Shulou(Shulou.com)11/24 Report--

CTOnews.com, July 6 (Xinhua)-- according to a new petition, the National Highway Traffic Safety Administration (NHTSA) is re-investigating whether a design defect in Tesla Model 3 could lead to sudden acceleration, Carscoops reported. The application was submitted by Dr. Ronald Bert, who claims that there is new evidence that the inverter design of the Model 3 may cause the vehicle to misread the throttle signal, even if the driver does not step on the throttle.

The issue was first raised with NHTSA in 2019 by Brian Sparks, who asked the agency to force Tesla to recall all Model S, X and 3 manufactured between 2013 and 2019. However, after assessment, NHTSA's defect investigation Office (ODI) agreed with Tesla that in almost all of the 232 accidents mentioned in the original application, the driver stepped on the accelerator, a conclusion based on data collected by the vehicle. As a result, ODI rejected Sparks' application in 2021.

However, this conclusion did not satisfy everyone, because in at least one accident, the driver claimed that the car accelerated while they were outside the car. Now, based on new information, Dr. Bert has submitted a new application to ODI to review Sparks' application.

Dr. Bert's new accusation is based on information gathered by some enthusiasts when they dismantled Tesla's car for purposes such as retrofitting electric vehicles. In Tesla Model 3, Dr. Bert accused his design of a defect that may cause vehicles to mistakenly believe that random voltage fluctuations are throttle signals in rare cases. This is because the Model 3 inverter uses a single 1.65V calibration signal to detect four ADC (analog-to-digital converters, or components that convert throttle position into vehicle-readable electrical signals). In some cases, especially when the vehicle is slow, such as when more power is needed for steering, the current on the 12-volt battery can cause relatively large voltage fluctuations within the system, causing the inverter to infer that the throttle has been pressed. resulting in sudden unconscious acceleration.

Dr Bert says the probability of this happening is low because voltage fluctuations (lasting microseconds) must occur at the same time as the vehicle is tested for ADC (which also lasts microseconds). However, this low probability coincides with the more than 200 accidents reported between 2013 and 2019. He also claimed that because of the nature of the fault-the inverter misunderstood the voltage fluctuation as throttle input-it would not be recorded as an error. So although car owners reported that they didn't step on the gas, the vehicle data were inconsistent with their claims, which may explain why ODI rejected the application in the first place.

Dr Bert further validated his theory by deliberately inputting the wrong calibration voltage into the inverter. When they enter a voltage of 0.28V or lower (instead of the expected 1.65V), which may occur when the 12V power supply briefly drops to 2.14V, the accelerator pedal position (APP) sensor will read the equivalent of stepping on the throttle. This can cause the car to suddenly accelerate out of control when the driver doesn't step on the accelerator.

The study also proposes two solutions. The first option is to add a second 12-volt power line with its own battery and DC / DC converter. This power supply line is only used to provide clean power for App sensors and ADC. The second option is to modify the calibration program software by testing the calibration voltage before use. The latter is easier and cheaper to implement in existing vehicles because only software updates are needed.

According to the petition, all Tesla models were affected, although the Model S and Model X used slightly different DSP controller chips. The NHTSA survey mentioned that 1.8 million vehicles were involved in the new investigation. The discovery is gratifying news for car owners who suddenly accelerate out of control but are told they caused it themselves, but for some it may be too late.

In addition, CTOnews.com learned from Bloomberg that the US National Highway Traffic Safety Administration (NHTSA) also wrote to Tesla on July 3 asking the automaker to provide an up-to-date response to its request for information related to its Autopilot autopilot defect investigation. NHTSA asked Tesla to describe all possible changes to the vehicle under investigation that might be related to driver participation or attention.

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