Recent Patents on Mechanical Engineering - Volume 2, Issue 3, 2009

The fast evolution of computing power together with the improvement of electronics and sensors in the last decade has resulted in the introduction of vehicle automation at a consumer level; therefore, every day, an increasing amount of commercial solutions are reaching the global market. The special shape in which agricultural fields are structured, on the other hand, makes off-road vehicles one of the best candidates for driving assistance. Very often, tractor or harvester operators are required to follow predefined rows for long periods of time, leading to physical and mental fatigue that can provoke dangerous situations or even fatal accidents. In such conditions, the aid brought by intelligent systems can represent a positive asset to farm production systems. The recent popularization of satellite navigation systems, such as GPS, has meant the final thrust to the deployment of automatic guidance systems. However, not only global positioning sensors are key in vehicle automation but a complex architecture comprising imaging, laser and ultrasonic devices can be found in recent models as well. This article presents an overview of patents issued in this field of automotive engineering over the last twenty years.

In many applications, the transmitted power by a gearbox is fluctuating strongly. For example, in wind energy converters the rotor torque depends on the wind velocity and therefore varyies over a wide range, whereas the rotor speed is constant. In automotive applications, both torque and speed vary according to the driving conditions. It is evident, that in order to test such gearboxes, test rigs are needed that enable torque and speed to vary during the test according to the testing requirements and simulate the actual loading conditions as accurately as possible. The first part of this paper is a review of the many known mechanical devices developed to load gears. Their advantages and disadvantages are commented and presented. The second part describes a novel system designed and built by the authors (patent pending), which makes it possible to apply the test torque and speed according to a given load pattern during the test of the gears. It can further be implemented in close power loop test rigs (known also as back-to-back test rigs) such as the FZG test rig. The gearboxes of the test rig may be similar enabling thus the measurements of the power loss and efficiency of the gear pairs. It can also be used in the research of fatigue related surface failures, such as pittings and micro-pittings. The system consists mainly of a self-locking planetary Wolfrom gear train. Its sun gear is connected to a high starting torque electric motor, while its two ring gears are connected to the shafts ends of the two gearboxes. The operation of the motor is controlled by a computer. The software compares the actually applied torque, which is measured by a contactless torque meter, with the required torque, which has been already prescribed.

Lithium bromide-water absorption cooling technologies is underpinned by the continual circulation of water, which is the refrigerant, powered by the hygroscopic nature of aqueous lithium bromide solution. The present energy and global warming crises engender a renewed interest in thermally driven cooling systems, for which lithium bromide-water absorption chiller is an archetypal example forming the focus of this review. We review more than 100 patents dated mainly from 1985 and later that offer panoply of solutions to better this genre of timely technologies. We classify the surveyed patents into four main categories: (1) absorption system developments, (2) machine components developments, (3) working fluid modifications and additives, and (4) novel applications of absorption cooling systems. Finally we also map out several important directions for future research and development.

Patent records document a continuous development of trace gas/particle preconcentrators for use in particle detection systems. The most common application proposed for the inventions is the detection of biological agents, chemical agents, or explosives for security purposes although other applications are clearly possible. Existing particle detection systems such as gas chromatograph/mass spectrometer (GC/MS) systems do not have the required sensitivity for the characteristic application. Existing sensor technologies require pretreatment of the sample including precon-centration. There have been two classes of trace gas/particle preconcentrators: cycled and continuous. Preconcentrators that are based on adsorption membranes cannot operate on a continuous basis, because the gas must be stopped, a desired amount adsorbed, then released. These types of preconcentrators may therefore not be able to maintain the time fidelity of the analyte gas concentrations. Hence, preconcentrators that can operate continuously may be useful for detecting in substantial real time variations in the concentration of the trace gases that are being analyzed. A recent patent of a mesoscale, continuous flow-through, trace gas preconcentrator can enable this specific application with the capability of achieving significant trace-gas concentration increases using one or two simple meso-scale mass diffusion separation stages. The continuous trace-gas concentrator could increase the sensitivity for portable gas sensors/detectors by several orders of magnitude in a device - with a size less than several centimeters and with power consumption in the tens of milliwatts range. It can be operated continuously; instead of using adsorption-desorption cycles, and the response time is predicted to be more than one order of magnitude shorter than most currently available cycled techniques.

Combustion processes are main constituents of several energy technologies. A key issue in combustion researches is the improvement in reduction of harmful emissions. Besides, the achievement of high-energy-efficiency processes through advanced heat recovery systems is desirable. When recirculated systems are utilized those two aspects can be achieved simultaneously. Therefore, the current review describes recent patented developments in heat and massrecirculating systems over the last 10 years (2000-2009). In relation to heat-recirculating systems recuperative, regenerative and porous media combustion are covered. The most significant inventions are discussed and their improvements and possible applications are emphasized. Further, flue gas recirculating systems' novel configurations and solutions are described. Their practical power engineering applications in the field of e.g. boilers, internal combustion engines, gas turbines and radiant tube burners are emphasized. For each group of patents the principles of improvements in thermal efficiency and in reducing harmful emissions are expounded.

Fluidic mixing is the process of mixing at least two liquids. It plays a very important role in many fields, including high-throughput synthesis, analytical chemistry, and microbiological analysis systems. In a microfluidic system, fluidic mixing is difficult because the scale of the channel generates laminar flow. The liquid is thus mixed only by molecular diffusion, which is too slow for many applications. In recent years, several mechanisms have been proposed and patented to improve microfluidic mixing efficiency. This paper reviews five kinds of active micromixer and four kinds of passive micromixer and then discusses their advantages.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by different analytical methods, designs, manufacturing and analysis of automobiles, aircrafts, manufacturing plants, industrial instruments, machines, heating and cooling systems and processes involved and related to mechanical engineering.