Re-Thinking Automotive Tire Pressure Monitoring Systems

Ivan Batinic, ATPS, Inc., San Martin, CA

The ATPS system is a new approach to implementing vehicular Tire Pressure Monitoring Systems (TPMS) that is more economical and ecological than existing systems. A passive, non-electronic sending unit (inside the tire) eliminates RF electronics, thermal compensation issues, raising of the RF noise-floor, and wasteful consumption of limited lithium resources for batteries. The TPMS is comprised of two fundamental components per wheel/tire assembly: an in-tire transducer, and an external, statically mounted chassis sensing component. Signal processing is performed by direct 2- or 3-wire sensor interfaces.

The pressure transducer directly converts air pressure to a known distance between two permanent magnets, relative to a standard barometric reference (25 ºC at sea level). This is accomplished by affixing a permanent magnet on both ends of a cylindrical aneroid bellows. The aneroid bellows is hermetically sealed with an internal atmosphere of nitrogen, which exhibits the same temperature coefficient of expansion as air, without the corrosive ozone or moisture components. The ATPS pressure transducer is extremely reliable and robust, and has a longer lifespan than the vehicle itself.

The active sensing of the magnetic moments, or sending unit’s, relative magnetic distance is accomplished with a magnetic sensor per-wheel, configured as a digital switch. This enables the transmission of vehicle tire air pressure information wirelessly, and without the use of RF or active circuitry. Each wheel sensor is mounted statically relative to the wheel spindle. The digital nature of this sensor eliminates any analog uncertainty incurred by real-world effects.

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Honorable Mentions

Module Wheelchair
Sebastian Menzel, Srem, Wielkopolska, Poland

This active wheelchair consists of two main parts: a seat module and a wheel module. The wheelchair folds without the help of other people. The small size makes it possible for the user to pack the wheelchair easily into a car. The user can choose different types of wheels, depending on need.

The user may change the angle of the seat to stabilize the body better. Moreover, since the wheels work like a tank tread, the user may protect their hands from injury. The wheelchair has great balance since 80% of the weight is focused at the main wheel axis.

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Low-Loss Planetary Shift Transmission
Richard Lloyd, Coventry, West Midlands, United Kingdom

A novel type of planetary shift transmission has been designed with reduced parasitic losses. Instead of oil-immersed multi-plate clutches, a small number of external dry-friction devices is used to engage the six available gear ratios. With dry friction, the application force and the drag when disengaged are significantly reduced.

The transmission provides 6 ratios, which are determined by the ring gear/sun gear ratios of the planetary gear sets, as well as the fixed internal structure. Since the friction devices are external, the transmission can function without electronic or electro-hydraulic systems, and the wearing elements are simple to replace. There are no rotating clutches with complex oil feed arrangements. The internal components are conventional gears, bearings, and shafts.

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