What does a 1.5VVT engine mean?

[DeBlakely]

A 1.5VVT engine means that the engine has a cylinder displacement of 1500cc. The 1.5 represents the displacement size of the vehicle's engine. VVT (Variable-Valve-Timing) is a variable valve timing system. This system adjusts the phase of the engine camshaft through its equipped control and execution system, allowing the timing of valve opening and closing to vary with engine speed, thereby improving air intake efficiency and increasing engine power. According to the working principle of an engine, during the intake stroke, the intake valve opens, and the piston moves downward to draw gas into the cylinder. When the piston reaches the bottom dead center, the intake valve closes, and the piston moves upward to begin the compression stroke. However, in actual design, the intake valve often closes after the piston passes the bottom dead center. There is a "lag time" for the intake valve closing. This mainly considers the inertia of the intake air; to allow more gas to enter the cylinder, the intake valve is appropriately delayed in closing. However, different engine speeds result in different intake airflow velocities, requiring corresponding adjustments to the intake valve closing timing to ensure optimal engine performance. Thus, the intake valve phase adjustment technology was born, abbreviated as VVT. If both the intake and exhaust valve phases are adjustable, it is called DVVT. For daily engine maintenance, the following methods can be used: Use lubricating oil of appropriate quality grade. For gasoline engines, SD--SF grade gasoline engine oil should be selected based on the additional devices of the intake and exhaust system and usage conditions; for diesel engines, CB--CD grade diesel engine oil should be selected based on mechanical load, with the selection standard not lower than the manufacturer's requirements. Regularly change the oil and filter. The quality of any grade of lubricating oil will change during use. After a certain mileage, performance deteriorates, causing various problems for the engine. To avoid faults, oil should be changed regularly based on usage conditions, and the oil level should be kept moderate. When oil passes through the fine pores of the filter, solid particles and viscous substances in the oil accumulate in the filter. If the filter is clogged and oil cannot pass through the filter element, the filter element may burst or the safety valve may open, allowing oil to bypass through the bypass valve, bringing contaminants back to the lubrication area, accelerating engine wear and internal pollution. Regularly clean the crankcase. During engine operation, high-pressure unburned gas, acids, moisture, sulfur, and nitrogen oxides from the combustion chamber enter the crankcase through the gap between the piston rings and cylinder walls, mixing with metal powder from part wear to form sludge. A small amount remains suspended in the oil, while a large amount precipitates, clogging the filter and oil holes, making engine lubrication difficult and causing wear. Regularly use a radiator cleaner to clean the radiator. Removing rust and scale not only ensures the engine's normal operation but also extends the overall lifespan of the radiator and engine.