The following are the key takeaways from this article:
- Valves are an important engine component that the ECU controls depending on the engine speed.
- There are two types of valves (inlet and exhaust valves), where the inlet valve allows the air-fuel mixture to enter the combustion chamber.
- Valves enable the exhaust gases to leave the chamber.
- Common valve problems include bent valves and burnt valves.
- If you hear ticking sounds along with excess tailpipe smoke and loss of engine power, it indicates damaged engine valves.
The ECU controls the amount of air-fuel mixture and the exhaust gases leaving the combustion chamber. The ECU directs the inlet valve to open so the air-fuel mixture can enter the combustion chamber (1). Similarly, the ECU directs the exhaust valves to open for the exit of exhaust gases. So, optimum valve design and their opening/closing timing play a major role in the effective combustion process. This article will further analyze engine valves’ history, function, and problems.
History of Engine Valve
They have fixed the multi-valves in the engine system, which are considered the most important component of the engine. They used the 16 valves in the 2-liter engine tank attached to a single camshaft. During the experiment, the input valves were driven by a single camshaft, and the same camshaft operates the output valve with the help of the rocker’s arm (1). The engine’s outstanding performance was observed using the valves in the engine system. With the development of technology, certain amendments are made to the design system (2). In the 1980s, the new four-valve engine was designed and is now used as the standard design because of its outstanding results and efficiency. But Honda is still using the 16-valve engine in their vehicles.
Types and Functions of Engine Valves
Thus, valves play a vital role in maintaining the flow of gases and liquids. This air then allows to speed up the ignition process, and as a result, the piston is pushed in the up and down direction. This helps in generating a high amount of power (2). The valves in the engine are situated above the piston stroke. As the piston is placed at the bottom of the cylinder, it lets the air and fuel enter the cylinder at the exact time. Thus, these valves open and close at accurate timings, and exact compression is generated, as results help the vehicle’s movement. The valves’ opening and closing depend on the camshaft’s functioning. Initially, the engine’s crankshaft gets the power, which helps move the camshaft. This helps in the movement of the intake valve to move in a downward direction and allows the air and fuel to enter the combustion chamber.
Similarly, the piston closes the intake valve during the compression stroke. Then, the camshaft is again moved during the exhaust stroke, opening the exhaust valves. As a result, the waste products and the fumes are released from the combustion chamber. So, the engine valves are necessary for maintaining the engine’s health.
Problems with the Engine Valves
Due to the synchronization fault, the valves are attached to the top of the piston, and due to the movement of the pistons, the valve becomes defective, and their performance becomes poor (1). Another reason for the bent valves is the misalignment of the timing belt. This impacts the movement of the camshaft, and the valves need to open and close at accurate times. As a result, the engine’s air-to-fuel ratio is disturbed, and the spark needs to be ignited on time. As a result, the minimum power is generated, and the vehicle fails to accelerate. Besides, the fumes and the combustion waste products should be released on time from the combustion chamber. These waste products start depositing on the walls of the cylinders. This results in the release of black smoke, having a rotten egg smell.
This happens when the sealing between the valves is loose. Thus, the required pressure is not generated, and the compression process slows down. Also, the burnt valves result in air leakage, and noise will be observed (2). This poorly impacts the air-to-fuel ratio in the engine. as a result, the engine check light will be illuminated to indicate the errors. Furthermore, due to the damaged exhaust valves, the engine’s performance becomes poor, rough, and idle, and noises are observed from the engine. This indicates the error of the damaged valves and the air leakage (5). As a result, the engine’s performance gets very poor, and the car may suffer serious damage due to the burnt valves.
Symptoms of Bad Engine Valves
Following are a few symptoms of bad engine valves:
The valves in most vehicles operate through hydraulic lifters. These lifters need proper lubrication for opening and closing the valves. So, any problem in the hydraulic lifters will impact the valve performance (4).
The lubrication oil settles this noise as the engine heats up and the car covers a few miles (3). So, if you hear a ticking/popping noise while driving, it indicates that engine valves are facing some problems and might require proper service/replacement.
Excess Smoke from Tailpipe
In this case, the smoke from the tailpipe will be blue, indicating engine oil burning. If you are observing excess black/white smoke from the tailpipe, it is also an indication that valves are not opening at the right time and the engine is burning an excess air-fuel mixture. A bad valve seal can also indicate a constant drop in the engine oil (5). Usually, a car needs oil replacement/refill after 3000-5000 miles. If your car is blinking, change the engine oil light before this traveling mileage, this can be an indication that the engine valves are malfunctioning.
Loss of Engine Power
So, greater acceleration will require the valves to open more frequently to allow the more air-fuel mixture to enter the combustion chamber. However, bad valves would not function optimally, so neither the air-fuel mixture will enter the combustion chamber optimally, nor the exhaust gases will leave timely (3). Therefore, another problem causing engine power loss will be the burnt valves resulting in pressure leakage, impacting the overall engine power loss.