Experimental optimization of a direct injection homogeneous charge compression ignition gasoline engine using split injections with fully automated microgenetic algorithms

2003 ◽  
Vol 4 (1) ◽  
pp. 47-60 ◽  
Author(s):  
M Canakci ◽  
R D Reitz
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Operating Conditions ◽  
Spray Angle ◽  
Injection Timing ◽  
Compression Ignition ◽  
Engine Operation ◽  
Homogeneous Charge

Homogeneous charge compression ignition (HCCI) is receiving attention as a new low-emission engine concept. Little is known about the optimal operating conditions for this engine operation mode. Combustion under homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and particulate matter (PM) as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to an HCCI direct injection (DI) gasoline engine. The engine features an electronically controlled low-pressure direct injection gasoline (DI-G) injector with a 60° spray angle that is capable of multiple injections. The use of double injection was explored for emission control and the engine was optimized using fully automated experiments and a microgenetic algorithm optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing and the split injection parameters (per cent mass of fuel in each injection, dwell between the pulses). The engine performance and emissions were determined at 700 r/min with a constant fuel flowrate at 10 MPa fuel injection pressure. The results show that significant emissions reductions are possible with the use of optimal injection strategies.

Effect of Optimization Criteria on Direct-Injection Homegeneous Charge Compression Ignition Gasoline Engine Performance and Emissions Using Fully Automated Experiments and Microgenetic Algorithms

2004 ◽  
Vol 126 (1) ◽  
pp. 167-177 ◽  
Author(s):  
M. Canakci ◽  
R. D. Reitz
Keyword(s):  
Gasoline Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Engine Performance ◽  
Function Optimization ◽  
Spray Angle ◽  
Injection Timing ◽  
Compression Ignition ◽  
Performance And Emissions ◽  
Engine Performance And Emissions

Homogeneous charge compression ignition (HCCI) is a new low-emission engine concept. Combustion under homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and PM as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. Control of the start of combustion timing is difficult with pre-mixed charge HCCI. Accordingly, in the present study charge preparation and combustion phasing control is achieved with direct injection. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to a direct-injection gasoline engine. The engine features an electronically controlled low-pressure direct injection-gasoline (DI-G) injector with a 60 deg spray angle that is capable of multiple injections. The use of double injection was explored for emission control, and the engine was optimized using fully automated experiments and a microgenetic algorithm optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing, and the split injection parameters (percent mass of fuel in each injection, dwell between the pulses) using three different objective (merit) functions. The engine performance and emissions were determined at 700 rev/min with a constant fuel flow rate at 10 MPa fuel injection pressure. The results show the choice of merit or objective function (optimization goal) determines the engine performance, and that significant emission reductions can be achieved with optimal injection strategies. Merit function formulations are presented that minimized PM, HC, and NOx emissions, respectively.

Assessing Double Injection and Intake Air Temperature Effects on Gasoline HCCI Engine Performance and Emissions Using Fully-Automated Experiments and Micro-Genetic Algorithms

2002 ◽  
Author(s):  
Mustafa Canakci ◽  
Eric Hruby ◽  
Rolf D. Reitz
Keyword(s):  
Air Temperature ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Spray Angle ◽  
Injection Timing ◽  
Engine Operation ◽  
Double Injection ◽  
Performance And Emissions ◽  
Engine Performance And Emissions

Homogeneous charge compression ignition (HCCI) is receiving attention as a new low emission engine concept. Little is known about the optimal operating conditions for this engine operation mode. Combustion at homogeneous, low equivalence ratio conditions results in modest temperature combustion products, containing very low concentrations of NOx and PM as well as providing high thermal efficiency. However, this combustion mode can produce higher HC and CO emissions than those of conventional engines. An electronically controlled Caterpillar single-cylinder oil test engine (SCOTE), originally designed for heavy-duty diesel applications, was converted to a HCCI direct-injection gasoline engine. The engine features an electronically controlled low-pressure common rail injector with a 60°-spray angle that is capable of multiple injections. The use of double injection was explored for emission control, and the engine was optimized using fully-automated experiments and a micro-genetic algorithm (μGA) optimization code. The variables changed during the optimization include the intake air temperature, start of injection timing, and split injection parameters (percent mass of the fuel in each injection, dwell between the pulses). The engine performance and emissions were determined at 700 rev/min with a constant fuel flow rate at 10 MPa fuel injection pressure. The results show that significant emissions reductions are possible with the use of optimal injection strategies.

Effects of Multi-Injection Mode on Diesel Homogeneous Charge Compression Ignition Combustion

2006 ◽  
Vol 129 (1) ◽  
pp. 230-238 ◽  
Author(s):  
Wanhua Su ◽  
Bin Liu ◽  
Hui Wang ◽  
Haozhong Huang
Keyword(s):  
Thermal Efficiency ◽  
Homogeneous Charge Compression Ignition ◽  
Fuel Injection ◽  
Direct Injection ◽  
Progressive Increase ◽  
Compression Ignition ◽  
Injection Mode ◽  
Hcci Combustion ◽  
Injection Modes ◽  
Homogeneous Charge

Early injection, well before top dead center (TDC), has perhaps been the most commonly investigated approach to obtain homogeneous charge compression ignition (HCCI) combustion in a direct-injection (DI) diesel engine. However, wall wetting due to overpenetration of the fuel spray can lead to unacceptable amounts of unburned fuel and removal of lubrication oil. Another difficulty of diesel HCCI combustion is the control of combustion phasing. In order to overcome these difficulties, a multipulse fuel injection technology has been developed for the purpose of organizing diesel HCCI combustion, by which the injection width, injection number, and the dwell time between two neighboring pulse injections can be flexibly regulated. In present paper, the effects of a series of multipulse injection modes realized based on the prejudgment of combustion requirement, on engine emissions, thermal efficiency, and cycle fuel energy distribution of diesel HCCI combustion are studied. The designed injection modes include so-called even mode, hump mode, and progressive increase mode, and each mode with five and six pulses, respectively. Engine test was conducted with these modes. The experimental results show that diesel HCCI combustion is extremely sensitive to multipulse injection modes and that thermal efficiency can be improved with carefully modulated ones. There are many modes that can reach near zero NOx and smoke emissions, but it is significant to be aware that multipulse injection mode must be carefully designed for higher thermal efficiency.

scholarly journals A thermodynamic model for homogeneous charge compression ignition combustion with recompression valve events and direct injection: Part I — Adiabatic core ignition model

2016 ◽  
Vol 18 (7) ◽  
pp. 657-676 ◽  
Author(s):  
Prasad S Shingne ◽  
Robert J Middleton ◽  
Dennis N Assanis ◽  
Claus Borgnakke ◽  
Jason B Martz
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Homogeneous Charge Compression Ignition ◽  
Direct Injection ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Auto Ignition ◽  
Dynamics Simulations ◽  
Compression Ignition Combustion ◽  
Homogeneous Charge

This two-part article presents a model for boosted and moderately stratified homogeneous charge compression ignition combustion for use in thermodynamic engine cycle simulations. The model consists of two components: one an ignition model for the prediction of auto-ignition onset and the other an empirical combustion rate model. This article focuses on the development and validation of the homogeneous charge compression ignition model for use under a broad range of operating conditions. Using computational fluid dynamics simulations of the negative valve overlap valve events typical of homogeneous charge compression ignition operation, it is shown that there is no noticeable reaction progress from low-temperature heat release, and that ignition is within the high-temperature regime ( T > 1000 K), starting within the highest temperature cells of the computational fluid dynamics domain. Additional parametric sweeps from the computational fluid dynamics simulations, including sweeps of speed, load, intake manifold pressures and temperature, dilution level and valve and direct injection timings, showed that the assumption of a homogeneous charge (equivalence ratio and residuals) is appropriate for ignition modelling under the conditions studied, considering the strong sensitivity of ignition timing to temperature and its weak compositional dependence. Use of the adiabatic core temperature predicted from the adiabatic core model resulted in temperatures within ±1% of the peak temperatures of the computational fluid dynamics domain near the time of ignition. Thus, the adiabatic core temperature can be used within an auto-ignition integral as a simple and effective method for estimating the onset of homogeneous charge compression ignition auto-ignition. The ignition model is then validated with an experimental 92.6 anti-knock index gasoline-fuelled homogeneous charge compression ignition dataset consisting of 290 data points covering a wide range of operating conditions. The tuned ignition model predictions of [Formula: see text] have a root mean square error of 1.7° crank angle and R2 = 0.63 compared to the experiments.

scholarly journals Thermodynamic model for homogeneous charge compression ignition combustion with recompression valve events and direct injection: Part II—Combustion model and evaluation against transient experiments

2016 ◽  
Vol 18 (7) ◽  
pp. 677-700
Author(s):  
Prasad S Shingne ◽  
Jeff Sterniak ◽  
Dennis N Assanis ◽  
Claus Borgnakke ◽  
Jason B Martz
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Combustion Model ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Ignition And Combustion ◽  
Compression Ignition Combustion ◽  
Homogeneous Charge

This two-part article presents a combustion model for boosted and moderately stratified homogeneous charge compression ignition combustion for use in thermodynamic engine cycle simulations. The model consists of two parts: one an ignition model for the prediction of auto-ignition onset and the other an empirical combustion rate model. This article focuses on the development of the combustion model which is algebraic in form and is based on the key physical variables affecting the combustion process. The model is fit with experimental data collected from 290 discrete automotive homogeneous charge compression ignition operating conditions with moderate stratification resulting from both the direct injection and negative valve overlap valve events. Both the ignition model from part 1 and the combustion model from this article are implemented in GT-Power and validated against experimental homogeneous charge compression ignition data under steady-state and transient conditions. The ignition and combustion model are then exercised to identify the dominant variables affecting the homogeneous charge compression ignition and combustion processes. Sensitivity analysis reveals that ignition timing is primarily a function of the charge temperature, and that combustion duration is largely a function of ignition timing.

Experimental and Numerical Analysis on the Influences of Direct Fuel Injection into Oxygen-Depleted Environment of a Homogeneous Charge Compression Ignition Engine

2021 ◽  
pp. 1-29
Author(s):  
Ratnak Sok ◽  
Kei Yoshimura ◽  
Kenjiro Nakama ◽  
Jin Kusaka
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Fuel Injection ◽  
Double Pulse ◽  
Gasoline Direct Injection ◽  
Oh Radicals ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Intake Stroke ◽  
Direct Fuel Injection ◽  
Homogeneous Charge

Abstract The oxygen-depleted environment in the recompression stroke can convert gasoline fuel into light hydrocarbons due to thermal cracking, partial oxidation, and water-gas shift reactions. These reformate species can influence the combustion characteristics of gasoline direct injection homogeneous charge compression ignition (GDI-HCCI) engines. In this work, the combustion phenomena are investigated using a single-cylinder research engine under a medium load. The main combustion phases are experimentally advanced by direct fuel injection into the negative valve overlap (NVO) compared with that of intake stroke under single/double pulse injections. NVO peak in-cylinder pressures are lower than that of motoring due to the limited O2 concentration, emphasizing that endothermic reactions occur during the overlap. This phenomenon limits the oxidation reactions, and the thermal effect is not pronounced. The 0-D chemical kinetics results present the same increasing tendencies of classical reformed species of rich-mixture such as C3H6, C2H4, CH4, CO, and H2 as functions of injection timings. Predicted ignition delays are shortened due to the additions of these reformed species. The influences of the reformates on the main combustion are confirmed by 3-D CFD calculations, and the results show that OH radicals are advanced under NVO injections relative to intake stroke injections. Consequently, earlier heat release and cylinder pressure are noticeable. Parametric studies on the effects of injection pressure, double-pulse injection, and equivalence ratio on the combustion and emissions are also discussed experimentally.

Parametric study of combustion characteristics in a direct-injection diesel homogeneous charge compression ignition engine with a low-pressurefuel injector

2005 ◽  
Vol 6 (3) ◽  
pp. 215-230 ◽  
Author(s):  
Y Ra ◽  
E J Hruby ◽  
R D Reitz
Keyword(s):  
Numerical Simulations ◽  
Diesel Fuel ◽  
Homogeneous Charge Compression Ignition ◽  
Direct Injection ◽  
Low Pressure ◽  
Combustion Characteristics ◽  
Compression Ignition ◽  
Fuel Injector ◽  
Compression Ignition Engine ◽  
Homogeneous Charge

Homogeneous charge compression ignition (HCCI) combustion is an alternative to current engine combustion systems and is used as a method to reduce emissions. It has the potential nearly to eliminate engine-out NOx emissions while producing diesel-like engine efficiencies, when a premixture of gas-phase fuel and air is burned spontaneously and entirely by an autoignition process. However, when direct injection is used for diesel fuel mixture preparation in engines, the complex in-cylinder flow field and limited mixing times may result in inhomogeneity of the charge. Thus, in order to minimize non-uniformity of the charge, early injection of the fuel is desirable. However, when fuel is injected during the intake or early compression stroke, the use of high-pressure injection is limited by the relatively low in-cylinder gas pressure because of spray impingement on the cylinder walls. Thus, it is also of interest to consider low-pressure injectors as an alternative. In the present paper, the parametric behaviour of the combustion characteristics in an HCCI engine operated with a low-pressure fuel injector were investigated through numerical simulations and engine experiments. Parameters including the start-of-injection (SOI) timing and exhaust gas recirculation were considered, and diesel and n-heptane fuels were used. The results show good agreement of behaviour trends between the experiments and the numerical simulations. With its lower vaporization rates, significant effects of the SOI timing and intake gas temperature were seen for diesel fuel due to the formation of wall films. The modelling results also explained the origin of high-temperature NO x-producing regions due to the effect of the gas density on the spray.

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