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Having the exhaust valve still open when the intake starts to open uses the exhaust "pull" out the exhaust port to help start the intake charge entering the chamber -- before the piston has started down and has generated it's own vacuum. Also, leaving the valves open longer (duration) increased the density of the intake charge and allowed the headers to better scavenge the exhaust gasses out.
What else can I help you with?
How important to change PCV valve Nissan pickup 1994?
It is very important to change PCV valve. If valve is old it will plug or seize. This will cause oil pressure to rise and may cause leaks. Most likely the valve cover gaskets will leak if PCV valve is plugged.
What is overlapping of valves?
Valve overlap occurs in a four-stroke engine at the end of the Exhaust stroke and at the beginning of the Induction stroke; and is when both the exhaust and inlet valves are open at the same time. At the end of the Exhaust stroke, the Exhaust valve is closing and the Inlet valve is starting to open in preparation for the induction of fuel and air into the cylinder. It is common knowledge that in vehicles that cannot alter the valve timing, the Inlet valve opens approx 6 degrees before top-dead-centre and the Exhaust valve closes at 9 degrees after top-dead-centre
What makes flames come out your exhaust?
Usually a product of valve overlap and exhaust. It's basically unburnt fuel coming through and igniting on the hot exhuast tip when it hits the air at the end of the exhaust pipe. In aspirated cars it's large valve overlap which helps scavenging and performance in the top end. Turbo cars, due to the large amounts of fuel at full noise. Normally happens after high RMP then throttle snapped shut.
For what reasons may an aortic valve replacement surgery be needed?
Aortic valve replacement surgery will be required if the valve in the heart is either too narrow for all of the blood to pass through or if the valve is leaking. This valve is very important as it prevents blood from rushing back into the heart after it has been pumped out.
What is the prognosis for aortic valve insufficiency?
The faulty working of the aortic valve can be caused by a birth defect; by abnormal widening of the aorta (which can be caused by very high blood pressure and a variety of other less common conditions).
What does valve overlap cause?
Valve overlap occurs when both the intake and exhaust valves of an engine are open simultaneously during a portion of the engine cycle. This overlap allows for better airflow, improving the engine's efficiency and performance by enhancing the scavenging of exhaust gases and facilitating the intake of fresh air-fuel mixture. However, excessive valve overlap can lead to reduced low-end torque and increased emissions, as it may cause some of the fresh charge to escape before combustion. Overall, valve overlap is a critical tuning parameter in engine design, affecting power delivery and efficiency.
Where is the EGR valve on a 1997 Hyundai Elantra?
Does not have one. The engine uses cam overlap to achieve the effect of the EGR valve.
What does the term valve overlap mean?
Valve timing overlap is the time when both exhaust and intake valves are open most engines with catalytic converters require valve overlap in order to send a small amount of raw fuel/ air mix to the converter's. An "open cam" has valve overlap a "closed" cam does not
How valve overlap affects engine performance?
Valve overlap refers to the period when both the intake and exhaust valves are open simultaneously during the engine's cycle. This can enhance engine performance by improving the scavenging of exhaust gases and allowing a better intake charge to enter the combustion chamber. However, excessive overlap can lead to reduced low-end torque and increased emissions, as fresh air-fuel mixture may escape through the open exhaust valve. Optimizing valve overlap is crucial for balancing power output, efficiency, and emissions across different engine speeds.
What is valve overlap?
Valve overlap occurs in a four-stroke engine at the end of the Exhaust stroke and at the beginning of the Induction stroke; and is when both the exhaust and inlet valves are open at the same time. At the end of the Exhaust stroke, the Exhaust valve is closing and the Inlet valve is starting to open in preparation for the induction of fuel and air into the cylinder. It is common knowledge that in vehicles that cannot alter the valve timing, the Inlet valve opens approx 6 degrees before top-dead-centre and the Exhaust valve closes at 9 degrees after top-dead-centre
What is purpose of valve overlap?
It improves the efficiency of the engine by allowing better exhaust out flow and intake in flow.
When the intake and exhaust valves are both open at the same time that length of time is called?
Valve overlap.
What does a overlap valve do?
send a small amount of raw fuel/air to the catalytic convertor,which increases the efficiency of the operating engine.
Why does valve overlap happen?
Valve overlap occurs in internal combustion engines when both the intake and exhaust valves are open simultaneously at the end of the exhaust stroke and the beginning of the intake stroke. This overlap allows for better exhaust gas scavenging and can enhance the filling of the combustion chamber with fresh air-fuel mixture, improving engine efficiency and performance. It is particularly beneficial in high-performance engines, as it can optimize power output and reduce emissions. However, excessive overlap can lead to rough idling and reduced efficiency at low speeds.
What are the disadvantages to have a large valve overlap?
High end Rpm output tails sooner, engines idle is lumpy, emissions are higher, too much overlap can cause rough low rpm driving, more chance of detonation.
What is meant by the term valve overlap?
There is a short time between the exhaust and intake stroke where all the valves are slightly open at the same time. This period of time is called valve overlap. This is because the intake valves are just starting to open as the exhaust valves are just finishing closing. This is done so flow through the engine can be maintained at engine operating speeds.
How long is the overlap between ruler?
The overlap between rulers can vary depending on their design and intended use, but generally, it is measured by the length of the combined scales that can be aligned. For standard rulers, there is typically no significant overlap since they are used individually. However, in specific applications or designs, such as folding rulers or adjustable rulers, the overlap can be a few centimeters. In practice, ensuring proper alignment is more important than the exact overlap length.
