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Internal Combustion Engine

ciechanow.ski

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Re: Internal Combustion Engine

#141

Post by jandrese »

londons_explore wrote: post #62
kirse wrote: post #37

Earlier quoted context omitted.

Pure EVs will reach a fundamental peak percentage similar to any other car class... Hybrid powertrains are really where the next 20-30 years are headed for the bulk of vehicles. Automotive racing and supercars have demonstrated hybrids are the most effective setup for the past decade, and barring some major breakthrough in battery tech that will all trickle down into consumer cars over the next 0-20 years.

As soon as governments get serious about CO2 emissions, Hybrid powertrains will end up as a "worst of both worlds" position. Already across most of Europe all subsidies and discounts that applied for "eco friendly cars" no longer apply to Hybrids. That leaves few people wanting to buy a hybrid - it won't be cheapest or most eco friendly.

I think the thinking on hybrids will shift from "smaller gas engine with an electric boost to help with merging on the highway" to "range extension option for the electric car." They'll be configured to not even fire up the gas engine until the battery pack is run down enough.

Re: Internal Combustion Engine

#142

Post by opwieurposiu »

toxik wrote: post #132
keanebean86 wrote: post #127

Earlier quoted context omitted.

What I want to try is replacing valves with electric iris mechanisms. The computer would signal the iris to open or close depending on the situation. No more complicated variable valve stuff. Just hold the iris open longer. Also no more interference engines and timing chain/belt changes. Iris: https://commons.m.wikimedia.org/wiki/File:Iris_Diaphragm.gif Edit: fixed typo, added link to iris gif

It’s a good question, why is only fuel injection and ignition computer controlled? The intake and exhaust valves must also be solenoid controllable.

This exists, but it is very expensive. https://www.freevalve.com/freevalve-technology/

Re: Internal Combustion Engine

#143

Post by snazz »

tmh88j wrote: post #98
londons_explore wrote: post #62

Earlier quoted context omitted.

As soon as governments get serious about CO2 emissions, Hybrid powertrains will end up as a "worst of both worlds" position. Already across most of Europe all subsidies and discounts that applied for "eco friendly cars" no longer apply to Hybrids. That leaves few people wanting to buy a hybrid - it won't be cheapest or most eco friendly.

Not sure I agree with that. I don't think you realize how many cars have switched over to hybrid powertrains, but are not advertised as a main selling point like the Prius or Volt. Volvo's entire lineup is now hybrid or electric along with their new performance brand Polestar. Mercedes is switching over to hybrid powertrains even on their AMG models. Audi's using hybrid powertrains even on their highest performance m…

It definitely feels like you get some free low end torque in a hybrid as well.

Re: Internal Combustion Engine

#144

Post by LeonM »

toxik wrote: post #132
keanebean86 wrote: post #127

Earlier quoted context omitted.

What I want to try is replacing valves with electric iris mechanisms. The computer would signal the iris to open or close depending on the situation. No more complicated variable valve stuff. Just hold the iris open longer. Also no more interference engines and timing chain/belt changes. Iris: https://commons.m.wikimedia.org/wiki/File:Iris_Diaphragm.gif Edit: fixed typo, added link to iris gif

It’s a good question, why is only fuel injection and ignition computer controlled? The intake and exhaust valves must also be solenoid controllable.

Swedish hypercar builder Koenigsegg has made a system like this, they call it FreeValve.

Their upcoming car called the Gemera will feature FreeValve, its 2.0L 4-cylinder is said to generate over 600HP. Though it must be said that this is a 1.5 million dollar car, so don't expect this kind of performance per displacement from other brands.

A guy on Youtube made his own version of freevalve, and got it to work on a Mazda Miata: https://www.youtube.com/watch?v=E9KJ_f7REGw

Re: Internal Combustion Engine

#145

Post by jacobsenscott »

swiley wrote: post #21
specialp wrote: post #15

I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive. Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of in…

I've always felt cars were like computers; most people (me included) pay a premium for something mediocre because they don't want to bother understanding it. My personal solution is to live near the metro and bike as much as possible.

Mediocre in what way? Buy almost any new car from a well known brand today and it will run for 200,000+ miles. You almost need to deliberately buy a mediocre car. Biking and taking the metro is better for the environment, your health, and your budget though. If you are fortunate enough to have that option.

Re: Internal Combustion Engine

#146

Post by Ambroos »

pram wrote: post #22
specialp wrote: post #15

I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive. Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of in…

I think automatic transmissions are more impressive looking than engines when they're open. They resemble EV motors too!

VW group has a dual-clutch automatic transmission that includes an EV motor for their plug-in hybrids, the DQ400E. It looks pretty cool indeed!

Re: Internal Combustion Engine

#147

Post by czinck »

elihu wrote: post #121
esaym wrote: post #93

Earlier quoted context omitted.

> EVs don't need a catalytic converter, so that's a big thing in their favor. I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, an…

I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health. The main greenhouse gas from a car is carbon dioxide. The amount you create is directly proportional to the amount of fuel you burn. I don't know why modern cats are expensive; it might have to do with the price of platinum, palladium, and so on, and the relative amount of t…

> I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health.

I thought the same thing, but interestingly that's only kinda true. If anything, cats increase CO_2 as a desired end goal, because it's better to have CO_2 than CO or NO_x (or so the EPA has decided, I am no where near qualified to decide that). The issue with running too lean is that the reactions in the cat would rather use plain O_2 than NO_x, and so if you have too much O_2 (lean) you won't get rid of any of the NO_x [0]. Before looking into this I thought lean engines produced more NO_x because of higher cylinder temps or something like that (which might be true as well).

Cats not reducing NO_x when lean is essentially why Volkswagen (and practically every other manufacturer has been caught doing similar things to diesel engines) was cheating the test. Diesels have no throttle so they are (almost) always lean, typically very lean.

This does make me wonder, though, does running lean actually increase fuel efficiency? Obviously rich lowers fuel economy because not all the fuel burns, but assuming it all burns what does it matter if you have 1 gram of fuel to 15 grams of air in the cylinder, or 1 gram of fuel to 18 grams of air in the cylinder? You'll still get the same amount of energy, right?

[0] https://en.wikipedia.org/wiki/Catalytic_converter#Three-way

Re: Internal Combustion Engine

#149

Post by golemiprague »

toxik wrote: post #132
keanebean86 wrote: post #127

Earlier quoted context omitted.

What I want to try is replacing valves with electric iris mechanisms. The computer would signal the iris to open or close depending on the situation. No more complicated variable valve stuff. Just hold the iris open longer. Also no more interference engines and timing chain/belt changes. Iris: https://commons.m.wikimedia.org/wiki/File:Iris_Diaphragm.gif Edit: fixed typo, added link to iris gif

It’s a good question, why is only fuel injection and ignition computer controlled? The intake and exhaust valves must also be solenoid controllable.

Because of reliability and the potential damage, not injecting fuel is not such a big deal but a stucked valve can cause serious damage with all the pressure inside the cylinder. There are some cars now with no camshaft, but they are very high end experimental sport cars like Koenigsegg
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