
Haibing Zhu ◽  
Kai Shen
Keyword(s):  
Fuel Consumption ◽  
Power Performance ◽  
Heavy Load ◽  
Cycle Variation ◽  
Combustion Duration ◽  
Combustion Phase ◽  
Gdi Engine ◽  
Gdi Engines ◽  
Gas Recirculation ◽  
Combustion Cycle

Abstract The application of exhaust gas recirculation (EGR) technology on GDI engines can suppress knocking, reduce fuel consumption, and reduce NOx emissions. The effects of EGR with enhanced intake tumble flow, on the combustion phase, combustion duration, knock index and combustion cycle variation of the engine, were studied at two speeds of 1500 r/min and 2000 r/min from low to medium and to full load. The research shows that although the commercial engine has been well calibrated and optimized, the optimization of EGR and enhanced tumble flow together with the optimization of the ignition angle can improve the engine's economy and emission characteristics, while maintaining relatively fast burning speed and low combustion cycle variation. From medium to heavy load, the economy can be improved by 2.6~10%, and the minimum fuel consumption can be reduced to 213 g/kW.h. Under heavy load conditions (BMEP more than 14 bars), power performance deteriorates due to insufficient boost performance. The 5~20% EGR rate brings 10% power loss. EGR combined with tumble intake has a significant effect on reducing the engine's NOx and CO, with average reductions of 60% and 22%, but HC increased by 32%.

Development of a Miller cycle engine with single-stage boosting and cooled external exhaust gas recirculation

2016 ◽  
Vol 231 (6) ◽  
pp. 766-780 ◽  
Author(s):  
Yongsheng He ◽  
Jim Liu ◽  
Bin Zhu ◽  
David Sun
Keyword(s):  
Fuel Consumption ◽  
Compression Ratio ◽  
Fuel Economy ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Single Stage ◽  
Exhaust Gas ◽  
Brake Specific Fuel Consumption ◽  
Miller Cycle ◽  
Gas Recirculation

In this paper, the development of a Miller cycle gasoline engine which has a high compression ratio from 11.5:1 to 12.5:1, single-stage turbocharging and external cooled exhaust gas recirculation is described. The improvement in the fuel economy by adding external cooled exhaust gas recirculation to the Miller cycle engine at different geometric compression ratios were experimentally evaluated in part-load operating conditions. The potential of adding external cooled exhaust gas recirculation in full-load conditions to mitigate pre-ignition in order to allow higher geometric compression ratios to be utilized was also assessed. An average of 3.2% additional improvement in the fuel economy was achieved by adding external cooled exhaust gas recirculation to the Miller cycle engine at a geometric compression ratio of 11.5:1. It was also demonstrated that the fuel consumption of the engine with external cooled exhaust gas recirculation was reduced by 3–7% in a wide range of part-load operating conditions and that the engine output of the Miller cycle engine at a geometric compression ratio of 12.5:1 increased at 2000 r/min in the full-load condition. The Miller cycle engine with external cooled exhaust gas recirculation at a geometric compression ratio of 12.5:1 achieved a broad brake specific fuel consumption range of 220 g/kW h or lower, with the lowest brake specific fuel consumption of 215 g/kW h. While there are still challenges in implementing external cooled exhaust gas recirculation, the Miller cycle engine with single-stage turbocharging and external cooled exhaust gas recirculation showed its potential for substantial improvement in the fuel economy as one of the technical pathways to meet future requirements in reducing carbon dioxide emissions.

scholarly journals Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine

2018 ◽  
Vol 20 (4) ◽  
pp. 381-392 ◽  
Author(s):  
Wei Guan ◽  
Hua Zhao ◽  
Zhibo Ban ◽  
Tiejian Lin
Keyword(s):  
Fuel Consumption ◽  
Control Strategies ◽  
Fuel Efficiency ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Valve Closure ◽  
Intake Valve ◽  
Gas Temperature ◽  
Exhaust Gas Temperature ◽  
Gas Recirculation

The employment of aftertreatment systems in modern diesel engines has become indispensable to meet the stringent emissions regulations. However, a minimum exhaust gas temperature of approximately 200 °C must be reached to initiate the emissions control operations. Low-load engine operations usually result in relatively low exhaust gas temperature, which lead to reduced or no exhaust emissions conversion. In this context, this study investigated the use of different combustion control strategies to explore the trade-off between exhaust gas temperature, fuel efficiency, and exhaust emissions. The experiments were performed on a single-cylinder heavy-duty diesel engine at a light load of 2.2 bar indicated mean effective pressure. Strategies including the late intake valve closing timing, intake throttling, late injection timing (Tinj), lower injection pressure (Pinj), and internal exhaust gas recirculation and external exhaust gas recirculation were investigated. The results showed that the use of external exhaust gas recirculation and lower Pinj was not effective in increasing exhaust gas temperature. Although the use of late Tinj could result in higher exhaust gas temperature, the delayed combustion phase led to the highest fuel efficiency penalty. Intake throttling and internal exhaust gas recirculation allowed for an increase in exhaust gas temperature at the expense of higher fuel consumption. In comparison, late intake valve closure strategy achieved the best trade-off between exhaust gas temperature and net indicated specific fuel consumption, increasing the exhaust gas temperature by 52 °C and the fuel consumption penalty by 5.3% while reducing nitrogen oxide and soot emissions simultaneously. When the intake valve closing timing was delayed to after −107 crank angle degree after top dead centre, however, the combustion efficiency deteriorated and the HC and CO emissions were significantly increased. This could be overcome by combining internal exhaust gas recirculation with late intake valve closure to increase the in-cylinder combustion temperature for a more complete combustion. The results demonstrated that the ‘late intake valve closure + internal exhaust gas recirculation’ strategy can be the most effective means, increasing the exhaust gas temperature by 62 °C with 4.6% fuel consumption penalty. Meanwhile, maintaining high combustion efficiency as well as low HC and CO emissions of diesel engines.

The determination of arc temperatures from shock velocities

1957 ◽  
Vol 240 (1220) ◽  
pp. 54-66 ◽  
Keyword(s):  
Shock Wave ◽  
Strong Shock ◽  
Weak Shock ◽  
Wave Theory ◽  
New Method ◽  
Shock Propagation ◽  
Plane Shock ◽  
Gas Temperature ◽  
Specific Heats ◽  
Arc Discharges

The measurement of the high gas temperatures associated with arc discharges requires special techniques. One such method, developed by Suits (1935), depends on the measure­ment of the velocity of a sound wave passing through an arc column, although in fact Suits measured the velocity of a very weak shock wave. The new method described in the present paper is one in which temperatures are determined from the measurement of the velocity of a relatively strong shock wave propagated through an arc. The new method has the merit of consistently producing accurately measurable records and of increasing the accuracy of the temperature determination. The shock velocities are measured by means of a rotating mirror camera. Within the arc, the shock propagation is observable by virtue of the increased arc brightness produced by the shock. In the non-luminous regions surrounding the arc, the shock propagation is displayed by means of a Schlieren system. The interpretation of the measurements depends upon a one-dimensional analysis given in this paper which is similar to that of Chisnell (1955) and which describes the interaction of a plane shock with a con­tinuously varying temperature distribution. In our analysis account is taken also of the continuous variation in specific heats and molecular weight which are of importance under high gas temperature conditions. In practice plane wave theory cannot adequately describe the shock propagation, since attenuation occurs both in the free gas and in the arc column. The effects of this attenuation on the temperature determinations may be accounted for by the use of an experimentally determined attenuation relationship given in the paper. The finally developed method yields temperature values to an accuracy of ± 2%. Experiments are described for carbon and tungsten arcs in air and nitrogen for currents up to 55 amperes and pressures up to 3 atmospheres. The values obtained range from 6200 to 7700° K and are in good agreement with values determined by other techniques.

An adaptive equivalent consumption minimization strategy considering catalyst temperature for plug-in hybrid electric vehicle

2021 ◽  
pp. 095440702110434
Author(s):  
Tao Deng ◽  
Ke Zhao ◽  
Haoyuan Yu
Keyword(s):  
Fuel Consumption ◽  
Electric Vehicle ◽  
Fuel Economy ◽  
Hybrid Electric Vehicle ◽  
Test Procedure ◽  
Catalyst Temperature ◽  
Equivalent Factor ◽  
Simulation Results ◽  
Hybrid Electric ◽  
Equivalent Consumption Minimization Strategy

In the process of sufficiently considering fuel economy of plug-in hybrid electric vehicle (PHEV), the working time of engine will be reduced accordingly. The increased frequency that the three-way catalytic converter (TWCC) works in abnormal operating temperature will lead to the increasing of emissions. This paper proposes the equivalent consumption minimization strategy (ECMS) to ensure the catalyst temperature of PHEV can work in highly efficient areas, and the influence of catalyst temperature on fuel economy and emissions is considered. The simulation results show that the fixed equivalent factor of ECMS has great limitations for the underutilized battery power and the poor fuel economy. In order to further reduce fuel consumption and keep the emission unchanged, an equivalent factor map based on initial state of charge (SOC) and vehicle mileage is established by the genetic algorithm. Furthermore, an Adaptive changing equivalent factor is achieved by using the following strategy of SOC trajectory. Ultimately, adaptive equivalent consumption minimization strategy (A-ECMS) considering catalyst temperature is proposed. The simulation results show that compared with ordinary ECMS, HC, CO, and NOX are reduced by 14.6%, 20.3%, and 25.8%, respectively, which effectively reduces emissions. But the fuel consumption is increased by only 2.3%. To show that the proposed method can be used in actual driving conditions, it is tested on the World Light Vehicle Test Procedure (WLTC).

Numerical and Experimental Study on the Impact of Mild Cold EGR on Exhaust Emissions in a Biodiesel Fueled Diesel Engine

2021 ◽  
Author(s):  
Alex Oliveira ◽  
Junfeng Yang ◽  
Jose Sodre
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Exhaust Emissions ◽  
Pollutant Emissions ◽  
Cylinder Pressure ◽  
Nox Formation ◽  
Ratio Distribution ◽  
Engine Model ◽  
Gas Recirculation ◽  
The Impact

Abstract This work evaluated the effect of cooled exhaust gas recirculation (EGR) on fuel consumption and pollutant emissions from a diesel engine fueled with B8 (a blend of biodiesel and Diesel 8:92%% by volume), experimentally and numerically. Experiments were carried out on a Diesel power generator with varying loads from 5 kW to 35 kW and 10% of cold EGR ratio. Exhaust emissions (e.g. THC, NOX, CO etc.) were measured and evaluated. The results showed mild EGR and low biodiesel content have minor impact of engine specific fuel consumption, fuel conversion efficiency and in-cylinder pressure. Meanwhile, the combination of EGR and biodiesel reduced THC and NOX up to 52% and 59%, which shows promising effect on overcoming the PM-NOX trade-off from diesel engine. A 3D CFD engine model incorporated with detailed biodiesel combustion kinetics and NOx formation kinetics was validated against measured in-cylinder pressure, temperature and engine-out NO emission from diesel engine. This valid model was then employed to investigate the in-cylinder temperature and equivalence ratio distribution that predominate NOx formation. The results showed that the reduction of NOx emission by EGR and biodiesel is obtained by a little reduction of the local in-cylinder temperature and, mainly, by creating comparatively rich combusting mixture.

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