Sensors arc the eyes, cars, and more, of the modern engineered product or system. Today''s-andmore importantly,tomorrow''s-automobile would not be what it is without an entire batteryof sensors that monitor, and control, everything from engine performance to passenger safetyand comfort. This authoritative reference work, part of Momentum Press''s new Sensor TechnologySeries,edited by Joe watson,will offer a review of the sensors and their associated controlssystems typically found in the modern automotive vehicle.
目錄:
Sensors in the Vehicle John Turner
Automotive Pressure Sensors M. J. Tudor and S. P. Beeby
Temperature Sensors John Turner
Automotive Airflow Sensors John Turner
Combustion Sensors Peter Eastwood
Automotive Torque Sensors John Turner
Displacement and Position Sensors Jonathan Swingler
Accelerometers Jonathan Swingler
Gas Composition Sensors Jonathan Swingler
Liquid Level Sensors Yingjie Lin and Francisco J. Sanchez
內容試閱:
In present-day vehicles the most likely consequence of a serious electronic systems failure is thatthe engine stops. While there is no doubt that this can be dangerous, in most circumstances it ismerely inconvenient. The drive to increase road usage, however, combined with the rise in traffic lev-els, implies that driving will become increasingly automated (or "telematic"). In the process more andmore sensors and monitoring systems will be needed as the electronics on a vehicle become increas-ingly safety critical. The engineers responsible for producing telematic systems that directly intervenewith the vehicle controls must, therefore, be extremely careful to ensure that their designs are fail safeand fault tolerant. Systematic techniques are needed to produce technology that "degrades gracefully,"to use an industry expression. In software this aim is partly achieved by the use of Lean Formal Meth-ods (LFM). However, similar formal design techniques will also be required for safety-critical hardwaresystems, and hardwaresoftware interactions will require particularly close scrutiny.
Convoy driving (perhaps using specially designated highway lanes) is under active considerationin many countries as a means of improving the traffic density and usage of motorways. Trials of thetechnology needed to achieve convoy driving have been undertaken in the United States, Europe, andJapan. The aim is to improve the traffic flow and density through the use of vehicle-to-vehicle com-munications. Convoys of electronically linked vehicles travelling with reduced headway are expected tosignificantly improve road usage and reduce fuel consumption, journey time, and driver stress.
Convoy driving systems are the logical extension of the Autonomous Cruise Control (ACC) systemsnow being deployed. However, it seems likely that safety concerns will require vehicle-based sensing tobe backed up by vehicle-to-vehicle data communications links. For convoy driving to be fail safe, eachvehicle will have to communicate its status (such as speed, intended lane changes, etc.) to its neighbors.
In theory, elimination of at least part of the human response from the control loop should allowvehicles to travel closer together than at present (headway reduction) with improved safety. The intro-duction of telematics systems such as ACC brings the advent of convoy driving much closer. However,the safety of convoy driving in the event of full or partial systems or mechanical failure on one of theconvoy vehicles has not been examined in depth, and further research in this area is urgently required.
Highway systems are also becoming more safety critical. Real-time traffic control is already beingundertaken, and, in some parts of the United Kingdom, variable speed limits have been in place for sev-eral years [34]. Consideration is currently being given to passing these speed limits to vehicles, initiallyfor driver assistance in the form of a dashboard display. However, the possibility of direct control ofvehicle speeds by the highway authorities is also being investigated, and the safety implications of failurein such a system are clear. It is likely that enhanced sensing and monitoring systems will be required ifcurrent patterns of vehicle use are to be maintained. It seems clear that the use of sensors and measure-ment systems on both road vehicles and highways will increase considerably during the next decade.