Computational Investigation of Low Load Operation in a Light-Duty Gasoline Direct Injection Compression Ignition [GDICI] Engine Using Single-Injection Strategy

2014 ◽  
Author(s):  
Bishwadipa Das Adhikary ◽  
Rolf D. Reitz ◽  
Stephen Ciatti ◽  
Christopher Kolodziej
Keyword(s):  
Single Injection ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Compression Ignition ◽  
Computational Investigation ◽  
Injection Strategy ◽  
Light Duty ◽  
Low Load

Simulations of Multi-Mode Combustion Regimes Realizable in a Gasoline Direct Injection Engine

2020 ◽  
Author(s):  
Sayop Kim ◽  
Riccardo Scarcelli ◽  
Yunchao Wu ◽  
Johannes Rohwer ◽  
Ashish Shah ◽  
...  
Keyword(s):  
Mixed Mode ◽  
Direct Injection ◽  
Flow Property ◽  
Gasoline Direct Injection ◽  
Combustion Model ◽  
Compression Ignition ◽  
Fuel Blend ◽  
Combustion Dynamics ◽  
Low Load ◽  
Multi Mode

Abstract Lean and dilute gasoline compression ignition (GCI) operation in spark ignition (SI) engines are an attractive strategy to attain high fuel efficiency and low NOx levels. However, this combustion mode is often limited to low-load engine conditions due to the challenges associated with autoignition controllability. In order to overcome this constrain, multi-mode (MM) operating strategies, consisting of advanced compression ignition (ACI) at low load and conventional SI at high load, have been proposed. In this 3-D CFD study the concept of multi-mode combustion using two RON98 gasoline fuel blends (Co-Optima Alkylate and E30) in a gasoline direct injection (GDI) engine were explored. To this end, a new reduced mechanism for simulating the kinetics of E30 fuel blend is introduced in this study. To cover the varying engine load demands for multi-mode engines, primary combustion dynamics observed in ACI and SI combustion modes was characterized and validated against experimental measurements. In order to implement part-load conditions, a strategy of mode-transition between SI and ACI combustion (i.e., mixed-mode combustion) was then explored numerically by creating a virtual test condition. The results obtained from the mixed-mode simulations highlight an important feature that deflagrative flame propagation regime coexists with ignition-assisted end-gas autoignition. This study also identifies a role of turbulent flow property adjacent to premixed flame front in characterizing the mixed-mode combustion. The employed hybrid combustion model was verified to perform simulations aiming at suitable range of multi-mode engine operations.

Simulations of Multi-Mode Combustion Regimes Realizable in a Gasoline Direct Injection Engine

2021 ◽  
pp. 1-26
Author(s):  
Sayop Kim ◽  
Riccardo Scarcelli ◽  
Yunchao Wu ◽  
Johannes Rohwer ◽  
Ashish Shah ◽  
...  
Keyword(s):  
Mixed Mode ◽  
Direct Injection ◽  
Flow Property ◽  
Gasoline Direct Injection ◽  
Combustion Model ◽  
Compression Ignition ◽  
Fuel Blend ◽  
Combustion Dynamics ◽  
Low Load ◽  
Multi Mode

Abstract Lean and dilute gasoline compression ignition (GCI) operation in spark ignition (SI) engines are an attractive strategy to attain high fuel efficiency and low NOx levels. However, this combustion mode is often limited to low-load engine conditions due to challenges associated with autoignition controllability. In order to overcome this constrain, multi-mode (MM) operating strategies, consisting of advanced compression ignition (ACI) at low load and conventional SI at high load, have been proposed. In this 3-D CFD study the concept of multi-mode combustion using two RON98 gasoline fuel blends (Co-Optima Alkylate and E30) in a gasoline direct injection (GDI) engine were explored. To this end, a new reduced mechanism for simulating the kinetics of E30 fuel blend is introduced in this study. To cover the varying engine load demands for multi-mode engines, primary combustion dynamics observed in ACI and SI combustion modes was characterized and validated against experimental measurements. In order to implement part-load conditions, a strategy of mode-transition between SI and ACI combustion (i.e., mixed-mode combustion) was then explored numerically by creating a virtual test condition. The results obtained from the mixed-mode simulations highlight an important feature that deflagrative flame propagation regime coexists with ignition-assisted end-gas autoignition. This study also identifies a role of turbulent flow property adjacent to premixed flame front in characterizing the mixed-mode combustion. The employed hybrid combustion model was verified to perform simulations aiming at suitable range of multi-mode engine operations.

Influences of the fuel injection parameters on the first-cycle firing and the combustion characteristics during the direct-start process for a gasoline direct-injection engine

2016 ◽  
Vol 231 (5) ◽  
pp. 585-599 ◽  
Author(s):  
Fangxi Xie ◽  
Yan Su ◽  
Wei Hong ◽  
Xiangyu Li ◽  
Xiaoping Li ◽  
...  
Keyword(s):  
Heat Release ◽  
Single Injection ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Injection Strategy ◽  
Fuel Mass ◽  
Direct Injection Engine ◽  
Gasoline Direct Injection Engine ◽  
Dual Injection ◽  
Start Process

The direct-start method without requiring a starter is a viable and cost-effective solution for generating a frequent and efficient restarting process when start–stop technology is used on a gasoline direct-injection engine. During the direct-start process, the first-cycle combustion characteristics play a key role in determining whether the start mode is successful or not, because the start energy is wholly derived from the in-cylinder combustion without the support of a starter motor on the gasoline direct-injection engine. However, the first-cycle fuel–air mixing and combustion characteristics during the direct-start process of a gasoline direct-injection engine are not fully understood. In this work, the influences of the injection parameters, including the delay between the injection and ignition, the excess air ratio for the single-injection strategy, the delay between the first injection and the second injection for the dual-injection strategy and the ratio of the fuel mass in the first injection to the fuel mass in the second injection for the dual-injection strategy, on the combustion pressure, the heat release rate, the accumulated heat release and the indicated work were investigated experimentally by cycle-by-cycle analysis. The results show that the optimal delay between the injection and ignition of the single-injection strategy was 200 ms as a longer delay or a shorter delay can result in a reduction in the heat released rate, the indicated work and the firing boundary. A shorter delay with the optimal injected fuel mass tended to be more beneficial to the accumulated heat released, the indicated work and the crankshaft speed. Furthermore, with increasing delay and increasing fuel ratio of the fuel mass in the first injection to the fuel mass in the second injection for the dual-injection strategy, the heat release rate, the accumulated heat release and the indicated work first increased and then decreased. The optimum delay was 10 ms and the ratios of the fuel mass in the first injection to the fuel mass in the second injection were 4/1 and 5/1 respectively under the test conditions. Additionally, the dual-injection strategy with an optimized control parameter produced a higher heat release and higher indicated work than the single-injection strategy did.

scholarly journals Comparisons of Laboratory and On-Road Type-Approval Cycles with Idling Emissions. Implications for Periodical Technical Inspection (PTI) Sensors

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5790 ◽  
Author(s):  
Barouch Giechaskiel ◽  
Tero Lähde ◽  
Ricardo Suarez-Bertoa ◽  
Victor Valverde ◽  
Michael Clairotte
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Gasoline Direct Injection ◽  
Compression Ignition ◽  
Particulate Filters ◽  
Technical Inspection ◽  
Diesel Vehicles ◽  
Type Approval ◽  
Road Type ◽  
Technical Specifications

For the type approval of compression ignition (diesel) and gasoline direct injection vehicles, a particle number (PN) limit of 6 × 1011 p/km is applicable. Diesel vehicles in circulation need to pass a periodical technical inspection (PTI) test, typically every two years, after the first four years of circulation. However, often the applicable smoke tests or on-board diagnostic (OBD) fault checks cannot identify malfunctions of the diesel particulate filters (DPFs). There are also serious concerns that a few high emitters are responsible for the majority of the emissions. For these reasons, a new PTI procedure at idle run with PN systems is under investigation. The correlations between type approval cycles and idle emissions are limited, especially for positive (spark) ignition vehicles. In this study the type approval PN emissions of 32 compression ignition and 56 spark ignition vehicles were compared to their idle PN concentrations from laboratory and on-road tests. The results confirmed that the idle test is applicable for diesel vehicles. The scatter for the spark ignition vehicles was much larger. Nevertheless, the proposed limit for diesel vehicles was also shown to be applicable for these vehicles. The technical specifications of the PTI sensors based on these findings were also discussed.

Numerical Simulations of Hollow Cone Injection and Gasoline Compression Ignition Combustion With Naphtha Fuels

2015 ◽  
Author(s):  
Jihad A. Badra ◽  
Jaeheon Sim ◽  
Ahmed Elwardany ◽  
Mohammed Jaasim ◽  
Yoann Viollet ◽  
...  
Keyword(s):  
Experimental Data ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Experimental Investigations ◽  
Attractive Alternative ◽  
Spray Parameters ◽  
Compression Ignition ◽  
Hollow Cone ◽  
Modeling Framework ◽  
Primary Reference

Gasoline compression ignition (GCI), also known as partially premixed compression ignition (PPCI) and gasoline direct injection compression ignition (GDICI), engines have been considered an attractive alternative to traditional spark ignition engines. Lean burn combustion with the direct injection of fuel eliminates throttle losses for higher thermodynamic efficiencies, and the precise control of the mixture compositions allows better emission performance such as NOx and particulate matter (PM). Recently, low octane gasoline fuel has been identified as a viable option for the GCI engine applications due to its longer ignition delay characteristics compared to diesel and lighter evaporation compared to gasoline fuel [1]. The feasibility of such a concept has been demonstrated by experimental investigations at Saudi Aramco [1, 2]. The present study aims to develop predictive capabilities for low octane gasoline fuel compression ignition engines with accurate characterization of the spray dynamics and combustion processes. Full three-dimensional simulations were conducted using CONVERGE as a basic modeling framework, using Reynolds-averaged Navier-Stokes (RANS) turbulent mixing models. An outwardly opening hollow-cone spray injector was characterized and validated against existing and new experimental data. An emphasis was made on the spray penetration characteristics. Various spray breakup and collision models have been tested and compared with the experimental data. An optimum combination has been identified and applied in the combusting GCI simulations. Linear instability sheet atomization (LISA) breakup model and modified Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) break models proved to work the best for the investigated injector. Comparisons between various existing spray models and a parametric study have been carried out to study the effects of various spray parameters. The fuel effects have been tested by using three different primary reference fuel (PRF) and toluene primary reference fuel (TPRF) surrogates. The effects of fuel temperature and chemical kinetic mechanisms have also been studied. The heating and evaporative characteristics of the low octane gasoline fuel and its PRF and TPRF surrogates were examined.

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