Slashdot Mirror
Electronic Valves For Diesel Engines
Anonymous Coward writes: "EETimes describes how electronic valves will replace camshafts in diesel engines starting in 2007. Lower emissions, better performance should follow." This wouldn't be a bad idea in gas engines, either. There's potential here for low emissions, better gas mileage, and greater performance, all at the same time.
"...electronic control will enable engines to change valve timing on the fly..."
Why, it's a run time optimizing just in time combustor!
Subject says all ; their prototype "camless" engine is already running. Basically, they use electric actuators instead of the usual cams. And since the engine's electronic already handles fuel injection and air intake... it's just one more parameter.
Camless engines are routinely used in economy races such as the Shell marathon (run as long as you can, with a single litre of gasoline)...
What's going to really rock is HDi (or GDi) + Camless + alternatmotor (basically, you replace the smaller alternator + starter combination by a bigger dual-use electric engine/alternator, which allows to give the thermic motor a boost when accelerating, allows stop-and-go when you're stuck on the Périph's monster traffic jams (zero emission, then, and zero noise). Unfortunately, that means switching the car's electric circuit to 48V at least).
And that's going to be much sooner than 2007 !
(Besides, Diesel in HDi + Anti-Particle Filter is much more efficient than classic unleaded ; Diesel is easier to refine, and gives a little more energy per mass unit. And direct injection gives the level of control necessary. See whan Peugeot does with Bosch injectors, it's just really amazing).
> you now have to worry about the engine itself
:-)
> crashing
Technically, you have to worry about that now. Damn near ever single car manufactured in the last decade has electronic fuel injection and spark control. Embedded microcontrollers take into account their increasingly important role in the overall system when designed. They're written to *not* "crash".
> but the crankshaft works so well
Actually, nobody wants to replace the crankshaft, just the camshafts. The problem with a typical camshaft design is that it fixes the cars valve operation profile throughout the entire RPM band. That's extremely inefficient. A standard 16-valve engine running at 7000 RPMs requires a dramatically different camshaft profile than one running at, say, 1500 RPM for maximum efficiency and power. By making valves electronically actuated, you allow the ECU to adjust *everything* automatically for peak operation. Sounds good to me, I just don't wanna be the one to mess up that tight timing code...one good bug would cost a company millions in new motor replacements.
Thomas Dorris
I have a silver-blue 1966 Ford Mustang coupe complete with a V8, dual exhausts, and a Pony Interior. My dad and I restored it ourselves when I was in high school. It's in great condition and I can safely say that it is the best looking hard-top Mustang I have ever seen anywhere.
I love my car dearly. But as much as I love it, we are going to have to get rid of it soon because having a car like that just isn't practical. Sure you can fix it yourself, and the abundance of reproduction parts means that you never have to go through dealers. So it seems that you can save a lot of money this way, right? Wrong. I have never heard of someone being able to save money by driving a vintage car. They are mechanically simple (you can open the hood and see through to the ground), but a consequence of that is that they are VERY POORLY ENGINEERED. If you have options like power steering and an automatic transmission, you'd better be ready to spend a lot of time lying on the garage floor with a wrench in your hand. Any money you save on labor and parts you turn around and spend on more tools and stuff.
Someone said once that Linux is only free if your time is worthless. You can say the same thing about DIY auto repair. If you work for X dollars per hour, then DIY repair only makes sense if you earn less than the mechanic charges for labor.
We're probably going to replace the Mustang with a Japanese car, like a Toyota. We have had several rice-burners over the years, and we don't even care that we can't fix them ourselves because they simply never need to be repaired. They were built right from the beginning, so they run forever on nothing but gasoline and regularly scheduled maintenance. We've never had any weird problems with any of the Toyotas we've had, and we put almost 200,000 miles on one of them.
Oh yeah, did I mention that they get over twice the gas mileage of the Mustang? They don't require the expensive 93 Octane gas either.
In short, simplicity isn't a virtue when it comes at the expense of functionality and reliability. Furthermore, something as incomprehensibly complex as a modern automobile doesn't have to be unreliable, provided that it was done right from the beginning.
The complexity of cars will continue to increase dramatically. Gas in South Carolina has doubled in price in two years, and if this continues, people will simply need the fuel efficiency.
Oh well -- I don't have time to finish, but I hope I've said enough so that my point makes sense.
Gotta run,
Steve
========
Stephen C. VanDahm
The idea is quite old now and I actually saw a working system demonstrated at Lotus a good few years before Colin Chapman died. It was used to help design camshaft profiles. You could even use a 'light pen' to pull the curve as the engine operated in real time.
BTW it definitely was electrohydraulic.
The patents system is sick, it really needs a overhaul. Here is a system that could have been implemented years ago and saved millions of gallons of fossil fuels from being wasted. What are future generations to think of us.
threadeds blog
...major improvements in electric engines.
One of the big bitches of electric cars is (besides battery life) the poor power/weight ratio of the electric engine against the gas (petrol) engine. Also, even more damning, is the relative reliability of the gas engine. What we really need are people putting alot more effort into making a better, lightweight electric engine.
We already have the parts to build a really good hybrid gas/electric car (which, face it folks, is the only kind of low-emissions vehicle you will see for years). We have the following parts:
The Honda Inspire and the coming competition from Nissan and Toyota are OK, but face it, we need something about the size of a Honda Accord, not a Honda Civic CRX. I can't see any reason (technically) right now why someone doesn't mass-produce a converted Accord. I mean, you can use the exact same design (maybe cheat and use alluminium body panels), just with a new powertrain (with an electric engine, you should probably have a continuously variable transmission, rather than an "automatic", and definately not a "standard") and still get at least 70+ miles/gallon (that is, 30km/l).
Hell, with the $4k US tax credit for buying a low-emission vehicle, and gas here at $1.85 in the Bay Area, I'd spend $5k more for a converted Accord over a normal one, and still make out like a bandit. So who're the morons in the Marketing Depts at the car manufacturers?
-Erik
There are always four sides to every story: your side, their side, the truth, and what really happened.
Diesels ain't that great at -40F anyways. You generally need to keep the block warm, either with a heater in the block or by leaving them running.
So, if the block is already being kept warm, getting the electronics up to a working temperature shouldn't be that difficult.
The problem is what's called i-squared-r: since every wire has a non-zero resistance R, the wire burns off an mount of power proportional to the square of the current in the wire. To deliver the same amount of power to a load, for every doubling of voltage, you halve the current: this is why we have high-tension lines: to deliver a thousand megawatts of power to a city at 100kV takes one thousanth the current that 100V would, so you get one millionth the losses in the wire.
Now, in automotive use, 12V is really a pain: consider a laptop computer drawing 52 watts of power. At the nominal engine running voltage of 14 volts, you need 4 amps of current to get 52 watts. If your connection to the car's electrical bus has one ohm of resistance (lighter sockets are a lousy interface), you burn off 4 watts of power in the connection (actually, a bit more, since you lose 4 volts across the drop, and now your laptop power supply is trying to get 4.5A to make up for the difference).
Now, you start getting into steer by wire, electronic valve actuation, ThunderThump 2000 Stereos, maximum-legal output ham radio systems, cell phones, computers, TVs, VCRs, and all of the other things that we are cramming into cars these days, and you are pulling about 2-3kW of power. At 12 volts, this is about 200-300 amps of current. At 42 Volts (three times the nominal run voltage of 14 V), you drop that down to 66-100 amps.
Of course, you have all the infrastructure of 12V lights and gizmos, all of which have to be replaced. So it isn't going to happen anytime soon.
www.eFax.com are spammers