Engine description parameters The standard description is: exhaust volume + arrangement type + number of cylinders + engine special features The basic parameters of the engine Engine placement Engine position is divided by crankshaft vertical and horizontal standards: Engine displacement The maximum power of the engine The maximum torque of the engine is an important parameter of engine performance. It refers to the average torque output from the crankshaft when the engine is running. It is commonly referred to as the engine's "swing." The size of the torque is also related to the engine speed. There are different torques at different speeds, so the unit of torque is Newton.meter/rpm (Nm/rpm). The structure of the engine Inline Engine (LineEngine) The V-type engine divides all cylinders into two groups. The adjacent cylinders are arranged at a certain included angle so that two cylinders form a plane with an angle, and the cylinder is V-shaped when viewed from the side, so it is called a V-type engine. Because the V-type engine is two cylinders, so the number of cylinders are even, as is common: V6, V8, V10, V12, etc., and the V-type engine displacement is relatively large, generally more than 2.5L. W-engine W-engine is a German Volkswagen exclusive engine technology. The principle is: the V-type engine on each side of the cylinder again a small angle staggered, simply put, W-type engine cylinder arrangement is composed of two small V-shaped form a large W-shaped, strictly speaking, W-type engine also Should be a variant of the V-engine. Added: The above small V-shaped scientific name called VR type also called wrong cylinder type, VR staggered small angle of about 15 °, two VR type combination for the W-type! H-type horizontally opposed engines If the in-line engine is viewed as a V-type engine with an angle of 0 degrees, when the angle between the two rows of cylinders is increased to 180 degrees, the cylinders are arranged horizontally opposite each other, which is a horizontally opposed engine. Rotor Engines Several of the above explanations are based on the reciprocating movement of the piston in the cylinder to eventually drive the car forward. All of them are reciprocating engines. The engine and the cylinder itself are relatively immobile. The rotary engine is a triangular piston rotary engine that uses a triangular rotor rotary motion to control compression and discharge. Hybrid Power System For its name, the hybrid power system is based on the traditional diesel engine, plus a power system for other energy sources. Nowadays, the hybrid system is widely used. That is to say, in a car of a diesel engine, an electric motor is added and the two engines work together. Engine intake method Naturally aspirated engines are usually naturally aspirated. Naturally aspirated engines use the negative pressure generated in the cylinder to draw in outside air. As with humans, this type of engine is called naturally aspirated. Gas engine. Turbocharged turbocharged engines are an engine that relies on turbochargers to increase engine air intake. The turbocharger (Tubro) is actually an air compressor. It uses the exhaust gas emitted by the engine as power to propel the turbine in the turbine chamber (in the exhaust passage). The turbine drives the coaxial impeller in the intake port, and the impeller compresses the fresh air sent from the air filter duct and sends it again. Into the cylinder. When the engine speed is increased, the exhaust gas discharge speed and the turbine speed are also synchronized, the air compression degree is increased, and the engine intake air amount is accordingly increased, so that the engine output power can be increased. The supercharger supercharger is connected with the engine crankshaft belt pulley and utilizes the engine speed to drive the internal blades of the supercharger to generate the supercharged air to be sent into the engine intake manifold to achieve supercharging and make the engine output. The purpose of higher power. Carburetor The carburetor type is a fuel supply method that has been eliminated. It mainly uses high-speed airflow to atomize the gasoline and mixes it with air. The cylinder then inhales and ignites the mixture. A single point EFI fuel injector replaces the carburetor with an injector. An ejector is installed in the throttle body in the intake manifold to perform centralized injection on each cylinder. Gasoline is injected into the intake airflow to form a combustible mixture. The air intake is distributed to each cylinder. Multipoint electrospray Unlike single-point electrospray, multipoint electrospray injects fuel from each individual cylinder in each cylinder. The fuel nozzle is installed at the position where the intake pipe is closest to the cylinder, fuel injection and intake air are mixed before the intake valve, and each cylinder is supplied with oil. Multi-point EFI is now the mainstream technology. At present, most models use multi-point EFI engines. . The direct injection fuel nozzle is installed in the cylinder and directly injects the fuel into the cylinder and mixes the intake air. The injection pressure is further increased, so that the atomization of the fuel is more meticulous, and the fuel injection is accurately controlled and mixed with the intake air, and the disadvantages of the injection outside the cylinder are eliminated. YANGZHOU GNEWY MACHINERY EQUIPMENT CO.,LTD , https://www.gnewy.com
According to the position of the engine relative to the body and the direction of its own placement, we divide the engine into the following two categories.
Before the engine is placed, the rear axle is divided:
The entire engine in front of the front axle is called the "front engine" (common English "F" indicates), most cars are front engine.
The whole engine is called "middle engine" (common English "M") between the front and rear axles. Many two-seater supercars adopt this arrangement, such as: Lamborghini LP640, Ferrari F430 and so on.
The whole engine behind the rear axle is called the “rear engine†(commonly used in English “Râ€). There are few such models, and the typical model is the Porsche 911.
The position of the engine is based on the crankshaft position. We divide the engine into two types: horizontal (common English "Q") and vertical (common English "L").
The crankshaft and the direction of the car body are called transverse engines at right angles. Generally, the front-wheel drive vehicles are transverse motors, for example, Volkswagen Sagitar, Peugeot 307, and Toyota Camry.
The parallel to the crankshaft and the direction of the body is called the longitudinal engine. Generally, most of the rear-wheel drive vehicles and all-wheel-drive vehicles are longitudinal engines, such as the Mercedes-Benz C-class, the BMW 3-series, and Toyota Reiz. However, there are exceptions, Audi is a typical front-wheel drive, but the vertical engine.
Maybe you still don't understand, and the point is simpler, if you stand in front of the front of the car, if the engine is horizontally placed in front of your eyes is a horizontal engine, longitudinal portrait in front of your eyes is a longitudinal engine.
Therefore, in our database, there are six cases of engine placement, which are: front engine, horizontal; front engine, longitudinal; middle engine, horizontal; middle engine, longitudinal; rear Engine, horizontal; rear engine, longitudinal.
Refers to the gas volume swept by the piston from top dead center to bottom dead center, also known as the single cylinder displacement, which depends on the bore and piston stroke. The engine displacement is the sum of the working volumes of the cylinders. It is generally expressed in milliliters (ml), and the displacement is one of the most important structural parameters of the engine.
The simple calculation formula for displacement: piston diameter mm × piston diameter mm × stroke mm × 0.7854 (for a fixed constant) / 1000 (converted into cc number) × number of cylinders.
Theoretically, the greater the displacement, the greater the power and torque. But this is not absolute, the key is to adjust the engine. In the same engine, the power tuning in a sports car is higher than that in a sport utility vehicle. On the contrary, the torque of an off-road vehicle is higher than that on a sports car. The purpose of the pursuit is different, and there will be differences in the tuning of the engine. At the same time, due to the intervention of booster technology, small-displacement has already surpassed the level of higher-displacement engine power.
The maximum power is also called the maximum horsepower. The unit of power is kilowatts (kw), the unit of horsepower is horses (PS), and 1 kW = 1.36 horses.
The output power has a great relationship with the speed of the engine. As the speed increases, the power of the engine increases accordingly. After a certain speed, the power will not increase, but will decrease. Therefore, the mark of maximum power will be marked with kilowatts and the corresponding engine speed. The expression of speed is how many revolutions per minute (rpm).
Therefore, the full engine maximum power expression is: kilowatts (rpm)/rotational speed, such as 100kw (136ps)/6000rpm.
Usually the maximum power determines the maximum speed of the car.
The greater the torque, the greater the "strength" of the engine output. Torque determines the car's acceleration, climbing ability and traction.
The structure of the engine is the arrangement of the cylinders. There are mainly the following ways:
All cylinders of the engine are arranged side by side at the same angle in a plane. The cylinders are arranged in a straight line. We call this engine an in-line engine.
Inline engine features: Its advantage is that the cylinder and crankshaft structure is very simple, and the use of a cylinder head, lower manufacturing costs, compact size. The in-line engine has high stability, good low-speed torque characteristics and less fuel consumption, but the disadvantage is that the length of the cylinder increases as the number of displacement cylinders increases. Therefore, in-line engines are generally four-cylinder machines, and a few have six-cylinder machines, such as BMW's famous in-line six-cylinder engine.
V-type engine characteristics: V-type engine height and length of the small size, more convenient in the car layout, but also to leave more space for the cockpit. V-type engine cylinder arrangement, can offset some of the vibration, making the engine run more smoothly; V-type engine's disadvantage is the need to use two cylinder heads, the structure is more complex and higher cost. In addition, after its width is increased, the space on both sides of the engine is small, and it is not easy to arrange other devices.
W Engine Features: The W-type is shorter than the V-type engine, which is advantageous to save space and at the same time the weight can be lighter; the disadvantage is that its wider width makes the engine room fuller.
Volkswagen's Phaeton 6.0 and Audi's A8L 6.0 both use the W12 engine, while the Bugatti Veyron uses the 8.0L w16 engine. W-type engines are generally large displacement engines.
Horizontally opposed engine features: Because its cylinder is "flat", it reduces the car's center of gravity, while allowing the front design to be flat and low. These factors can enhance the driving stability of the car. The horizontally opposed cylinder layout is a symmetrical stable structure, which makes the engine more smoothly than the V-type engine, and the power loss during operation is also minimal. However, due to the horizontal arrangement of the two rows of cylinders, resulting in a very wide engine block, the arrangement of the engine compartment will become more complex, so few manufacturers use.
Currently, only two companies use horizontally opposed engines, namely Subaru and Porsche.
Compared with the reciprocating engine, the rotary engine eliminates useless linear motion, and therefore the same power of the rotary engine is smaller in size, lighter in weight, and lower in vibration and noise, and has greater advantages. Rotary engine's movement is characterized by the fact that the center of the triangle rotor revolves around the center of the output shaft. At the same time, the triangle rotor rotates around its center. When the trigonal rotor rotates, the ring gear centered on the center of the trigonal rotor meshes with the gear centered on the center of the output shaft. The gear is fixed on the cylinder and the ratio of the number of teeth of the ring gear to the gear is 3 to 2.
The above-mentioned kinematic relationship makes the trajectory of the apex of the triangular rotor (ie, the shape of the cylinder wall) look like an "8" shape. The triangular rotor divides the cylinder into three separate spaces. Each of the three spaces completes intake, compression, work, and exhaust. The triangular rotor rotates one revolution and the engine is ignited for three times. Due to the above motion relationship, the output shaft rotation speed is 3 times the rotor rotation speed, which is totally different from the 1:1 movement relationship between the piston and the crankshaft of the reciprocating engine.
Rotor engine characteristics: The advantages of a rotary engine are obvious. It is small in size, light in weight, powerful in power, and extremely low in vibration and noise. The disadvantage is that the rotor technology is complex, the manufacturing cost is extremely high, and the durability is also lower than the conventional engine. Classic example: Only a Mazda manufacturer is currently using a rotary engine. The RX-8 sports car uses a 1.3-liter rotary engine.
The hybrid system is actually a compromise before the alternative energy is researched. His greatest advantage is that he can effectively reduce fuel consumption. The most common hybrid models on the market today are the Toyota Prius, the Honda Civic Hybrid, and the Lexus RX400H.
Supplement for W-type engine and V-type engine: The above small V-shaped scientific name is VR type, the small angle of VR is about 15°, and the two VR type combination is W type! The angle of the V type is generally 60°-90°.
Naturally aspirated engine is characterized by: The power output is very smooth, no sudden sudden acceleration due to the change of the speed, and the service life is longer and the maintenance is easier.
TurboCharacteristics: Normally boosted engine power is 40% or more higher than the original engine; the disadvantage is what we often call "hysteresis." However, after technical improvements, the turbocharger can intervene at a lower engine speed, and the "hysteresis" feel is very small. Currently, in addition to the single-turbo engine, many sport-type vehicles will also be equipped with twin-turbo or even four-turbo engines in pursuit of high performance.
Typical example: Saab is the original user of turbocharged engines and his entire lineup is turbocharged. More common are: Volkswagen Magotan 1.8TSI, Buick Regal 2.0T, 1.6T are turbocharged engines, BMW 335i uses a twin turbocharged engine, Bugatti Veyron is equipped with a 8.0L W16 four turbocharged engine.
Mechanical supercharacteristics: The advantage of mechanical supercharging is "full-time intervention", which makes it possible to obtain supercharging under low rotational speeds. The acceleration experience is quite linear without supercharging lag; the disadvantage is that it depends on the engine crankshaft-driven supercharger. The loss of the power of a certain amount of engine, the high speed loss, and the lower fuel economy are not as good as the turbocharger system. At present, ordinary cars use more than one mechanical supercharger, and some supercars are equipped with dual supercharged engines equipped with two superchargers to obtain greater power. These two superchargers each serve half a cylinder.
Typical example: Nowadays, the most common supercharged engines in China are the 1.8L supercharged engine on the Mercedes C200K and the 3.0L supercharged 3.0T engine on the Audi.
The disadvantage of the carburetor is that the control is not precise enough. In normal driving, it is not possible to quickly reflect changes in the engine load and adjust the mixture concentration. As a result, the engine is often in a state of incomplete combustion. Therefore, the content of harmful substances in exhaust emissions cannot meet the increasingly stringent emission regulations, and at the same time, it will result in higher fuel consumption. By the end of the 1990s, the state had banned production, and now it has completely Was eliminated.
Models used: 1994 Poussin JV carburetor engine, 90 years of Xiali and so on.
The single-point EFI achieved electronic control and the accuracy of fuel supply was improved. However, there is a common defect in carburetor and single-point injection. The location of fuel atomization and intake air mixing is located at the farthest end of the cylinder from the intake manifold. After oil and gas are mixed, it must be distributed to each cylinder, and accurate proportioning cannot be achieved. And even oil and gas mixture, so the high fuel consumption and low power. So single-point EFI is now basically eliminated, and there are few models used.
Use models: Geely Pride 1.3L three-cylinder single-point EFI engine, Chery’s first 1.6L engine.
Multi-point injection enables accurate on-demand fueling per cylinder demand, thus significantly reducing fuel consumption and emissions. However, the disadvantage of this type of “out-of-cylinder injection mixing†is that the mixture entering the cylinder can only be passively controlled through the opening and closing of the valve, and cannot fully meet the requirements of different operating conditions of the engine. Also, the mixture of oil and gas is greatly affected by the intake air flow, and it also adsorbs on the intake pipe wall and the valve to form carbon deposits, causing waste and affecting the engine performance.
The traditional gasoline engine collects the position of the cam and the related conditions of the engine through the computer to control the injector to inject gasoline into the intake manifold. Gasoline begins to mix in the manifold and then enters the cylinder for combustion. The optimal mixing ratio of air to gasoline is 14.7/1 (also known as the stoichiometric air-fuel ratio). Because conventional gasoline is mixed with air in the intake manifold, they can only be mixed together, so the theoretical air-fuel ratio must be achieved. In order to obtain better dynamic and economical, but due to the fuel injector has a certain distance from the combustion chamber, the mixture of gasoline and air is greatly affected by the intake air flow and the valve switch, and tiny oil particles will be adsorbed on On the wall of the pipeline, this theoretical air-fuel ratio is difficult to achieve, which is a problem that traditional engines cannot solve.
To solve this problem, it is necessary to inject fuel directly into the cylinder. Direct-injection gasoline engines use a fuel supply technology similar to that of a diesel engine. A piston pump provides the required pressure above 100 bar to provide gasoline. Electromagnetic injector located in the cylinder. Then the injector is directly controlled by the computer to inject the fuel directly into the combustion chamber at the most appropriate time. Through the design of the internal shape of the combustion chamber, the mixture can generate a strong vortex to fully mix the air and gasoline. Then, the surrounding area of ​​the spark plug can have a relatively rich mixture, and other peripheral areas have a relatively thin mixture gas, which ensures lean combustion as much as possible in the case of a smooth ignition.
Now many manufacturers have begun to use gasoline direct injection technology, such as Volkswagen's 1.8TSI, Audi's 3.2FSI, BMW's 3.0L twin turbocharged direct injection engine, Buick Lacrosse on the 3.0L gasoline direct injection engine.