Wer mal einen etwas detaillierteren Einblick kriegen will , wie bei Harley konstruiert wird (alle anderen können weiterblättern):
Und ewig zieht sich sich wie ein roter Faden das Thema Sumping und Ölpumpe samt Lecköl durch die TC-Konstruktions- und Nachbesserungsgeschichte.Â
Ich bin mal gespannt, wer nach dieser Lektüre immer noch hofft, dass Harley beim M8 die Sache im Griff hat.
Der Verantwortliche bei Harley für dieses Thema war von 1995 - 2005 :
Paul Troxler
https://www.linkedin.com/in/paul-troxler-8185722b/
Wie man sieht, fing er 1995 als Newcomer und Zuständiger für das in der Motorenbranche exotische Thema bei Harley an und hat Harley nach ca 1/3 der Entwicklungszeit des M8(!!!!) verlassen.
https://www.cycleworld.com/harley-davids...istory-big-twin
1996 Test motorcycles run for the first time with the P-22 engine. Piston temperatures are high, requiring oil jets, which in turn push up oil temperature to 260-280F. Original Evo-dimensioned finning was not enough, but the styling department naturally wanted to keep the proven "look." The idea of bigger fins took some digesting, but in the end, Harley-Davidson promotional material says, "Better engine thermal management due to 50 percent more fin area and piston cooling jets." (Engineering Chief Earl Werner said 60 percent!). Conflict between styling and engineering is understandable. Styling seeks to manage how we feel about the product, and engineering manages how it works
In development there were problems with oil return. Many hours of testing were done on a motoring dyno (engine non-firing, turned by an electric motor), using an engine equipped with windows so oil behavior could be seen. Everything was complicated by the whoosh of air from the crankcase as the two pistons headed down. Velocette had a related problem with their 350 single in the 1920s. Oil sent to lube the valve train in the head wasn't returning to the crankcase. Velo's first solution was to place a second small scavenge pump in the head, returning oil directly to the oil tank. Harley gradually figured out the dynamics of how oil and crankcase air were interacting and devised simpler solutions.
1998 In a conversation with a consulting engineer I ran into, he said P-22 needs an oil cooler but styling won't let them have it. Evolution big twins at this point have 280-degree-Fahrenheit oil temp at a steady 60 mph in 110 F air temp. Cylinder head temp at this time (CHT) exceeds 585F (307C). He says he thinks Werner (who had been head of Corvette engineering) was hired as an organizer but keeps pushing tech-y solutions. He is responsible for the new H-D Tech Center. Of the VR1000 road race engine's problems the consultant said, "How about 39g of vibration at the intake manifold?" To him, a 90-degree engine (self-balancing) makes most sense. The new ignitions have flash EPROMs-no more chips. He says Harley-Davidson would have had their EFI two years earlier but they spent the time "looking for a generator that would supply the extra current required." He finds it incredible that Harley-Davidson moved so slowly as compared with the great "ponderous" auto industry.
Now a discovery split the temperature problem in two. If reducing oil temperature to make an oil cooler unnecessary is a paramount goal, engineering saw how to do it; circulate less oil to the engine's hottest parts - the cylinder heads. This solved Styling's problem by making an oil cooler unnecessary, but it also drove cylinder head temperature up, giving engineering enough leverage to get their request for more head and cylinder fin area some consideration. There was plenty of data on hand relating high CHTs to classic air-cooled failure modes such as chronic detonation, exhaust valve and seat burning, and cylinder head warpage. The price of doing away with the oil cooler was the "big-fin engine," and the changes would cost a good deal of money.
1999 The P-22 bears fruit-Twin Cam 88 is produced as 3.750 x 4.000-inch bore and stroke = 88.36 cu.-in. (1450cc). Spring-type cam chain tensioners are good for 30,000 miles, best case. Twin Cam engines have a crank-speed gerotor oil pump driven from the timing end of the crank. Thus excessive crank run-out, if present, can have ill effects on the oil pump. That's why the Harley-Davidson how-to books all have a photo of someone pointing to scores in the gerotor pump housing.
2000 TC88-B, the engine with counter-balancers, is produced. This system adds 14 pounds to engine weight and reduces primary shaking force by 90 percent
To the surprise of engineers, the smoothness of the new counterbalanced engines resulted in some half-shifting of the gearbox (neutral between gears, or "getting air"). Without vibration, there was nothing to overcome the friction in the shift mechanism, causing hung shifts. A general program of higher surface finishes, mounting the hollow cast-steel shift drum on ball instead of needle bearings, and change to a roller shift drum detent "made shifting almost imperceptible" (race engine shift mechanisms have been prepared this way for decades). To recover a positive feel, the three spring tensions had to be increased. A total of six million shifts were made in this gearchange development program. Speaking of methodology, I was told, "In the old days, engineering would come up with a design, then we'd throw it over the wall to production," who would then have to find some way to make it. The new watchword is "design for production."
New oil pump has wave-spring to zero out end clearance in order to prevent oil drain-back
2006 Now a six-speed gearbox on Dyna. In August this year TC96 is introduced for 2007 model year, non-counterbalanced "A" and counterbalanced "B" variants intro at same time. Torque is up 8 percent from TC88 (displacement is up by 9 percent). When this engine showed overheating at low speed, Parade Mode was created. TC96 dimensions are 3.750 x 4.375 inches = 96.6-cu. in. Mixture is leaned out by automotive-style closed-loop operation of EFI.
New cam plate with plain outer cam bearings instead of rollers, roller chain for cams, nylon tensioner pads, and hydraulic cam chain tensioner for Dyna models. Improved oil pump delivers 10 percent more oil and scavenge side has 23 percent increase in capacity (in all, four different cam support plates have been produced).
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„I don‘t like valves that look like golf tees. Intake valves should be the size of trash can lids, and pistons should be the size of manhole covers“ (Jay Leno)
Dieser Beitrag wurde schon 2 mal editiert, zum letzten mal von motorcycle boy am 16.10.2018 12:20.
