the working principle of p>CVVT is no different from that of VVTI, only controlling valve timing has no function of controlling valve lift. Therefore, the engine will only change the time difference between intake and exhaust, and cannot change the intake volume. To put it simply, its working principle is that when the engine changes from low speed to high speed, the electronic computer will automatically press the oil to the small turbine in the driving gear of the intake camshaft, so that under the action of pressure, the small turbine will rotate at a certain angle relative to the gear housing, so that the camshaft will rotate forward or backward within 6 degrees, thus changing the opening time of the intake valve and achieving the purpose of continuously adjusting the valve timing. Therefore, under the action of the above structure, the engine can be ensured to change the valve opening and closing time according to different road conditions, and the fuel economy can be improved while ensuring sufficient traction output.
the p>CVVT system includes the following parts: oil pressure control valve, intake cam toothed disc, crank sensor, cam position sensor, oil pump and engine electronic control unit (ECU).
The toothed disc of the air intake cam comprises an external gear driven by a chronograph belt, an internal gear connected with the air intake cam and a control piston which can move between the internal gear and the external gear. When the piston moves, the spiral gear on the piston will change the position of the external gear, thus changing the timing effect. The displacement of the piston is determined by the oil pressure control valve, which is an electronic control valve and its oil pressure is controlled by the oil pump. When the computer (ECU) receives input signals, such as engine speed, intake air volume, throttle position and engine temperature, it determines the operation of the oil pressure control valve. The computer will also use the cam position sensor and crankshaft position sensor to determine the actual valve timing of the intake cam.
when the engine is started or shut down, the position of the oil pressure control valve is changed, so that the intake cam timing is delayed. When the engine is idling or loading at a low speed, the timing is also in a delayed position, which improves the stable working state of the engine. The intake cam is in the advanced position when it is in the middle, and it is in the advanced angle position to increase the torque output when it is in the middle and low speed and high load. While at high speed, it is in a delay position to facilitate high-speed operation. When the engine temperature is low, the cam position is in the delay position, which stabilizes the idle speed and reduces fuel consumption.
i-VTEC, "I" means intelligent engine,
i -VTEC is a combination of Honda's original technology and VTC (Valiable Timing Control), a highly intelligent variable valve engine.
in order to accelerate on the expressway more easily and smoothly, stop &; Go, climb the hill more forcefully. I hope to drive with higher performance, but the fuel cost is saved as much as possible. On the engine side, it has various performances for various driving conditions. However, it is generally impossible to meet the needs of various levels in the development of engines, and it often causes deficiencies on the other hand when focusing on a certain key point. At the same time, the low emission of waste gas is also a problem that cannot be solved. All of the above will affect the performance of the engine. The most important thing is that the valve system when the engine combustion chamber inhales mixed gas and exhausts gas after combustion, the length and quantity of the ideal valve in the open state, and the relationship between the opening and closing timing of the suction end and the discharge end are completely different. The first thing that makes valve system variable here is Honda's original VTEC. As the core of Honda's high-performance engine technology, it is used in various kinds of vehicles. In order to explore the possibility of VTEC, it is combined with the newly developed VTC (continuously variable samarium suction timing and phase control mechanism) to complete a more advanced new generation of intelligent engine DOHC i -VTEC. High-quality realization of "high power", "low fuel consumption" and "low exhaust emissions" and various different characteristics.
VVTI is a valve. Usually, this kind of car doesn't have a valve with this function, and its angle is dead. The performance of VVTI is universal. Generally speaking, why should it be changed? When its engine is at high speed, it is necessary to increase the power of its engine, and its exhaust has the function of scavenging air.