Variable valve timing device

Abstract

The invention discloses a variable valve timing device used for controlling opening and closing timing of a valve of a vehicular engine. The variable valve timing device comprises a camshaft, a rotary driving part and a phase adjusting mechanism, wherein the camshaft is used for driving opening and closing of the valve, the rotary driving part for driving the camshaft is capable of rotating with an engine crankshaft synchronously and capable of rotating relative to the camshaft, and the phase adjusting mechanism is used for changing a relative rotary phase between the rotary driving part and the camshaft so as to allow adjustment of the opening timing of the valve at the least. Besides, the phase adjusting mechanism comprises a motor which is only in drive connection with the camshaft, and when the valve needs to be opened in advance, the motor drives the camshaft to rotate forwards relative to the rotary driving part, so that the valve is opened in advance. By the aid of the variable valve timing device, the valve can be opened continuously, and the variable valve timing device is larger in air inflow as compared with that in the prior art under the high-rotational-speed high-load working condition. The overall weight of a valve timing mechanism can be reduced, arrangement of the valve timing mechanism is realized by making small modifications on a cylinder head system, and accordingly the variable valve timing device is high in universality.

Description

technical field [0001] The present invention relates to the field of automobiles, and more particularly, to variable valve timing devices. 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 muc...

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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