Sensors play an important role in the automotive sector

Sensors play an important role in the automotive sector – especially in the manufacture of vehicles. For example, sensors are useful when a car is being painted as they can measure the thickness of the coating as it is being applied. Earlier this year, Micro-Epsilon, a global manufacturer of sensors, introduced a dual-sensor system that can be attached to a robotic arm. This allows automotive manufacturers to monitor the thickness of the paint being sprayed on instruments, controls and airbag claddings.

Till Micro-Epsilon’s dual-sensor was launched, automotive OEMs used single eddy current sensors to judge the thickness of a coat of paint. The single eddy current sensors need to touch the paint to judge the thickness which could damage the paint surface. Micro-Epsilon’s combination sensor uses a EU15(05) eddy current sensor along with an opto-NCDT laser-based optical triangulation sensor. While the former measures the distance to the spray mould, the latter measures the distance to the sprayed area.

Micro-Epsilon also manufactures sensors for engines. The company’s eddy current displacement sensors built into pistons on gasoline-run engines, measure the displacement between the piston and the cylinder bore in real time. This allows engineers to study how the piston moves within critical engine operation parameters such as cylinder pressure and engine speed. One company that has used this sensor is Mahle Powertrain Ltd, which supplies the automotive industry with piston systems, cylinder components, valve train systems, air and liquid management systems.

Mahle used Micro-Epsilon’s eddy current sensors to help in an engine development project. Because the test environment was so harsh, it was important for Mahle to use the proper sensors. Micro-Epsilon, after consulting with Mahle, supplied them with its U05 eddy current displacement sensor.

The German Micro-Epsilon, has a more than 30-year history in the manufacture of sensors. The company manufactures a range of sensors that measure displacement to distance, position, vibration, dimensions, thickness and temperature using both contact and non-contact measurement techniques. The company says that these techniques include inductive, differential transformer, eddy-current, capacitive, laser-optical, potentiometric, draw-wire and infra-red principles.
“With more than 30 years’ experience in the industry, Micro-Epsilon isn’t just a sensor manufacturer. The company is highly innovative and understands the importance of providing complete solutions and support services for its customers. The firm is renowned for its expertise in consulting, development and application of industrial sensors to complex, customer-specific solutions for measurement, inspection and automation. The focus is on selling technical solutions to its clients,” says the company.

Micro-Epsilon’s sensors also help automotive OEMs find faults in tires. The company’s scanCONTROL 2800 laser profile sensor, hunts for irregularities as minute as a few tens of microns on tires. According to Micro-Epsilon, what makes this laser particularly effective is that it does done much faster than other similar products. The system displays the next image while the current image is being read out. And the FireWire interface allows the control of multiple systems from a single computer.

The company says that it offers low-cost draw-wire sensor for sturdy and reliable sensing solutions for OEMs. Its wireSENSOR range offers three methods of measurements – multi-turn potentiometer, an incremental encoder or an absolute encoder. “The innovative optris CS temperature sensor series are ideal for industrial OEM users and combine high quality and accuracy of metrological parameters, with a rugged, high-grade stainless steel housing and an attractive price per measuring point. The technology was designed specifically for OEM customers, who to date may have avoided infra-red measurement due to its relative high cost. The optris CS is therefore compact, with a M12 thread and a length of 87 mm. The sensor also comes with an in the cable integrated electronics,” says the company on its website.

Some of Micro-Epsilon’s other sensors aimed at automotive OEMs include the turboSPEED 135, which measures the number of revolutions of turbocharger blades both in mobile and stationary situations. The sensors – which come in different models – are simply mounted on the turbocharger. Then there are two versions of Micro-Epsilon’s U05 eddy current sensors – the miniature version for passenger vehicle diesel engines and the regular model for commercial vehicles. These sensors show the exact timing/displacement behavior of the needle valve in order to optimize the functioning of the diesel injection pump.

Micro-Epsilon’s vision4A sensor, measures the roundness of the ends of brake hoses during production. The pipe to be inspected is supplied automatically in the horizontal position and examined by two axially opposite cameras with telecentric objectives. The flexible vision system acquires the data and calculates the deviation of the actual circle geometry on the complete 360° radius.

Automotive Industries spoke to Johann Salzberger, Marketing, Micro-Epsilon Messtechnik and Karl Wisspeintner, managing director, Micro-Epsilon Messtechnik.

AI: How do Micro-Epsilon’s displacement sensors help in making engine improvements?

Ever increasing demand for lower fuel consumption, lower emission and higher engine efficiency makes the use of high precision sensors indispensable.

AI: What makes your sensors different from others that are used by the automotive industry?

The technology Micro-Epsilon uses allows for extremely rugged sensors that still deliver the precise measurements, which are demanded by the automotive industry.

AI: Please tell us a little about the technological breakthroughs Micro-Epsilon has made in dual-sensors.

Many different types of sensors exist for every conceivable measurement principle. But each measurement principle has its own strengths. Similarly, each technique has restrictions in its conceivable applications. For example, a laser sensor cannot be used for distance measurement through rubber, which in contrast can be carried out extremely well by an eddy current sensor.

In this respect, a new approach by Micro-Epsilon is conceptually very simple: to combine the strengths of two different measuring principles without allowing the restrictions to accumulate. From this concept, new fields of measurement applications arise.

Dual-sensors have many applications in thickness measurement.

For example a dual-sensor of eddy-current and a laser sensor detects the thickness of plastic parts in a production mould. Or a combination of eddy-current and a optical micrometer measures the thickness of flat films and coatings

AI: What are some of the challenges faced when designing displacement sensors for new engines?

The environment inside engines is extremely harsh. Sensors built to work inside engines have to endure extreme temperatures, high pressure, being immersed in oil and vibrations including shock forces. Furthermore, all EMC requirements have to be met and last but not least – sticking to the budget is always an issue.

AI: Please give us examples of automotive companies using your displacement sensors while developing engines.

Almost all major designers and manufacturers of automobile engines are familiar with sensors delivered through Micro-Epsilon and use them regulary.

AI: Who are some of the companies that are currently using scanCONTROL 2800 sensors that sense irregularities in tires? Please give us case studies.

Continental, for example. They use the system for 100% inline quality measurement. Three scanCONTROL measure on rotating wheels the whole surface of a tire. Dents and bulges are detected reliably.

AI: How extensive is Micro-Epsilon’s global reach? Are your products more popular in developed countries or are developing countries also using your sensors?

You can buy Micro-Epsilon products all over the world. This is enabled through several subsidiaries and sales offices. For sure, high-tech products are strongly requested in developed countries, but with a rising part also in developing ones.

AI: How much of your business comes from the automotive industry? And what are some of the new technologies/products Micro-Epsilon is working on that will be aimed at the auto market?

A substantial percentage of Micro-Epsilon’s business is already earned with sales to the automotive industry. Besides supplying to the manufacturing, developing and QA departments we are now looking forward to supply more sensors for use in the vehicles themselves. The technology is similar to other industrial applications, but optimized to the specific vehicle requirements.