People always need to breathe, Toyota Exhaust Manifold breathe throughout a person's life. People breathing during sleep gentle, greedily breathing during exercise. Engine at work as well, at a high load cylinder requires inhaling more air mixing; at low load, in order to reduce fuel consumption and emissions should reduce the intake air. And how much control the intake air amount in addition to the throttle valve opening and closing, is more direct valve timing and lift control technology of.
In order to optimize engine efficiency at different speed conditions, automotive engineers invented the variable valve timing technology. Variable valve timing technology, the industry also called VVT (variable valve timing), through the camshaft angle control, delayed and delayed time to reach the valve opening and closing the intake and exhaust efficiency optimization. At high speed, the intake valve closed postpone, postpone the exhaust valve open, ascended into the air while allowing the fuel burn more fully; at low speed, the intake valve early close, the exhaust valve opens early, at the same time saving fuel exhaust more fully. Variable valve timing technology essentially standard in almost all models now on the market, VVT for owners who is already accustomed to the logo. With the engine systems and processes increasingly sophisticated, variable valve lift system is introduced into the engine system. VTEC is probably familiar to everyone, a variable valve lift technology, it is also a proud Honda engine technology, in the past ten years through several generations of Honda's VTEC improved, valve lift control and more accurate and fast. Today, VTEC technology is not the most advanced and most accurate variable valve lift technology, the fundamental fatal in its regulation of the valve lift is segmented (the latest but not widely used Honda AVTEC already have stepless valve lift control). The most advanced variable valve lift technology are infinitely variable adjustable lift technology, real-time according to engine operating conditions of the valve lift to be adjusted. This stepless adjustable valve lift adjustment system mostly uses the mechanism of the eccentric shaft or intermediate lever, making stepless adjustment of the valve lift. This article will compare introduce 3 infinitely variable valve lift adjustment system - BMW's Valvetronic, Nissan's VVEL, Toyota's Valvematic.
 BMW is always at the forefront of technology. In January 2001, the first generation Valvetronic system was first used in-line 4-cylinder engine N42 on the E46 3 Series. Valvetronic variable lift system with Bi-Vanos valve timing system makes N42 engine is very advanced in the industry at the time. The second generation is applied to the BMW Valvetronic N46, N52, N62 and other engines. The N52 inline six-cylinder naturally aspirated engine, this is the most by type of attention, to be with in the E60, E66, E90 equivalents on generation models. The third-generation Valvetronic system will meet the latest turbocharged engine is the latest generation of the N55 engine.
   Valvetronic is an intermediate leverage core technology, the valve lift of the camshaft to achieve stepless adjustment phase can be adjusted by driving the intermediate lever. Below is the latest third-generation BMW Valvetronic organization chart, Valvetronic mechanism comprises five important components: the eccentric shaft drive motor, an eccentric shaft drive gear, eccentric shaft, E46 Camber Plates cam shaft, intermediate lever.