How Does Variocam Work
from web site
VarioCam Plus uses a combination of variable valve timing and variable valve lift on the intake side to enhance power, torque and fuel usage across the whole engine speed range. Essentially, the system provides two engines in one: the first for low-speed and city usage, the second for optimal high-speed efficiency. Regardless of the huge distinctions in between these two states, VarioCam Plus makes a smooth transition using the current in electronic engine management.
VARIABLE VALVE TIMING
The consumption and exhaust valves are driven by 4 overhead camshafts and pail tappets with hydraulic valve lash payment. Consumption camshaft opening times are controlled by Porsche's patented timing system VarioCam ™ system.
If you are interested in more tips, check original site for yourself.
With an automatic chain tensioner and hydraulic valve lash compensation, VarioCam modifies camshaft timing for greater engine torque. Utilizing a timing piston, managed by the Bosch Motronic M 5.2 engine management system, positioned in between the two sides of the timing chain in between the intake and exhaust cams.
When activated, the piston advances the timing of the consumption cam by broadly 15 crankshaft degrees or 7.5 camshaft degrees. This earlier valve timing flatter creates more valve overlap and an earlier closing time than typical, resulting torque in additional engine torque.
At high engine speeds, the piston is shifted back curve to its later timing position for more power.
Late intake webcam timing leads to shorter valve overlap durations and decreased hydrocarbon emissions at low speeds and at idle. Early valve timing and long valve overlap times produce exhaust gas recirculation at low loads and moderate engine speeds, lowering NOx emissions. VarioCam valve timing also improves cold-start emissions.
Variable Valve Raise System includes a two-stage tappet which is operated via an electro-hydraulic changing valve. Each tappet is comprised of two primary components: a main pin-like aspect and a round outer sleeve. When needed, these elements can be combined utilizing a hydraulically actuated shaft. The central pin is actuated by a small-profile lobe on the camshaft, while the outer sleeve stays in constant contact with two bigger profiles on either side. Considering that there are successfully two cam contours on each intake camshaft, it is possible to apply two various valve-lift curves. The phase angle, or timing, on each of the cams, can be advanced or retarded utilizing an electro-hydraulically actuated adjuster.
SMALL CAM. LOW RAISE. OPTIMUM COMBUSTION
VarioCam Plus offers a number of benefits when starting the engine from cold. Combustion is improved throughout the warm-up process, therefore lowering emissions. The system likewise supplies smoother idling while boosting fuel economy.
Under low throttle load: VarioCam Plus utilizes a long positive overlap i.e., increases the duration during which both valves are open concurrently-- as a means of taking full advantage of fuel effectiveness. Considering that a reasonably high percentage of exhaust gas is present during combustion, there is also a significant reduction in NOx emissions.
Full-throttle mode: Big webcam. High lift. Optimum efficiency, the valve equipment is changed for maximum power and torque. The valve lift is changed to the high web cam setting, making it possible for optimum torque output of 560 Nm on the 911 Turbo from as low as 2,700 rpm. The curve stays flat all the way to 4,600 pm, covering a significant part of the engine speed range.
VARIABLE VALVE TIMING
The consumption and exhaust valves are driven by 4 overhead camshafts and pail tappets with hydraulic valve lash payment. Consumption camshaft opening times are controlled by Porsche's patented timing system VarioCam ™ system.
If you are interested in more tips, check original site for yourself.
With an automatic chain tensioner and hydraulic valve lash compensation, VarioCam modifies camshaft timing for greater engine torque. Utilizing a timing piston, managed by the Bosch Motronic M 5.2 engine management system, positioned in between the two sides of the timing chain in between the intake and exhaust cams.
When activated, the piston advances the timing of the consumption cam by broadly 15 crankshaft degrees or 7.5 camshaft degrees. This earlier valve timing flatter creates more valve overlap and an earlier closing time than typical, resulting torque in additional engine torque.
At high engine speeds, the piston is shifted back curve to its later timing position for more power.
Late intake webcam timing leads to shorter valve overlap durations and decreased hydrocarbon emissions at low speeds and at idle. Early valve timing and long valve overlap times produce exhaust gas recirculation at low loads and moderate engine speeds, lowering NOx emissions. VarioCam valve timing also improves cold-start emissions.
Variable Valve Raise System includes a two-stage tappet which is operated via an electro-hydraulic changing valve. Each tappet is comprised of two primary components: a main pin-like aspect and a round outer sleeve. When needed, these elements can be combined utilizing a hydraulically actuated shaft. The central pin is actuated by a small-profile lobe on the camshaft, while the outer sleeve stays in constant contact with two bigger profiles on either side. Considering that there are successfully two cam contours on each intake camshaft, it is possible to apply two various valve-lift curves. The phase angle, or timing, on each of the cams, can be advanced or retarded utilizing an electro-hydraulically actuated adjuster.
SMALL CAM. LOW RAISE. OPTIMUM COMBUSTION
VarioCam Plus offers a number of benefits when starting the engine from cold. Combustion is improved throughout the warm-up process, therefore lowering emissions. The system likewise supplies smoother idling while boosting fuel economy.
Under low throttle load: VarioCam Plus utilizes a long positive overlap i.e., increases the duration during which both valves are open concurrently-- as a means of taking full advantage of fuel effectiveness. Considering that a reasonably high percentage of exhaust gas is present during combustion, there is also a significant reduction in NOx emissions.
Full-throttle mode: Big webcam. High lift. Optimum efficiency, the valve equipment is changed for maximum power and torque. The valve lift is changed to the high web cam setting, making it possible for optimum torque output of 560 Nm on the 911 Turbo from as low as 2,700 rpm. The curve stays flat all the way to 4,600 pm, covering a significant part of the engine speed range.
