Wyniki wyszukiwania - BazTech

1

Simulation of the work of a spark-ignition engine with a dual-injector fuel system

Sendyka B., Noga M.

Journal of KONES

|

2010

|

Vol. 17, No. 1

399-410

EN

This paper is about computer modelling of a four-stroke spark-ignition engine with a dual-injector system. Using a KIVA-3V program for Linux, computer simulations were performed for one of the cylinders fuelled by multipoint injection and by the dual-injector system, i. e. with direct injection into the cylinders on top of MPI. The modelling was done for a combustion engine Toyota 2SZ-FE with a dual-injector system. Both simulations were done for the same parameters of engine's work, i.e. at the same RPM of 2000 and the intake pipe pressure of 0.079 MPa. KIVA-3V program models the processes taking place in an internat combustion engine while taking into account physical and chemical phenomena occurring during the formation of a charge and during its combustion. Using a stochastic model of injection the program takes into account the movement of droplets and their dispersion. The results of the simulation show that the dual-injector system has an improved volumetric coefficient, i.e. improved engine performance. An increase in the engine's indicated pressure was also observed; this increases the engine's total efficiency. The intensification of the charge's angular momentum in a cylinder with a dual-injector system can explain the improvements in the course of combustion process. Because the air-fuel mixture was already partially formed in the engine there was a small increase in the unburned hydrocarbons in the cylinder. However, a marked drop in the carbon monoxide and nitric oxide were observed for the dual-injector system. Analyzing the overall results of the simulations one can ascertain a positive impact of using a dual-injector system on the working parameters of a spark-ignition engine.

2

Effects of using a dual-injector fuel system on a process of combustion in a spark-ignition engine

Sendyka B., Noga M.

Journal of KONES

|

2010

|

Vol. 17, No. 1

389-397

EN

This paper analyzes aprocess of combustion in a spark-ignition engine. The aim of the analysis was to determine the differences in the combustion process between the engine with a classic multipoint injection system and a system which injects fuel directly to the cylinders as well. To aid in the analysis the measurements of the high variable pressure in the engine's cylinder against the crankshaft angle were taken. This allowed us to obtain indicated diagrams for both types of engines. To eliminate distortions, both functions were approximated using combined functions. The other basic parameters were also measured: torque, RPM and instantaneous fuel consumption. The analysis of the indicated diagrams yielded an indicated mean pressure and thermal efficiency for both fuel systems. Then, a comprehensive analysis ofpressures in cylinders was performed in order to determine the way the flame spreads in the cylinder for the two types of engines. The results obtained from this analysis show that the speed of combustion is greater for the charge formed by the dual-injector fuel system. The increased speed of the combustion, especially when it reaches a 50% fraction of the exhaust gas in the cylinder, is what accounts for the increase in the indicated mean pressure and the increase in the thermal efficiency of the engine with a dual-injector fuel system. The time of the spreading of the flame, as well as the fast burn period were reduced. The increased efficiency of the combustion process in the cylinder me ans that the heat losses through the cylinder sleeve are greatly reduced. The results of the research in this paper confirm the purposefulness of using a dual-injector fuel system in a spark-ignition engine.

3

An impact of using a dual-injection system on a combustion engine's working parameters

Sendyka B., Noga M.

Journal of KONES

|

2010

|

Vol. 17, No. 1

379-388

EN

The paper analyses the impact of using a dual-injection system on the engine's working parameters. The analysis is based on the results of the test stand research on a four-stroke four-cylinder, spark-ignition engine. Dual-injection system combines the multipoint injection with additional injection directly into the combustion chamber. It is used to increase the performance of an engine without affecting the fuel consumption or the low toxicity of exhaust gas. For the purposes of this research an engine from Toyota Yaris was fitted with the direct injection by installing high pressure injectors on the cylinder head. This engine is factory-equipped with MPL Based on the tests performed four controlling characteristics of the torque and brake specific fuel consumption were prepared. The controlling value was the proportion of the fuel injected into the inlet channel to the fuel injected directly into the combustion chamber. The same relationships were also described in relation to temperature of the exhaust gas and the fraction in volume in the exhaust gas of ingredients such as carbon monoxide, carbon dioxide, unburned hydrocarbons and nitric oxide. Points of measurement were decided upon basedon the existing literature on the subject. The analysis of the test results shows apossibility ofa 2-4% decrease in the brake specific fuel consumption for the dual-injection engine in the low and middle RPM range and for the partial loads. The dual-injection engine also shows a decrease in the nitric oxide's fraction in the exhaust gas and a lower temperature of the exhaust gas. There was a small increase in the carbon monoxide and hydrocarbons.

4

Determination of optimal fuel mass relation dosed by a dual-injector fuel system in a spark ignition engine

Sendyka B., Noga M.

Silniki Spalinowe

|

2009

|

R. 48, SC2

285--289

EN

The paper concerns application of the dual-injector fuel system in a four cylinder in-line spark ignition engine. Each of the cylinders is equipped with one port fuel injector and another high-pressure inchamber direct fuel injector. During investigations function of the Brake Mean Effective Pressure and Brake Specific Fuel Consumption in dependence on mass fraction of directly-injected fuel was determined for different revolutions and loads. The test was carried out at constant value of relative air-to-fuel ratio. Results of performed tests show, that the maximum of the Brake Mean Effective Pressure and minimum of Brake Specific Fuel Consumption occurs at different fraction of directly-injected fuel in dependence on load and revolution of the engine. A comparison of performance of the engine fueled at the optimal fraction of directly-injected fuel and results gained at only one point of fuel supply shows a real improvement in performance of the engine at dualinjector operation.

PL

Praca dotyczy zastosowania dwuwtryskiwaczowego systemu zasilania w czterocylindrowym silniku z zapłonem iskrowym. Na każdy z cylindrów badanego silnika przypada jeden wtryskiwacz dawkujący paliwo do przewodu dolotowego oraz drugi wtryskujący je do komory spalania. Przeprowadzono badania w celu określenia zależności średniego ciśnienia efektywnego i jednostkowego zużycia paliwa od udziału paliwa dawkowanego bezpośrednio do cylindra z zachowaniem stałego globalnego współczynnika nadmiaru powietrza. Wyniki przeprowadzonych prac badawczych wskazują, że maksimum średniego ciśnienia efektywnego i minimum jednostkowego zużycia paliwa występuje przy różnych udziałach paliwa wtryśniętego bezpośrednio do cylindra w zależności od obranego punktu pracy silnika. Porównanie osiągów silnika zasilanego przy optymalnym udziale benzyny wtryskiwanej w sposób bezpośredni z wynikami uzyskanymi tylko dla jednego miejsca podawania paliwa wskazuje na istotny wzrost w przypadku zasilania dwuwtryskiwaczowego.