AVINASH KUMAR AGARWAL
@iitk.ac.in
Mechanical Engineering
IIT Kanpur
RESEARCH INTERESTS
IC Engines, Emission and Fuels
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Avinash Kumar Agarwal, M. Krishnamoorthi, and Harsimran Singh
Elsevier BV
Avinash Kumar Agarwal, Vikram Kumar, Hardikk Valera, Nalini Kanta Mukherjee, Shanti Mehra, and Devendra Nene
Elsevier BV
Scott Curran, Angelo Onorati, Raul Payri, Avinash Kumar Agarwal, Constantine Arcoumanis, Choongsik Bae, Konstantinos Boulouchos, Flavio Dal Forno Chuahy, Manolis Gavaises, Gregory J Hampson,et al.
SAGE Publications
Shipping is one of the most efficient transportation modes for moving freight globally. International regulations concerning decarbonization and emission reduction goals drive rapid innovations to meet the 2030 and 2050 greenhouse gas reduction targets. The internal combustion engines used for marine vessels are among the most efficient energy conversion systems. Internal combustion engines dominate the propulsion system architectures for marine shipping, and current marine engines will continue to serve for several decades. However, to meet the aggressive goals of low-carbon-intensity shipping, there is an impetus for further efficiency improvement and achieving net zero greenhouse gas emissions. These factors drive the advancements in engine technologies, low-carbon fuels and fueling infrastructure, and emissions control systems. This editorial presents a perspective on the future of ship engines and the role of low-life cycle-carbon-fuels in decarbonizing the marine shipping sector. A selection of zero-carbon, net-zero carbon, and low-lifecycle-carbon-fuels are reviewed. This work focuses on the opportunities and challenges of displacing distillate fossil fuels for decarbonizing marine shipping. Enabling technologies such as next-generation air handling, fuel injection systems, and advanced combustion modes are discussed in the context of their role in the future of low-CO2 intensity shipping.
Utkarsha Sonawane and Avinash Kumar Agarwal
ASME International
Abstract Dimethyl ether is a new-generation alternative fuel to mitigate cold-start issues in compression ignition engines. It has a higher cetane number and offers superior spray atomization and fuel evaporation characteristics. This simulation study compares dimethyl ether and baseline diesel sprays and their evaporation characteristics in a constant volume spray chamber. Fuel properties greatly influence spray atomization and evaporation characteristics. This study is based on the Eulerian–Lagrangian approach adopted in the Reynolds-averaged Navier–Stokes framework. The liquid spray penetration obtained by simulation matched well with the experimental results of dimethyl ether and baseline diesel. Spray model constants were tuned for diesel and dimethyl ether separately, as the fuel properties of both test fuels are completely different. These tuned models were used to simulate dimethyl ether and diesel sprays at fixed fuel injection timings and ambient conditions. Results showed a lower spray penetration length for dimethyl ether than baseline diesel because of the flash boiling of dimethyl ether. Smaller diameter droplets formed due to dimethyl ether’s lower viscosity, density, surface tension, and higher evaporation rate. The reduction in Sauter mean diameter was quite sharp after the start of injection for the dimethyl ether. Diesel spray showed retarded spray atomization and evaporation characteristics compared to dimethyl ether. The vapor penetration length of both fuels was almost the same; however, the vapor mass fraction was higher for dimethyl ether than baseline diesel. Dimethyl ether spray exhibited superior spray atomization and improved evaporation of fuel droplets.
Ankur Kalwar, Rahul Kumar Singh, Ankit Gupta, Ranjeet Rajak, Gokul Gosakan, and Avinash Kumar Agarwal
Elsevier BV
Ashutosh Jena and Avinash Kumar Agarwal
AIP Publishing
The location and orientation of the injector play a crucial role in determining engine performance and emissions from spark ignition and dual-fuel compression ignition engines. This study focuses on the spray atomization and downstream mixing of gasoline injected from a multi-hole port fuel injector in a crossflow. This study employed the phase Doppler interferometry technique to extract the droplet size and velocity distributions for the flow confined in a circular duct with a diameter similar to the intake port of the dual-fuel compression ignition engine. The flow velocity was maintained at 10 m/s at 1 atm pressure and 299 K temperature. The spray characteristics were compared for the quiescent and crossflow cases. The spray evolution was analyzed using a high-speed imaging technique. Near wall impingement analysis has been carried out using the spray impingement models. The early stage spray evolution was similar for the quiescent and crossflow cases. The horizontal velocity of the spray was found to be ∼12 m/s at 20 mm downstream of the injector. The velocity remained similar for the flow and no-flow cases, as drag force was found to have an insignificant effect. The drag force was estimated to be one order of magnitude higher for the 15-μm droplet than the 50-μm droplet. The maximum Sauter mean diameter observed for the flow case inside the spray was 53 μm, which was 18% higher than the maximum Sauter mean diameter of the no-flow case. The droplet Sauter mean diameter increased along the spray due to the coalescence of slow-moving droplets. The droplet breakup was found to be insignificant downstream of the spray. The flow entrained the droplets smaller than 30 μm. The spray-wall impingement criterion estimated around 42% of droplets to bounce off the surface at 50 mm, compared to 22% without flow.
Avinash Agarwal, Omkar Yadav, and Hardikk Valera
SAE International
<div>Methanol is emerging as an alternate internal combustion engine fuel. It is getting attention in countries such as China and India as an emerging transport fuel. Using methanol in spark ignition engines is easier and more economical than in compression ignition engines via the blending approach. M85 (85% v/v methanol and 15% v/v gasoline) is one of the preferred blends with the highest methanol concentration. However, its physicochemical properties significantly differ from gasoline, leading to challenges in operating existing vehicles. This experimental study addresses the challenges such as cold-start operation and poor throttle response of M85-fueled motorcycle using a port fuel injection engine. In this study, M85-fueled motorcycle prototype is developed with superior performance, similar/better drivability, and lower emissions than a gasoline-fueled port-fuel-injected motorcycle. An open electronic control unit was installed using suitable wiring harness/sensors and actuators to control the engine. Then the motorcycle electronic control unit was calibrated for transient operations on a chassis dynamometer. The motorcycle was tested under road load simulation and wide-open throttle conditions on the chassis dynamometer to compare its performance with a baseline gasoline-fueled motorcycle. Evaluation parameters included power at wheels, maximum vehicle speed, and time-based and speed-based acceleration characteristics. Transient emissions were evaluated following the Indian driving cycle protocols. The effectiveness of the catalytic converter for M85 fueling was assessed by comparing various emissions upstream and downstream of the catalytic converter. M85-fueled motorcycle generated higher power at wheels and similar maximum speeds as baseline gasoline-fueled motorcycle. Fine-tuned M85-fueled motorcycle exhibited superior acceleration characteristics over baseline gasoline-fueled motorcycle, indicating that an appropriate tuning strategy could tackle the issue of “drivability.” M85-fueled motorcycle emitted lower carbon monoxide and hydrocarbon during the warm-up cycles in the Indian driving cycle protocol. The inherent fuel oxygen of M85 enhanced the carbon monoxide–carbon dioxide conversion, reducing carbon monoxide emissions in the engine exhaust. The existing catalytic converter was also suitable for M85 fueling since the hydrocarbon, nitric oxide, and carbon monoxide emissions were effectively reduced downstream of the catalytic converter in all test conditions.</div>
Avinash Agarwal, Omkar Yadav, and Hardikk Valera
SAE International
<div>Limited fossil fuel resources and carbonaceous greenhouse gas emissions are two major problems the world faces today. Alternative fuels can effectively power internal combustion engines to address these issues. Methanol can be an alternative to conventional fuels, particularly to displace gasoline in spark ignition engines. The physicochemical properties of methanol are significantly different than baseline gasoline and fuel mixture-aim lambda; hence methanol-fueled engines require modifications in the fuel injection parameters. This study optimized the fuel injection quantity, spark timing, and air–fuel ratio for M85 (85% v/v methanol + 15% v/v gasoline) fueling of a port fuel-injected single-cylinder 500 cc motorcycle test engine. Comparative engine performance, combustion, and emissions analyses were performed for M85 and baseline gasoline. M85-fueled engine exhibited improved combustion characteristics such as higher peak in-cylinder pressure, heat release rate, and cumulative heat release due to higher flame speed and the effect of fuel oxygen. The brake thermal efficiency increased by up to 23% at lower loads and 8% at higher loads for M85 fueling. Carbon monoxide was reduced by 11.4–94% and 46.1–94.4% for M85 w.r.t. baseline gasoline at 2500 and 3500 rpm, respectively, at varying engine loads. Hydrocarbon emissions showed mixed trends for M85 w.r.t. baseline gasoline. Nitric oxide emissions were 4–90.2% higher for M85 w.r.t. baseline gasoline at 2500 rpm, at varying engine loads; however, mixed trends were observed at 1500 and 3500 rpm. Carbon monoxide, hydrocarbons, and nitric oxide emissions were 4.6, 38.9, and 84.3% lower for M85 than baseline gasoline during idling. Overall the M85-fueled motorcycle engine emitted fewer harmful pollutants, indicating its superior environmental sustainability, except for slightly higher NO emission.</div>
Ashutosh Jena, Utkarsha Sonawane, and Avinash Kumar Agarwal
Elsevier BV
Ayush Tripathi and Avinash Kumar Agarwal
Elsevier BV
Tao Cai, Dan Zhao, Lin Ji, and Avinash Kumar Agarwal
Elsevier BV
Avinash Kumar Agarwal, Shanti Mehra, Hardikk Valera, Nalini Kanta Mukherjee, Vikram Kumar, and Devendra Nene
Elsevier BV
Avinash Kumar Agarwal and Muniappan Krishnamoorthi
SAGE Publications
Particulates from compression ignition (CI) engines have received serious attention in the last two decades. CI engines emit higher particulate matter (PM) and nitrogen oxides (NOx) than spark ignition (SI) engines. Both these species are harmful to human health and the environment. Compared to NOx emissions, PM constitutes many more chemical species in solid and liquid phases. This review paper focuses on soot morphology and chemical characterization of PM emissions from CI engines. Effects of different fuels, lubricating oil, and engine operating conditions on particulate characteristics are analyzed exhaustively. The first part of this paper focuses on the effects of particulates on living organisms, the consequences of exposure to diesel particulates, and the composition of diesel particulates. In recent decades, micro and nano-scale characteristics of PM have been exhaustively investigated to understand its structure, formation, and chemical functionalities. Typically, particulates comprise of elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), the soluble organic fraction (SOF), and trace metals. This paper summarizes most aspects of diesel particulate emissions for the benefit of active researchers in the field and underlines the importance of particulate emission reduction from the CI engines. Diesel combustion generates particles with enormous long-chain aggregates of smaller sizes and immature soot particles. Low-temperature combustion (LTC) modes and oxygenated fuels reduce the soot emissions and generate compact/clustered aggregates. Oxygenated fuels in CI engines produce more nucleation mode particles (NMPs) and high-reactivity soot aggregates. Higher trace metal concentrations were observed in diesel origin particulates than biofuel origin particulates. Biodiesel origin particulates possess higher mutagenicity and carcinogenicity because of nitro-PAHs. Transient engine operations cause higher particulates than steady-state engine operations.
Avinash Kumar Agarwal, Akhilendra Pratap Singh, and Vikram Kumar
Elsevier BV
Ankur Kalwar, Akhilendra Singh, and Avinash Kumar Agarwal
SAE International
<div class="section abstract"><div class="htmlview paragraph">Considering the demand for sustainable transport, alternative fuels are a keen research topic for IC engine researchers. Among various alternative fuels being explored, Di-ethyl ether (DEE) is gaining popularity off-late for compression-ignition (CI) engines owing to its high cetane rating, oxygen presence in its molecular structure, and lower carbon content. This study explores the suitability of DEE blends in tractor engines. DEE blends [15% and 30% (v/v)] with diesel were compared with baseline diesel for combustion, and emission characterisation, keeping all parameters identical, including the fuel injection timings. Results were analysed for different engine loads at 1500 rpm. Delayed combustion was observed with DEE blends with diesel, possibly due to a higher cooling effect from DEE vaporisation and retarded dynamic fuel injection due to its higher compressibility. However, the DEE blend fuelled engine performance was comparable to baseline diesel. Considerable reductions in NOx and soot emissions were observed with DEE30. Hence, compared to DEE15, DEE30 emerged as a more suitable fuel for heavy-duty tractor engines using a mechanical fuel injection system, exhibiting lower emissions and comparable efficiencies.</div></div>
Utkarsha Sonawane, Ashutosh Jena, and Avinash Kumar Agarwal
SAE International
<div class="section abstract"><div class="htmlview paragraph">Di-ethyl ether (DEE) belongs to the family of oxygenated fuels, which have been investigated as an alternative to conventional diesel. However, increasing the proportion of DEE in DEE-diesel blends changes its physicochemical properties. This work shows the non-evaporating and non-reacting spray characteristics of diesel, DEE20 (20% v/v DEE and 80% v/v diesel), and DEE40 (40% v/v DEE and 60% v/v diesel) were investigated. The effect of fuel injection pressure (FIP: 500 and 800 bar) on the spray morphology and droplet size distribution at different axial locations along the spray axis was done. FIP of 800 bar showed a reduction in Sauter mean diameter (SMD) of spray droplets with increasing axial distance due to improved spray atomisation because of the drag forces of the surrounding air on the fuel droplets. DEE20 showed a higher number of droplets having a smaller diameter than DEE40. DEE20 and DEE40 showed superior spray atomisation characteristics than diesel. A slight increase in radial velocity was also observed with the axial location for all test fuels. DEE40 exhibited lower radial velocity compared to DEE20 and diesel. Higher fluctuation in the axial velocity of droplets was observed at an axial distance of 60 mm compared to 20 mm for diesel. This was due to increased droplet velocity distribution after the end of the injection. An increased number of smaller droplets resulted in lower jet momentum in the axial direction at the FIP of 800 bar. As a result, the average axial droplet velocity was higher at lower FIP. DEE40 showed more fluctuations amongst all test fuels, possibly due to drastic droplet diameter changes due to its superior evaporation characteristics. In this study, DEE40 at a FIP of 500 bar showed superior atomisation and evaporation characteristics. This indicated that a low-cost fuel injection system could be used for the maximum diesel replacement by DEE.</div></div>
Avinash Kumar Agarwal, Vishnu Singh Solanki, and M. Krishnamoorthi
Elsevier BV
Avinash Kumar Agarwal, Vishnu Singh Solanki, and M. Krishnamoorthi
SAE International
<div>Climate change and stringent emission regulations have become major challenges for the automotive sector, prompting researchers to investigate advanced combustion technologies. Gasoline compression ignition (GCI) technology has emerged as a potential solution, delivering higher brake thermal efficiency with ultra-low nitrogen oxides (NOx) and particulate emissions. Combustion stability and controls are some of the significant challenges associated with GCI. This study investigates the combustion characteristics of a two-cylinder diesel engine in GCI mode. GCI experiments were performed using a low-octane fuel prepared by blending 80% (v/v) gasoline and 20% (v/v) diesel (G80). Baseline experiments were conducted in conventional diesel combustion (CDC) mode. These experiments investigated the effects of double pilot injection, first pilot fuel ratio, and the start of main fuel injection timing (10–8°CA before top dead center, bTDC). The results indicated that the GCI mode produced significantly lower (~10%) in-cylinder pressure than the CDC mode. Higher pilot fuel proportions exhibited a lower heat release rate (HRR) at low loads. Retarded main injection showed a lower heat release in the premixed combustion phase than the advanced main injection case at all loads. In addition, retarded main injection timing showed retarded start of combustion (SoC) and end of combustion (EoC). GCI mode exhibited higher cyclic variations than baseline CDC mode, which need to be addressed.</div>
Avinash Kumar Agarwal, Vishnu Singh Solanki, and M. Krishnamoorthi
SAE International
<div>Internal combustion (IC) engines play an important role in the global economy by powering various transport applications. However, it is a leading cause of urban air pollution; therefore, new combustion strategies are being developed to control emissions. One promising advanced low-temperature combustion (LTC) technology is gasoline compression ignition (GCI). This experimental study assesses the performance of a two-cylinder engine, emissions, and exhaust particulate characteristics using G80 (80% v/v gasoline and 20% v/v diesel) blend operating in GCI mode vis-à-vis baseline conventional diesel combustion (CDC) mode using diesel. The effects of double pilot injection, Pilot-1 proportion (10–30%), and main injection timing were investigated on the GCI combustion. Experiments were performed at different engine loads (3, 4, and 5 bar brake mean effective pressure [BMEP]) at a constant engine speed (2000 rpm). GCI combustion showed higher brake thermal efficiency (BTE) than CDC mode at medium loads. Hydrocarbon (HC) and carbon monoxide (CO) emissions increased in GCI mode, but oxides of nitrogen (NOx) were reduced than the baseline CDC mode. High pilot ratio and late main injection timing tests showed higher HC and CO emissions in the GCI mode at low engine loads. The GCI mode engine emitted higher nucleation mode particles and nanoparticles than baseline CDC mode at high engine loads. Using a triple injection strategy, GCI engines simultaneously reduced NOx and particulate matter (PM) emissions, especially at high loads. Controlling these emissions in baseline CDC mode engines is otherwise quite challenging.</div>
Akhilendra Pratap Singh, Ashutosh Jena, and Avinash Kumar Agarwal
SAGE Publications
In the last decade, advanced combustion techniques of the low-temperature combustion (LTC) family have attracted researchers because of their excellent emission characteristics; however, combustion control remains the main issue for the LTC modes. The objective of this study was to explore premixed charge compression ignition (PCCI) combustion mode using a double pilot injection (DPI; pilot-pilot-main) strategy to achieve superior combustion control and to tackle the soot-oxides of nitrogen (NOx) trade-off. Experiments were carried out in a single-cylinder research engine fueled with 20% v/v biodiesel blended with mineral diesel (B20) and 40% v/v biodiesel blended with mineral diesel (B40) vis-à-vis baseline mineral diesel. Engine speed and rate of fuel-mass injected were maintained constant at 1500 rpm and 0.6 kg/h mineral diesel equivalent, respectively. Pilot injection timings (at 45° and 35° before top dead center (bTDC)) and fuel quantities were fixed, while three fuel injection pressures (FIPs) and four different start of the main injection (SoMI) timings were investigated in this study. Results showed that multiple pilot injections resulted in a stable PCCI combustion mode, making it suitable for higher engine loads. For all test fuels, advancing SoMI timings led to relatively lesser knocking; however, engine performance characteristics degraded at advanced SoMI timings. B40 exhibited relatively superior engine performance among different test fuels at lower FIP; however, the difference in engine performance was insignificant at higher FIPs. Fuel injection parameters showed a significant effect on emissions, especially on the NOx and particulates. Advancing SoMI timing resulted in 20%–50% lower particulates emissions with a slight NOx increase; however, the differences in emissions at different SoMI timings reduced at higher FIPs. Somewhat higher particulates from biodiesel blends were a critical observation of this study, which was more dominant at advanced SoMI timings. Qualitative correlation between NOx-total particulate mass (TPM) was another critical analysis, which exhibited the relative importance of different fuel injection parameters for other alternative fuels. Overall, B20 at 700 bar FIP and 20° SoMI timing emerged as the most promising proposition with some penalty in CO emission.
Quangkhai Pham, Mengzhao Chang, Ankur Kalwar, Avinash Kumar Agarwal, Sungwook Park, Byungchul Choi, and Suhan Park
Elsevier BV
M. Krishnamoorthi and Avinash Kumar Agarwal
Springer Nature Switzerland
Dhananjay Kumar and Avinash Kumar Agarwal
Begell House
In recent decades, stringent emission norms have been enforced upon the engine research community and OEMs to encourage them to develop new spark ignition engine technologies, such as variable valve lifts, turbocharging, and direct injection spark ignition (DISI) engines. For further development, greater control of parameters such as in-cylinder air motion, spray characteristics, injection, and ignition events is required. Spray characterizations are crucial for understanding the mixing phenomena in heated and pressurized engine combustion chamber conditions. Spray pattern, fuel injection pressure (FIP), rate shape, and thermodynamic conditions of the combustion chamber play a vital role in the mixture preparation. The present study uses Mie-Scattering techniques to examine spray structures of fuels like methanol and ethanol and compare them to gasoline, which is of great interest to DISI engines. Three different temperatures of 50, 100, and 200&deg;C and two chamber pressures, 4 and 8 bar, are considered to simulate typical engine-cylinder conditions. It is observed that the initial chamber conditions greatly influence the spray structure. Spray collapse is lesser for alcohol than gasoline. Three semi-empirical models for predicting spray penetration are analyzed: Dent, Hiroyasu and Arai, and Arr&#232;gle. These models could not differentiate between the test fuels, particularly methanol and ethanol, for predicting spray penetration length. The degree of deviation in predictions is the lowest in the Hiroyasu and Arai model and the highest in the Dent model. Spray penetration length increased with an increasing FIP regardless of ambient conditions; however, the spray penetration length decreased with increasing chamber pressure.
Ankur Kalwar, Avinash Kumar Agarwal, Quangkhai Pham, Suhan Park, and Sungwook Park
Begell House
Several studies have shown that the split-injection strategy has improved the shortcomings of the high particulate matter emissions and cycle-to-cycle variations in homogeneous and stratified combustion modes of gasoline direct injection (GDI) engines. However, the spray behavior under the split injection strategy is poorly understood. This study uses computational fluid dynamics (CFD) simulations in Converge software to investigate the spray characteristics of gasoline and methanol-gasoline blends under a split-injection strategy. The simulation studies were performed for a multihole GDI injector in a constant volume spray chamber, replicating the ambient conditions similar to a GDI engine's homogeneous and stratified combustion modes. Appropriate models for simulating different spray phenomena, such as spray breakup, collision, and coalescence, were used. The CFD model was validated using the experimental spray penetration length provided in the engine combustion network database. The results showed that the split-injection reduced the Sauter mean diameter (SMD) of fuel spray droplets and liquid fuel mass content than a single injection case. The dwell time of 2 ms was found suitable for homogeneous mode conditions, while its effect was insignificant in stratified mode conditions. Further, a split ratio of 80:20 resulted in smaller SMD during the injection period and a higher fuel evaporation rate. The effect of methanol addition was also explored under the split-injection mode. M85 showed higher deviations in the liquid spray penetration, SMD, and liquid spray mass content than G100.