What are the types of variable valve technology

[Lorraine]

1. Honda Variable Valve Lift Technology: VTEC, i-VTEC Applicable models: All currently sold Honda and Acura models in China. Honda was the first manufacturer to apply variable valve lift technology to automotive engines. Unlike other manufacturers who first used variable valve timing and later added variable valve lift technology, Honda's engineers developed these two technologies simultaneously from the outset. The characteristics of Honda's variable valve lift mechanism are its simple structure and ingenious design. 2. Nissan Variable Valve Lift Technology: VVEL Applicable models: Infiniti G37, Infiniti FX50. Nissan's engineers added a set of screws (bolts) and nuts to the engine's valve rocker arms to enable continuous (stepless) variation of valve lift. The specific implementation method is also very simple, and we have to admire the ingenuity of these engineers. First, the onboard computer determines the position of the nut based on the current engine speed, and the black DC motor is used to drive the nut. The nut is connected to a control rod via a link, and the lateral movement of the nut can drive the rotation of the control rod. When the control rod rotates, the rocker arm connected to it also rotates, and the rocker arm is connected to link B. When the rocker arm rotates counterclockwise, it drives link B to push the output cam at the top of the valve tappet, which ultimately lifts the valve to change the valve lift. 3. BMW Variable Valve Lift Technology: Valvetronic Applicable models: All currently sold BMW models in China except the M3 and M5. Compared to Nissan's VVEL, BMW's Valvetronic variable valve lift technology is more well-known. This is BMW's own variable valve lift technology released in 2001 and widely used in BMW engines. Currently, all BMW models sold in China except the M3 and M5 have this feature. Like Nissan's VVEL, BMW's Valvetronic is also one of the few variable valve lift technologies that can achieve continuous variation.

[AdalynnLynn]

After all these years in car repair, I've seen quite a few variable valve technologies. Simply put, they make engine valves more flexible. There are mainly three types: The first is variable valve timing, like Toyota's VVT-i, which adjusts valve opening and closing times based on RPM to improve low-speed torque and fuel efficiency. The second is variable valve lift, such as Honda's VTEC, which can change valve lift height to deliver stronger power at high speeds. The third combines both systems, like BMW's VANOS or Audi's Valvelift, simultaneously adjusting timing and lift to ensure smooth operation under all driving conditions. The benefits of these technologies are obvious – reducing fuel consumption by about 10%, lowering emissions for a greener car, and extending engine life. However, they're also more complex. Common repair issues include actuator wear or hydraulic system oil leaks. I recommend owners check the timing chain every 5,000 kilometers to avoid major problems. Like the old Civic I worked on last month – when VTEC failed, the power dropped, but replacing a small part fixed it. Overall, car brands love using this for competition, and Hyundai's iVTEC is similar, making driving feel more exciting.