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

Author(s):  
Mustafa Canakci ◽  
Eric Hruby ◽  
Rolf D. Reitz

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.

2004 ◽  
Vol 126 (1) ◽  
pp. 167-177 ◽  
Author(s):  
M. Canakci ◽  
R. D. Reitz

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.


2019 ◽  
Vol 19 (4) ◽  
pp. 337-357
Author(s):  
Haroun A.K. Shahad ◽  
Emad D. Abood

Hydrogen is a clean fuel for internal combustion engines since it produces only water vapor and nitrogen oxides when it burns. In this research, hydrogen is used as a blending fuel with diesel to reduce pollutants emission and to improve performance. It is inducted in the inlet manifold, of a single cylinder, four stroke, direct injection, water cold diesel engine, type (Kirloskar). Hydrogen blending is done on energy replacement basis. A special electronic unit is designed and fabricated to control hydrogen blending ratio. The maximum achieved ratio is 30% of input energy and beyond that engine operation becomes unsatisfactory when the air temperature is 20 oC and injection timing of -35o CA which represent the first part of this work. Inlet air heating system is built and added in the experimental work. The heating system allows to increase the air temperature up to 100 oC. A heating of air to 60 oC with injection timing of -30o CA and 55% of hydrogen blending is executed in the second part of this study. Tests are done with 17.5 compression ratio and 1500 rpm. The brake specific fuel consumption is reduced by 29% and 46%, the engine thermal efficiency is increased with 16% and 21% for the 1st and 2nd part respectively. The pollutant emissions of carbon oxides, UHC, and smoke opacity are dramatically decreased by 19.5%, 13%, and 45% respectively for the 1st part and 41%, 38% and 65.6% for the 2nd part while NOx emission is increased by 10% and 25% for the 1st and 2nd part respectively.


2003 ◽  
Vol 4 (1) ◽  
pp. 47-60 ◽  
Author(s):  
M Canakci ◽  
R D Reitz

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.


Author(s):  
Junfeng Yang ◽  
Monica Johansson ◽  
Valeri Golovitchev

A comparative study on engine performance and emissions (NOx, soot) formation has been carried out for the Volvo D12C diesel engine fueled by Rapeseed Methyl Ester, RME and conventional diesel oil. The combustion models, used in this paper, are the modifications of those described in [1–2]. After the compilation of liquid properties of RME specified as methyl oleate, C19H36O2, making up 60% of RME. The oxidation mechanism has been compiled based on methyl butanoate ester, mb, C5H10O2 oxidation model [3] supplemented by the sub-mechanisms for two proposed fuel constituent components, methyl decanoate, md, C11H22O2, n-heptane, C7H16, and soot and NOx formations reduced and “tuned” by using the sensitivity analysis. A special global reaction was introduced to “crack” the main fuel into constituent components, md, mb and propyne, C3H4, to reproduce accurately the proposed RME chemical formula. The sub-mechanisms were collected in the general one consisting of 99 species participating in 411 reactions. The combustion mechanism was validated using shock-tube ignition-delay data at diesel engine conditions and flame propagation speeds at atmospheric conditions. The engine simulations were carried out for Volvo D12C engine fueled both RME and conventional diesel oil. The numerical results illustrate that in the case of RME, nearly 100% combustion efficiency was predicted when the cumulative heat release, was compared with the RME LHV, 37.2 kJ/g.. To minimize NOx emissions, the effects of 20–30% EGR levels depending on the engine loads and different injection strategies were analyses. To confirm the optimal engine operation conditions, a special technique based on the time-transient parametric φ-T maps [4] has been used.


Author(s):  
E. Movahednejad ◽  
F. Ommi ◽  
M. Hosseinalipour ◽  
O. Samimi

For spark ignition engines, the fuel-air mixture preparation process is known to have a significant influence on engine performance and exhaust emissions. In this paper, an experimental study is made to characterize the spray characteristics of an injector with multi-disc nozzle used in the engine. The distributions of the droplet size and velocity and volume flux were characterized by a PDA system. Also a model of a 4 cylinder multi-point fuel injection engine was prepared using a fluid dynamics code. By this code one-dimensional, unsteady, multiphase flow in the intake port has been modeled to study the mixture formation process in the intake port. Also, one-dimensional air flow and wall fuel film flow and a two-dimensional fuel droplet flow have been modeled, including the effects of in-cylinder mixture back flows into the port. The accuracy of model was verified using experimental results of the engine testing showing good agreement between the model and the real engine. As a result, predictions are obtained that provide a detailed picture of the air-fuel mixture properties along the intake port. A comparison was made on engine performance and exhaust emission in different fuel injection timing for 2600 rpm and different loads. According to the present investigation, optimum injection timing for different engine operating conditions was found.


2016 ◽  
Vol 55 (1) ◽  
pp. 243-251 ◽  
Author(s):  
Mohamed M. EL-Kassaby ◽  
Yehia A. Eldrainy ◽  
Mohamed E. Khidr ◽  
Kareem I. Khidr

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