In 1976 Mechanical Engineering magazine, the official publication of the ASME (American Society of Mechnical Engineers) had an article on what would succeed the nearly “obsolete” piston Otto engine. Gas turbines, stirling engines, opposed free piston engines, etc. were proposed to succeed the Otto engine by 1990 latest.
As Mark Twain once said: “The rumors of my death are greatly exaggerated!”
What side of the road we drive on goes back to antiquity. It starts with the fact that most people (warriors) are right-handed. When riding a horse or on foot the ability to pull one’s sword with the right hand and then stab an enemy made traffic keep left; carts followed the horsemen, and the Romans established driving on the LEFT side for all of Europe.
There are a number of quarries in England where stone was quarried for buildings. The tracks into the quarries are shallow and on the left, while the tracks out of the quarries with loaded wagons are much deeper.
Under the Roman Empire traffic moved on the left. Why then did Europe, except for England move to the right. You can thank Napoleon for that. He was a product of the French revolution and also left handed. Since he upset the social order in Europe by introducing the metric system and other revoutionary things, he also moved traffic to the right which suited his left-handedness.
During the age of colonization, the British probably made all traffic move on the left. If you visit the countries that were British colonies, allmost all keep left. Thailand was never colonized, but they admired all things British, rather than French and kept left. Same for Japan.
In colonial America everyone probably kept left; how US trafiic moved to the right could be expained by Karl Sieger Conestoga Wagon theory or that Americans had a lot more admiration for the French than the British in the post revolutionary period, and being revolutionaries themselves, like the French wanted to drive their carts on the other side of the road.
All countries originally colonized by non-British, drive on the right side.
Canada is a bit of an oddball; an ex-British colony that drives on the right. This is probably because the US industrialized much earlier than Canada, and when the time came to decide, it made sense to drive on the right.
I welcome other posts on this topic, since it still leaves some questions unanswered.
Well, Docnick, as usual you’ve put thngs in a good space-time nutshell. I might go back to before there were warriors on horseback. I’m assuming even cave men were predominantly right handed, so as they walked down the path, and later; the road; they walked on the left, because when two people came upon each other they grabbed each other’s right hand in a kind of “balance of power”. I understand this is where the
handshake comes from. I heard a joke once about a human; who; by accident; runs into a Martian and instinctively shakes hands with him/her…
I was wondering after reading some of the above posts: 1. What percentage of modern engines use even versus uneven firing intervals? 2. Are there charts to check what firing interval a given engine has? I personally like the uneven rhythm of the 60 degree, I think it is, Harley V-Twin.
You guys are all trying too hard to simplify this. To fill out even more 2008 new straight six engines, Suzuki (Daewoo) Verona and it is transverse. The GM engine is shared by Envoy/TrailBlazer/Bravada/Rainier/Saab97x/Isuzu Ascender. Dodge Cummins TurboDiesel. Lexus had some until only a couple years ago. Jeep too. VW/AudiQ7 VR6 is also interesting. It is a V but only 15 degrees between banks and it has only one cylinder head not 2. Two more factors not quite mentioned yet why fewer straight sixes now – V6 engines more likely to be able to share architecture with other engine layouts by same manufacturer and be usable in more different vehicle platforms across the model line. Long narrow engine mounted lengthwise is hard to design collision safety around (note Volvo being transverse).
Yeah we’ve gotta give old Nick Otto credit. While other designers were using the downward motion of the piston to suck in the charge, which then ignited with the piston halfway down; (early 2 stroke; poor efficiency); and others were going with one stroke designs, he pioneered the 4 stroke, whose efficiency was deceptive to say the least, what with the intake stroke taking in more charge than his competitors; and the compression stroke pre-heating the charge. People were flabergasted when they witnesssed the results.
Of all the engines you have listed, the only engine that does not have an even firing order is the V6, all others do. It is not balance that makes the I6 or V12 so smooth. The reason they are the smoothest configurations is because the cosine of 60? is .5.
What that translates to is that 60? either side of the peak power point represents the half power point of a sine wave. In the power generation business, all power generators are three phase, as are all high powered electric motors. As one phase drops off to its half power point, the next phase is rising to its half power point. Where the two phases cross, the two half powers added together match the peak power. The power band is not perfectly flat, but it is flatter than any other number of phases except for multiples of three.
In a four cycle engine, you need six cylinders to match this because you only fire on every other revolution. So while a four cylinder fires every 180? BTW thats 0?, 180?, 0?, 180? and not 0, 180, 180, 0, the power drops to zero from each phase before the next phase starts its power stroke. In a V8, the power cross over occurs when the decreasing phase and increasing phase are at 45? resulting in a peak at this point of about 1.4 times the peak of an individual power stroke.
One more thing, an I6 is not necessarily more expensive to build than a V6. In an OHC configuration, it would only need one head and one (pair of) cam(s). For manufacturing, the process of building an inline engine is always much simpler. Its primary disadvantages are length and marketing resistance. The V6 sounds more modern. The inline 6 is generally perceived to be a dated design.
Also note that BMW’s inline sixes are installed at a slant to clear their low hoods. They just don’t CALL them slant sixes as that would harken to an earlier age when Chryco used that name.
Inline 6 is inherently in ballance while a V6 has several periods of vibration that can not be totally eliminated.
V6 is cheaper to cast as the shape is more compact, cheaper to build since the crank and cam are 1/2 as long
and only uses 4 main bearings instead of 7 of most modern inline 6 engines.
I realize that in most cases, 2 heads are better than one. However, when designing and costing an engine, having 2 heads with all the accompanying stuff, is definetely more expensive. However, as all other poster have pointed out, the packaging of the modern car requires a compact engine, and the V6 makes the most sense.
A v shaped engine is more expensive to cast, especially an Aluminum block engine. It is also more difficult to insert cylinder liners and pistons. The parts count is lower with the inline engine and you don’t need 7 main bearings, many I6 engines have gotten by with only 4.
That would be the aforementioned 4.2L I6 Atlas.
Well I think my question has been answered : )
I was told that Datsun bought the tooling for the 240Z engine from Mercedes.
All Straight 6 engines I’ve been associated with have been excellent. I ran F150’s for year with 300 straight 6’s in them. The 300 6 didn’t have the horsepower of a 302 V8, but it would out torque a 302 any day of the week. I don’t doubt there’s 300 6cyl Fords running around with better than half a million hard miles on them. You can’t hardly kill one of those engines. To give you an idea how tough they are, I was changing a water pump on one when I lived in Knoxville and the parts house (Ford Dealer in Alcoa) didn’t tell me it didn’t come with a gasket, I assumed it was in the box. I had the pump off and was ready to install the new one before I found that out. I actually Drove that truck with no water pump even on the engine to Alcoa and back to get the gasket. Yes, I stopped 3 times and let it cool a little, but were talking about a 15 mile run at least with no water pump in it. I didn’t have a minutes trouble from that. That same truck had been a rebuilt total when I bought it and the front brackets for the ac/alternator/etc were welded to the block because the bolts had been jerked out in the wreck ruining the block. We just welded the brackets on the block, and drove on. If a person actually took care of one of those engines instead of abused it the way 99% of them are, they’d probably run a million miles.
Chevy’s 250 I-6 was another fairly trouble free engine. I assume the I-6 they re using in Trailblazers now is a modernized version of it and Jeep’s 4.0 I-6 is a pretty rugged dependable trouble free engine.
I believe Jeep went to a v6
Here’s one more transverse six.
Yes, the Atlas I6 is rock solid…with the exception of the afterthought EGR setup. The EGR valves are prone to failure. Sound familiar? At least they’re < $100 and seem to last around 50k miles before they seize up entirely.
Your bank angle synopsis is not correct. The optimum bank angle depends on the crankshaft and if the engine is even or odd firing. 60 deg is generally the best angle to use, but not for the reasons you describe.
There are both even fire and odd firing V6s. V6?s based on V8s are typically odd firing, have 90deg bank angles, and use a 3-throw crank shaft.
Most modern v6s are even firing and use a 6-throw crankshaft to permit even firing.
What is the displacement on the Honda? I seem to recall I6’s at about 250 cc and I5s at 125 cc in their racing line.