Effects of rail pressure control on fuel consumption, emissions and combustion parameters in a turbocharged diesel engine

Abstract

The influence of rail pressure control on fuel consumption, emissions and combustion in an automotive downsized turbocharged diesel engine was investigated, considering different operating modes in three-part load working conditions. These modes were selected according to the results of a previous step of the study, where low NO X and fuel consumption levels were obtained managing a hybrid exhaust gas recirculation (EGR) system and the turbocharger variable nozzle turbine (VNT). Aiming at limiting observed soot penalties, increased values of rail pressure were applied, deepening the interactions with engine-controlled sub-assemblies and the related variations in operating, environmental, energy and combustion parameters. At low levels of engine speed and load, major reduction in NO X emissions and fuel consumption were observed, with acceptable soot and noise combustion increase, while turbocharger speed was also enhanced. No variations in fuel consumption were achieved at higher load and speed, while soot penalty remained significant. A simplified method to describe and model engine behaviour and combustion process was also developed, defining linear relationships between rail pressure and engine quantities, including a wide set of combustion parameters derived from in-cylinder pressure diagrams and heat release curves.

Assessment of Microalgae Oil as a Carbon-Neutral Transport Fuel: Engine Performance, Energy Balance Changes, and Exhaust Gas Emissions

“…The rates of heat release curves for D100 and MAO100 are shown in Figure 2b, coupled with two derivative combustion parameters-ROHR MAX (the maximum value of heat flux) and HR PREMIX (the heat released during the premixed phase of combustion) [22]. This phase ranges between the start of combustion (at 3.5 degCA) and the CA corresponding to ROHR MAX (14.5 degCA for D100 and 16.0 degCA for MAO100) [22].…”

“…The main combustion outlined a different development, with slightly higher levels of ROHR MAX and HR PREMIX for microalgae oil combusted under EGR Off mode while under the 18% EGR mode both unary fuels demonstrated similar values. Nevertheless, only a qualitative evaluation is possible, while these parameters had to be evaluated for a more detailed analysis [22]. At the crank angles corresponding to the particular volume of 10% (5.8 degCA for D100 and 6.5 degCA for MAO100), 50% (15.0 degCA for both D100 and MAO100) and 90% (37.0 degCA for D100 and 34.0 degCA for MAO100) of the MFB, the combustion duration (MFB 90-10) and its impact on exploitation parameters of an engine are assessed for the sufficient explanation of the experimental results that were extensively discussed in Sections 3.2 and 3.3.…”

Engine performance and emissions evaluation of surfactant-free B30 biodiesel–diesel/water emulsion as alternative fuel

“…However, in a modern diesel engine equipped with a common rail fuel injection system, it is argued that the effects of the aforementioned properties were rather insignificant. This is because, high pressure fuel injection introduced by the common rail fuel injection system enables improved fuel droplets atomization and evaporation, therefore enhancing combustion process 8 . Nonetheless, biodiesel emit higher nitrogen oxides (NO x ) emissions when taking into account longer ignition delays caused by higher peak combustion temperatures as the result of higher oxygen content in biodiesel 9 .…”

Effect of a turbocharger and EGR on the performance and emission characteristics of a CRDI small diesel engine

“…These engines must satisfy the higher torque requirement without affecting the fuel economy and, at the same time must follow all the emission norms. 2 But, small diesel engines have become one of the vital contributors to pollution. Large diesel engines have been using a system such as catalytic converters, common rail direct injection (CRDI) system, exhaust gas recirculation (EGR), and turbocharger to lower pollution and enhance the thermal efficiency of the engine.…”