Influence of piston shape and injector geometry on combustion and emission characteristics of syngas in direct-injection spark-ignition engine

Abstract

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand -outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Numerical investigation of the effect of injection timing on the in-cylinder activity of a gasoline direct injection engine

“…Due to the axisymmetric structure, half of the engine geometry was taken out for the study in order to reduce the computational effort, as shown in Figure 1. According to Zanforlin and Boretti, 44 Fiore et al, 45 such a modeling approach is acceptable. The fuel injector (six holes) was installed adjacent to the spark plug and injected the fuel after the exhaust valve closing and during the intake stroke.…”

A Numerical Investigation on Laminar Flame Speed of Syngas in Air with Ozone Addition

“…In this context, hydrogen and syngas represent alternative fuels to conventional fossil fuels, with an increasingly important role in the development of highly efficient and low-emission propulsion and energy production systems, such as Internal Combustion Engines (ICEs) or gas turbines [3][4][5][6][7][8]. Syngas is mainly composed of 𝐶𝐶𝐶𝐶 and 𝐻𝐻 2 , but its composition depends significantly on both the source and the gasification process.…”

Combustion and Emission Characteristics of Gasoline Engine Blended Combustion Syngas

“…Even though fast combustion of syngas suggested late injection for a better combustion, performance and emission, the lower calorific value resulted in operational limitation for the direct injection system particularly at a higher speed maintaining the air–fuel ratio close to stoichiometry. Fiore et al 23 studied the influence of piston shape and injector geometry on the combustion and emission characteristics of spark ignition engine fueled by syngas (50% by volume of hydrogen, 50% by volume of carbon monoxide) under low/medium load conditions. The result showed that the Omega Combustion Cup (OCC) piston shape was certainly the best choice in order to optimize the combustion process and performance, even if it may lead to a higher nitrogen oxide emission.…”