Sensor-based monitoring systems for tire pressure can warn of potential problems, but there’s much more to the story than just a pressure-measurement system. The TPMS adds a highly specific safety-related feature to cars. However, as with many presumably good ideas, the “devil is in the details”, and that’s especially true for the TPMS. There are […]
The automotive Tire Pressure Monitoring System, Part 3: Implementation
Sensor-based monitoring systems for tire pressure can warn of potential problems, but there’s much more to the story than just a pressure-measurement system. Once the decision was made to use the direct measurement technique, IC vendors developed the needed components and equally important packaging. A TMPS requires a significant amount of analog, digital, and RF […]
The automotive Tire Pressure Monitoring System, Part 2: Perspectives
Sensor-based monitoring systems for tire pressure can warn of potential problems, but there’s much more to the story than just a pressure-measurement system. During the comments phase before the formal safety mandate was published per the legislative direction, the automotive-related communities had differing views on the need or wisdom of the electronic TPMS: The auto […]
The automotive Tire Pressure Monitoring System, Part 1: The situation
Sensor-based monitoring systems for tire pressure can warn of potential problems, but there’s much more to the story than just a pressure-measurement system. You may have had the misfortune to have the “Check Engine” light come on in your car. This single illuminated indicator encompasses a wide range of possible problems ranging from trivial where […]
Be wary when they say, “That change should be no big deal“
It’s easy to assume that implementing a small design change will be trivial when the actual impact is often more extensive and more painful than unanticipated. At its core, engineering design is finding the right balance among tradeoffs, driven by product objectives while, at the same time, being bounded by constraints. If it weren’t for […]
The PC-board atomic clock, Part 3: The CSAC cesium physics cell
Atomic clocks have shrunk from room-sized assemblies down to PC-board mountable modules, admittedly with lower performance than their big siblings but still far better than crystal-based timing alternatives. Every engineer knows that developing a viable design and product is not just a matter of theorizing a design, identifying the constituent components, or building a single […]
The PC-board atomic clock, Part 2: The CSAC design
Atomic clocks have shrunk from room-sized assemblies down to PC-board mountable modules, admittedly with lower performance than their big siblings but still far better than crystal-based timing alternatives. Engineering is largely about tradeoffs and constraints, and atomic clocks are no exception to this situation. As these clocks are being designed into smaller packages through innovations, […]
The PC-board atomic clock, Part 1: Primary and secondary standards
Atomic clocks have shrunk from room-sized assemblies to PC-board mountable modules, admittedly with lower performance than their big siblings but still far better than crystal-based timing alternatives. Atomic clocks are based on the transitions of energy states of specific elements such as cesium, ytterbium, rubidium, and others under specific and tightly controlled conditions. They are […]
Electronic engines valves: an idea whose time has come…and gone?, Part 4: The camless outlook
The electronically controlled, cam-free internal combustion engine seemed like a good idea, but technical and market realities stifled its acceptance. The camless engine is more than just a dream. In addition to working prototypes Sturman, Camcom, and Freevalve, manufacturers such as International Truck and Engine Corp (part of Navistar) had planned to use it in […]
Electronic engines valves: an idea whose time has come … and gone?, Part 3: The electronic camless approach
The electronically controlled, cam-free internal combustion engine seemed like a good idea, but technical and market realities stifled its acceptance. The previous parts of this article discussed the operation of the standard, cam-driven internal combustion engine with a mechanically driven intake and exhaust valve pair for each cylinder. This section looks at the alternative of […]