有启停功能(比如等红灯时)的发动机是否比传统发动机磨损得更快？
ELI5: How don''t those engines with start/stop technology (at red lights for example) wear down far quicker than traditional engines?
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讨论汽车发动机要不要预热的问题
正文翻译
ELI5: How don't those engines with start/stop technology (at red lights for example) wear down far quicker than traditional engines?
有启停功能(例如等红灯)的发动机是否比传统发动机磨损得更快？
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On top of everyone else's answer, it's important to note the role that the motor oil plays in the process. Motor oil that is at operating temperature and hasn't been broken down allows the metal surfaces inside the engine to almost never touch. The wear goes into the oil and not the metal, the former being much easier to replace than the latter.
When an engine is shut off, the oil is still hot (typical operating temperature is 205°F-220°F depending on the manufacturer/design) and it's continuing to drip and cover all of the metal surfaces such as the pistons, valve springs, etc etc. Starting the engine in this state causes very, very little wear as again, it's the oil taking the wear and not the metal.
Cold, winter starts are when the engine takes the most wear, when the oil is most viscous. Start/Stop systems typically do not kick in when they detect the engine is not at operating temperature or power needs exceed a certain threshold.
重点是要注意机油在这个过程中所起的作用。处于工作温度且未被分解的机油可以保证发动机内部的金属表面几乎不会相互接触。磨损的是机油而不是金属，而机油比发动机更容易更换。
当发动机关闭时，机油仍然是热的(典型的工作温度是205~220华氏度，96~104摄氏度，取决于制造商和设计)，它继续充满并覆盖所有的金属表面，比如活塞、气门弹簧等。在这种状态下启动发动机只会造成非常非常小的磨损，同样的，磨损的是机油而不是金属。
寒冷的冬季启动是发动机磨损最严重的时候，这时机油最粘稠。这时启停系统通常不会启动，因为电脑检测到发动机不在工作温度或功率需求超过某一阈值。
So my vehicles that have been sitting much more during the pandemic with drastically lower miles could be worse off than if i had used it normally?
I let the engine warm up before putting it in gear, religiously.
ETA: everybody commenting i don't need to warm up the engine are fundamentally flawed on so many levels. I'm not some no nothing car owner lol I've built engines and know my way around an engine bay.
那么，我的汽车在疫情期间经常闲置，行驶里程大幅降低，可能比我正常使用更糟？
我非常谨慎地让发动机预热后才挂上档位。
编辑：很多评论说我不需要预热发动机，他们的说法都是有问题的。
Folks, if you have the time, just let it warm before driving. It isn't hard to do and it's better for your engine.
开车前绝对应该热车。当然，在寒冷天气，相比原地热车，平稳驾驶可以让车更快热起来。但是，激烈驾驶对冷的发动机是有害的，你很难判断什么才算平稳。暖车不需要很久的（除非外面很冷)。在寒冷和温暖时，油的重量是不同的。
朋友们，如果你们有时间，开车前先让它热一下。这并不难做到，这对你的发动机有好处。
So my vehicles that have been sitting much more during the pandemic with drastically lower miles could be worse off than if i had used it normally?
It depends. For most people, that's okay that it sits for a little bit longer. Cars are meant to be driven, and when they sit for a year or more is when it becomes something to be concerned about. As long as it's being driven often enough that you don't need to jump start it, you should be okay because you're keeping the fluids inside moving and not letting the coolant/fuel/oil separate.
——那么，我的汽车在疫情期间经常闲置，行驶里程大幅降低，可能比我正常使用更糟？
视情况而定。对大多数人来说，它闲置时间长一点没关系。汽车本来就是用来驾驶的，当它们闲置了一年或更久时，就该注意了。只要经常驾驶，保证不需要接电，你的车应该没事，因为你保持了内部的液体流动，不让冷却剂、燃料、机油分离。
You may want to start driving sooner. An idle engine won't warm up as fast as a working engine, and you want to get the engine up to operating temperature as soon as possible. Advancements in oil technology have brought motor oils to the point that they're still quite effective for low loads at low temperatures while keeping the engine protected.
You can try this for yourself on a cold winter day: five minutes in an idle car and the heater doesn't really get that much warmer. Five minutes of driving and you'll already start to feel some heat coming through the vents.
On top of that, most vehicles nowadays have electronically controlled thermostats. Your radiator usually doesn't do any work cooling the coolant and it's instead rerouted back into constantly until you're at operating temperature.
——我非常谨慎地让发动机预热后才挂上档位。
你最好尽快开车。怠速发动机的预热速度不如正常行驶的发动机快，你应该尽快让发动机达到工作温度。石油工业的进步使机油在低温低负荷的情况下仍然非常有效，同时可以保护发动机。
你可以在寒冷的冬天自己尝试一下：在怠速汽车里呆五分钟，加热器不会真的变热。而开车五分钟，你就会开始感觉到一些热度从通风口涌来。
最重要的是，现在大多数汽车都有电子控制的恒温器。你的散热器一般会原地怠工，直到你的发动机达到工作温度。
Certified_GSD
Minimal sitting is okay as long as it's still being driven often enough that the battery (assuming it's in good health) doesn't need to be jumped. Most car batteries can go three to six months without being charged.
This will keep the fluids from separating, which will cause its own issues. You should still change the oil once a year no matter how many or few miles were driven, as oil tends to collect dirt and water. Same with fuel: don't let it sit for longer than a year without fresh fuel, as most fuels are blended with ethanol which attracts water.
You'll want to park the vehicle in a temperature controlled garage, or at least in a covered spot to minimize UV damage to the paint. The former is to have better control over the humidity to hopefully minimize any water retention in the brake fluid.
只要保持足够频繁的驾驶，不需要更换电池(假设电池健康状况良好)，这样偶尔闲置是没问题的。大多数汽车电池不充电可以使用三到六个月。这将防止会导致问题的液体分离。不管你开的距离有多少，你还是应该每年换一次机油，因为机油容易积聚灰尘和水。燃料也一样：在不加新燃料的情况下，不要让它存放超过一年，因为大多数燃料都与乙醇混合，会吸水。
你最好把车停在恒温的室内停车场，起码也是能遮风挡雨的地方，免得紫外线损伤车漆。最好是湿度也是适宜的，这样可以尽量减少刹车油吸水。
Minimal sitting is okay as long as it's still being driven often enough that the battery (assuming it's in good health) doesn't need to be jumped. Most car batteries can go three to six months without being charged.
This seems rather optimistic, at least with colder temperatures if you are parking outside. I'd consider 2-3 months the uppper limit with all the computers and stuff that is always running in cars these days, even in sleep mode, and would try to move the car maybe once a month or so to be on the safe side. And if you are living somewhere wet or worse, drove in wet or icy conditions with road salt on the ground, your brakes will probably start sticking in a week and may be hard to get moving again after only a few weeks sitting.
I usually try to drive at least every other week and far enough, to really get the engine and exhaust warm and the one time I didn't and my car got snowed in for 2 months, I needed a jump start and my brakes were noticably pitted afterwards.
——只要保持足够频繁的驾驶，不需要更换电池(假设电池健康状况良好)，这样偶尔闲置是没问题的。大多数汽车电池不充电可以使用三到六个月。
似乎过于乐观了，至少在气温较低的情况下，如果你把车停在室外。我认为2-3个月，就是现在这些汽车上的电脑和设备的上限了——即使是在睡眠模式下，为了安全起见，我可能会试着每月动一次车。如果你住在潮湿或更糟糕的地方，在潮湿或结冰的条件下开车，加上路面上有盐，你的刹车可能会在一周内卡住，可能停了几周就很难开动了。
我通常至少每隔一周开一次车，开足够远，让发动机和排气暖起来，但有一次我没有这样做，我的车被雪困了两个月，我需要搭电，然后我的刹车明显出了故障。
spottyPotty
You should still change the oil once a year no matter how many or few miles were driven, as oil tends to collect dirt and water.
I've always been suspicious about this part and have thought that it was my mechanic's way of ensuring regular business for himself. Isn't the oil circulation system a closed system? If so, where would the dirt and water come from? If oil is good for years sitting in it's can, why can't the same be said for oil sitting inside a car that's not used very often?
I'm just talking about the oil here. I understand that seals and such dry out and crack when not lubricated.
不管你开的距离有多少，你还是应该每年换一次机油，因为机油容易积聚灰尘和水。
我一直对此有疑虑——机油循环系统不是封闭的吗？如果是这样，这些灰尘和水从何而来？如果把机油放在罐子里几年都没问题，为什么机油放在不经常使用的汽车里就会有问题？
Dirt or other contaminates can make their way into the system from the air intake (the air filter is good but not perfect). Things can also make their way in from the air and currents moving around and into little crevices here and there. This isn't too much a concern.
What is the bigger concern is the water content. Oil tends to attract water, even moreso depending on the different additives in the oil that can attract water and moisture in the air since it isn't sealed in a vacuum. Water is, compared to oil, a terrible lubricant.
If oil is actually sealed in a can or bottle, it's generally sealed away from the environment. An engine isn't necessarily sealed perfectly, there are small tiny spaces all over where outside contaminates can sneak in.
灰尘或其他污染物会从进风口进入系统(空气过滤器有用，但不是完美的)。一些东西也可以通过空气和气流进入这里那里的小裂缝中。这不是一个太大的问题。
更重要的是水含量。由于机油不是密封的在真空中的，因此更容易吸水，确切来说，机油中各种添加剂可以吸收空气中的水分。与油相比，水是一种糟糕的润滑剂。
如果机油真的被密封在罐子或瓶子里，它通常是密封的，远离空气。发动机不一定密封得很好，到处都有很小的缝隙，外部的污染物可以溜进来。
Is it bad to not change it once a year? Not necessarily. But why is it recommended? As a preventive maintenance precaution, it's easier and cheaper to pay $100 for an oil change than to potentially damage the engine in the long term due to potential factors such as moisture retention or oil breakdown or accumulation of contaminates.
It's the same logic as replacing the water pump when changing the timing belt or replacing the engine rear main seal when removing the transmission: even if these items are still functioning correctly, it's preventive maintenance that's done anyways to minimize risk that costs a little now so it doesn't cost a lot later.
也有可能机油已经分解，不能像新的合成石油那样保护机器。
如果不一年换一次会不好吗？不一定。但是为什么推荐这么做呢？作为一种预防性的维护措施，花100美元换一次油要比因为水分、分解、污染物造成发动机损害更方便，也更便宜。相同的逻辑也适用于更换了正时皮带时更换水泵，或者拆卸变速箱时更换发动机主密封——即使这些东西仍然正常，但预防性维护，会最小化风险，现在花小钱，将来避免花大钱。
Just wanted to echo the previous : idling to warm up is (for modern high efficiency vehicles) worse than gently driving, to the point where most European makes have removed the ability to remote start.
The reason goes something like this: Significantly more wear occurs when the engine is cold, and this wear occurs regardless of engine load. More wear occurs under high torque demand, but it happens regardless.
Idling in a modern aluminium block car can take 30 minutes or more to heat up, whereas driving normally takes more like 5 minutes.
So 5 minutes of low load when cold is far better than 30 minutes of idling, wear wise, and uses less fuel to boot.
（对于现代高性能汽车来说)怠速预热比缓慢驾驶更糟糕，以至于大多数欧洲汽车都取消了远程启动的功能。原因大致是这样的：当发动机处于低温状态时，磨损会显著增加，而且这种磨损与发动机负载无关。在高扭矩下，磨损会更多，但无论如何都会发生。
在现代铝块汽车中，怠速需要30分钟或更多的时间来加热，而正常驾驶则只需要5分钟左右。所以5分钟的低负荷热车比30分钟怠速，磨损更少、油耗更低。
原创翻译：龙腾网 http://www.ltaaa.cn 转载请注明出处
Older cars have mechanical thermostats that do not open before at least 80C too.
For as long as ECU started to be in use, cold engines retard their timing in order to heat faster. This helps the catalytic converter too.
老汽车也有机械恒温器，至少在80摄氏度之前不能启动。
ECU开始使用后，冷发动机就会延迟它们的时间，以便更快地加热。这也有助于催化转换器。
I let the engine warm up before putting it in gear, religiously.
That will actually reduce engine life on a long run. You should depart immediately but slowly.
Idling a cold engine and waiting to warm-up before departing reduces the engine life. Why? Precisely because the engine shouldn’t run cold. Let me explain.
When idling at, say, 750 rpm, the engine warms up very slowly. It will take, say, 15 minutes of idling to warm up. 15 × 750 = 11,250 revolutions. This means that all of the moving components made 11,250 cold, component-wearing revolutions.
If you depart immediately but slowly and drive at, say, 1500 rpm, the engine will reach proper temperature much sooner, after only, say, 3 minutes. 3 × 1500 = 4,500 revolutions. This means that all of the moving components made only 4,500 cold, component-wearing revolutions.
怠速预热实际上会降低发动机的长期寿命。你应该马上离开，但要慢慢驾驶。
当怠速为750转时，发动机升温非常缓慢。它需要，比如说，15分钟时间来预热。15 × 750 = 11250转。这意味着所有的运动部件都要进行11250次的冷磨损。
如果你马上离开，但慢慢驾驶——以1500转/分的速度行驶，发动机会更快地达到适当的温度，只需要3分钟。3×1500 = 4500转。
Counter-intuitively, the colder the weather, the more damaging idle warming is: the already long idle warm-up time is even longer. So, in winter, it is even more important to depart immediately but slowly.
So, if we we order the start-up styles from the most damaging to the least damaging:
Cold engine, aggressive start (most damaging)
Cold engine, waiting to warm-up while idling (moderately damaging)
Cold engine, immediate slow departure (least damaging).
I understand this is counter-intuitive (many things about cars are!), but if you really think about it makes perfect sense.
如果你急加速，发动机会更快地升温，但组件的负载将抵消更快升温的好处。
与我们的直觉相反，天气越冷，怠速预热的破坏就越大，所以，在冬天，更重要的是要立即缓慢地离开。
所以，如果我们排序的话：
冷发动机，急速启动(最具破坏性)
冷发动机，怠速预热(中度损坏)
冷发动机，立即慢慢离去(损失最小)。
我知道这是违反直觉的(很多关于汽车的事情都是这样!)，但如果你仔细想一下，这是完全有道理的。
Overall you're correct.
However if it's really cold outside it's advised to let the engine idle for a short amount of time till all the components are lubricated. This usually takes less than 30 seconds.
In practice I'll just leave my car idling while I'm freeing the windows from frost and ice.
总的来说你是正确的。然而，如果外面真的很冷，建议让发动机怠速一小段时间，直到所有部件都润滑。这通常需要不到30秒的时间。现实里，我只是在我擦车窗的霜和水雾时候，让我的车怠速，。
So interesting. What kind of damage can be done if you do not let a car warm up before driving frequently?
有意思。如果经常开车前不让车预热会造成什么损害？
Gold
Generally with the advances of synthetic "multi" weight oils, as long as you don't redline the engine until it reaches proper operating temperature is okay. 5W-30, a common Midwestern oil weight, acts like a lighter 5 weight oil cold and once warmed up behaves like a heavy 30 weight oil. The lighter oil helps it lubricate and move through the oil channels when cold, whilst at temperature the heavier properties of oil protect the metal surfaces more.
The wear that generally occurs at startup is in the components at the top of the engine, such as the valvetrain components as the oil pump must draw oil to the top of the engine. Things on the bottom typically still are submerged in oil or have a film of oil, like the pistons.
一般只要是先进的合成机油，只要你在它达到适当的工况温度前转速不破发动机红线就没问题。在启动时，磨损通常发生在发动机顶部的部件，比如气门总成，因为油泵必须把机油抽到发动机顶部。底部的东西通常仍然浸在油中，或者有一层油膜，比如活塞。
Even in a warm climate, it's very important you let the engine and oil/coolant get up to proper temperature before asking it to work hard. Remember, it's usually 205°F-220°F which is only achieved from it being on. Pretty much all modern vehicles will try to reach this as quick as possible by using more fuel and hence why your fuel economy usually sucks for the first ten or fifteen minutes your vehicle is first turned on (on top of cold engines being inefficient and fuel not mixing as well).
现在，冷的、粘的油并不能很好地流动。如果你在寒冷的天气里急加速，很有可能机油在管道中流动得不够快，从而导致金属摩擦。老斯巴鲁发动机就因为机油通道小而臭名昭著，加上喜欢烧机油，结果造成臭名昭著的活塞敲击。
即使是在一个温暖的气候，让发动机和机油/冷却剂达到适当的温度也是非常重要的。记住，它通常是96~104摄氏度。几乎所有现代汽车将通过消耗更多燃料来尽快达到这个温度。这就是为什么你的车首次启动时，通常前10、15分钟油耗非常垃圾。
Leucippus1
Helpful
What wears an ICE engine is thermal cycles, that is warming it up, cooling it down, and warming it up again. If you start an engine that is already warm, there is very little wear. The wear comes from starting a cold engine that has been sitting for a while.
Take an example, have you ever pulled the starter cord on a cold weed whacker / weedeater, or similar small engine? When it is cold, it is relatively hard to pull that cord, and you have to yank it a bunch of times. Now, run the engine for a while and turn it off. Wait about a minute and start it again. It is way easier when the engine is warm, and you usually get it on the first pull.
造成冷发动机磨损的是——即加热，冷却，再加热。如果你启动一个已经预热的发动机，磨损很小。磨损来自于启动一个已经闲置了一段时间的冷发动机。
举个例子，你有没有拉过冷的除草机的起动绳？或者类似的小发动机?天气冷的时候，拉绳子相对比较困难，你不得不拉它很多次。现在，启动一下发动机运行一段时间，然后把它关掉。等一分钟再开始。当发动机是热的时候就容易多了，一次就能拉启动。
Now, lets be honest, in a consumer vehicle with a liquid cooled engine, you are unlikely to get to the point where you will wear the engine so badly that you need to overhaul or rebuild. Engines that drive across the continent (truck diesels), or airplane piston engines, will see use that will require an overhaul/rebuild. You would have to start/stop excessively to match the kind of wear you get on a truck or airplane engine. Airplane engines because they are air cooled and the thermal cycles are rather extreme, and truck engines because they are massive and used for many times more driving miles than your typical car or SUV ICE.
冷发动机的磨损更严重的原因是，已经闲置一段时间的机油和所有润滑发动机的东西已经冷却和沉淀。在你启动冷发动机的那一小段时间里，你没有得到很好的润滑。这就是发动机磨损发生的地方。比如说，密封和垫圈脱离润滑太长时间，他们失去了其柔韧性，然后一个冷启动立马就爆缸。我想到的例子是一个已经好几年没有运行的发电机，有一次停电时启动它，一点火立即喷出了所有的机油。
现在，说实话，在一辆使用液冷发动机的乘用车中，就算你冷启动，磨损也不太可能严重到需要大修或更换发动机的地步。而横跨大陆的发动机(比如卡车柴油发动机)，或飞机活塞发动机，如果经常冷启动，将需要大修、更换。因为飞机发动机是空气冷却的，热循环是相当极端的，而卡车发动机非常巨大，使用的行驶里程比一般汽车或SUV多很多倍。
原创翻译：龙腾网 http://www.ltaaa.cn 转载请注明出处
Truck and aircraft engines spend most of their revolutions under heavy load. Automotive engines are mostly idle.
卡车和飞机发动机的大部分都是在重载状态下运转。而汽车发动机大多是空转的。
Automotive engines are mostly idle.
So does driving count as idle? Because i certainly spend more time driving than i do standing still in my car... Or do you mean turned off most of the time?
而汽车发动机大多是空转的。
那开车也算空转吗？因为我开车的时间肯定比原地静止的时间要长。或者你的意思是大部分时间发动机都是关闭的？
They mean "low load", not "idle".
Normal daily driving, you're at steady speed most of the drive. This means low unchanging RPM in the highest gear available. For my car, this means 1200-1500RPM (it idles at 800 and maxes out at 6500). For any appreciable drive, this will be 90% of the drive or more, unless you're in some absurd traffic jam.
A normal passenger car maintaining steady speed doesn't need to use a whole lot of power. Most estimates are that for highway speeds (55-60mph) a regular car needs only 40 horsepower to overcome friction with the road and drag, and keep that steady speed. This isn't a lot at all, and is reflected by EPA estimates for Highway fuel mileage being significantly higher than city mileage (where you're stopping and starting a lot more, which requires more power).
他们的意思是“低负荷”，而不是“空转”。
正常的日常驾驶，你大部分时间都以稳定的速度行驶。这意味着在最高档位，以低转速运转。比如我的车，通常是1200-1500转(它怠速时转速为800转，最高转速为6500转)，90%或更多的驾驶都是这种情况，除非你遇上了大堵车。
一辆正常的乘用车保持稳定的速度不需要使用大量的动力。大多数估计是，高速公路的速度(55-60英里/小时)，一辆普通汽车只需要40马力就能克服道路的摩擦和空气阻力，并保持稳定的速度。这根本不算多，所以EPA测试高速公路的油耗明显低于城市中(在城市，你需要频繁加减速，这需要更多的动力)。
You can feel the difference yourself if you use a stationary exercise bike with variable resistance. Set it to low resistance to simulate a passenger car, and high resistance to simulate a heavy truck. To maintain the same speed, you have to do a lot more work at high resistance. Because of that, you get tired much more quickly. The same thing happens to the pistons of the truck engine. They have a lot of resistance making them not want to move, and are being forced to, which tires out the surfaces that bear those forces (the piston head and cylinder walls) much faster than if there was no load resisting movement.
货运卡车的重量明显比客车重(高达80000磅，而一辆客车重3500磅)。这意味着它们需要克服更多的摩擦力，为了保持稳定的速度，它需要使用更多的动力。发动机做了更多的功来克服摩擦和阻力，很多时候他们会换到较低的档位来提高转速，从而提高功率。
如果你使用一辆阻力可变的健身车，你自己就能体会到不同。设置低阻力模拟乘用车，设置高阻力模拟重型卡车。为了保持同样的速度，你必须在高阻力下做更多的功。正因为如此，你会更快地感到疲劳。卡车发动机的活塞也会发生同样的情况。它们承受更多阻力，这使承受这些力的表面(活塞头和气缸壁)比没有负载时磨损更快。
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