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Topic: Variable Cam Timing

	Variable Cam Timing - Wikipedia, the free encyclopedia
		Variable Cam Timing (VCT) is an automobile variable valve timing technology developed by Ford.
		It varies the timing of the intake valves by using hydraulic pressure to rotate the camshaft.
		The VCT system is used in Ford's Triton 3-valve V8 engine and the Australian Barra 182 and 240 Inline-6s.
	en.wikipedia.org /wiki/Variable_Cam_Timing (115 words)

	Variable valve timing - Wikipedia, the free encyclopedia
		Valve timing gears on a Ford Taunus V4 engine — the small gear is on the crankshaft, the larger gear is on the camshaft.
		The profile, or position of the cam lobes on the shaft, is optimized for a certain engine rpm, and this tradeoff normally limits low-end torque or high-end power.
		Variable valve timing was the sole domain of overhead cam engines until the 2005, when General Motors began offering the LZE and LZ4, pushrod V6 engines with VVT.
	en.wikipedia.org /wiki/Variable_valve_timing (901 words)

	BMW World - Technology
		The crankshaft drives a sprocket on the exhaust cam, and the exhaust cam sprocket is bolted to the exhaust cam.
		On the end of the cam is a gear that is also helical on the outside, but it's too small to connect to the teeth on the inside of the big sprocket.
		On most BMW engines that use a single VANOS, the timing of the intake cam is only changed at two distinct rpm points, while on the double-VANOS system, the timing of the intake and exhaust cams are continuously variable throughout the majority of the rpm range.
	www.bmwworld.com /technology/vanos.htm (934 words)

	Variable valve timing: Just the facts... (Site not responding. Last check: 2007-11-04)
		Variable valve timing, or VVT, is a generic term for an automobile (4-wheeled motor vehicle; usually propelled by an internal combustion engine) piston engine (additional info and facts about piston engine) technology.
		The profile of these cams is optimized for a certain engine rpm (Rate of revolution of a motor), and this tradeoff normally limits low-end torque (A twisting force) or high-end power.
		The first functional variable valve timing system, including variable lift, was developed at Fiat (A legally binding command or decision entered on the court record (as if issued by a court or judge)).
	www.absoluteastronomy.com /encyclopedia/v/va/variable_valve_timing.htm (913 words)

	Media.Ford.com: The Products
		In combination with precise control of spark timing, fuel injection and the use of electrically controlled Charge Motion Control Valves in the intake ports, this technology produces impressive power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
		The cam lobes press down on rocker arms to open the intake and exhaust valves, which are closed by coil springs, as in all Ford's V-8 engines.
		Variable camshaft timing allows the valves to be operated at different points in the combustion cycle, to provide performance that is precisely tailored to the engine's specific speed and load at that instant.
	media.ford.com /products/presskit_display.cfm?vehicle_id=857&press_subsection_id=423&make_id=92 (3711 words)

	TrailerBoats.com - Online Articles for the Boating and Watersports Enthusiast
		It is important to note that cam timing (when the cam opens and closes the valve), duration (how long the cam holds the valve open), intake and exhaust tuning, and engine rpm are interrelated.
		The combination of timing and duration that produces the best idle will not be optimum for top speed, and the best tuning for top-end horsepower is not likely to produce good midrange torque or a satisfactory idle.
		The VCT system is designed to both advance and retard cam timing in response to rpm and engine loading.
	www.trailerboats.com /output.cfm?id=945613 (2616 words)

	The WRX engine
		Most significantly is the fact that its cam timing is optimized for emissions and part throttle, low boost running while the Japanese standard WRX engine has different cams optimized for mid-range power and variable intake timing to provide quite a different feel to the engine.
		While we might want to say this is because of the variable valve timing, in fact the presence of variable valve timing and the improved drivability is directly attributable to the difference in the fuel the engine is being fed and also the effects of the stringent emissions and fuel economy regulations in the US.
		A variable intake cam timing engine can use a bit more intake/exhaust valve overlap in the low rpm regions for better off boost throttle response and then close down the overlap and at the same time extend intake closing time, which lets the cylinder fill better for more power.
	www.spdusa.com /driving_the_wrx_engine.htm (1002 words)

	Variable Valve Timing (VTEC)
		Variable valve timing has been developed, tested and put into production.
		This results in better fuel economy, and quicker response time when sudden application of power is required.
		At the same time docile handling qualities are retained for starting and slow running.
	www.firewall.ca /VTEC.html (635 words)

	BorgWarner Delivers DualTronic(TM) Transmission Technology and Variable Cam Timing Presentations at SAE World Congress ... (Site not responding. Last check: 2007-11-04)
		Variable cam timing is a means of precisely controlling the flow of air into and out of an engine by allowing the camshaft to be dynamically phased relative to its crankshaft.
		BorgWarner VCT technology includes devices that use camshaft torque as their actuation energy, in contrast to conventional phaser devices that depend on engine oil pressure for actuation.
		The new technology is beneficial for both overhead valve and overhead cam engines, and represents a leap to the next generation of cam phasing.
	www.aiada.org /article.asp?id=37288 (820 words)

	All Ford Mustangs News - Whats New - 2005 Mustang: More Power
		Variable camshaft timing was a key in the quest to wring more power from the Mustang’s 4.6-liter, three-valve MOD V-8 engine, while simultaneously improving efficiency and reducing emissions.
		VCT lets allows the valves operate at optimum points in the combustion cycle, tailored to the engine’s speed and load at that instant.
		Cam position is controlled by an electronic solenoid that modulates oil pressure to advance or retard the cam timing based on input from the engine’s electronic control computer.
	www.allfordmustangs.com /artman/publish/article_325.shtml (2557 words)

	The 2004 Ford F150 (part 2) (Site not responding. Last check: 2007-11-04)
		The new engine will be Ford’s first modular V-8 to use variable cam timing, which allows Ford engineers to optimize intake and exhaust valve actuation across the engine speed range.
		In combination with precise control of spark timing, fuel injection and use of electrically controlled Charge Motion Control Valves in the intake runners, this technology produces improved power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
		For 2004, the Triton is equipped with 3 valves - 2 intake and 1 exhaust
	www.motorsportscenter.com /printer_130.shtml (2827 words)

	United States Patent Application: 0050201994
		The method of claim 1, wherein the antibody comprises: (a) a heavy chain variable region of a human V.sub.H 3-30.3 gene; and (b) a light chain variable region of a human V.sub.K A-27 gene.
		Variants of the nucleotide sequence have been reported, including a G to A transition at position 49, a C to T transition at position 272, and an A to G transition at position 439.
		In one embodiment, the human monoclonal antibodies are produced by a hybridoma which includes a B cell obtained from a transgenic non-human animal, e.g., a transgenic mouse, having a genome comprising a human heavy chain transgene and a light chain transgene fused to an immortalized cell.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=189&f=G&l=50&d=PG01&s1=mccoy&p=4&OS=mccoy (16583 words)

	3-Valve Technology is Featured in the ’04 Ford F-150, Underhood Service, February 2003
		In combination with precise control of spark timing, fuel injection and use of electrically controlled Charge Motion Control Valves in the intake ports, this technology produces improved power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
		The cams press down on roller-finger cam followers to open the intake and exhaust valves, which are closed by coil springs as in all of Ford’s V8 engines.
		Variable-cam timing allows the valves to be operated at different points in the combustion cycle, to provide performance that is precisely tailored to the engine’s specific speed and load at that moment.
	www.babcox.com /editorial/us/us20344.htm (1183 words)

	JWFisher: 12.24.2004: Ford Hurricane Engine (Site not responding. Last check: 2007-11-04)
		Ford created an experimental version of the head with the valves repositioned over the bores so that they could breath considerably better (this is all publicly documented in an interesting and very worthwhile engineering paper).
		Cam phasing is the largest benefit - but it's not the most optimum variable cam timing because it has to move the intake and exhaust together.
		So, what I'd like to see from Ford is a 4.6 DOHC engine with variable cam timing on the intake side (with architectural provisions for future exhaust cam timing).
	www.jwfisher.com /sec-automobilia/sec-imho/2004.12.24-no-hurricane (1311 words)

	Variable Valve Timing \| Advance Auto Parts (Site not responding. Last check: 2007-11-04)
		The cams are turned in precise relation to the crankshaft by chains, belts or gears—or a combination thereof.
		Basic variable cam timing systems advance the whole cam, which means that the valves affected open sooner at high revs (good) but also close sooner (often not necessarily desirable).
		An electronically controlled system then moves the cam laterally in proportion to engine rpm, so that the effective cam timing, lift and duration can be varied.
	www.advanceautoparts.com /ENGLISH/youcan/html/dsm/dsm20040901vt.html (677 words)

	[No title]
		that there are times within a cycle where the tendency of the cam is to "run away" from the crank.
		The outer diameter of the annular piston is mated to the sprocket by a straight spline, while the inner diameter is mated to the intake camshaft by a helical spline.
		So the power to drive the cam still comes from the crank, and only the adjustment has to be provided by a stepper motor.
	retro.co.za /efi/DIY_EFI/1996/efi1-139.txt (3280 words)

	Which Variable Valve Timing is better ? ? - Honda-Acura.net
		Of those 3 VVt-i is probably the best because the variation is done in the head, not in the cam as is the case with VTEC and MIVEC reducding paracidic loss to wight in the valve train.
		The way I remember I tell the difference between variable cam timing and varible valve timing, is that vvt changes the actual lift and duration of the valves (as can be seen by the fatter lobes on a vtec cam).
		Now, the various options out there are basically a combination of one or both of these options, and either on one or both cam or on a single-cam motor.
	www.honda-acura.net /forums/showthread.php?t=34779 (1650 words)

	Media.Ford.com: 3-Valve Technology Improves Modular V-8 Efficiency, Performance
		In combination with precise control of spark timing, fuel injection and use of electrically controlled Charge Motion Control Valves in the intake ports, this technology produces class-leading power and torque, particularly at the lower engine speeds that are so important to applications such as towing and heavy hauling.
		The cams press down on roller-finger cam followers to open the intake and exhaust valves, which are closed by coil springs as in all Fordâs V-8 engines.
		Behind this cover, the cam chains are now controlled by a new tensioner, which is reshaped to control small side-to-side chain movements, and the sounds associated with them.
	media.ford.com /article_display.cfm?article_id=13620 (2907 words)

	Indiacar News-BorgWarner Launches Breakthrough VCT Technology
		BorgWarner Morse TEC has begun production of its first high-volume variable cam timing (VCT) systems for a new family of General Motors V6 engines being introduced this year.
		The launch is BorgWarner's first production of its VCT technology and constitutes a major step in the expansion of BorgWarner's growing engine management business.
		BorgWarner VCT technology includes devices that utilize camshaft torque as their actuation energy, in contrast to conventional phaser devices that depend on engine oil pressure for actuation.
	www.indiacar.com /xnewdet.asp?id=n8893 (424 words)

	US Patent No. 6,932,037 VCT system with increased cam torsionals (Site not responding. Last check: 2007-11-04)
		In a variable cam timing (VCT) system that has a crank shaft coupled to at least one cam shaft.
		The timing gear includes at least two groups of toothlike projections including a first group having a first distance to the center of the wheel, and a second group having a second distance to the center of the wheel.
		The system may further include a resonator which is positioned upon the at least one cam shaft, the resonator including at least one mass and at least one elastic element.
	www.lightlink.com /bbm/6932037.html (193 words)

	[No title]
		Relative to the speed of the crank, if the cam gear is rotating slower, the valve is opened for longer.
		But the cam can't turn slower than the crank, at least not for very long, unless it turns faster later on to make up the difference.
		The cam is in a seperate casting above the head and acts directly on the tappets.
	retro.co.za /efi/DIY_EFI/1996/efi1-134.txt (1397 words)

	F150online Ford Truck News --- 3-VALVE TECHNOLOGY IMPROVES MODULAR V-8 ENGINE EFFICIENCY, PERFORMANCE
		The VCT design allows Ford engineers to optimize intake- and exhaust-valve actuation across the rev range.
		It represents the industry’s first mass application of dual-equal variable-cam timing that shifts the intake and exhaust valve timing together.
		Multiple valves also enhance the engine’s ability to “breathe” — that is, to move large volumes of air in and out of the cylinders — which is a key to generating maximum horsepower.
	www.f150online.com /fordnews/view.cfm?nnum=148 (1047 words)

	Bill Sherwood's Engine Page - Variables
		This is a the start of how the various variable cam timing systems around the world work.
		This is why variable cam timing is a good thing for making a wider torque curve, and hence making the engine more driveable.
		Formula One engines also use a variable length inlet system, but unlike the relatively crude Toyota system they employ an infinitely variable length (within certain limits of course) inlet system to make the engines work over another one or two thousand revs.
	www.billzilla.org /engvariable.html (1018 words)

	BorgWarner
		Fully integrated timing chain systems include roller, bushing and silent chains, sprockets, tensioners, control arms, guides, and variable cam timing phasers.
		BorgWarner Morse TEC’s latest breakthrough technology in variable cam timing (VCT) represents a leap to the next generation of cam phasing.
		Engines equipped with VCT technology will provide drivers of vehicles with improved fuel economy, reduced emissions, and enhanced performance which is greater than conventional oil-pressure actuated devices.
	www.morsetec.com (231 words)

	biology - Variable valve timing (Site not responding. Last check: 2007-11-04)
		VVT allows the lift or duration and timing (or all) of the intake or exhaust valves (or both) to be changed while the engine is in operation.
		The next big step was taken by Honda in the 1980s and 90s, where Honda began by experimenting with variable valve lift.
		GM DCVCP (Double Continuous Variable Cam Phasing) - Varies timing with hydraulic vane type phaser
	www.biologydaily.com /biology/VVT (541 words)

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