Variable valve timing method

Abstract

The invention discloses a variable valve timing method used for controlling opening and closing timing of a valve of a vehicular engine. When the valve needs to be opened in advance, a phase adjusting mechanism drives a camshaft to rotate forwards relative to a rotary driving part; when the camshaft rotates to a position enabling the valve to be maximum in lift basically, the phase adjusting mechanism keeps the camshaft at the current position, so that the valve is kept at the maximum lift basically; and after the camshaft is kept at the current position for a period of preset time, the rotary driving part drives the camshaft to rotate continuously. The valve can be opened continuously by the variable valve timing method, and the variable valve timing method is larger in air inflow as compared with that in the prior art under the high-rotational-speed high-load working condition.

Description

technical field [0001] The present invention relates to the automotive field, and more particularly, to variable valve timing methods. Background technique [0002] It is known from the prior art that the higher the engine speed, the shorter the intake time of the cylinder in one working cycle. At high speed and heavy load, more air intake is required to improve the combustion efficiency of the engine, so that the engine has a higher power output; Achieve good fuel economy. Therefore, more and more vehicle engines use variable valve timing (VVT) technology to change the valve timing of the intake and exhaust valves. [0003] The traditional VVT technology can improve the power and fuel economy of the engine to a certain extent by adjusting the opening of the valve in advance, but the valve timing system does not change the duration of the valve opening, and the intake air volume per unit time does not improve much, so for The performance of the engine doesn't help much ei...

AI Technical Summary

Problems solved by technology

However, the application defect of this technology is that the mechanism is complex and the power output is not linear enough.

Other continuously variable valve lift technologies, although the smoothness of power output has been improved, but the actuators are more complex

[0004] Comprehensive analysis of several variable valve lift technologies on the market, all of which use the camshaft as the power source to drive complex kinematic pairs and change the valve lift through mechanical movement. Such mechanisms are complex in structure and have many parts, which will inevitably increase the Weight; the movement is cumbersome, which inevitably causes friction loss; too many positions need cooling and lubrication, which has almost strict requirements on the design of the oil circuit; in order to assemble this mechanism, the cylinder head system needs to be modified in a large area, and the versatility is poor

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