V6--vs--L6--引擎好处与坏处--为什直列式6气缸发动机被淘汰❓V6 vs L6 Good Or Bad Which One Is Better ❓

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V6引擎：
所有 V6 发动机（无论气缸组之间的 V 角如何）都会受到由直列三缸发动机组成的每个气缸组引起的主要不平衡，因为每个气缸组中的气缸数为奇数。直列六缸发动机和六缸发动机不会出现这种不平衡。为了减少由这种不平衡引起的振动，大多数 V6 发动机在曲轴和/或反向旋转平衡轴上使用谐波阻尼器。
由于六缸发动机的动力冲程重叠，六缸设计的动力传递比四缸发动机的脉动更小。在四缸发动机中，在任何给定时间只有一个活塞处于做功冲程。每个活塞在下一个活塞开始其做功冲程之前完全停止并反转方向，这导致做功冲程之间的间隙，尤其是在较低的发动机转速 (RPM) 下。在具有均匀点火间隔的六缸发动机中，下一个活塞在前一个活塞完成之前 60° 开始其做功冲程，从而使动力更平稳地传递到飞轮。
在测功机上比较发动机，V6 发动机显示瞬时扭矩峰值高于平均扭矩 154%，谷值低于平均扭矩 139%，在做功冲程之间有少量负扭矩（发动机扭矩反转）。在四缸发动机的情况下，峰值大约比平均扭矩高 270%，比平均扭矩低 210%，在冲程之间传递 100% 的负扭矩。然而，具有 90° 和 150° 不均匀点火间隔的 V6 显示出比平均扭矩高出 185% 和低于平均扭矩 172% 的大扭矩变化。
V6 Engine：
All V6 engines-regardless of the V-angle between the cylinder banks-are subject to a primary imbalance caused by each bank consisting of an inline-three engine, due to the odd number of cylinders in each bank. Straight-six engines and flat-six engines do not experience this imbalance. To reduce the vibrations caused by this imbalance, most V6 engines use a harmonic damper on the crankshaft and/or a counter-rotating balance shaft.
Six-cylinder designs have less pulsation in the power delivery than four-cylinder engines, due to the overlap in the power strokes of the six-cylinder engine. In a four-cylinder engine, only one piston is on a power stroke at any given time. Each piston comes to a complete stop and reverses direction before the next one starts its power stroke, which results in a gap between power strokes, especially at lower engine speeds (RPM). In a six-cylinder engine with an even firing interval, the next piston starts its power stroke 60° before the previous one finishes, which results in smoother delivery of power to the flywheel.
Comparing engines on a dynamometer, a V6 engine shows instantaneous torque peaks of 154% above mean torque and valleys of 139% below mean torque, with a small amount of negative torque (engine torque reversals) between power strokes. In the case of a four-cylinder engine, the peaks are approximately 270% above mean torque and 210% below mean torque, with 100% negative torque being delivered between strokes. However, a V6 with uneven firing intervals of 90° and 150° shows large torque variations of 185% above and 172% below mean torque.
直列六缸发动机：
直列六缸发动机实际上处于完美的初级和次级机械平衡，无需使用平衡轴。发动机处于初级耦合平衡状态，因为前后三个气缸是镜像的，并且活塞成对移动（当然，360° 异相和 4 冲程循环的不同冲程）。也就是说，活塞#1 反映#6、#2 反映#5 和#3 反映#4，很大程度上消除了否则会导致的极地摇摆运动。
由于曲轴有六个曲柄，布置在三个偏移 120° 的平面上，因此在很大程度上避免了二次不平衡。结果是由活塞偏离纯正弦运动引起的大部分二次力总和为零。具体来说，二阶（两倍曲柄速度）和四阶惯性自由力（参见发动机平衡文章）总和为零，但六阶及更高阶非零。在大多数应用中，这通常是一个很小的贡献，但对于非常大的位移可能很重要，尽管在这些应用中，通常和有利地使用长连杆减少了活塞运动中的二次（二阶和向上）振荡。
L6 Engine:
An inline six engine is in practically perfect primary and secondary mechanical balance, without the use of a balance shaft. The engine is in primary couple balance because the front and rear trio of cylinders are mirror images, and the pistons move in pairs (but of course, 360° out of phase and on different strokes of the 4-stroke cycle). That is, piston #1 mirrors #6, #2 mirrors #5, and #3 mirrors #4, largely eliminating the polar rocking motion that would otherwise result.
Secondary imbalance is largely avoided because the crankshaft has six crank throws arranged in three planes offset at 120°. The result is that the bulk of the secondary forces that are caused by the pistons' deviation from purely sinusoidal motion sum to zero. Specifically, the second-order (twice crank speed) and fourth-order inertial free forces (see engine balance article) sum to zero, but the sixth-order and up are non-zero. This is typically a tiny contribution in most applications, but may be significant with very large displacements, despite the usual and advantageous use of long connecting rods reducing the secondary (second-order and up) oscillation in the piston motion in those applications.