[jacquesm]

A gasoline based ICE is so incredibly inefficient it needs to shed heat or it would melt down. It makes more heat than that it makes motive power (the thing it is designed to do...). A 50 KW engine makes 200 KW(!!) of heat (at full throttle). Most of that heat energy exits the system through the exhaust gases but there is plenty that gets stuck in the body of the engine and you need to remove it from there somehow before it causes damage. That's where your cooling system comes in, a coolant (typically: water or glycol or a mixture) passes through its own channels in the engine around the thermally loaded parts such as the cylinder and head walls to remove the heat. This coolant is pumped around in the engine using the coolant pump to a radiator, usually located at the front of the car in the airstream to help reject the heat to the environment. The interior heater of a car basically just re-routes a bit of that heat in the cooling system into the cabin through a miniature radiator with a fan connected to it that doesn't vent into the environment but into the cabin.

So there is plenty of waste heat to go around. Some diesels got so efficient though that they needed an extra in-line heater to have enough heat for the cabin in specific operating domains (low power engine, low revs).

It is effectively co-generation: you get two different kinds of energy (motive and heat) and you use them for different purposes.

[dmix]

I always wonder how you know so much about so many topics to make quality comments on a wide variety of topics on HN. Truly a jack of all trades.

Maybe it's like how I spend so much time reading random Wikipedia articles on topics because I need to know how everything works.

[jacquesm]

Hm... too many projects :)

And that list is only getting longer, I think I'll pass it on to my kids.

Right now (and for the past couple of years) it has been mostly music but also still some more interesting tools to play with. Currently making a set of super realistic traffic lights for my youngest including pedestrian crossing and automatic cycle influencing (road coil pickup to detect car presence in front of the lights) for his model cars. Green wave, the works.

I've mostly stopped writing up the projects, but still have a bunch of posts pickled that I probably should finish. Most recent software bit: ear training module for pianojacq.com is work in progress (press low 'A' on an 88 key keyboard to enable the secret menu that will enable the ear trainer, it is not quite ready for mass consumption yet but it is getting there).

[rebuilder]

Even more off-topic, but something I’m struggling with personally: how do you find the time for projects, with kids in the picture? Me, I can just barely eke out a truncated workday, then it’s kids and housework until the kids go to sleep and maybe 1.5 hours of time until bed, which mostly I spend with my partner.

So I see people with diverse interests and kids and I just wonder: how!

[jacquesm]

Hm, that's a hard one. I try to involve my kids in them, this doesn't always work, but when it does it is fantastic.

I'm also an insomniac (it's 7:20 am here and I'm still awake...) so I have a ton of time when everybody is asleep (that's when I do most of my coding and reading), and when everybody is off to school I catch up on sleep. Not ideal but it mostly works. Another nice-to-have is that I can make ends meet with a relatively small fraction of the year spent on work (and that simply means I'm not reducing my savings, if I want to grow my savings I'd have to work more than that).

[Shocka1]

Yup, the trick with kids is simply staying up later. I usually do a couple 2 to 4am nights for freelance work, then do an early bed night, then repeat. Waking up at 7 to take the kids to school is a little rough, but a stop at the coffee shops always fixes that.

[dmix]

Oh cool, not to further derail this thread but the music direction is interesting. I've also just gotten (back) into music production using an MPC One+ and I used https://www.audiblegenius.com/ for music theory+ear training. A frequent theme I've noticed in Youtube tutorials is a ton of >35 software engineers mentioning they are getting into music and feeling the need to say how old they are, as I guess the meme is learning music is for naive 20yr olds.

[jacquesm]

For me it was COVID that drove me back to music, I had a ton of time on my hands and we'd just bought an old (and really crappy) piano so I decided to get more serious about it. Long way to go though before I'll be satisfied with it, and I doubt I ever will be. Not giving up, it is just too much fun.

Thank you for that link!

[jacquesm]

So, you're officially an influencer now, I bought the course. Very high quality material, a ton of work must have gone into that. I hope to get my own stuff up to that level of polish, it certainly sets an example.

[sbierwagen]

>Some diesels got so efficient though that they needed an extra in-line heater to have enough heat for the cabin in specific operating domains

I live on the top of a hill, so the first seven minutes or so of me driving anywhere is coasting at minimum engine power. Once air temp gets below 10C it's a long, slow painful wait for the vents to start blowing warm air. Especially unfortunate when you're waiting for the defroster to start doing something. I've considered installing a block heater, even though it wouldn't be needed to start the engine at all, just to warm the coolant up!

[jacquesm]

Such a slow warmup is probably also bad for your engine (the oil will be super hard to pump around so you'll have very little lubrication and very high oil pressure until it warms up a bit) so that block heater may well be useful in more ways than one.

You may want to look into oil that flows better at low temps in winter based on what temperature your engine eventually reaches when it is fully warmed up. There is a good chance that your engine will work better with different oils for winter and summer, also if you have an older car you may get some mileage out of blocking off a piece of the radiator.

[sbierwagen]

It's supposed to run 5W-30 but for the cold months I do 5W-20. After watching the Project Farm metal on metal wear tests of 0W oils, and the fact I'm not running the engine at -20C, I'm not eager to go any lighter: https://www.youtube.com/watch?v=xtSwaF2evTU

[literalAardvark]

Do 0w-30 not Xw-20. The number on the left is cold temperature performance, where cold temperature =not at operating temperature.

The number on the right is in the manual and you only change it when you go to the track.

Atm you're running a lighter oil than your car is designed to use and it's very likely to be a bad idea.

In the video you linked the only oils you can compare in the way he is comparing them are the 0w-20 and the 5w-20.

Later edit: I've watched that and since the tests the oils only at cold temperature it is entirely inconclusive wrt protection at operating temperature.

And cooking test is just dumb. Your oil rarely above operating spec. The only oil exposure to above spec temps is the oil in the top side while the engine is cooking after being stopped, and the oil in the burn chamber which burns and is then filtered out.

If you want to know how your oil is doing collect it after a service interval and send it to be tested.

[jacquesm]

This.

The latter is also useful to check for impending headgasket doom (or cracks) before it is otherwise visible.

[sbierwagen]

Here's the oil analysis from my most recent change: https://bbot.org/etc/oct2022change.png

The cold starts aren't great for driver comfort, but don't seem to have a big effect on engine internals.

[jacquesm]

Definitely go for the 0W-30 if you're doing cold runs even if it isn't at -20C. I use it myself in the winter on an older engine for very similar reasons. That video is ... questionable ....

[Roark66]

Maybe check if your EGR is operating properly? Also the resistance heater if equipped.

Most diesel cars equipped with EGR also detect its (frequent in older cars) failures, but I suppose it's possible to have a fault without it being detected.

EGR is responsible for recirculating exhaust gases back into the intake primarily to increase efficiency, but a nice side effect is that it heats up the engine a lot quicker.

Also, many diesel cars sold around here since 2000 or so are equipped with a resistance heater that kicks in when the engine is cold. Perhaps that's different in other markets.

[almostnormal]

> EGR is responsible for recirculating exhaust gases back into the intake primarily to increase efficiency, but a nice side effect is that it heats up the engine a lot quicker.

Efficiency does not need EGR. EGR only helps to keep NOX down when running efficiently. In some (many) vehicles EGR is disabled at cold temperatures.

[semi-extrinsic]

Better than (or in addition to) a block heater is to have an AC cabin heater. Defa makes some really nice stuff, it's more or less "standard extra equipment" here in Scandinavia.

[queuebert]

I'd like to add that ICEs need to run hot to minimize cylinder wall heat losses and allow more of the explosion to be converted into work instead of heat, although too hot and they break of course. Ideally the engine block would be at the same temperature as the combustion temperature, but we don't have the materials to achieve that yet.

[jacquesm]

There have been some experiments with uncooled diesels that almost made it.

[akira2501]

> It makes more heat than that it makes motive power (the thing it is designed to do...).

Sure.. but try running that same engine when it gets too cold, which is why "block heaters" exist and get used in certain parts of the world. The operating temperature of the engine _is_ part of the design criteria.

[jacquesm]

Absolutely, but to get it there it has to work first or you'll have to pump in heat from some other source. Starting a large diesel in sub-zero temps can be quite challenging.