Tag Archives: Mechanical Engineer

Who Damaged My Car? Ask the Infotainment System.

Infotainment Expert Witness

Robert S. Kinder, Jr., MS, Mechanical Engineer

Although cars do not currently answer our questions in the same manner as Michael Knight’s vehicle, KITT, in the Knight Rider series, cars have been “speaking” to us through electronic data for over two decades. The data answers questions about the moments leading up to a collision, including how fast the vehicle was traveling or if an occupant’s seatbelt was buckled. Such information is extracted from, what is commonly referred to as, an Event Data Recorder (EDR). While EDR information can be helpful, the ever-increasing complexity of newer vehicles allows for an enhanced data set, providing insight to more than just the moments leading up to a collision. Modern vehicles contain over 70 computer systems, creating what seems to be a consistently expanding flow of data. Given the vast collection of computers exchanging data in the vehicle network, it should come as no surprise that some of the components, such as the infotainment and telematic systems, retain a wealth of data.

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Windshield Mystery

John R. Yannaccone, P.E., Sr. Mechanical Engineer

Case Description: Late one evening, as the plaintiff was crossing a bridge on his drive home, another vehicle entered his travel lane and impacted the front of his vehicle. The police report indicated the encroaching vehicle had impacted the bridge and rotated as it crossed the centerline prior to striking the plaintiff’s vehicle. The police report also indicated that the plaintiff was unbelted and sustained serious head injuries when his head passed through the windshield. The defendant in the case alleged the plaintiff’s failure to wear his seatbelt substantially contributed to his serious injuries.

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Vehicle Fires

R. Scott King, BSME, Principal Automotive / Mechanical Engineer

Several years ago, a busy turnpike service structure sustained substantial fire damage. Fire investigators suspected the fire originated within a turnpike service vehicle parked nearby. Separately, but soon thereafter, another turnpike service van sustained extensive fire damage while responding to a road-side emergency call. Mindful of the coincidence, the turnpike authority commissioned an engineering investigation of the root cause of each loss.

An evaluation of the physical evidence remaining at the structure fire revealed patterns and fire effects confirming the fire originated within the turnpike service vehicle. Containment of fire to the second vehicle was self-evident. Based on these observations, both vehicles were closely examined revealing evidence of electrical system malfunctions. Although each fire was caused by different malfunctions, both were related to aftermarket adaptations to the vehicle’s electrical systems. Further, an engineering analysis revealed that the workmanship, not the aftermarket components, was the root cause of the malfunctions. Based on these findings, the turnpike commission extended the investigation to its entire fleet of road-side emergency vehicles.

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Vehicle Safety Recalls Week, March 2-6

NTSA Recall

R. Scott King, BSME, Principal Automotive / Mechanical Engineer

In 2019 the National Highway Traffic Safety Administration (NHTSA) administered the recalls of more than 38 million vehicles. Of those recalled vehicles, however, NHTSA estimates that only about 75% were ever fixed. Noticing similar historic uncompleted recall rates, NHTSA has initiated Vehicle Safety Recalls Week. Planned as a twice-yearly event coinciding with spring and fall clock changes, NHTSA hopes that car owners will visit their site and check for vehicle recalls after replacing the batteries in their smoke detectors.

The NHTSA website has a user-friendly search tool that allows owners to enter a vehicle’s 17-digit identification number, often found on a label affixed to the driver’s door jam, and find out whether the vehicle is subject to any uncompleted recall. If it is, the website provides details about the recall and how to get repairs. Moreover, the website database is updated regularly; so, it can be helpful to check regularly. In addition to its primary goal of improving highway safety, this search tool is proven to be a valuable tool in automotive claims and related investigations.

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Facial Steamer Malfunction: Design or Improper Use?

Spa Facial Steamer

John R. Yannaccone, P.E., Senior Mechanical Engineer

Case Synopsis: During a facial treatment at a spa, the steamer being used ran low on water and the esthetician stopped to refill the reservoir. Shortly after refilling, hot water was expelled by the steamer onto the client’s neck and chest, causing serious burns. The insurance carrier for one of the defendants requested assistance in determining the cause of the incident.

Expert Analysis: The spa and esthetician both reported the steamer was taken out of service following the incident; however, at the time of the expert’s inspection the spa could not identify which of their four steamers was involved in the incident. Three of the four were still in service, while the fourth was reported to have stopped heating just over a year after the incident. Inspection of the four steamers did not reveal any evidence of modifications or damage that would have caused hot water to be expelled onto the client’s neck and chest.

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Pressurized Water Tank Explosion


John R. Yannaccone, P.E., Senior Mechanical Engineer

Case Synopsis: A worker was operating a system used to supply water from a tank mounted on a utility vehicle. Instead of using a pump, this system used a 120-gallon water tank, which was pressurized from a compressed air cylinder. The air pressure pushes water out of the tank, referred to as an “air over water” system. While operating the system, a worker near the vehicle was blown 20 feet from where he was standing. He sustained severe blunt force trauma and died as a result of his injuries. Photographs from the incident showed that the end of the water tank dislodged from the main portion of the tank.

Expert Analysis: An inspection of the system revealed that the tank was in good condition, with no signs of corrosion or other damage. The 120-gallon water tank had a label indicating the maximum working pressure for the tank was 75 psi and must be equipped with an adequate size pressure relief valve; however, there was no pressure relief valve in this system.

The air used to pressurize the tank was supplied from a 4500 psi air cylinder through a regulator connected to the water tank with a 250 psi working pressure plastic hose. The procedure for using the tank indicated that the regulator for the air would be adjusted to 50 psi. The system’s pressure regulator was tested to determine the set pressure at the time of the incident. Testing was discontinued when the supply pressure reached 635 psi. The outlet pressure was 630 psi, indicating either the regulator was set too high or had failed. The regulator was disassembled and found to have foreign material, likely a dry lubricant not used by the regulator manufacturer, inside which likely affected the operation of the regulator. Additionally, the valve pin, which controls the flow of air through the regulator, was found to be slightly bent.

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