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Historically, vehicle fluid condition has been monitored by measuring miles driven or hours operated. Many current vehicles have more sophisticated monitoring methods that use additional variables such as fuel consumption, engine temperature and engine revolutions to predict fluid condition. None of these monitoring means, however, actually measures a fluid property to determine condition, and that is about to change. New sensors and diagnostic systems are being developed that allow real time measurement of some lubricant physical and/or chemical properties and interpret the results in order to recommend oil change intervals and maximize performance. Many of these new sensors use electrochemical or acoustic wave technologies. This paper examines the use of these two technologies to determine engine oil condition and focuses on the effects of lubricant chemistry on interpreting the results.

This paper investigates Homogeneous Charge Compression Ignition (HCCI) combustion on an engine that is fuelled with ethanol, iso-octane, and ethanol/iso-octane. The engine is a four-stroke three cylinder indirect injection type diesel engine converted to a single cylinder HCCI operation. In order to clarify the effects of fuel chemistry on HCCI combustion, the trials were done at a constant engine speed, a fixed initial charge temperature and engine coolant temperature. The HCCI engine was fuelled with a lean mixture of air and fuel (ethanol, iso-octane or mixture of ethanol/iso-octane). The engine performance parameters studied here include indicated mean effective pressure (IMEP) and thermal efficiency. Heat-release rate (HRR) analysis was done to determine the effect of fuels on combustion on-set. The experimental results demonstrate that the addition of iso-octane to ethanol retards the on-set of combustion and subsequently leads to a reduction of the IMEP and thermal efficiency.

For the prediction of the vibro-acoustical vehicle behaviour up to higher frequency ranges, modal approaches are not very applicable. Hybrid frequency response function based substructuring methods are therefore proposed, in which the high modal density components are represented by experimental data, and in which the lower density components are represented by finite element models. The frequency response function synthesis of the lower denstty component can be based on modal synthesis. In this paper, an application of coupling a rear twist beam suspension with a car body is discussed. In this case the vibro-acoustical behaviour of the car body is the high density component, the low density component is the suspension finite element model. Aspects of accuracy, related to truncation, influence of rotational degrees of freedom, symmetry of the experimental matrix, and prestraining of the suspension springs are discussed.

Some special features of cloud-to-ground (CG) lightning discharges in the verge of Qinghai-Tibetan Plateau have been found by using the data from wide-band slow antenna system with 1μs time resolution. It has been found that (CG) lightning usually follows intracloud (IC) discharges. K-changes during the IC discharge part initiate from negative charge region and propagate downward to the lower positive charge region with an average speed of 1.5×107 m/s. The radiation waveforms of return stoke begin with a slow front which last for about 9.4 μs to about half of the field peak amplitude, and the zero-to-peak rise time was 10.9μs for negative first return strokes.