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A Honda K24A Engine with i-VTEC. VTEC (described as Variable Valve Timing & Lift Electronic Control, but stands for Valve Timing Electronically Controlled) is a system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine, resulting in higher performance at high RPM, and lower fuel consumption at low RPM.
The timing, duration and lift of these valve events has a significant impact on engine performance. Without variable valve timing or variable valve lift, the valve timing is the same for all engine speeds and conditions, therefore compromises are necessary to achieve the desired result in intake and exhaust efficiency . This has been described ...
Three-stage VTEC is a multi-stage implementation of Honda's VTEC and VTEC-E (colloquially known as dual VTEC) technology, implemented in some of the company's D series engines from 1995 to the present day, allowing the engine to achieve both fuel efficiency and power. VTEC-E (for "Efficiency") is a form of VTEC that closes off one intake valve ...
VVT varies the valve timing throughout the RPM range. Together they function similarly to Honda's VTEC system. The SR20VE is the most common engine with NEO VVL. There have been two main versions of this engine. The first version made 187 hp (139 kW) and 145 lb⋅ft (197 N⋅m) torque. This engine was used by Nissan from 1997 to 2001.
The Alfa Romeo Twin Spark engine, introduced in the 1987 Alfa Romeo 75, also uses variable valve timing. [3] [4] The Alfa system varies the phase (not the duration) of the cam timing and operates on the inlet camshaft. [5] Alfa Romeo's variator is a cylindrical chamber that contains a pressure chamber and piston along with helical splines.
MIVEC (Mitsubishi Innovative Valve timing Electronic Control system) [1] is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors. MIVEC, as with other similar systems, varies the timing of the intake and exhaust camshafts which increases the power and torque output over a broad engine speed range ...
The system allows optimum timing of intake valve operation. MultiAir technology can increase power (up to 10%) and torque (up to 15%), as well as reduce consumption levels (up to 10%) and emissions of CO 2 (up to 10%), particulates (up to 40%) and NOx (up to 60%) [3] [7] when compared to a traditional petrol engine. The system also provides ...
Variable valve lift (VVL) is an automotive piston engine technology which varies the height a valve opens in order to improve performance, fuel economy or emissions. There are two main types of VVL: discrete, which employs fixed valve lift amounts, and continuous, which is able to vary the amount of lift.