Concept for High-performance Direct Ignition Gas Engines

Fuchs, Jochen; Leitner, Alexander; Tinschmann, Georg; Trapp, Christian

doi:10.1007/s38313-013-0048-x

Cited by 7 publications

(3 citation statements)

References 1 publication

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“…After nearly one nanosecond, the plasma has the characteristic teardrop-like shape (2). Until the end of the laser pulse, the plasma propagates primarily towards the laser beam direction.…”

Section: Plasma Imaging During Energy Transfermentioning

confidence: 99%

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Influence of focal point properties on energy transfer and plasma evolution during laser ignition process with a passively q-switched laser

et al. 2016

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Miniaturized passively q-switched laser ignition systems are a promising alternative to conventional ignition sources to ensure a reliable ignition under difficult conditions. In this study the influences of focal point properties on energy transfer from laser to plasma as well as plasma formation and propagation are investigated as the first steps of the laser induced ignition process. Maximum fluence and fluence volume are introduced to characterize focal point properties for varying laser pulse energies and focusing configurations. The results show that the transferred laser energy increases with increasing maximum fluence. During laser emission plasma propagates along the beam path of the focused laser beam. Rising maximum fluence results in increased plasma volume, but expansion saturates when fluence volume reaches its maximum.

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“…After nearly one nanosecond, the plasma has the characteristic teardrop-like shape (2). Until the end of the laser pulse, the plasma propagates primarily towards the laser beam direction.…”

Section: Plasma Imaging During Energy Transfermentioning

confidence: 99%

“…Stratified charge engines and large gas engines use lean combustion to achieve these objectives [2,3], resulting in longer combustion durations and lower power density of the engine. To avoid efficiency losses, the grade of turbulence and the boost pressure can be increased [4].…”

Section: Introductionmentioning

confidence: 99%

Influence of focal point properties on energy transfer and plasma evolution during laser ignition process with a passively q-switched laser

et al. 2016

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“…Besides manufacturers of vehicle engines and gas turbines, especially manufacturers of stationary natural gas engines are realizing these strategies in current and future engine concepts. 1 However, both approaches lead to increasing requirements for the ignition process due to a more complex flame kernel formation. 2 To avoid losses of engine efficiency, it is necessary to increase the flow velocity as well as degree of turbulence in case of leaner burning and increasing the intermediate pressure.…”

Section: Introductionmentioning

confidence: 99%

Pulse train ignition with passively Q-switched laser spark plugs

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et al. 2015

International Journal of Engine Research

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Leaner burning and downsizing are two concepts pursued by engine developers to reduce fuel consumption and emissions. Both approaches lead to increasing challenges concerning ignition, as these concepts are typically associated with an increase in flow velocity and degree of turbulence as well as raised pressure at the moment of ignition. In this context, the use of miniaturized passively Q-switched laser spark plugs with pulse train ignition is considered as a promising alternative to conventional spark plugs.However, the application of these passively Q-switched laser spark plugs inevitably leads to the question of optimum pulse train parameters. For a better understanding, this study deals with improved flame formation by passively Qswitched laser pulse train ignition under engine-like conditions. The entire ignition process is investigated with a special focus on interactions of consecutive pulses. Therefore, three methods are combined: energy transfer measurements from laser pulse to plasma with high temporal and spatial resolution show the breakdown process depending on different pressures and fluid mixtures. The temperature decrease in the induced plasma is analyzed with measurement strategies for temporal high-resolved plasma spectroscopy especially adapted to passively Q-switched lasers. In combination with high-speed schlieren measurements, the changing local ignition conditions during pulse train ignition are demonstrated. The experiments show how consecutive pulses interact and contribute to the ignition in case of a gas flow. The used prototypes of laser spark plugs are provided by Robert Bosch GmbH.

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