Downsizing is one of the crucial activities being performed by every automotive engineering organization. The main aim is to reduce – Weight, CO2 emissions and achieve cost benefit. All this is done without any compromise on performance requirement or rather with optimization of system performance. This paper evaluate one such optimization, where-in radiator assembly with two electric fan is targeted for downsizing for small commercial vehicle application. The present two fan radiator is redesigned with thinner core and use of single fan motor assembly. The performance of the heat exchanger is tested for similar conditions back to back on vehicle and optimized to get the balanced benefit in terms of weight, cooling performance and importantly cost. This all is done without any modification in vehicle interface components except electrical connector for fan. The side members and brackets design is also simplified to achieve maximum weight reduction.
This four-hour short course provides an introduction to contamination control principles in aircraft hydraulic systems. Topics covered include an introduction to the types of contamination in aircraft hydraulic systems, contaminant measurement, and reporting methods. In addition, the impact of contamination on hydraulic components is discussed in detail. Along with an introduction to filtration mechanisms, information on testing, rating, and specifying filters will be provided.
This four-hour short course provides an introduction to fluids for aerospace hydraulic systems. Topics covered include an introduction to basics fluid properties, rheology, tribology, and fluid product development. In addition, the history and performance of different classes of fluids are discussed in detail, and specific failure modes such as erosion and sludge formation will be described. Along with an introduction to fluid degradation, information on used oil analysis test methods and interpretation will be provided.
The efficiency of ICEs is strongly affected by the heat losses of exhaust gases and engine cooling system, which account for about 60% of the heat released by combustion. Several technologies were developed to recover waste heat in ICEs, from turbochargers to ORCs, Stirling cycles and piezoelectric generation. A promising approach is to transfer the waste heat to a fluid, like water, and inject it into the combustion chamber. In such a way, the recovered energy is partially converted into mechanical work, by improving both engine efficiency and performance. In this work, the engine benefits obtained by using supercritical water as the vector to recover heat losses are analysed. Water has been chosen since it has a relatively high heat capacity and can be extracted directly from exhaust gases. A quasi-dimensional model has been implemented to simulate the ICE work cycle. Specifically, in this paper a spark ignition ICE, four-stroke with port fuel injection (PFI) has been considered.
The potentiality of knock mitigation by means of the control of the coolant flow rate is investigated. As a first step, the dynamic behavior of the wall temperature in response to a sudden variation of the coolant flow rate is analyzed experimentally in a small displacement, 4-valve per cylinder SI engine, which is equipped with an electrically driven pump. Subsequently, the influence of the wall temperature on knock onset is analyzed through a zero-dimensional model and the Livengood and Wu integral. Finally, an experimental activity on the engine test bed is carried-out in order to evaluate the influence of the coolant flow rate and of the engine inlet coolant temperature on the knock phenomenon. Results show that, even though a retarded spark advance and a mixture enrichment are not avoidable in the early stage of knock onset, a cooling control can help reducing the time of use of these fuel consuming strategies in the case of prolonged high-load conditions.
The efficient operation of test benches within the framework of research and development projects directly correlates with the "health" of the examinee to be investigated. The use of so-called Early Damage Detection Systems (EDDS) is becoming increasingly popular for reasons of Unit Under Test (UUT) monitoring. In the context of this publication the expectations of an EDDS and its structure are discussed as well as its advantages and disadvantages in test bench operation analyzed and compared with the results of measurements. The used EDDS should primarily prevent the damage, up to the loss of the test object by a total loss, in order to ensure a finding possibility of the damaged part at the examined test object. A deviation of the test object behavior from the undamaged condition must be recognized in an early status and must lead to a shutdown of the test bench operation after reaching a defined limit value.
In the last years, the increase of the specific power of the modern engines has required a parallel improvement of the performances of the cooling system. In this context, also the control of the oil temperature has become an important issue, leading to the introduction of dedicated cooling circuits (air-cooled or liquid-cooled). Among the two, the liquid-cooled solution results in a more compact installation in which the oil-to-liquid heat exchanger is directly mounted on the engine block and integrated in the engine cooling system. It is clear that, in a liquid-cooled solution, the design of the heat exchanger represents an issue of extreme concern, which requires a compromise between different objectives: high compactness, low pressure drop, high heat-transfer efficiency. In this work, a computational framework for the CFD simulation of compact oil-to-liquid heat exchangers, including offset-strip fins as heat transfer enhancer (turbolator), has been developed.