9 Types of Engine Systems (For 2021)

All kinds of cars and other vehicles have a variety of systems. They work together in harmony to keep your car up and to run. Thus, it’s essential that you know each type and understand how they work. If you wonder how many types of engine systems exist and what these systems are, here’s the answer.

There are nine types of engine systems. They are Starting System, Fuel System, Ignition System, Cooling System, Lubrication System, Intake System, Exhaust system, Charging System, and Engine Electronic Control System. Each of these systems performs a task for the overall performance of your car.

Since each engine system plays a specific role in a car, you must understand how each one works to grasp your car’s performance. In this article, we’ll walk you through each one to have an idea about these systems.

Types of Engine Systems

What Are Types of Engine Systems?

All cars and vehicles consist of a variety of engine systems that have specific functions. All these engine systems work simultaneously and in harmony. Thus, a failure of one can result in your car’s failure as well.

Below is a list of the nine engine systems.

  • Starting System
  • Fuel System (different for diesel engines )
  • Ignition System (different for diesel engines)
  • Cooling System
  • Lubrication System
  • Intake System
  • Exhaust system
  • Charging System
  • Engine Electronic Control System

One thing to note is that these nine systems are what you will usually see in petrol engines. If you own a diesel engine, you may find a different system for fuel and ignition. However, the rest would likely be the same.

Another thing is that these systems are built into the engine, while others are attached. Moreover, some parts are on the body panels in the engine hood.

Let’s take a better look at each one.

Starting System

The first engine system to understand is the starting system since it’s where all the work begins. This system works by rotating the engine during starting.

It consists of parts like an electric motor and a drive. The latter has a small pinion meshing with the ring gear on the flywheel while you start.

Further, the battery gives the electric current to operate the starter. It rotates the engine until it fires and runs on its own.

Starting System

Fuel System

From the name itself, the fuel system concerns the fuel of the whole engine. In general, this system can be classified into four basic types. They are as follows:

  • Carburetor system for petrol engines
  • Fuel injection system for petrol engines
  • Gas fuel systems
  • Diesel Injection system

These systems operate in different ways. However, they all have a fuel tank or cylinder to store fuel. Further, all systems have a way of supplying the engine with fuel.

Aside from these functions, all four fuel systems supply air and fuel mixed in appropriate portions. As a result, they effectively burn in the combustion chambers.

Fuel System

Ignition System

Petrol engines and engines running on gas need an ignition system. The system works by providing sparks that fire the charges in the combustion chambers.

Thus, petrol engines are often known as spark-ignition engines. It separates them from diesel engines. The diesel engines don’t need spark because they use compression-ignition.

Combustion in diesel happens when the fuel gets sprayed into the combustion chamber. The air present in the cylinder will come at a high temperature due to compression.

The temperature would be high enough to ignite the fuel sprayed from the injector.

Ignition System

Cooling System

The next type of engine system is the cooling system. It’s a no-brainer that the continuous fuel burning would result in extreme heat. It’s where the cooling system plays its part.

While some of the heat do some work, the others get transferred to other parts of the engine. Then, the remaining heat would then get released through the exhaust.

Still, there will always remain some heat that can cause damage, and it’s where the cooling system starts to play its role. In general, the cooling system removes one-third of the heat brought by the engine.

Aside from heat removal, the system also maintains the engine temperature at a certain amount. In a liquid-cooling engine, such work gets done by circulating the coolant through water jackets.

In an air-cooled engine, the cooling work gets done by passing the air through the cooling fins.

Cooling System

Lubricating System

This system consists of an oil pump, a relief valve, and a filter. It also includes the pipes, passages, and drilling in parts of the engine where the oil can flow.

The lubricating system work begins when an amount of oil gets held in the oil pan. From this point, the pump would take the oil, circulating throughout the engine until it returns to the pan.

During the process, it lubricates all the moving parts. It does not only reduce friction. Moreover, it also prevents wear and damage.

The crankshaft directly drives the oil pump in the system. Moreover, it includes an oil cooler, and you can see it at the filter mounting under the filter.

Lubricating System

Air Intake System

The Air Intake system works in various ways, depending on the engine type.

In petrol engines with electronic fuel injection, the air intake system includes:

  • Air Cleaner
  • Ducting
  • Throttle Valve Assembly
  • Intake Manifold

The nozzles of the fuel injectors spray fuel into the air passing from the intake manifold into the intake ports.

In carburetor fuel systems, a mixture of air and fuel gets carried from the carburetor. It passes through the intake manifold and in the engine through the intake ports.

On engines operating on gas, the intake manifold takes the mixture of air and gas into the engine.

Lastly, petrol engines with fuel injection diesel engines get clean air only through the intake manifold.

Air Intake System

Air Exhaust System

The next one is the air exhaust system, and it works by carrying away the burnt gases away from the engine. As a result, it reduces noise along the process. This system consists of:

  • Exhaust manifold
  • Exhaust pipes
  • Catalytic converter
  • Muffler

The arrangement of these parts may vary depending on the engine type. An engine can even have more than a single muffler and catalytic converter.

Some engines don’t have a catalytic converter. Among these are the engines running on lead replacement petrol and diesel engines.

The exhaust system work begins when in-taken air enters. At the same time, the exhaust gases get released from the engine through the valves.

The exhaust manifold collects the burnt gases from all cylinders in one place. Afterward, it passes through the muffler. In automobiles, a catalytic converter gets installed to convert CO into CO2.

Air Exhaust System

Charging System

The charging system works by transforming mechanical energy into electrical energy. This work happens through the alternator.

The battery provides energy for the starter, the ignition system, and the electronic fuel pump.

The battery will continue doing so until the engine runs on its own. Afterward, the alternator supplies all the electrical energy.

It also recharges the battery to replace the energy used during starting.

Charging System

Engine Electronic Control System (ECU)

The last type of engine system is the engine electronic control system (ECU). It consists of parts such as sensors, a control unit, and actuators.

It starts working as the control unit receives signals from the sensors. As soon as it does, it will then send the signals to various actuators.

The sensors in the engine are in other systems such as the intake and exhaust. The injectors serve as actuators, adjusting the spray of fuel.

Moreover, some actuators are in the ignition system, advancing and retarding the spark.

Engine Electronic Control System


In a nutshell, there are nine types of engine systems that you can find in car engines. These nine are Starting System, Fuel System, Ignition System, Cooling System, Lubrication System, Intake System, Exhaust system, Charging System, Engine Electronic Control System.

These nine systems are what you’ll likely find in a petrol engine. However, you can also find the same in diesel engines, excluding the duel and ignition systems.

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Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more