The variable intake manifold PDA (Port De-Activation
Valve) by changing the intake pipe length or cross-sectional area, to improve the efficiency of combustion, make the engine more stable at low speeds, more adequate torque, high speed more smoothly, the power is more powerful!
One end of an intake manifold connected with the intake valve, is connected to the rear end of the intake manifold intake resonance chamber, each cylinder has an intake manifold. Engine
machine is in operation, the intake valve continuously open and close, when the valve is opened, the intake manifold air mixture into the cylinder at a constant speed through the valve, the valve closing when the mixed gas is blocked it will rebound, the cycle will produce vibration frequency. If the intake manifold is short, clear that this frequency will be faster; if intake manifold is long, the frequency becomes relatively slow. If the oscillation frequency of the intake valve in the intake manifold of the mixture gas reaches the resonance time of opening, then the intake efficiency at this time is obviously very high. Thus variable intake manifold, to provide best engine valve at high speed and low speed. When the engine speed is low, a long and thin with the intake manifold, air flow velocity can be increased and the strength of the intake air pressure, and so be better gasoline atomization, better combustion, improved torque. (Like the pinch flat water, the water will be more strongly) requires a lot of mixed gas of the engine at high speeds, which is the intake manifold and the crude will become short, so as to inhale more gas mixture, increasing the output power. Technology Principle
Since the gas is a mixture of fluids having mass flow in the intake pipe in the state is changing, the fluid mechanics often works to optimize its internal design, for example the inner wall of the intake manifold polished smooth reduce resistance, or to deliberately create a rough surface to create a swirling motion within the cylinder. However, the work of a car engine speed interval of up to thousands of revolutions required for each intake demand conditions are not the same, this is a great test tube for ordinary intake manifold. So, the day of the intake manifold engineers had developed deep – so that the intake manifold “change” them.
Variable length
4-stroke automobile engine piston reciprocates up and down the second cycle is considered a complete work cycle, only 1/4 of the time the intake valve is opened, so that the intake manifold an intake pipe caused by a pulse. The higher the engine speed, the valve openingKai interval is shorter, the higher the pulse frequency. Simply put, the greater the vibration of the intake manifold. Engineers changing the length of the intake manifold, improved flow stream. The intake manifold is designed to be spiral snail, located in the middle of the engine block, from the gas stream enters the middle. When the engine is running at low speed 2000prm, black control valve is closed, forced air flow from the pipe into a long cylinder manifold, at this time, the intake manifold of the natural frequency is reduced to accommodate the low speed airflow. When raised to 5000 rpm for the engine rotational speed, intake frequency is increased, when the control valve is opened to bypass air flow duct directly into the cylinder lower portion, which reduces the resonance frequency of the intake manifold, the intake facilitates high speed.
The above structure of this embodiment is simple, but only adjustable level 2, which obviously can not fully meet the needs of the respective intake engine speed. The solution is to design a mechanism continuously variable intake manifold length. BMW V12 engine assembly 760 on the use of the design.
intermediate BMW intake mechanism designed to control a rotor of the length of the intake manifold, by varying the rotor angle, the intake air flow into the length of the cylinder is continuously variable. This is obviously better meet the intake efficiency at each speed. More linear power output, torque distribution is more uniform, more excellent fuel economy.
variable section
We know that the valve is set to a short-stroke low speed when open, the valve opening stroke is set to grow at high speed, it is “negative” mess out disaster. So in addition to the valve, intake manifold can not achieve the same effect?
principles of fluid mechanics, the larger cross-sectional area of the pipe, the less fluid pressure; the smaller pipe cross-sectional area, the greater the fluid pressure. For example: a child we all played tap, pinch flat front end of the pipe, the water pressure can become very large.
According to this principle, the engine needs a mechanism, the use of larger cross-sectional area of the intake manifold at high speed, intake air flow rate increase; the use of smaller cross-section in the intake manifold at low speed area, increase the intake negative pressure cylinder, a vortex can be sufficiently formed in the cylinder, so that better mixing of air and fuel.
In four-valve engine, for example, two in row 2 design in which an intake pipe with a valve, the valve being in a straight ECUAccess control. When the engine low speed operation, low required cross-sectional area of the intake manifold, the valve can be closed at this time, only one of the two intake valves can be air, which is equivalent to half the cross-sectional area is reduced. Also, the high engine speed operation, the valve is opened under the control of ECU, two intake valves simultaneously, which is equivalent to increase the cross-sectional area. # 8203;