Paint Films Could Reveal Vehicle Scratches


A patent application from German automobile and motorcycle manufacturer BMW was recently published for a vehicle scratch detection system that would allow drivers to be alerted when their car is scuffed.

The system would consist of the vehicle body capable of detecting a scratch, a control unit and an alarm device. The control unit would be able to trigger the alarm device to send a signal after analyzing and processing the detection information of the scratch.

The scratch detection film would be applied to the lower portion of four sides on the vehicle body, as well as the front and rear fenders of the vehicle, exterior trim panels of vehicle doors, a side of a trunk or exterior panels of front and rear bumpers.

According to the patent, the paint film is a pressure-sensitive film or a piezoelectric film, energized by being subjected to an external force, such as a scrape changing the current signal, and a current variation signal can be transmitted to the control unit.

BMW reports that the film would have a high degree of customization, matching the contour of a vehicle body. The film is reportedly low cost, light weight, high sensitivity, high mechanical strength, reliable and durable.

The signal to the driver would vary, potentially sending an audible, visual or other sensible signal. A driver could access the information while in their vehicle via sound, light or image, but also possibly through a mobile network to access on their phone, allowing them to timely handle an accident.

While the automaker has not been granted the patent yet, patents don’t always mean the company intends to produce the product. However, based on the patent, the technology originates in China, where serious traffic problems and tight parking spaces have arisen in older areas of the country as automobile use becomes more popular.

BMW explains that cameras can be installed in parking lots or on streets, or security personnel could be hired to monitor parking lots or communities, but the invention provides a scratch detection system for the vehicle as a potential solution.

“Compared with manual monitoring, the vehicle scratch detection system according to the present invention can reduce the labor cost and raise the accuracy,” read the patent.

“Compared with the method of detecting collision by a collision acceleration of the vehicle collision system, the vehicle scratch detection device according to the present invention significantly improves the sensitivity of the system in response, and is capable of detecting a minute scratch that cannot trigger the collision alarm system, without being affected by vehicle bumps such as to give rise to false alarms.”

Other BMW Paint Projects

At the beginning of the year, BMW revealed a first-of-its kind car that changes color using technology found in eReaders. The BMW iX Flow premiered at CES 2022 in Las Vegas in January.

Drivers can change the vehicle’s color using a phone app, switching between shades or changing the design, such as racing stripes. BMW research engineer Stella Clarke said, in the future, changes could also be controlled by a button on the car’s dashboard or even by hand gestures.

While currently the vehicle can switch between black and white, BMW plans to expand the technology to cover many colors. The electrophoretic coloring is based on a technology developed by E Ink that is also used in eReaders, described as a kind of “digital paper.” Millions of microcapsules are contained inside the coating laminate, each the diameter equivalent to the thickness of a human hair.

The microcapsules contain negatively charged white pigments and positively charged black pigments. An electric field then causes the white or black pigments to collect at the surface of the microcapsule when a setting is chosen, changing the color of the car to white or black. This creates an Electronic Paper Display, or EPD.

Many triangular, fitted ePaper segments are applied to the vehicle body and tire rims, with generative design processes implemented to ensure the segments reflect the contours of the vehicle and resulting variations in light and shadow. The algorithms also enable the formability and flexibility to tailor the ePaper to the design lines of the car.

Each segment is created using high precision laser cutting technology before being applied to the vehicle. Once connected the electrical field power supply, the body is warmed and sealed to guarantee uniform color reproduction.

The E Ink technology is reportedly energy efficient, requiring no energy to keep the chosen color state, unlike displays or projectors. Current only flows when the colors are changing. According to BMW, changing the vehicles appearance with E Ink offers options for driver’s aesthetic preferences, environmental conditions or functional requirements.

Being able to switch from black to white also benefits the interior and efficiency of the vehicle. While lighter surfaces reflect more sunlight, darker surfaces can help absorb heat to keep the car warm. Drivers would be able to shift between white or black in different weather, cutting the amount of cooling and heating required from the air conditioning.

This reduces the amount of energy on the vehicle’s electrical system, lowers the amount of fuel or energy consumption and increase the range in electric vehicles, like preventing the dashboard from overheating.

Then, in July, PaintSquare Daily News reported that BMW was teaming up with global chemical company BASF to create a new sustainable paint made from sewage, working to replace petroleum-based components in the process with raw materials from organic waste, such as biowaste.

According to BMW's release, BASF’s production process allows makes it possible to replace petroleum-based precursors, such as naphtha, with renewable raw materials from organic waste, starting in the early stages of paint production. This reduces consumption of fossil fuel resources, but also avoids the CO2 emissions associated with the production, transport and processing of crude oil.

BMW reports that the corrosion protection and matte paints used at BMW Group Plants Leipzig and Rosslyn are chemically identical to the paints previously used, with all the same properties as conventionally manufactured body coatings. 

The biomass balance approach uses renewable raw materials like bio-based naptha and biomethane from organic waste. BASF reports that the proportion of bio-based raw materials is then arithmetically assigned to certain sales products according to a certified method, with the attribution model comparable with the principle of green electricity.

The sustainable manufacturing process reduces the CO2 emissions from paint production by more than 40%. Overall, BMW anticipates saving over 15,000 tons of CO2 emissions between now and 2030.

An independent certification reportedly confirms that BASF has replaced the quantities of fossil resources required for the biomass-balanced product sold with renewable raw materials.

However, BMW has not announced what shades are available for the new sewage-based paint. Some news outlets have joked that one could “probably venture a guess at what color most of us think it should be.”


Tagged categories: Abrasion; Abrasion resistance; Asia Pacific; Automotive coatings; Coating Materials; Coating Materials; Coatings Technology; Coatings technology; EMEA (Europe, Middle East and Africa); Latin America; North America; Quality Control; Technology; Z-Continents

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