Internal combustion engine layout

The engine can be said to be the most important part of a car, and its layout has a great impact on the performance of the car. For passenger cars, the layout of the engine can be simply divided into three types: front-engine, mid-engine, and rear-engine. Currently, most models on the market adopt front-engine, while mid-engine and rear-engine are only used in a few high-performance sports cars.
Of course, according to the arrangement of the engine, it can also be divided into transverse engine and longitudinal engine.
Front Engine
Front-engine means that the engine is located in front of the front axle. The advantages of front-engine are that it simplifies the structure of the vehicle's transmission and drive axle, especially for the current mainstream front-wheel drive models. The engine directly provides power to the front wheels without the need for a long drive shaft. This not only reduces power transmission loss, but also greatly reduces the complexity and failure rate of the power transmission mechanism.
In addition, placing the engine in front of the driver can protect the driver from impact in the event of a frontal collision, thus improving vehicle safety.
Mid-engine
Mid-engine means that the engine is located between the front and rear axles of the car, and the cockpit is generally located before or after the engine. It can be said that a mid-engine car is definitely rear-wheel drive or four-wheel drive.
When the car turns, due to inertia, all parts of the car will move outwards, and the engine is the heaviest part. Therefore, the force exerted on the car body by the engine due to inertia has a crucial impact on the steering when the car turns. The characteristic of a mid-engine is that it places the engine, which has the largest inertia of the vehicle, in the center of the car body, which can make the weight distribution of the car body close to the ideal balance state. Generally speaking, only supercars or sports cars that focus on driving pleasure will use mid-engine.
Rear Engine
Generally speaking, the most authentic rear-engine layout is behind the rear axle, the most representative of which is the bus. Among the few passenger cars that use rear-engine, the most representative is the Porsche 911, and of course, the Smart is also a rear-engine. The classic models of the Volkswagen Beetle and Fiat 126P are also rear-engine.
Transverse Engine
A transverse engine refers to an engine that is parallel to the front axle of the car. Simply put, you are standing in front of the car, facing the engine. If the engine is horizontally placed in front of you, it is a horizontally placed engine.
Generally speaking, front-wheel drive compact cars, most mid-size cars, and a few high-end cars use a transverse engine layout.
Vertical Engine
A vertical engine refers to an engine that is perpendicular to the front axle of the car. Simply put, you are standing in front of the car facing the engine. If the engine is perpendicular to your front, it is a vertical engine.
Generally speaking, rear-wheel drive vehicles use longitudinal engines because the power needs to be transmitted to the rear axle. In the case where the transmission distance cannot be shortened, it is necessary to minimize the change in the direction of power as much as possible. If a transverse layout is adopted, because the direction of the crankshaft and the drive shaft are perpendicular, it is necessary to change the direction first before transmitting the power through the drive shaft. However, the direction of the drive shaft is also perpendicular to the direction of the rear axle, so it is necessary to change the direction of rotation again at the rear axle, which will undoubtedly reduce the efficiency of the transmission system. After using a vertical engine, the crankshaft can be parallel to the drive shaft, reducing one change in the transmission direction, which undoubtedly reduces energy loss.
Inverted Engine
"Inverted" is a special arrangement of transverse engines. Usually, the exhaust manifold of a transverse engine is in the front and the intake manifold is in the rear, simply put, it is "front-in, rear-out". If the intake and exhaust positions are reversed, the intake manifold is in the front and the exhaust manifold is in the rear, becoming "front-in, rear-out", it is called "inverted". Only horizontally installed engines have the concept of "front-in, rear-out", while vertically installed engines have intake and exhaust manifolds on the left and right ends respectively, and there is no significant difference after swapping, so there is no such concept.