Understanding DOHC Engine Technology in Cars: Functions and How It Works

26 February, 2023
7 minutes read

Image Understanding DOHC Engine Technology in Cars: Functions and How It Works

First off, this machine is considered revolutionary in the automotive world, especially for cars. Because of its advantages, DOHC engines have been used in various types of cars, from private vehicles to sports cars.

This machine has also become a favorite of many manufacturers because it can offer better performance and more efficiency. This engine is very important because it is able to provide better performance and higher efficiency in circulating air and exhaust gases in the engine.

Then, how can the DOHC engine improve the performance of motorized vehicles, and why is it the right choice for motorized vehicles with high performance needs? For more details, see the meaning, function, how it works, to the difference with the SOHC engine.

What Is a DOHC Engine?

The DOHC engine, which stands for Double Overhead Camshaft or in Indonesian it is referred to as the double overhead camshaft, is a type of automotive engine used in cars. In this machine there are two steering shafts which are located at the top of the engine block and function to drive the intake and exhaust valves in the engine cylinders.

In addition, this type of engine has different characteristics from other types of engines, such as SOHC engines. This makes the use of DOHC engines increasingly popular in the latest cars.

The following is an explanation of the DOHC engine:

  • DOHC has two crankshafts and two camshafts which are above the cylinder block. This allows the engine to have more and more accurate opening valves, thereby increasing fuel combustion efficiency and engine performance.
  • DOHC engines have more components than SOHC engines, such as camshafts, tappets and rocker arms. However, this engine can produce more power and faster response because of these components.
  • These engines are easier to modify, as they have separate components that can be replaced easily. This makes this engine a popular choice for racers looking to improve the performance of their car.

Fungsi DOHC pada Mobil

DOHC Function on Cars

The DOHC engine has a very important function in the car. Essentially, it functions as the prime mover of the car to generate power and spin the wheels of the car.

1. Improve Fuel Combustion Efficiency

With the presence of two camshafts that control the opening valves on each cylinder, this engine is able to produce more efficient combustion. This can improve fuel efficiency and reduce exhaust emissions.

2. Improve Engine Performance

This engine is also capable of producing more power and faster response because it has more opening valves and more accurate components. This makes it a popular choice for high-performance cars.

3. Increase Car Speed

This engine can also produce more power at high speeds, so that the car can reach higher speeds.

How DOHC Engines Work

DOHC is a very popular engine technology in automotive circles. This technology is used in modern high-performance car engines. However, how exactly does this machine work? Here's an explanation:

1. Controls Intake and Exit Valves

It has two separate camshafts, one to control the intake valves and one to control the exhaust valves. The camshaft that controls the intake valves opens and closes the intake valves while the piston is in the upward motion. Meanwhile, the camshaft that controls the exhaust valve opens and closes the exhaust valve when the piston is in the downward movement.

The DOHC valve mechanism is different from the SOHC valve. The piston moves from top dead center (TDC) to bottom dead center (BDC) with the in valve position open and the ex valve closed. This causes air or gas to enter the combustion chamber through the intake system.

Furthermore, the piston moves from TMB to TMA, with the inlet and outlet valves closed. This process results in compressed air or gas in the combustion chamber. Before the piston reaches top dead center, the ignition process occurs with the spark plug flame. The burning gas will increase the pressure in the combustion chamber, causing the piston to be pushed back to the bottom dead center.

This process will generate power. Finally, the piston moves back from bottom dead center to top dead center with the inlet valve closed and the outlet valve open. This process makes the remaining combustion gas be forwarded to the exhaust hole.

2. Improves Fuel Efficiency

When the engine is running, air mixed with fuel enters the combustion chamber. Then, the air and fuel mixture will burn and produce power. With DOHC technology, the inlet and exhaust valves can be opened and closed more timely so as to make combustion more efficient. With better combustion efficiency, the engine can produce more power while still saving fuel.

3. Improve Engine Performance

DOHC technology can improve engine performance by producing more power. With two separate camshafts to control the intake and exhaust valves, the engine can work more effectively. This engine can produce more power than a SOHC engine at higher engine speeds.

Perbedaan DOHC dan SOHC

The Difference Between DOHC and SOHC

DOHC and SOHC are two types of engine designs that are often used in vehicles. These two terms refer to the position of the engine crankshaft and the number of camshafts that actuate the valves.

Then, what's the difference? For more details, see the difference of DOHC vs SOHC below:

1. Principles and How DOHC Works

DOHC has a valve drive system that has two camshafts located above the engine block. Each camshaft has two or more camshafts that actuate the valves. The upper camshaft controls air intake and the lower camshaft controls the exhaust. This system can provide better performance because it allows the engine to circulate air and exhaust gases more efficiently.

2. Principles and How SOHC Works

SOHC or Single Overhead Camshaft is a valve drive system that has only one camshaft which is located above the engine block. The camshaft has one camshaft that drives all the valves. In a SOHC system, the camshaft controls air intake and exhaust. Because it has only one camshaft, the SOHC system is simpler than the DOHC and easier to maintain.

3. Main Differences DOHC and SOHC

The difference in the number of camshafts and camshafts used to drive the valves. DOHC has two camshafts and several camshafts, while SOHC has only one camshaft and one camshaft.

4. DOHC & SOHC Performance Differences

The difference is that DOHC can provide better performance, but is more complicated and expensive to maintain. Meanwhile, SOHC is simpler and easier to maintain, but its performance tends to be lower than DOHC. An example of a DOHC engine can be seen in the Wuling New Cortez, which has a Turbocharged inline 4-cylinder engine with a capacity of 1,500 cc and can produce power equivalent to 140 horsepower at 5,200 rpm and 250 Nm of torque. This fuel consumption is also economical, and good maneuverability makes the driver more efficient. With extraordinary engine capabilities, the price of the Wuling Cortez CT remains pocket-friendly.

DOHC Advantages and Disadvantages

The latest cars that pursue performance aspects usually use DOHC engine technology. So it's no wonder, there are several advantages that make this machine continue to be developed, also supported by variable valve technology.

The advantages of DOHC engines for cars:

  1. Provides a higher response rate
  2. Stronger and longer torque
  3. More responsive acceleration
  4. Reducing the load on the fuel system
  5. More efficient performance

Although it has many advantages, this machine also has weaknesses. The most visible is the construction of the camshaft which is quite complicated.

Weaknesses of DOHC engines for cars:

  1. The number of components required for this machine makes maintenance costs and replacement of spare parts quite high.
  2. More complicated and more difficult to maintain
  3. Requires a lot of space to install
  4. More complicated to modify
  5. More wasteful of fuel.

The New Cortez MPV car is a family vehicle that has an engine capacity and a combination of DOHC engines that are beneficial to its users. Thus, choosing a car that has been optimized for DOHC engine technology provides a more powerful advantage when driving.

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