On most vehicles mounted internal combustion engine (ICE). Device it is difficult even for a specialist, especially for the average driver-layperson. However, when buying a car always always refers to the characteristics of the engine. The layman is usually lost before choosing a car at all, or a specific version of it in particular. Try to understand the main technical characteristics of the internal combustion engine.
How many cylinders?
In modern cars from 2 to 16. This rather impressive result. Thus, the two engines of the same size and capacity can differ in other ways.
Position of cylinders
Two types: in-line (sequential) and V-shaped (double row), when one crank shaft cylinders are arranged on both sides. In this case, an important role is played by the camber angle cylinders. Large camber angle lowers the center of gravity, and facilitates cooling oil flow, but it reduces the dynamic characteristics of the increased inertia. Small angle reduces the weight and inertia, but leads to a more rapid overheating.
Radical species - Boxer engine with an angle of a breakdown in 180 °. In this case, all the advantages and disadvantages of the highest. Another variety - W-shaped (four, two synchronized and connected to the overall drive system V-shaped engine).
A very rare type of engine - row-V-shaped, a synthesis of these two species. The cylinders are arranged in series, but with a tolerance on both sides, which contributes to cooling.
Generally speaking, between the two main types of engine weight and dimensions vary. NOdnako important that the lowest level of noise and vibration is achieved when in a row an even number of cylinders.
The combustion chamber
In other words, the volume of the engine. It directly affects absolutely all the other characteristics of the engine. In most cases, an increase leads to a higher power, and of course, fuel consumption.
Material Engine
Usually three options - cast iron or other ferrous alloys (maximum strength, but a lot of weight). aluminum and its alloys (low weight and the average strength) magnesium alloy (minimum weight, high strength, but the price is very high.)
These characteristics are, in general, speak only of the resource, and noise and vibration.
In practice, the output characteristics are more important:
• Power. It is measured in horsepower (hp - the traditional unit of measurement) or kilowatts (kW). It determines the speed and the acceleration car.
• The torque created by the engine maximum traction. Measured in Newton-meters (N • m). Indirectly affects the speed and acceleration and straight - the "elasticity" of the engine that is capable of accelerating at low revs.
• The maximum number of crankshaft revolutions per minute (rev / min)
Shows how many revolutions per minute of the crankshaft the engine can withstand without loss of strength in the resource. The higher the speed, the more dramatic and dynamic vehicle has.
However, an equally important flow characteristics:
• Fuel consumption. Usually measured in liters per 100 kilometers . Consumption in urban, suburban and mixed version is different.
• The type of fuel. Mark of its gasoline or diesel fuel (DF). In modern cars can use any brand, but at lower octane falling resource strength and power, and with an increase in excess of - increased capacity, but reduced resource. Also at higher octane number, the heat transfer, which may lead to early overheating. Example fuel brands: A-76, A-92, A-98, A-95Evro, DT, DT Euro, DT Super.
• Oil consumption. Measured in liters, but by 1000 km . The maximum rate - 1l/1000km for sound machine.
• Make consumed oil. Usually oboznachetsya hhWhh. The first number - the density of the oil, the second - its viscosity. For example - 0W40 and 5W40 - synthetic oils, 10W40 - semi-synthetic oil, 15W40 and 20W40 - mineral oils .. More dense and viscous oils improve the strength and reliability of the engine, less dense - improve the dynamic output performance.
Attention! Oils such as 70W90 or 95W100 gear and are in any case can not be used in the engine - it is guaranteed to cause a malfunction of the engine!
• Resource strength, that is, how often should the engine maintenance. Usually within 5 000-30 000 km
This is a basic consumer characteristics.
However, it should be noted a wide range of more advanced features:
• Type of fuel - petrol and diesel engines. Gasoline typically have more power, but diesel has lower consumption and high torque.
• The type of gasoline injection system. In modern vehicles electronic fuel injection (injection) fuel, which allows for more efficiency. Older, most carburetor fuel intake system. Carburetor sprays, as the injector, the fuel in the combustion chamber, and throws it in the jet, which increases fuel consumption, reduces efficiency and makes the management, less convenient.
Usually installed on the engine carburetor one mnogokarbyuratornye engines are more common tuning and sports models.
• The type of gasoline injection systems - single-point and multi-point fuel injection. Single-point system is almost never used because loss of power far exceeds the savings topliva.Mnogotochechny - distribution and direct injection. With Multi-point injection in the combustion chamber creates a homogeneous mixture, which provides stability on all modes and simplicity.
Direct (direct) injection, paradoxically, increases and power, and resource strength, reduces fuel consumption. But in this case, high-value, high-quality fuel is required and there is instability of operation at low speed and at cold start.
Disadvantages of both systems combined offset (double) injection. It is the application of both systems separately - when changing the electronics "choose" the right one.
• Diesel injection system
Although diesel engine easier gasoline, fuel injection system of its complex, built on a different principle:
Pump - the most simple system of diesel injection with low qualities. System with unit injectors. In this case, each spray nozzle is also a pump supplying fuel to the combustion chamber. Data in this case is better, but the stable operation of the engine is also problematic. Both systems are individually hardly used.
The combination of the high pressure pump and unit injectors - the total ramp fuel high pressure Common Rail. Fuel pump delivers fuel to the ramp, where it is subjected to compression and high pressure is injected into the combustion chamber. Now it is the best system because it provides high power performance and fuel economy.
Improving previous - Battery-returnable ramp Common Rail second generation. Compression occurs in the rail due to the accumulation of fuel, and the surplus goes back to the fuel pump - it reduces pumping losses of power and fuel economy.
• Nozzle injection - mechanical or pezotronnye. They do not affect the characteristics of the engine, but pezotronnye give a smoother work cycle and they are easier to set up.
• Valve Inlet / Outlet 2 to 5 per cylinder. The larger valves, the smoother operation and greater power, though it slightly increases fuel consumption.
Compressor. His role - compression inlet mixture.
• Atmospheric engines - Compressor not.
Engines with compression - compressor (mechanical compressor) and turbo-charged, different type of drive.
• The mechanical compressor is driven directly from the engine crankshaft, which creates some loss of power and increase fuel consumption, turbocharging has turbine impeller, which was driven by the pressure of the exhaust gases. It's more reliable and does not loss but gain less torque, especially at low speeds.
Sometimes placed on the engine, multiple compressors in series (improved stability) or parallel (increase in peak performance mode).
Gas distribution system - valve gear, camshafts and drive. Number of junction trees can vary, but usually one for every 8 valves.
Drive timing - chain or belt. Belt is simpler, but requires regular replacement. Chain safer, but produces more noise (metallic clang), and more.
Valve gear
The simplest - a static mechanism. Dynamic - height adjustable valve lift and variable valve timing.
Changing the height of valve lift allows you to switch between the two modes of motion - for example cost and speed. Variable valve timing provides a smooth operation throughout the operating speed range of crankshaft.
There are many other features of the engine, but they are less affected by their characteristics.
No comments:
Post a Comment