Thermodynamic Analysis and Optimization of Two-Stroke Gasoline Engines

Landfahrer, Klaus; Plohberger, Diethard; Alten, Hans; Mikulic, Leo A.

doi:10.4271/890415

Cited by 21 publications

(3 citation statements)

References 7 publications

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“…The problem of short mixture preparation time in engine cylinder after exhaust port closure and scavenging is performed with air alone or a lean mix-direct fuel injection systems can be resolved if an air-fuel mixture were to be injected into the engine ture. The work involving direct liquid fuel injection [1,[4][5][6][7] can broadly be classified into those using a cylinder instead of fuel alone. The mixture can be prepared in a separate mixture preparation unit new engine shows the potential to meet future emission norms and yet deliver satisfactory per-or within the conventional crankcase, whereas the scavenging is carried out with air alone.…”

Section: Introductionmentioning

confidence: 99%

“…Researchers formance. A detailed description of this engine has been presented previously [25,26]; however, a short at AVL [6] have reported a direct mixture injection (DMI) system in which the mixture is prepared in description of the same is included below. The engine operates on a DMI principle and uses a chamber connected to the engine cylinder via a mixture injection valve in the cylinder head.…”

Section: Introductionmentioning

confidence: 99%

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In-cylinder charge stratification and fuel-air mixing in a new, low-emission two-stroke engine

Bakshi¹,

Anand

Ravikrishna

2007

International Journal of Engine Research

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A new air-assisted injection system-based two-stroke engine has been developed at the Indian Institute of Science, Bangalore over the past few years and shows the potential to meet emission norms such as Euro II and Euro III and yet deliver satisfactory performance. The 70 cc engine works on the direct mixture injection principle with scavenging performed by air alone instead of an air-fuel mixture. A small 20 cc pump driven off the engine is used for mixture preparation prior to in-cylinder injection of the mixture. In the present study, the mixture injection and subsequent charge stratification process inside the engine cylinder is modelled. A three-dimensional compressible flow code with a standard k-ε turbulence model with wall functions is developed and used for this modelling. To account for the moving boundary or piston in the engine cylinder domain, a non-stationary and deforming grid is used in this region with stationary cells in the ports and connecting ducts. A flux conservation scheme is used in the domain interface to allow the in-cylinder moving mesh to slide past the fixed port meshes. The initial conditions for flow parameters are taken from the output of a three-dimensional scavenging simulation. The state of the inlet charge is obtained from a separate modelling of the air-assisted injection system of this engine. The simulation results show that a large, near-stoichiometric region is present at most operating conditions in the cylinder head plane. The state of the in-cylinder charge at the onset of ignition is studied, leading to a good understanding of the mixing process. In addition, the sensitivity of two critical parameters in the mixing and stratification is investigated. The suggested parameters substantially enhance the flammable proportion at the onset of combustion. The predicted pressure-crank angle history from a combustion simulation supports this recommendation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In-cylinder charge stratification and fuel-air mixing in a new, low-emission two-stroke engine

Bakshi¹,

Anand

Ravikrishna

2007

International Journal of Engine Research

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“…Separating the task of scavenging from mixture preparation and charge injection is the key consideration in solving this problem. Direct mixture injection (DMI ) systems incorporate this principle by introducing a separate mixture preparation unit from where the mixture is directly injected into the engine cylinder after or slightly before the exhaust port closure [5].…”

Section: Introductionmentioning

confidence: 99%

Multidimensional simulation of the air-flow and fuel transport process in the air-assisted injection system of a new, low-emission two-stroke engine

Bakshi

Ravikrishna

2003

Proceedings of the Institution of Mechanical Engineers, Part D:

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The aim of this work is to model the air and fuel ow process in the air-assisted injection system of a new, low emission two-stroke engine with a view to determine the critical features in the system that in uence the engine performance. A computational method for multidimensional, compressible, two-phase ow using a Lagrangian-Eulerian approach is developed and used for this analysis. Good agreement is observed between computations and measurements of fuel consumption and pressure recovery in the injection system of the current prototype. The results show a strong dependence of the typical air ow characteristics of the injection system on engine speed. Signi cant fuelling after inlet port closure, higher fuel transport e ciency at low speeds and a substantial impingement of liquid fuel on the solid walls of the injection system are also evident from the results of the computations. This suggests a delayed transient response and strong speed dependence of the quality of mixture preparation in this system, which explains certain observed trends in the current prototype of the engine. NOTATIONtransport e ciency of fuel from throttle body to the pneumatic pump l control volume length n droplet number density inside the control volume P o ambient pressure P t pressure at the ori ce tip P t P o fuelling forcing function at the ori ce tip r detachment radius from the fuel ori ce R radius of the fuel ori ce U gas phase velocity at the ori ce tip U av average ow velocity at the intake V droplet phase velocities V g gas phase velocity m dynamic viscosity of the gas phaseThe MS was

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Intake-port flow behavior in a motored and fired two-stroke research engine

Chehroudi

Schuh

1995

Experimental Thermal and Fluid Science

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Thermodynamic Analysis and Optimization of Two-Stroke Gasoline Engines

Cited by 21 publications

References 7 publications

In-cylinder charge stratification and fuel-air mixing in a new, low-emission two-stroke engine

In-cylinder charge stratification and fuel-air mixing in a new, low-emission two-stroke engine

Multidimensional simulation of the air-flow and fuel transport process in the air-assisted injection system of a new, low-emission two-stroke engine

Intake-port flow behavior in a motored and fired two-stroke research engine

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