[jbkiv]

I remember when Mercedes Benz bought Freightliner, the major US truck manufacturer,in the 80s. The Mercedes Benz engineeers were astonished to see how UN-sophisticated the engineering of Freightliner trucks was. Example: no assisted steering!!! That choice was justified as more macho. I was told that assisted steering was not manly enough...

[anarazel]

The noise level of some US trucks still surprises me. Jet engine like.

[LinuxBender]

If it's when they are slowing down it's likely the jake-brakes j-brakes you are hearing especially if they have straight pipes. Diesel engines don't have engine braking by design so a mechanism was added to the heads to create artificial engine braking that can be toggled on per head.

[ Edit for clarification: ] I have created some confusion with this statement. For clarification diesel engines never had engine braking due to the lack of a throttle plate but this has been worked around with add-ons using different techniques. On a big-rig this is jake-brakes. On smaller modern vehicles this is usually a small turbo or an exhaust baffle. The operator of a modern diesel vehicle will effectively experience engine braking when they let off the throttle. On older diesel pickups and cars there was no engine braking.

[gambiting]

>>Diesel engines don't have engine braking by design

First time I hear about this. I've driven and owned plenty of diesel vehicles in my life and diesel engines definitely do have engine braking(unless it's different in semis? but I don't see why it would be - just leave it in gear and let it slow down?)

[garaetjjte]

Technically diesel engines do not strictly "engine brake" because of lack of throttle plate, and thus lack of pumping losses. However that doesn't mean that it won't slow down: friction losses, heat loss to cylinder walls, etc. still occur. Surely diesel passenger car will decelerate stronger when left in gear than in neutral. Given how many pages and pages of discussions you can find people arguing whether petrol or diesel engines brake stronger, it seems pumping loss doesn't make that much difference.

[LinuxBender]

The engine itself has no braking due to the lack of the variable air-intake that gasoline engines have that would otherwise starve the engine for air especially when downshifting and closing the throttle.

Specifically on non-big-rigs, modern diesel cars and pickups create engine braking using a small turbo and tighten the spline or in some cases have an exhaust feedback baffle or flap, varies with year/model. Big rigs still use jake-brakes.

[tomxor]

Interesting. I was only taught engine breaking from the practical perspective of down-shifting, but not the details of why it works. I understood the implicit effects of shifting down - maintaining the same high RPM with the same high resistance as a vehicle slows... but never gave much thought to what exactly those resistances were, I just assumed it was a combination of friction, compression, driving an alternator, other arbitrary mechanical losses etc.

Would there really be no significant braking effect without that "high manifold vacuum"? I suppose the engine does have a lot of mass so I could believe the effect could be too slow to be useful.

[mcguire]

Gasoline engines have a throttle plate that, when you let off the throttle, prevents intake air from reaching the cylinders. The pistons try to draw air into the cylinders and create a pretty decent vacuum. (Respect to the throttle plate. :-))

Diesel engines don't; the throttle controls fuel flow into the cylinders. Let off the throttle and air flows through the intake, cylinders, and exhaust just without producing any power.

The effects of friction are roughly the same on both engines, and they are what engine designers and builders want to minimize to maximize fuel efficiency and power.

[throwaway0a5e]

It doesn't have "no" braking. But it has a hell of a lot less than it would if there were some restriction on it, e.g. a throttle.

[spookthesunset]

I've done what feels like engine braking in "consumer" diesel trucks. Since I never had to flip switches or anything, how does the engine know how to enter into this "engine braking" mode?

Never even crossed my mind that diesels don't natively engine brake. Then again how diesels work is a bit of a mystery to me... mostly because I never bothered to look into it much.

[LinuxBender]

Newer diesel engines use a turbo or baffle. Most commonly a turbo to create effective braking. This is operationally superior to jake-brakes in that the mechanism is tied into the ECM and transmission allowing for things like cruise control to function as expected. Jake-brakes on the other hand require a bit of technique by the driver to use correctly and avoid jack-knifing the vehicle with its trailer, especially on ice. Some modern pickups can even be put into "towing mode" to make better use of the add-on braking mechanism and allow cruise control to work downhill.

I suppose this the right time for an important PSA. If anyone tows something heavy in an older diesel pickup be aware the only braking you have is what your brake pedal provides. Glaze those brakes and you are going on an exciting adventure.

[jbkiv]

Thanks! I learned something new today.

[skywal_l]

Diesel engines do not have engine breaking? Are you sure? For me, engine breaking is just the fact that the engine, without power, have moving pieces which, by inertia, is going to slow down the vehicle. Diesel engine being heavier than "regular" engine, the engine brake effect is more important.

At least that's my experience with the cars I used to own.

Edit: For the record, my experience is for 4-strokes diesel engines. Apparently, 2-strokes are still in use in the US.

[pwg]

Diesel engines have no throttle plate that controls the airflow into the engine.

The closed throttle plate in a gasoline engine is what creates a gasoline engine's brake effect, by pulling a vacuum in the intake below the closed throttle plate, which produces the brake effect.

With no throttle plate, the remaining mechanical components in a diesel engine provide minimal friction, certainly not enough to produce any brake effect.

The jake brake (https://en.wikipedia.org/wiki/Jake_brake) converts the diesel engine into a huge air compressor when activated, which provides an engine brake effect. Unfortunately it also often creates a very distinctive, and often loud, sound from the exhaust as well.

[seszett]

> With no throttle plate, the remaining mechanical components in a diesel engine provide minimal friction, certainly not enough to produce any brake effect.

I'm not sure if maybe we have different definitions of "braking", but a diesel engine definitely slows down a car when one throttles down. The vehicle slows down faster than when on neutral, and the braking power depends on which gear is engaged, which seems to indicate very much that there is engine braking going on.

[ska]

Posters point wasn't that the vehicles you drive didn't effectively have engine breaking, but that in diesel designs this is something that had to be added intentionally - with [edit gas engines] you get it whether you want it or not.

Fun fact - the effect can be strong enough on a high compression motorcycle engine to break your rear tire free (obviously lots of other parameters there).

[roelschroeven]

> With no throttle plate, the remaining mechanical components in a diesel engine provide minimal friction, certainly not enough to produce any brake effect.

I don't understand. I've driven multiple diesel engine cars throughout the years, and they most definitely have a brake effect. I'm not even sure they brake less than the gasoline cars I've driven. Easily enough to slow down for taking an exit from the freeway, for example, when shifting down appropriately. To the point that there regularly are situations when I lightly press the brake pedal not to brake but to simply light the brake lights, if there are cars behind me.

It does sound plausible that the lack of a throttle leads to less or no brake effect, but it simply doesn't fit my observations.

I'm talking about regular cars here, both recent and less recent (the oldest one was built in 1989).

Maybe there are different diesel engine types with different brake capabilities? Or do some gasoline engines brake much more than what I'm used to, and my reference for what is and isn't significant braking is all wrong?

[mcguire]

https://www.youtube.com/watch?v=o8Cta2cC2Co

https://en.wikipedia.org/wiki/Engine_braking#Diesel_engines

[pwg]

See @ska's comment at https://news.ycombinator.com/item?id=30195348

[skywal_l]

Diesel engines might not have throttle plate but they use injection which certainly do not inject air when acceleration is released, so the cylinders will act exactly the same way. Reading the web I see conflicting account on this subject. Strange...

Also, I though that modern petrol engines did not have throttle plates anymore and use the same injection system than diesel engines (no more carburetors).

[ska]

> use injection which certainly do not inject air when acceleration is released,

FWIW injectors don't inject air; the airflow is separate, get's compressed (and hence heated) then the fuel is injected, then bang (in diesel)

[throwaway0a5e]

The fuel system doesn't provide restriction on the air going through the engine.

A diesel engine that's not dumping in fuel (because your foot isn't on the pedal) has about as much engine braking as a gas engine that's run out of fuel but the operator has floored the pedal.

A gas engine has a throttle that can restrict airflow. A diesel can either be equipped with an exhaust brake or compression brake. The latter is tons more effective but louder.

[LinuxBender]

Diesel engines themselves have no engine braking. Each personal vehicle implementation of diesel engines have worked around this using different techniques. The most common outside of big-rigs is a turbo that tightens a spline or closes a feedback baffle.

To the operator of the vehicle it will appear there is engine braking on modern diesel engines. Older pickups and cars have no engine braking.

[spookthesunset]

> Older pickups and cars have no engine braking.

So what did they do on long downhill mountain passes? Just ride the brakes? Were the brakes designed to accommodate being ridden for so long?

Asking 'cause I downshift all cars I drive when going down mountain passes...

[LinuxBender]

They would drive slowly and carefully and take alternate routes when possible.

Just ride the brakes?

No that will overheat and glaze the brakes. That is why long steep hills initially had run-away ramps created. The run-away ramps are still used but not nearly as much as they used to be. In many places alternate routes were created for people towing heavy things. A good example of this is the grapevine on I-5 in southern California. There is a truck route and the main route. That also has many run-away ramps.

[schwap]

There's nowhere near enough inertia in the rotating assembly of an engine to significantly slow down a vehicle.

[jacquesm]

It's not the inertia that does the job (that keeps things going, actually) but the compression and shedding the compressed air that will slow things down. But for a big rig doing that idling it won't be enough, especially not on a descent with 25 tons pushing you downhill.

[BenjiWiebe]

It's also the friction of everything turning. And you've still got your alternator, oil pump, water pump, fan etc that are removing energy.

[jacquesm]

A Jake brake is for long descents, it essentially uses the engine to slow down instead of the brakes to avoid overheating them.

Normal diesels do engine braking just fine, but not aggressive enough to shed speed on a long descent without over-revving, and you really don't want to do that with a diesel engine.

[kfarr]

There can be value in simplicity - fewer things to break and easier to repair.

[CountSessine]

Exactly. The irony of Mercedes-Benz engineers marveling at how unsophisticated a simply-engineered vehicle is brought a smile to my face. Most owner-operator truck drivers want to be able to fix and maintain their trucks on their own, not bring the truck into the dealer every 3 months like some temperamental S-class.

Although I guess Mercedes was still pretty reliable back in the 80's.

[PaulDavisThe1st]

Actually, I think the irony is the other way around. I've read that worldwide, MB vehicles dominate many markets (e.g. African taxi and trucking) precisely because they are so easy to do local non-dealer maintainance on. Most of the world thinks of many MB vehicles as workhorses, not luxury or sophisticated vehicles.

[CountSessine]

I've often wondered about this. Here in North America we only get the Mercedes models that need their disc rotors replaced every 30k, and we see nothing of the indestructible and serviceable models that seem to wind up in places without posh MB dealerships.

I've always thought that this was because NA has air pollution laws that are strictly and honestly enforced and that that would make diesel cars difficult to offer.

[xxpor]

>I've always thought that this was because NA has air pollution laws that are strictly and honestly enforced and that that would make diesel cars difficult to offer.

Yes, the US regulates NOx emissions much more than Europe. This makes it very hard to offer passenger diesel engines in the US. On the other hand, the EU regulates/taxes CO2 emissions, which the US does only indirectly through CAFE (fuel efficiency) regulations.

[oblio]

How is US fuel efficiency, though?

In Europe cars using 5 liters per 100 km (~48 miles per gallon for the SI-resistant amongst us) are very common.

[throwawayboise]

Yes, MB deliberately cultivated a "luxury" brand image in the US and did not import very many of the "workhorse" models (the ones with smaller engines, manual transmissions, and few options) that the rest world knows.

[jacquesm]

MB trucks are an entirely different kettle of fish than the consumer and light transport stuff. It all changes above the 3500 kg mark.

[throwaway0a5e]

In the US their Sprinters compare to the competition about the same way an S-class compares to a Camry. In both cases it's generally considered ill-advised to own it into old age.

I wouldn't call that "entirely different"

[jacquesm]

Sprinters routinely clock half a million K. You need to maintain them but that goes for all vehicles.

And they are still below that 3500 kg limit. It really starts at Atego:

https://www.mercedes-benz-trucks.com/nl_NL/models/atego-cons...

[throwaway0a5e]

If the Sprinter took a comparable amount of maintenance to deliver the same service it would not have the reputation it does. It's not like people are jumping to conclusions based on brand either. It was initially branded as a Dodge or Freighter/Sterling. The only operators who like it are high end passenger fleets that depreciate them and then get new ones. Now, in its defense, people do generally hate the FWD Fiat van more...

[Teknoman117]

There days Mercedes doesn't really export non-luxury vehicles to the US except for maybe sprinter vans.

[cycomanic]

You really think that owner operators repair their own trucks? That doesn't make any economic sense. This is not a hobby, they need to drive to make money not to play truck repairman.

I'm always astonished how US Americans try to justify poor engineering with "advantage of simplicity". It's like arguing that you want to program using punch cards because that makes you feel closer to the machine and you have a "physical" copy of your programs.

[harpersealtako]

>US Americans

This is a side note, does this bother anybody else? I'm at least a teensy bit bothered by it. I know the point is to reduce ambiguity between the U.S.A and Latin/North/Central/South America, but it still feels a bit condescending, like we're not even allowed to have a unique name anymore or even have a say in we should call ourselves/be called in our native language (and it doesn't help that the only time I hear "US Americans" is when someone is talking shit about us). There's only one country on the continent with the word America in its name. I'm curious if I'm the only one who feels this way or if I'm overthinking it.

[ReleaseCandidat]

> reduce ambiguity between the U.S.A and Latin/North/Central/South America,

And the continent 'America'.

Just for comparison: what do you think 'South Africa' (the country, not the region ;) should be called?

[kompatible]

In Romance languages, the continent is known as the supercontinent "America", but in Germanic languages (like English) and other languages that borrow from it call them the "Americas" as two continents "North" and "South" America. So, for people to bring it over as 'America' can sometimes be seen as pedantry instead of insightfulness.

[harpersealtako]

South Africa? I would call it South Africa if that's what they want to be called. I definitely wouldn't call citizens of South Africa "RS Africans" or something unless they preferred that for some reason.

[allendoerfer]

The grandparent might just be German using a literal translation. In German, it is pretty common to call Americans "US-Amerikaner", even when we are not talking shit about you.

The shit-talking is by the way something you should not take too serious. I have seen it directed at Germany from smaller European countries as well. It is just natural to target the bigger, more powerful neighbour, especially when he behaves a bit too full of himself.

Just think of Don Draper answering to "I feeld bad for you!" with "I don't think about you at all."

[TMWNN]

>There's only one country on the continent with the word America in its name.

Not just the continent(s). The United States of America is the only country in the world with the word "America" in its name.

>I know the point is to reduce ambiguity between the U.S.A and Latin/North/Central/South America

This is only a thing in Spanish. In Portuguese, Americans (that is, those from and of the USA) are often called americanos. In French, américain is much more commonly used than États-Unien.

The Spanish meaning of americano that does not include Americans in this way is very unusual among major Western languages (<https://en.wikipedia.org/wiki/American_%28word%29#Other_lang...>). I don't mean to say that the equivalent of "American" in those languages is the only way to refer to those of the USA, or that equivalents to "USA" and such don't exist. In Portuguese, Italian, and German, however, saying Americano/Americano/Amerikanisch would generally be understood as referring to that of the USA without additional context, as opposed to a Brazilian or Argentinean, in a way that Americano wouldn't in Spanish.

Further, in Spanish the ambiguity is worse. "Los Estados Unidos" is another term for the US, despite the existence of Mexico (AKA United Mexican States / Estados Unidos Mexicanos). Norteamericano for "American" is also used, despite that term literally including those living in Canada, Mexico, and the Caribbean.

(Yes, I know that in practice, Spanish speakers understand that "Los Estados Unidos | EE. UU" and "Norteamericano" refers to the US and its residents. That's my point; shouldn't "Americans" also be understood in context that way?)

>but it still feels a bit condescending, like we're not even allowed to have a unique name anymore or even have a say in we should call ourselves/be called in our native language (and it doesn't help that the only time I hear "US Americans" is when someone is talking shit about us)

Correct; those who use it think that they are making a sly subtle dig against the warmongering imperialistic USAmericans.

[CountSessine]

You really think that owner operators repair their own trucks? That doesn't make any economic sense. This is not a hobby, they need to drive to make money not to play truck repairman.

I've known several owner-operators, friends of family mostly, and yes, they routinely strip and repair their own kit. It's a lot cheaper and very often faster than taking it into a shop.

I'm always astonished how US Americans try to justify poor engineering with...

O_o

[sumtechguy]

Simplicity also means less time in the shop when needed too, they usually charge by the hour. Also in the 80s I could totally see that. On the side of the road, hood up fix it right there. Remember they probably had CB radio which is limited range, no phone and the closest town is 50 miles behind you.

Also depending on the job it can make very good economic sense to DIY. My brother in law just had to fix something on his car. They quoted him 2500. He fixed it himself for about the cost of some used parts (80 bucks) and a half day of his time. Trucks are no different.

[serial_dev]

I don't think your argument and analogy makes sense. Simplicity is not only valuable when an owner himself needs to repair the truck.

It's valuable when your truck breaks down in a middle of nowhere, and the closest official repair shop is hundreds of miles away, whereas there might be an "okay" level independent mechanic every 20 miles or less (the actual distance is not the point, the point is that an "okay" mechanic will be probably 10-50x more common).

Simplicity is also valuable with missing parts. Sure, the sophisticated solution is better in terms of performance, electronics, and whatnot, but it might take weeks to receive a part (even before COVID), because the shop doesn't have it and have to be ordered from China. Compare this with simple parts that you can again find in many old trucks and even smaller towns, making it much easier to replace.

Just to put it in coding analogy: if my business needs a website, or a landing page, I'm not going to hire a team of former Googlers and ask them to write a performant backend framework in Rust and invent a new frontend framework. I'm going to ask my uncle who is a hobby designer and can set me up a static site/WordPress in a day. I'm not trying to "justify poor engineering", I just prefer simplicity and the "poor engineering" approach gets my problem solved in one tenth of the time. Who is doing poor engineering now?

Also, coming back to the trucks. There don't need to be poor engineering from either side. Maybe the different requirements just caused trucks evolve in different directions?

[iypx]

> You really think that owner operators repair their own trucks? That doesn't make any economic sense. This is not a hobby, they need to drive to make money not to play truck repairman.

Oh yes! I have seen this unfold once in front of my own eyes, a real spectacle. Driver working for a driver company servicing a distribution company, tries to start the truck, something wrong with brakes, truck is driveable though, gets off, calls boss (company policy). One hour late boss finally arrives, gets in, unhooks trailer, parks the truck three meters to the side, gives the driver a different truck to take. 1 hour more paperwork to process, the trailer finally leaves the distribution warehouse 2.5 hours late. The driver company is apparently paying both late fees and parking fees to logistics company while this ordeal unfolds..

~4AM (5 hours later) a truck fixing mini-buss from a 3rd party truck fixing company arrives with two technicians. They plug into the truck, their diagnostics software shows nothing wrong, they leave.

Next day a different truck fixing company shows up and finally tows the truck after dancing around it for almost two hours with diagnostics software.

Quite a few thousands of pounds burned in just two days of people following rules and policies...

This is apparently "normal", this makes much "economic sense".

[lotsofpulp]

There are many areas of the US where a truck driver might find themself hours away from a mechanic or tow truck. I assume there is some value in fixability, assuming the reliability is not too much less than a less fixable truck.

[BenjiWiebe]

Yep, owner operators repair their own trucks. Sometimes even fairly major engine work.

However, you can have well-engineered simplicity, too, and that seems to be rare. (As opposed to poorly engineered simplicity or highly engineered complexity.)

[nemo44x]

You don’t know what you’re talking about. 99% of the ride is on interstates. Much of that remote for that type of rig.

It’s the same reason Jeep’s use very simple mechanics. You can repair them yourself and carry appropriate spare parts.

[stevehawk]

Do they want to spend their time doing it? No. Do they have a choice in most of the country? No. Trucks don't conveniently break down at the mechanic's shop.

[iSnow]

That's not something a German engineer will easily understand, though :)

[throwaway0a5e]

It's really easy to spin a naive fanboy (of a particular brand, technology or otherwise) narrative like this and when you aim your tropes ("ze backwards yankees") right at audience's bias you're sure to get a bunch of virtue points in response.

The fact of the matter is that there's very, very, few secrets in the automotive and heavy equipment industries. If someone is or isn't doing something it's because they've run the numbers and they don't think it pencils out for what they build and who they sell to.

[reaperducer]

It's really easy to spin a naive fanboy narrative like this and when you aim your tropes right at audience's bias you're sure to get a bunch of virtue points in response.

That's one of the big problems with internet blogs. They do a bunch of Googling and speculation and that's it. Laughably, they sometimes they even call themselves "journalists."

How hard would it have been to go to a truck stop and sit at the counter and ask some truckers? They know all about trucks. And after being along all day, truckers love to talk.

If you're afraid of people, get a $10 CB radio from Goodwill and talk to them on the radio.

[renewiltord]

Yeah, but those people are perhaps the worst to get insight on the industry from. For instance, most truck drivers in the US haven't driven a Scania truck (and flipped for the EU). They can't give you comparative information, so everyone's natural tendency to defend their choice will give you a bunch of rationalizations that you can falsely assume to be reasons.

It's the same as how you could ask people why SF doesn't have gigabit fiber Internet for $60 when Bucharest does for $30, and people on the Internet will make up all sorts of reasons. However, SF does have gigabit fiber Internet. Explaining is easy. Truth-seeking is hard.

[brudgers]

Historically, Freightliner’s reputation was for driving fast…and you would be prudent to get out of the way when one was coming into the mirrors.

Speed perhaps explains the lack of power steering. In multiple ways.

[potamic]

What does speed have to do with power steering?

[EricE]

Extra crap = extra weight. Extra crap = extra complexity = extra maintenance costs. "Sophistication" does not always equal better!

More macho - what a laugh! Keep it stupid simple.

[gambiting]

But also extra effort from the driver = more tired driver, higher chance of accident, more mistakes and issues with every delivery.

I have not driven a truck like that personally, but I know what sort of difference all the modern assistance systems have done on my cross-continental drives. Previously a 12 hour drive would leave me absolutely exhausted, like I'd need a full day to recover after that - in a modern car with lane assist and adaptive cruise and comfortable seats and what not - I arrive relaxed every time. Long dull stretches of road don't take such a mental toll anymore.

I imagine the exact same principle applies to trucks.

[PaulDavisThe1st]

In my 30s and 40's I could drive 14-16hrs a day without a problem, in a stick-shift car, in the USA. In my 50s, 10hrs is still reasonably OK.

However, a 4 or 5 hour drive on roads in the UK in an automatic modern car and I am completely exhausted.

At least for some of us, the road conditions are a far larger impact than the features of the vehicle.

[davidw]

Absolutely! We visited family in Italy last summer, and had an all-day drive. Just constant attention and input, compared to cruising along some 2 lane road in the US. Cars coming up behind you, whizzing by you. A slow old car up ahead. Big truck to pass. Tight curve. Road narrows. Road widens. Some dude in a BMW riding your bumper. For like 8 hours... I was so glad to get out of the car. If it hadn't been for the pandemic, I would have much rather taken a train and relaxed.

[gambiting]

Yeah....that 12 hour drive I mentioned includes driving across the entire width of Germany and jesus it is stressful. Yes, the unlimited sections are "fun" and it's really cool to be able to drive at 150mph+ for a while when the conditions allow, but it also means you need to be on like 10x the alertness level as normal. Like really really really pay attention a lot at all times. It can be super harsh. But the last few times I'd just set the cruise control to something more sensible and just relax, with the modern systems the car basically drives itself.