“Tough Gear”and “High Quality” for New X-TRAIL - 5. NV Technology to Achieve EV-Level QuietnessFig. 6 Diagram of engine-mounting system 6.1 Engine mount6.1.1 Configuration of the mounting system6.1.2 Effect of using two lower torque rods6.2.1 Exhaust noise reduction concept using 27Fig. 7 Input load dividing by dual torque rodsFig. 8 Comparison of the torque rod system stiffness6.2 Exhauste-POWER featuresto prevent stiffness increase when load is applied. Combining this rod to the main rod, it allows reduced input load (Fig. 7) and stiffness increase, even use of a current rod structure with a stopper function.Thus, the torque rod, which contributes to booming noise, is divided into two rods to achieve lower spring rates even at full-throttle acceleration. Low-stiffness torque rods that exhibit little change in rigidity over the entire range are used (Fig. 8).In the new X-TRAIL e-POWER, the following is done to ensure vehicle quietness, especially in urban driving scenes,・Low engine speed operation・Engine running at high torque for power generation.Both lower engine speed operation and higher torque increase exhaust noise. To achieve a high level of vehicle quietness during engine operation, exhaust noise reduction is required. To this end, we have developed long-flow exhaust technology that lowers the full-length resonance of the exhaust system.To reduce exhaust noise when the 3-cylinder high-torque engine is in operation, a large-capacity muffler is required in the center and rear of the vehicle. However, Moreover, high-efficiency sound insulation technology is introduced to block high-frequency engine radiation noise sufficiently to realize overwhelming quietness.The engine mount requires component technology to achieve EV-level quietness, not to bother drivers even when the engine is running. This chapter well describe a low-stiffness pendulum mount system dedicated design for the 3-cylinder high-torque e-POWER system. Mount system is develop to ensure a small change in stiffness, up to full-throttle acceleration, and maintain a balance between an optimal mount arrangement that considers the 3-cylinder vibration mode and the engine room layout for the new X-TRAIL.The conventional pendulum mount system is commonly used to support a lightweight, low-torque 3-cylinder engine. When the pendulum mount system handles a high-torque engine, an upper torque rod is added above the right mount to support reaction force, which will reduce input load to each mount.For the new X-TRAIL e-POWER-dedicated mount system, the lower torque rod layout was accomplished to fit within the size of a current size torque rod by, reducing the input load and dividing the lower torque rod into a main rod and support rod. The two torque rods are placed across the nodes of the 3-cylinder engine 1st order vibration (rotational couple around the X and Z-axis of the vehicle) combined with an appropriate stiffness balance with the right-side and left-side mount. This will cancel phase of the 3-cylinder engine 1st order vibration and achieve an optimal anti-vibration engine mount design (Fig. 6). The use of two lower torque rods contributes not only to compatibility with the layout and 3-cylinder engine 1st order vibration but also to quietness, because it ensures low-stiffness with small change up to full-throttle acceleration.The support rod does not have a stopper structure and rubber shape is designed to be used in a shear direction
元のページ ../index.html#32