61–70 of 112 posts
I still remember the first time I tore down a pushrod V8. I decided it had to be close to the pinnacle of elegant design. Nothing wasted, everything had a purpose, and it all came together in a perfect mechanical symphony. We have since made engines which are significantly more efficient and powerful, but all of that at the cost of elegance, slapping on overhead cams and machinery just to adjust the valve timing, etc…
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It's 0.0015, that's 1.5 to 2.5 thousandths, or 15-25 "tenths" as they're called. That's not a particularly tiny gap in the machinist world, it's large so that you can pump viscous oil in it and deal with a wide variety of temperature changes. 25 thousandths would be sloppy, a nominal clearance hole for a 1/4x20 bolt is about that much.
> 25 thousandths would be sloppy, a nominal clearance hole for a 1/4x20 bolt is about that much. Isn't that 0.250 which would be 250 thousandths?
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Probably better for the environment too.
The carbon footprint of producing an EV is higher than an ICE. Nobody disputes that. But the lower carbon footprint of operating the an EV makes the EV have a lower footprint over the life of the vehicle. This is true even if your electricity comes purely from coal, as a coal power plant gets an economy of scale that an ICE doesn't achieve. If your power comes from a renewable source, then the trade-off happens even…
This is a stupid question but I'm a stupid EE/SWE who knows very little about physical objects. In the all these animations of the pistons I see linear motion translated into rotary motion using the crank shaft - but how do you design the pison/crank to always turn clockwise or counter clockwise (based on how you view it, obviously)? Is it possible for the crank shaft to lock up if it's perfectly oriented at 0 degree…
Worth noting the design of the internal combustion engine hasn't changed much in 50 years. The thing that has changed is the control systems. What used to be a primitive mechanical way of mixing fuel and air (the carburettor), is now an electronic fuel injection system, with the fuel air ratio very carefully matched to reduce pollution (fun fact: modern cars release so little carbon monoxide, you won't kill yourself…
Given to how precise these need to be these days, I would've guessed they would've switched to electronically actuated valves.
An instagram filled with beautiful landscape photographs, an "X" page consisting only of links back to this blog, and a Patreon with hardly any more information that that.
I love this. Fantastic content. Zero ego. And if there was any AI use, it's invisible. Certainly there is none in the writing.
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Auto start/stop isn't off for enough time for the oil to drain from the galleries and especially not out of the bearing journals. It's the first few seconds after an engine has been off for hours (or worse, for potentially years) that are the problem.
I thought it pretty well established that auto on/off is bad for the engine, as is intermittently turning off some cylinders as some do. Is that wrong?
This paper seems to say that generally they aren’t a problem. I’ve only seen unsubstantiated claims that they are one.
Worth noting the design of the internal combustion engine hasn't changed much in 50 years. The thing that has changed is the control systems. What used to be a primitive mechanical way of mixing fuel and air (the carburettor), is now an electronic fuel injection system, with the fuel air ratio very carefully matched to reduce pollution (fun fact: modern cars release so little carbon monoxide, you won't kill yourself…
What I am surprised by is that cams are still used to operate the valves. Given to how precise these need to be these days, I would've guessed they would've switched to electronically actuated valves.
Worth noting the design of the internal combustion engine hasn't changed much in 50 years. The thing that has changed is the control systems. What used to be a primitive mechanical way of mixing fuel and air (the carburettor), is now an electronic fuel injection system, with the fuel air ratio very carefully matched to reduce pollution (fun fact: modern cars release so little carbon monoxide, you won't kill yourself…
What I am surprised by is that cams are still used to operate the valves. Given to how precise these need to be these days, I would've guessed they would've switched to electronically actuated valves.
And here's an example of someone that retrofitted a Miata to use a similar [air-actuated valve system](https://youtu.be/E9KJ_f7REGw)
Thank you!