Numerous components work together in the internal combustion engine. This is the only way for the engine to function properly. Unlike other parts of the engine, the most important engine components are not or hardly visible. Find out now which important core components are hidden inside the combustion engine and what their function is.

Engine block

The engine block is the heart of the combustion engine. It houses numerous components such as the crankshaft and crankshaft bearings. It also unites the cylinders and provides space for the pistons and connecting rods. One or more cylinder heads are located at the top of the cylinder banks of the engine block. Depending on the design of the engine, the engine block can be constructed differently and have a different shape. For example, engine blocks for V-engines differ from those for in-line engines or boxer engines. In liquid-cooled engine variants, the block also includes cooling ducts and the water jacket for engine cooling.

Cylinder head

The cylinder head seals off the combustion chamber of the internal combustion engine from the engine block. The interior of the cylinder head also houses all the important components of the mechanical gas exchange control system. In addition, the cylinder head dissipates combustion heat and also forms the upper closure of the engine. The cylinder head contains numerous valve control components and the corresponding channels for supplying lubricant to the valve train. These include the intake and exhaust valves together with the intake and exhaust ducts for the cylinders. The injection nozzles are also located in the cylinder head. In addition, the spark plugs in gasoline engines and the glow plugs in diesel engines.

Cylinder

The cylinders guide the pistons of the internal combustion engine and support them as they move. The combination of engine pistons, cylinders and cylinder head defines the engine’s combustion chamber. When the internal combustion engine operates, the piston moves up and down in its associated cylinder. An oil film on the cylinder wall provides lubrication. Depending on the engine design, cylinders can differ in terms of their design and material. In modern engines, the surfaces of cylinders are sometimes specially coated to allow the piston to run better. The heat generated during combustion is dissipated via the cylinders and delivered to the cooling system in the engine block.

Piston

The engine’s pistons are moving components inside the engine block. During operation, the engine pistons move in the cylinders and transmit power to the connecting rods. Together with the cylinder, the pistons form a closed cavity. The volume of this space changes depending on the position of the piston inside the cylinder. Each piston is firmly connected to an engine connecting rod, which in turn is coupled to the crankshaft. When the piston is at about the top point of the cylinder, ignition of the fuel-air mixture in the cylinder occurs. The piston is accelerated by the energy released and transmits this as mechanical work to the crankshaft via the connecting rod.

Crankshaft

The crankshaft converts the power released during operation of the internal combustion engine into rotary motion. The motion thus generated is fed to the driveline, which ultimately transmits it to the wheels of the vehicle. For this purpose, the crankshaft is connected to the engine’s pistons, each of which can only move linearly in the cylinders, via a separate connecting rod. To convert the linear motion of the pistons, the crankshaft has a special shape and is forged from steel. The shaft is shaped according to the principle of several cranks, and differs depending on the engine principle and the number of cylinders. Thus, the shape of the crankshaft ultimately also determines at which position in the cylinder which piston is located.

Connecting rods

The connecting rods provide the connection between the crankshaft and the pistons in the cylinders. These engine components are sometimes also referred to as connecting rods or connecting rods. The connecting rod is connected to the piston on one side and to the crankshaft on the other. Both connections allow the rod to move. If the piston moves up and down in the cylinder, this force is transmitted directly to the connecting rod. Connecting rods are subjected to considerable loads during engine operation. These include tensile forces, compressive forces and forces with regard to bending and buckling. For this reason, the connecting rods of the internal combustion engine are often made of alloy steels or sintered metals.

Camshaft

The camshaft is an important component of the engine control system of the internal combustion engine. It is a shaft that is equipped with cams. Through these, the shaft in turn opens and closes the valves of the engine. This allows air or combustion mixture to flow in and exhaust gases to flow out at the appropriate time. The position of the camshaft can vary depending on the engine design. In modern engines, the camshaft is usually located in the cylinder head, from where it controls the valves. The shaft is set in motion by the crankshaft when the engine is running. For this purpose, it is connected to the crankshaft by means of a timing chain, a toothed belt or gears.

Valves

The valves of the internal combustion engine control the exchange of charges and thus the inflow and outflow of gases at the cylinders. When closed, a valve securely seals the combustion chamber so that an optimum gas exchange takes place. Each cylinder is equipped with at least one intake valve and one exhaust valve, but often with more than one. The engine’s valves are arranged in the cylinder head, where they are subject to optimum lubrication and heat dissipation. The movements of each valve are controlled and triggered by the camshaft. When the intake valve is open, fresh air or ignitable mixture can flow in. When the exhaust valve is open, exhaust gases are safely discharged.

Spark plugs

The spark plugs of an engine provide the ignition spark and ignite the mixture in the cylinder at the right time. This ignition of the mixture of fuel and air is only necessary in gasoline engines. Therefore, no spark plugs are installed in diesel engines. In gasoline engines, combustion depends on reliable ignition of the ignitable mixture. At least one spark plug is installed in each cylinder of the internal combustion engine. Depending on the engine speed, the spark plug must ignite the mixture several thousand times per minute. Spark plugs have a metal core and a ceramic insulator. At its tip, the spark plug is equipped with a center electrode and a ground electrode; this is where the ignition spark is generated.

Injectors and injection valves

Injectors or injection nozz les are responsible for injecting fuel into the combustion chamber or intake tract of the internal combustion engine. In diesel engines, the term injection nozzle has become established for these components. In gasoline engines, they are often referred to as injection valves. Both variants differ in part in their design. Injection nozzles and injection valves ensure that fuel is supplied at the right moment and increase the efficiency of the modern combustion engine. Today, electrically actuated valves are mostly installed as injection valves in engines. These enable the fuel to be injected with a specific spray pattern, which ensures optimum combustion.

Timing belt or timing chain

The timing belt or timing chain in the engine takes over the control of the combustion engine. Depending on the engine type and design, either one or the other is installed. However, both components form the connection between the camshaft and the crankshaft. This transmits the movement of the engine to the valve control system. Engine components such as the timing chain or timing belt are important for the combustion engine to function properly. If the component is elongated or otherwise defective, the timing of the valves will not match the movement of the pistons. The timing chain is made of metal links, while the timing belt is made of elastic plastic.