Nissan’s Variable Compression Engines Under Investigation by U.S. Safety Regulators
Introduction
U.S. safety regulators are currently investigating Nissan’s variable compression engines due to multiple reports of engine failure, power loss, engine knocking, and the discovery of metal chunks and shavings in oil pans.
Engines Under Investigation
The engines being investigated are Nissan’s 1.5-liter KR15DDT three-cylinder and 2.0-liter KR20DDET inline-four engines. These engines are found in certain Nissan Rogues, Altimas, and Infiniti QX50s, totaling approximately 454,840 vehicles according to the National Highway Traffic Safety Administration (NHTSA).
Awareness of Flaws
During discussions with Nissan, NHTSA discovered that the automaker was aware of the engine’s flaws. Nissan had implemented multiple manufacturing process changes over time to address damage to the main bearing and L-link, which could lead to seizing.
Vehicles Under Investigation
Variable Compression Technology
The engines in question feature variable compression technology, which utilizes a multi-link system to vary the pistons’ top dead and bottom dead center positions, thereby changing the compression ratio. This technology allows the engine control unit (ECU) to dynamically adjust the engine’s performance based on different circumstances, offering advantages in power and efficiency.
Preliminary Evaluation
While the root cause of the engine issues has not been specified by Nissan or NHTSA, the focus on these specific engines suggests that the variable compression system may be partially responsible. NHTSA has opened a preliminary evaluation to assess the scope, frequency, and safety consequences of the problem. Depending on the findings, Nissan may be required to initiate a recall.
Conclusion
The investigation into Nissan’s variable compression engines highlights concerns over potential engine failures and related issues. As NHTSA continues its evaluation, further actions may be taken to ensure the safety and reliability of these vehicles.