The effect of thermal stratification on the ignition of a lean homogeneous n-heptane/air mixture at constant volume and high pressure is investigated by direct numerical simulations (DNS) with a new 58species reduced kinetic mechanism developed for very lean mixtures from the detailed LLNL mechanism (H.J. Curran et al., Combust. Flame 129 (2002) 253–280). Two-dimensional DNS are performed in a ...

operating an engine with homogeneous charge compression ignition (hcci) technique is a promising technique to lower nox and pm emissions of engines while achieving high efficiency and lower fuel consumption. nevertheless, applications for hcci are still limited due to the absence of a definite means to control ignition timing and narrow operating region. a single cylinder diesel engine with com...

The fuel entropy and required drive energy for an inertial confinement fusion implosion are set by a sequence of shocks that must be precisely timed to achieve ignition. This Letter reports measurements of multiple spherical shock waves in liquid deuterium that facilitate timing inertial confinement fusion shocks to the required precision. These experiments produced the highest shock velocity o...

In this paper we consider signal processing algorithms for detecting knock, i.e. auto-ignition of unburned fuel, in spark-ignited engines. To operate an engine with optimal efficiency, there is a need to operate close to the knock limit. This motivates the need for efficient knock detection algorithms that not only indicates knock, but also gives estimates on knock timing and size. The proposed...

The effects of spark timing and exhaust valve timing change on exhaust gas temperature during cold start of an SI engine are studied through engine bench tests. It is observed that the exhaust gas temperature increases when the spark timing and valve timing are retarded individually or simultaneously, due to late combustion or slow flame speed. However, using COVimep it is also investigated tha...

Homogenous Charge Compression Ignition (HCCI) engines hold promise of high fuel efficiency and low emission levels for future green vehicles. But in contrast to gasoline and diesel engines, HCCI engines suffer from lack of having direct means to initiate combustion. A combustion timing controller with robust tracking performance is the key requirement to leverage HCCI application in production ...

It has been shown previously that applying forced induction to Homogeneous Charge Compression Ignition (HCCI) of bioethanol with residual gas trapping, results in a greatly extended load range compared to normal aspiration. However at very high boost pressures, very high cylinder pressure rise rates develop. The approach documented here explores two ways that might have an effect on combustion ...