valvetronic engine technology - IFET College of Engineering

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• taking a modular approach in order todevelop specific engine variants;• ensuring a significant potential for ongoingdevelopment; and• providing the foundation for otherengine variants, i.e. communality withfutureengines.All of this led to the developmentof a fully variable valve drive system,BMW Valvetronic, helping tosignificantly reduce fuel consumptionwhile maintaining stochiometric drivingconditions with all the usual advantages.What Is Valvetronic?The Valvetronic engine is theworld's first engine without a throttlebutterfly. Valvetronic allows the engineto run without a throttle butterfly, thecylinder charge being determined underpart load as a function of the valveopeningperiod. The intake and outletcamshafts are driven by variable camadjustment, BMW’s Vanos technology.A further advantage of this concept isthat it allows worldwide use of theproven three-way catalyst for emissionsmanagement, thus meeting even thestrictest emissions standards in the US.Innovative technology wasessential in order to reach the demandingobjectives and functional requirementsdesired. However, at the same time, thisconcept demanded the utmost of theelectronic control and managementsystems in the engine.ConceptTaking nature as the role model: humanbeings also apply the ValvetronicprincipleA comparison with the humanbeing clearly explains how Valvetronicworks: Whenever we are required tomake a great effort, we human beingsbreathe in a deep and long process ofventilation. Whenever we need less air,we do not throttle the supply of air by,say, closing our nose or our mouth, butsimply breathe in a shorter, flatterprocess of ventilation. In a conventionalcombustion engine the throttle butterflyis basically comparable to a humanbeing keeping his nose or mouth at leastpartially closed. With its large valve lift(= deep, long ventilation) and shortvalve lift (= flat, short process ofventilation), Valvetronic, on the otherhand, is able to breathe in the same way
as nature – always in line with currentrequirements, without any kind ofthrottling effect and therefore withmaximum efficiency.Valvetronic TechnologyAccordingly, the Valvetronicengine no longer requires a throttlebutterfly, which has quite literallyrestricted the free ventilation of theinternal combustion engine ever since itsinvention. Now Valvetronic replaces thisconventional function by infinitelyvariable intake valve lift, offering aquantum leap in technology quitecomparable to the changeover from thecarburetor to fuel injection.Its most important feature is thatit is able to save at least 10 per cent fuelthroughout the entire operating rangerelevant to the customer, with acorresponding reduction in exhaustemissions, regardless of fuel quality.And a further important point is that theefficient operation of Valvetronic doesnot require any unusual types and gradesof oil possibly difficult to obtain.As a result of these particularfeatures the 85 kW/115bhp BMW 316ticompact with its top speed of 210 km/hor 125 mph consumes a mere 6.9 litersof premium fuel on 100 kilometers in theEuropean test cycle, equivalent to 40.9mpg Imp. This is a significant 0.7 litersless than the former 77 kW/105 bhpcompact and well over a liter less thanall competitors in this class.The Valvetronic system is basedconsistently on BMW’s proven double-VANOS (VANOS = variable adjustmentof the camshafts), with infinite camshaftadjustment to meet specificrequirements. The additional, variablevalve lift adjusts the effective cam actionand, accordingly, the opening crosssectionof the valves.This is done by a lever positionedbetween the camshaft and the intakevalves, its distance from the camshaftbeing adjusted infinitely by an additionaleccentric shaft operated by an electricmotor. Depending on the position of theValvetronic control system, the leverconverts the cam contour into a larger orsmaller valve lift, whatever may berequired.
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valvetronic engine technology - IFET College of Engineering

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