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A strategy to reduce the powertrain noise, vibration, and harshness (NVH) associated with starting/restarting an internal combustion engine.
About
Inventors at Georgia Tech have developed a novel strategy based on time-scale separation and command shaping to reduce the powertrain noise, vibration, and harshness (NVH) associated with starting/restarting an ICE. By tailoring the torque profile provided by the electric machine (EM), the ICE can be started with minimal residual vibrations. The strategy uses a linear combination of constant and time-varying torque components. The time-varying portion of the torque is calculated using an analytical ICE model and a perturbation technique for separating scales and isolating the nonlinear response. Command shaping is then applied to the linear response governed by the remaining scale. Using this technique, effective mitigation of the residual vibrations was demonstrated in a simulation using mathematical models of the ICE and EM. Future work will include the development of a more extensive ICE model and experimental implementation of the concept.
Key Benefits
· Uses a linear combination of constant and time-varying components to tailor the torque profile provided by the EM · Results suggest a promising and straightforward technique for reducing vibrations during ICE starting/restarting · Reduced NVH associated with starting/restarting the ICE of an HEV will improve drivability and the overall driving experience, resulting in increased consumer acceptance of HEVs · Approach can also be utilized to address other HEV-related drivability issues associated with powertrain mode changes
Applications
This invention has applications in the automotive industry, particularly HEVs, where engine stop-start features are common. The approach can also be utilized to address other HEV-related drivability issues associated with powertrain mode changes, such as the blending of hybrid power sources and the engaging/disengaging of clutches.