In gasoline engines, there were many development stages happened in fuel supply system and currently gasoline direct fuel injection is the latest technology is there with the gasoline engines where the gasoline is directly injected into an engine cylinder at higher pressure. To achieve the advanced emission norms, the spray guided mode strategy replaced by the combined air-wall guided mode with pent roof piston crown imparts turbulence effect for better mixing of compressed air with sprayed fuel at high pressure. Also the pent roof piston crown with small bowl which diverts the fuel sprays flow towards the spark plug to initiate the combustion. The FIP, FI timing, split injection with durations, ignition timing were also play important role over the combustion and emission characteristics of an engine.
The gasoline blends with iso-propanol and iso-Butanol from 0 to 30% by volume were tested at 20 and 40 bar injection pressures, the results show that at low temperature, the blends provide low carbon intensity because of its knocking suppress characteristics and the properties were matching with gasoline fuel (Scott et al. 2021). The emission factors of 5 vehicles tested on chassis dynamometer shows that decrease rematkably with emission standard from 11.7 to 6 µg per km (Zheng et al. 2018).
To anticipate ignition of linear and iso-methyl or butyl alcohols with gasoline blends for enriching spark ignition, the enhanced thermo-chemistry kinetics model was developed to boost up an engine combustion performance at low temperature (Saggese et al. 2021).
N-butanol has higher calorific value than other alcoholic fuel used; its blend result shows comparatively higher indicated mean effective pressure and thermal efficiency (Gorbatenko et al. 2019). 2, 5 Di-methyl furan has relatively higher octane number than gasoline fuel; other than ethanol, DMF’s energy density similar to gasoline fuel. Because of higher calorific value and density, DMF blend test results show more concentration of NOx and soot particle emissions in an engine exhaust (Xu and Wang 2016; Hoang et al. 2021).
Ethanol gasoline blends were tested on a two wheeler engine at speed ranges 200, 400, 600, 800 and 1000 rpm; results show that E10 blend at 800 rpm, SFC was comparatively low, 26% gain in brake thermal efficiency at 1000 rpm, less soot particle emissions; E50 blend shows less NOx emissions; E30 blend shows comparatively low CO emissions (Sameeth et al. 2019). EGR fitted GDI engine was tested with hydrogen fuel from exhaust gas fuel reforming with side mounted solenoid fuel injector; results indicated that decrease in PN level and soot mass emissions (Fennell et al. 2014). Ethanol proportions at 10, 20 and 30% by volume with gasoline was tested and observed that CO and NOx emissions were reduced than gasoline and a remarkable reduction in HC emission than oxygen free gasoline (Iodice et al. 2017). An increase in anhydrous ethanol-gasoline blend results in significant drop of CO and THC emission concentrations (Ribeiro et al. 2018). Evaluated the urban environmental impact of gasoline-ethanol blended fuels in a passenger vehicle engine with different speeds (Duarte et al. 2021).
N-Heptane and Iso-octane gasoline binary blends at different octane numbers were tested; the ignition timings and laminar flame speeds were perfectly projected over a range of engine operating conditions (Lapointe et al. 2019). 12 and 20% N-Butanol gasoline blends were tested for performance and emissions of SI engine and observed that HC and CO emissions were relatively lower than petrol; BSFC is found to be higher than gasoline due to its lower calorific value (Abdulazeez et al. 2018).
Methanol-gasoline blends with 5, 10 and 15% proportions were tested repeatedly and noted that M10 blend has less BSFC compared with other blend proportions. M15 shown comparatively lower emissions than other blend fuels and also it has higher A/F ratio (Danaiah et al. 2012). Even through DMF has an option to serve as a SI engine fuel blend without any modifications, it fail to satisfy the existing emission norms, majorly NOx and soot particle emissions (Shukla et al. 2014).
Methanol-gasoline blends were burned in a small volume with the same ignition timing and the heat released in shorter time; higher pressure of exhaust gas was developed closer to TDC; increased proportions of methanol results in increased brake thermal efficiency. M85 blended fuel results in reduced of HC, CO and PM emissions (Yanju et al. 2008).
N-heptane methanol blended fuels were tested towards the burning characteristics and observed that the azeotropism between methanol and heptane lowers the burning quality compared to gasoline fuel (Zihe et al. 2021). Use of blended fuels with chambered type non perforated muffler to bring drowns the concentrations of CO2 emissions; the results show that CO2 emissions is at maximum level where BMEP is 3.57 bar with turbo type muffler (Chandra et al. 2020).
Economic and emissions technological advantages by using bio-fuels has imparting few public policy requirements and provides recommendations for the transition of fuel to bio-fuels based with economy (Ahmad and Tabrez 2018).
For implementing the advanced injection parameters with effective reduced emissions and superior combustion performance. Kirloskar make, single cylinder, diesel engine gives more benefit on operating cost. SCO is the cost benefit fuel with high levels of harmful emissions and can be improved with dual fuel mode of gaseous fuels (Karthic et al. 2020). The use of methyl-ester rapeseed oil biodiesel was recommended to reduce the total mass of particulate and metal emissions from diesel engines (Coufalík et al. 2019).
The chambered turbo type muffler with methanol gasoline fuel blends was tested towards better fuel property, performance and emission characteristics (Prakash et al. 2018). On road tests were conducted to characterize the harmful gas emissions from petrol and diesel engines, the concentrations of CO and NOx decreased comparatively. With lower rate of EGR with modification on the intake manifold for using the engine with bio-diesel blends which results in high NOx emissions (Lanyi et al. 2020; Khan 2020).
Synthetic oil was mixed up with ethanol gasoline blends and tested for its effects towards its lubrication properties and observed that it decreases the viscosity of the engine oil an increases the acidic rating compared to gasoline fuel; also degradation of oil. E10 blend has very less impact on frictional wear properties than other blends (Khuong et al. 2017).
Gasoline, N-Butanol blends show decrement in SFC and CO2 emissions at steady state; with increase of N-Butanol proportions in the blend results in reduced HC, CO, NO and soot emissions. Ethanol gasoline fuel blends shows significant reduction of HC, PN and NOx than other alcohol blends (Haifeng et al. 2019).
Methanol gasoline blends at 5, 10, 20, 30 and 50% proportions were tested for engine performance and emissions; results show that torque and power increases, BSFC also increases with the increase of concentrations of methanol in the blend (Iliev et al. 2020).
Gasoline direct injection and Port FI engines were tested at various engine torques: 25, 50 and 75%; the soot particle emissions from a three way catalytic converter was also evaluated. Six different particles are observed to be ejected by the engine such as Organic, Iron Rich, Sulphur Rich, Calcium and manganese Rich (Xing et al. 2017).
Ethanol gasoline blends at proportions of 10, 20 and 100% were tested on both laboratories with chassis dynamometer and on on-road conditions, observed that 2% reduction in the power output and torque; also in CO and NOx emissions with E20 blend fuel. HC and CO2 emissions wee slightly increased with E20 blend (Tibaquirá et al. 2018).
The timings of fuel injection and ignition; also the combustion chamber modifications were play important roles towards fuel consumption, proper mixing, superior combustion and emissions control; especially NOx and soot particle emissions (Shivakumar et al. 2020; Kumar 2020). NOx emissions were reduced to more than 90% using HCCI combustion technology with natural gas (Verma et al. 2021).
The main objective of this work is to obtain the optimal results towards mainly the reduction of NOx and PM emissions; reduction in SFC and also other performance and emission characteristics, the combustion chamber geometry was modified by keeping the spark plug and the fuel injector at proper locations. The piston crown shape is modified like pent roof structure with a small bowl on one side of the pent roof (fuel injection side) to provide better turbulence, swirl and squish effects for better mixing of air with fuel. The injected fuel over a small bowl on the pent roof is directed towards the spark plug tip to initiate the combustion process. The fuel injection pressure was optimized at 150 bar using NI fuel injection driver. The ignition timing was optimized at 10° bTDC using a self developed ignition driver circuit and the fuel injection timings were optimized using NI fuel injection driver. The compression ratio of an engine was maintained at 10:1 while modifying a piston crown shape. The exhaust gas recirculation was optimized at 10%. Finally, the combined air-wall guided combustion chamber geometry GDI engine was tested towards its performance and emission characteristics.