Combustion Model for a Homogeneous Turbocharged Gasoline Direct-Injection Engine

Author(s):  
Sedigheh Tolou ◽  
Ravi Teja Vedula ◽  
Harold Schock ◽  
Guoming Zhu ◽  
Yong Sun ◽  
...  

Homogeneous charge is a preferred operation mode of gasoline direct-injection (GDI) engines. However, a limited amount of work exists in the literature for combustion models of this mode of engine operation. Current work describes a model developed to study combustion in a homogeneous charge GDI engine. The model was validated using experimental data from a 1.6 L Ford EcoBoost® engine, tested at the U.S. EPA. The combustion heat release was approximated using a double-Wiebe function, to account for the rapid initial premixed combustion followed by a gradual diffusion-like state of combustion, as observed in this GDI engine. Variables of Wiebe correlations were adjusted into a semipredictive combustion model. The effectiveness of semipredictive combustion model was tested in prediction of in-cylinder pressures. The root-mean-square (RMS) errors between experiments and numerical results were within 2.5% of in-cylinder peak pressures during combustion. The semipredictive combustion model was further studied to develop a predictive combustion model. The performance of predictive combustion model was examined by regenerating the experimental cumulative heat release. The heat release analysis developed for the GDI engine was further applied to a dual mode, turbulent jet ignition (DM-TJI) engine. DM-TJI is a distributed combustion technology with the potential to provide diesel-like efficiencies and minimal engine-out emissions for spark-ignition engines. The DM-TJI engine was observed to offer a faster burn rate and lower in-cylinder heat transfer compared to the GDI engine.

Author(s):  
Sedigheh Tolou ◽  
Ravi Teja Vedula ◽  
Harold Schock ◽  
Guoming Zhu ◽  
Yong Sun ◽  
...  

Homogeneous charge is a preferred operation mode of gasoline direct-injection (GDI) engines. However, a limited amount of work exists in the literature for combustion models of this mode of engine operation. Current work describes a model developed and used to study combustion in a GDI engine having early intake fuel injection. The model was validated using experimental data obtained from a 1.6L Ford EcoBoost® four-cylinder engine, tested at the U.S. EPA. The start of combustion was determined from filtered cycle-averaged cylinder pressure measurements, based on the local maximum of third derivative with respect to crank angle. The subsequent heat release, meanwhile, was approximated using a double-Wiebe function, to account for the rapid initial pre-mixed combustion (stage 1) followed by a gradual diffusion-like state of combustion (stage 2) as observed in this GDI engine. A non-linear least-squares optimization was used to determine the tuning variables of Wiebe correlations, resulting in a semi-predictive combustion model. The effectiveness of the semi-predictive combustion model was tested by comparing the experimental in-cylinder pressures with results obtained from a model built using a one-dimensional engine simulation tool, GT-POWER (Gamma Technologies). Model comparisons were made for loads of 60, 120, and 180 N-m at speeds ranging from 1500 to 4500 rpm, in 500 rpm increments. The root-mean-square errors between predicted cylinder pressures and the experimental data were within 2.5% of in-cylinder peak pressure during combustion. The semi-predictive combustion model, verified using the GT-POWER simulation, was further studied to develop a predictive combustion model. The performance of the predictive combustion model was examined by regenerating the experimental cumulative heat release. The heat release analysis developed for the GDI engine was further applied to a dual mode, turbulent jet ignition (DM-TJI) engine. DM-TJI is an advanced combustion technology with a promising potential to extend the thermal efficiency of spark ignition engines with minimal engine-out emissions. The DM-TJI engine was observed to offer a faster burn rate and lower in-cylinder heat transfer when compared to the GDI engine under the same loads and speeds.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2099
Author(s):  
Jian Gao ◽  
Anren Yao ◽  
Yeyi Zhang ◽  
Guofan Qu ◽  
Chunde Yao ◽  
...  

The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug failure. However, the effect of misfire on engine combustion has not been paid enough attention to, particularly regarding connection to super-knock. The paper presents the results of experimental investigation into the relationship between super-knock and misfires at low speed and full load conditions. In this work, a boosted gasoline direct injection (GDI) engine with an exhaust manifold integrated in the cylinder head was employed. Four piezoelectric pressure transducers were used to acquire the data of a pressure trace in cylinder. The spark plugs of four cylinders were controlled manually, of which the ignition system could be cut off as demanded. In particular, a piezoelectric pressure transducer was installed at the exhaust pipe before the turbocharger to capture the pressure traces in the exhaust pipe. The results illustrated that misfires in one cylinder would cause super-knock in the other cylinders as well as the cylinder of itself. After one cylinder misfired, the unburned mixture would burn in the exhaust pipe to produce oscillating waves. The abnormal pressure fluctuation in the exhaust pipe was strongly correlated with the occurrence of super-knock. The sharper the pressure fluctuation, the greater the intensity of knock in the power cylinder. The cylinder whose exhaust valve overlapped with the exhaust valve of the misfired cylinder was prone to super-knock.


Fuel ◽  
2011 ◽  
Vol 90 (5) ◽  
pp. 1855-1867 ◽  
Author(s):  
D.C. Rakopoulos ◽  
C.D. Rakopoulos ◽  
R.G. Papagiannakis ◽  
D.C. Kyritsis

Author(s):  
Sayop Kim ◽  
Riccardo Scarcelli ◽  
Yunchao Wu ◽  
Johannes Rohwer ◽  
Ashish Shah ◽  
...  

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.


2003 ◽  
Vol 4 (3) ◽  
pp. 219-231 ◽  
Author(s):  
N. P. Kyrtatos ◽  
E. I. Tzanos ◽  
C. I. Papadopoulos

Transient operation of a direct injection heavy duty (DI HD) diesel engine equipped with an NOx storage catalyst (NSC) was simulated using a ‘virtual powerplant’ simulation code with a zero-dimensional multizone combustion model. For the regeneration of the NSC the engine is required to work with lean/rich operation switches, which necessitates advanced engine management schemes for the fuelling, throttle and turbocharger wastegate. An optimization procedure, using the simulation model, resulted in a proposed schedule for the control of the various engine components involved in such engine operation.


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