【作者】

Patrice FLOT，Alain MESLATI

【摘要】

论文已在上海2013年CIMAC大会上发表，论文版权归CIMAC所有。 In order to stay ahead of their competition, engine builders are permanently reducing manufacturing cost by various means; either by improving manufacturing processes, through procurement efforts, or technically by using the latest design and calculation tools made available with the most advanced computer aided systems. Cost is mainly related to weight of the engine, where the sales price is related to mechanical power produced by the engine. The customer is effectively buying power out-put, when engine builder is paying for weight of materials needed to build the engine! This is why, for many years, engine designers are increasing power density, or power to weight ratio. The typical methods for most of the engine builders to achieve higher power density, is to increase power output of an existing engine, step by step, just by slightly modifying the engine. Power is a result of engine rotational speed and torque. But increasing rotational speed faces limitations on mean piston speed, plain bearing peripheral speed, inertia of pistons and connecting rods, and spring systems for valves, so limited progress has been made that way. Increasing torque or BMEP has always been, and is still preferred. There are existing methods to increase the flow of air and fuel, thanks to more efficient turbochargers, and mod-erm fuel pumps delivering higher injection pressures, along with common rail technology. As a result of increased BMEP, the maximum combustion pressure has been dramatically increased, and consequently the peak pressure on the bearings. By optimising the bearing design and using better materials for bearing shells, both engine builders and bearing shell manufacturers have been successful at managing bearing pressure increase and reduced oil film thickness. However, during engine service, the slightest maintenance mistake will result in much higher risk of catastrophic failures. Additionally, end users want to save time on maintenance, and to reduce skill requirements of their maintenance teams; all resulting in higher risk. Thus, to reduce maintenance constraints and mitigate associated risks, engine builders are looking for methods to monitor bearing conditions. Not only high speed and medium speed engine builders are concerned, but also low speed engine builders (although low speed engines do, historically, show high reliability of their bearings). To satisfy this increasing demand, a new sensor, called TB3, has been designed for monitoring the temperatures of moving parts inside the engine, such as the connecting rod big end bearings. Design of the TB3 sensor boasts short response time, easy installation, simple maintenance and low cost in order to be standardised on series engines above 200 mm bore. The TB3 sensor is based on well-known SAW-Surface Acoustic Waves-technology, which has been specifically engineered and patented for serving the purpose of measuring the temperature of moving parts inside engines. Compared to other commercially avail-able protection devices, the TB3 sensor is a techno-logical breakthrough allowing wireless signal transmission up to one meter distance inside the engine. The sensor system is made of several dynamic sensors fit-ted on the moving parts, and only one large antenna fixed to the crankcase wall inside each cylinder compartment. The large antennas are directly communicating with the ECU by simple connection to the CAN bus line existing on the engine, thus reducing the cost of wiring system outside the crankcase. The paper will review todays bearing challenges and protection devices. After a quick look at wireless sensors, it will describe TB3 sensor hardware and software technologies, and expected advantages on industrial engines, in regards of installation design, service, and safety.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

1

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