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TECHNOLOGY

Engineering smart sensors for a safe digital world.

For many years, KMW has set new standards with its innovations in the field of sensors. A highly-qualified team of research and development experts focusses on all relevant aspects in order to create products that substantially raise their end-user’s productivity.

Thin-film sensors – robust, sensitive and application-specific

KMW has decades of experience in the design, development and series production of measuring and functional elements employing thin-film technology. This fund of know-how forms the basis for our broad spectrum of generic and customer-specific sensor products. With our class ISO 5 cleanroom and our state-of-the-art production facilities we are able to coat a varied range of substrates in steel, ceramics, special alloys or synthetic materials with masks in diverse geometries.

Ceramic or metals serve as functional layers and contact materials. The substrate, insulation and functional layers are designed by our development team using simulation and “Design of Experiments” so that they are optimised to each other and form a precise and, at the same time robust, sensing element that fulfils the specific requirements of the specific sensor application.

Development and production processes perfected from the basis of Automotive Standard IATF 16949 guarantee on time, on budget product evolution and the outstanding quality of the sensing elements in series applications at the customer.

Connection and packaging technologies

The major elements in the integration and packaging of sensing elements for the application of the finished sensor are qualified and dependable connection and packaging technologies.

As well as a range of soldering processes, KMW employs a broad spectrum of wire-bonding processes to create robust electrical joints between connecting and microelectronic components, including the series-processes used for mounting and bonding.

Hermetic, pressure-resistant joints are made between metal parts such as sensing elements, media connectors and housings using electron beam, laser and resistance welding.

To further increase temperature and vibration resistance for extreme operating conditions, the connection and packaging of our sensors has always been a major focus of our research and development work.

Smart and safe sensors from a single source

KMW’s overall offering also comprises the development and production of complete, finished sensors, transmitters and measuring devices.
As well as the standard transmitters and sensing elements detailed in our data sheets, KMW is also a single source provider of services, offered in accordance with the Automotive Quality Standard IATF 16949:

  • Design of sensor configurations and housings with customer- specific interfaces for media and data
  • Individual electronics and software development with customer-specific signal conditioning and processing
  • Design, qualification and certification according to a range of industrial standards such as CE, UL, E1, ATEX, Functional safety SIL2/3 and PLd
  • Devising and qualification of all the relevant production and testing processes necessary for complete series production of sensing elements or sensors.

Our aim of maximizing product benefits for our customers dictates that we work to design into our sensors the optimum degree of product integration during their packaging and during their intended applications  We aim to make sensors that are intelligent, robust, precise, safe and available and with high availability.

Hydrogen pressure measurement

KMW produces sensing elements and sensors for the measurement of pressure in hydrogen in fuel cells or for use in the hydrogen supply infrastructure. They are offered for measurements in an overall range of 3.5 to 900 bar

Our new hydrogen-resistant functional layers are highly sensitive and enable the use of steel from the 316L group for sensing element substrates with a significantly thicker membrane and hence considerably higher resistance to over-pressure. A sensing element for 3.5 bar nominal pressure will remain undamaged even at a pressure of 20 bar, for example.

Our hydrogen sensor technology has been tested under extreme conditions and is already in commercial use in industrial gas applications.

Our current target is to make available pressure transmitters in accordance with Standard EC79.

On-engine applications

With their inherent benefits, KMW sensors are suitable for the measurement of pressure and temperature in applications in the major systems of large diesel, gas and dual-fuel engines (high, medium and low speed).

Cylinder (combustion) pressure measurement

KMW has more than 20 years’ experience in the development and production of sensing elements and transmitters for the measurement of cylinder pressure cycles in large engines.

During combustion in high, medium and low speed engines cylinder pressure sensors are subject to high pressure and temperature levels and gradients of change, as well as strong vibrations. As a result, durable and reliable solutions are generally expensive and rare.

For these applications KMW offers sensors employing nickel-based sensing elements with a high temperature resistant functional layer in ceramic material (continuous temperature > 250 °C, peak temperature > 350 °C).

In spite of the extreme temperature and pressure fluctuations, fatigue in the membrane is very low; the relatively small temperature coefficient of the functional layer significantly reduces temperature influences. Voltage drift after 20,000 operating hours remains within < 0,5 %. To further reduce thermo-shock effects on the sensing element, KMW employs our patented flame protection feature.

A major benefit of KMW’s measuring principle derives from the fact that the technologies available to KMW result in comparatively low costs for series applications.

Fuel injection equipment 

With the ability to measure up to 2000 bar, pressure transmitters from KMW’s M01 range are suitable for measuring pressures at various points in modern, high-pressure common rail fuel injection systems. They thus enable:

  • Close control of fuel accumulator (rail) pressure
  • Monitoring and diagnosis of overall system condition and faults.

Turbochargers

Based on their high resistance to temperatures and pressures, KMW sees considerable potential for our Z01 sensor in the measurement of pressures and temperatures in exhaust gases and charge air before and after the turbines and compressors of turbochargers for large engines. Potential applications include both research and development and field operation tasks: 

  • Calculation of compressor and turbine maps
  • Determining actual charge air pressure ratios
  • Determining actual turbocharging/turbocharger efficiency
  • Monitoring and diagnosis by comparison of actual and theoretical performance (compressor map, turbine map)
  • Monitoring and diagnosis of overall turbocharger condition for on-condition maintenance
  • Creating accurate “real-life” operating profiles

Multisensors – one substrate – multiple functionality

The robust, modern processes available at KMW for the packaging and connection of thin-film sensors is ideally suited to the inclusion of multiple sensing functions on a single sensing element. This enables economic series production of highly durable, extremely precise, multifunctional “Multisensors”.
Well thought-through design of the sensor carrier material and geometry, of the functional layers and masks, as well as of the appropriate electrical and mechanical joints, makes it possible to offer the measurement of several values in a single package. Characteristics are tailored to the installation situation or applied to the customer’s components.

Even with small or medium-sized lots, there are considerable customer benefits:

  • The measured data can be created via only one connection to the medium and transmitted via a central data interface
  • Mutually influencing or interdependent measured values can be compensated or computed in the sensor itself
  • The degree of integration is correspondingly high and installation time and effort are saved.

Among others, the combinable measured values already realised or targeted by KMW’s R&D team comprise:

  • Pressure
  • Temperature
  • Conductance
  • Fluid flow
  • Volumetric flow (in both gases and liquids)

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