Diesel Generator Knowledge

In a diesel generator set, a diesel engine generates a certain amount of power by burning mixed air. There are armature windings and field windings or permanent magnets inside the alternator. The armature windings are conductors, and the field windings or permanent magnets can generate magnetic fields. Therefore, the power of the diesel engine is used to drive the armature winding or field winding or permanent magnet of the generator to rotate. Using the principle of “electromagnetic induction”, the generator will output induced electromotive force, and current can be generated through the closed load circuit.
So simply speaking, the power generation principle of the diesel generator set is that the diesel engine transfers mechanical energy to the alternating current generation so that the closed-circuit inside the generator and the magnetic field in the generator cut the magnetic field lines to generate electric energy.

The structure of the engine

Answer: Engines are classified into gasoline engines, diesel engines, and gas engines according to different fuels. Although there are many structural forms of the engine, and the specific structure is also diverse, but because of the same basic working principle, the basic structure is still the same as the overall function. The gasoline engine is composed of two major mechanisms and five major systems. The diesel engine Because the combustion of diesel is compression spontaneous combustion, the ignition system is missing.
<1> Crank and connecting rod mechanism
The crank connecting rod mechanism is the main moving part of the engine to realize the working cycle and complete the energy conversion. It consists of a body group, a piston connecting rod group, and a crankshaft flywheel group.
<2> Air distribution mechanism
The function of the valve mechanism is to regularly open and close the intake valve and exhaust valve according to the working sequence and working process of the engine so that combustible mixture or air enters the cylinder, and exhaust gas is discharged from the cylinder to realize the air exchange process. The opening and closing of the intake and exhaust valves are controlled by the camshaft. The camshaft is driven by the crankshaft through a toothed belt or gear or chain. The intake and exhaust valves, camshafts, and other parts together form the valve train.
<3> Fuel supply system
The function of the gasoline engine fuel supply system is to formulate a certain amount and concentration of mixed gas according to the requirements of the engine, supply it to the cylinder, and discharge the burned exhaust gas from the cylinder to the atmosphere;
Diesel engines rely on natural compression to mix air, so the fuel supply system of diesel engines is relatively complicated. The function of the diesel engine fuel supply system must not only configure a certain amount and concentration of mixed gas but also have a certain pressure. The diesel engine sucks in pure air during the intake stroke. When the compression stroke is nearing the end, the diesel oil is increased to over 10MPa through the fuel injection pump and injected into the cylinder through the fuel injector. It mixes with the compressed high-temperature air in a short period of time to form a combustible mixture. Due to the high compression ratio of diesel engines (usually 16-22 ), the air pressure in the cylinder can reach 3.5-4.5 MPa at the end of compression, while the temperature is as high as 750-1000 K (while the gas mixture pressure of gasoline engines at this time will be 0.6-1.2 MPa, The temperature reaches 600-700K ), which greatly exceeds the auto-ignition temperature of diesel. Therefore, after diesel fuel is injected into the cylinder, it will immediately self-ignite and burn after being mixed with air within a short period of time. The air pressure in the cylinder rises rapidly to 6-9MPa, and the temperature also rises to 2000-2500K. Driven by the high-pressure gas, the piston moves downward and drives the crankshaft to rotate to perform work. The exhaust gas is also discharged into the atmosphere through the exhaust pipe.
<4> Lubrication system
The function of the lubrication system is to deliver a certain amount of clean lubricating oil to the surface of the relative moving parts to achieve liquid friction, reduce friction resistance, and reduce the wear of mechanical parts. And clean and cool the surface of the parts. The lubrication system usually consists of a lubricating oil passage, an oil pump, an oil filter, and some valves.
<5> Cooling system
The function of the cooling system is to dissipate part of the heat absorbed by the heated parts in time to ensure that the engine works at the most suitable temperature. The cooling system of a water-cooled engine usually consists of a cooling water jacket, a water pump, a fan, a water tank, and a thermostat.
<6> Ignition system
In a gasoline engine, the combustible mixture in the cylinder is ignited by electric sparks, and the ignition system is usually composed of batteries, generators, distributors, ignition coils, and spark plugs.
Diesel engines rely on compression for spontaneous combustion due to the combustion of mixed gas, so diesel engines lack an ignition system compared with gasoline engines.
<7> Starting system
It is not difficult to understand this. To make the engine transition from a static state to a working state, the crankshaft of the engine must first be rotated by an external force to make the piston move back and forth. The combustible mixture in the cylinder burns and expands to work, pushing the piston to move to make the crankshaft rotate. The engine can run on its own, and the work cycle can proceed automatically. Therefore, the whole process from when the crankshaft starts to rotate under the action of external force to when the engine starts to run automatically is called engine start. The device required to complete the starting process is called the engine’s starting system.

What is an OEM manufacturer?

Answer: OEM production, namely OEM production, also known as OEM production, commonly known as “OEM”, because it’s English expression is Original Equipment/Entrusted Manufacture (translated as an original equipment manufacturer or origin commissioned processing), so it is abbreviated as OEM. The basic meaning of the brand producers do not directly produce goods, but to use their own grasp of the key core technology responsible for the design and development of new products, control of distribution channels, the specific processing tasks entrusted to other manufacturers of similar products through contractual subscription basis, after Buy out the ordered products at a low price and directly paste their own brand trademarks. This cooperative method of entrusting others to produce is referred to as OEM. The manufacturer that undertakes the processing task is called the OEM manufacturer, and the products it produces are called OEM products.

The main brands and characteristics of diesel generator set currently on the market

Answer: At present, diesel generator sets in the domestic market can be divided into the following according to their production locations:
The original imported diesel generator set means that the production place of the whole set of products is outside China. The main brands on the market are FG Wison ( Wilson) -Origin: the UK, Caterpillar (Caterpillar) -Origin: the United States, Cummins Power Generation (Cummins Power System)-Origin: the United States, MGS-Origin: Singapore, etc.
Domestic assembled diesel generator sets refer to the production of the whole set of products in China, the main component engine is an imported product, and the brand naming of each manufacturer is customary to name the diesel engine brand. Such as VOLVO (Regal), MTU (Mercedes-Benz), P Perkins (Perkins), Mitsubishi (Mitsubishi), Doosan Daewoo (Doosan – Daewoo), MAN (MAN), Deutz (Deutz hereby), and the like.
The purely domestic diesel generator set refers to the complete set of diesel generator sets produced by domestic manufacturers, and its main components are also domestic products, such as Wuxi Power, Jichai, Shangchai, and other diesel engines sets.
The following is a brief analysis of the current situation of major brand engines in the market:
<1> Cummins series engine
Cummins INC. (USS) was founded in 1919 and is headquartered in Columbus, Indiana, USA. Chongqing Cummins Engine Co., Ltd. (CCEC) is a Sino-US joint venture producing heavy-duty and high-power diesel engines. It is the first production base invested by Cummins in China.
The unique fuel supply system adopts an advanced PT pump and fuel injection system, which can greatly reduce leakage and greatly increase the fuel atomization rate to make the combustion more complete. It is also a representative of Cummins’ advanced technology.
Cummins engines meet the most stringent environmental protection standards, and products meet the requirements of the California Air Resources Board (CARB), the US Federal Agency (EPA), the Japanese Builders (MOC ) and the European Union No. 1/2, and the European No. 3, etc. The most stringent emission standards
General matching unit power range: 2KW—2000KW
<2> Volvo series engines
VOLVO heavy trucks and cars are well-known all over the world, and VOLVO diesel engines are also outstanding. The cost of use is one of the first things users must consider. VOLVO-PENTA, located in Gothenburg, Sweden, has always put the interests of users in the first place since its establishment in 1868. Since the production of single-cylinder engines in 1907, the first automobile engine order was received in 1926, and the introduction of turbocharging technology into automobile diesel engines for the first time in 1954, VOLVO has been fully committed to research on reducing diesel engine fuel consumption and emissions. Volvo diesel engines dominate the world with low fuel consumption, low emissions, and low noise. They are regarded as a model of energy-saving and environmental protection, to minimize the operating cost and emission toxicity of each engine.
General matching unit power range: 68KW—506KW
<3> Perkins (PERKINS) series engine
British Perkins (PERKINS) is a well-known diesel engine manufacturing company with a history of more than 60 years in Europe. Founded in 1932 by entrepreneur and engineer Frank Perkins. At present, it has three production bases and more than 4,000 global after-sales service networks, with an annual output of 300,000 engines. As a professional engine manufacturer, PERKINS provides a wide range of diesel engine varieties for users to choose from. Whether it is used for trucks, construction machinery, marine power, generator sets, or military supplies such as tanks and speedboats, PERKINS will always be loved and loved by users.
Perkins engines all use an independent direct fuel injection system, low smoke emissions (1306, 2206, 2506, 2806 series EFI engines reach Euro 3 standards), stable performance, good power-to-weight ratio, small size and compact structure, beautiful appearance, convenient installation, easy maintenance, abundant spare parts, timely technical support.
General unit power range: 9.5KW—2000KW
<4> MAN series diesel engine
The world’s first diesel engine was born in the German MAN company in 1897.
The German MAN Group has been a world-renowned classic engine manufacturer for one hundred years.
Today, the German MAN Group is already one of the leading companies in the European machinery and vehicle manufacturing industry, with annual sales of 16 billion euros and approximately 76,000 employees. In core areas such as diesel engines, commercial vehicles, industrial services, and printing machinery, it has a leading position both in technology and in the market.
General matching unit power range 200KW—704KW
<5> MTU (Benz) series diesel engines
Mercedes-Benz is the world’s top car brand, and its world’s first steam-powered engine was manufactured by Mercedes-Benz. MTU diesel engine’s unique electronic management system (MDEC ) enables the diesel engine to have the best performance under various operating conditions. At the same time, it is also the only one of many brands to use electronically controlled common rail fuel injection systems on high-power units to ensure low fuel value and the best emissions.
General matching unit power range 515KW-2750KW
<6> Mitsubishi series diesel engines
Mitsubishi Heavy Industries is the largest military manufacturing company in Japan. In 2003, the military industry orders received from the Defense Agency amounted to 280 billion yen, ranking first among all military industry enterprises. The equipment produced by Mitsubishi Heavy Industries, such as F-2 and F-15J fighters, and Type 90 tanks, play a central role in the Air Self-Defense Force and the Ground Self-Defense Force. In the Maritime Self-Defense Force, Mitsubishi Heavy Industries has built almost half Of the submarines and a third of destroyers. Its position in the Japanese military industry is evident. Since its establishment in 1917, Mitsubishi Heavy Industries has continuously improved its engine product technology. The current Mitsubishi MGS series diesel generator sets provide higher power generation and more advanced control systems than before and continue to research and develop to ensure the highest reliability. Therefore, the quality of Mitsubishi diesel generator sets has also been affirmed by the public.
General matching unit power range 5KW—1600KW
<7> Wuxi Power
Wuxi Wandi Power Engineering Group Co., Ltd. is a large-scale backbone enterprise that develops and produces internal combustion engines, turbochargers, diesel generator sets, and their parts. It is a high-tech enterprise in Jiangsu Province and a top 100 enterprise in Wuxi City. The predecessor was a public-private joint venture established in 1956. Wuxi Power Machinery Factory. In 1994, Wuxi Power Engineering Co., Ltd. was standardized and restructured into a privately raised joint-stock company, and Wuxi Wandi Power Engineering Group Co., Ltd. was established in the same year. In 2004, it was restructured into a limited liability company with diversified investment entities. In January 2008, it was restructured into a joint-stock enterprise collectively held by the backbone of the enterprise. It is the leader of domestic diesel generator sets.
General matching unit power range 250KW—720KW
<8> Ji Chai
Founded in 1920, Jichai is one of the earliest manufacturers of diesel engines in my country. It was named “Jinan Diesel Engine Factory” in 1953 and is still in use today. As early as the 1960s, the high-power 190 diesel engine was successfully developed, giving China Petroleum drilling rigs their own heart. Over the years, Jichai engines have equipped more than 90% of China’s oil rigs, breaking the technical constraints and price monopoly of similar products abroad, and have made due contributions to the development of China’s petroleum industry.
In recent years, under the guidance of the scientific development concept, Jichai has adhered to the character development path, vigorously implemented the “diversified and international” development strategy, and created a series of internal combustion engines that can be applied to multiple fuels, suitable for multiple fields, and different cylinder diameter series. Won the only domestic non-road internal combustion engine well-known trademark in China. Its products cover petroleum, marine, military, power station, combustible gas utilization, environmental protection, and many other fields, and are exported to more than 50 countries and regions in the world. The industry has expanded to the upstream and downstream of the business chain and power extension products, forming an industrial cluster dominated by compressor manufacturing and skids, hydraulic transmission, gas power integration, and power electrical control devices. At the same time, Jichai is also actively operating to build enterprises abroad, and localized production in South America and Southeast Asia will soon become a reality. In 2009, when the international financial crisis spread arbitrarily, Jichai faced challenges, internal pressure, and seized opportunities to promote development. Its operating income still maintained a 50% growth momentum, which is also one of the few in the industry.
General supporting unit power range 500KW-2400KW

What are the types of control screens?

Answer: The control panel of the diesel generator set is divided into an ordinary unit control panel and an automatic control panel. The ordinary control panel is suitable for the control of ordinary diesel generator sets, and the start/stop, power supply/off, state adjustment, etc. of the set are all manually operated: the automatic control panel is suitable for the control of automatic diesel generator sets, and the start/stop of the set Power supply/cut-off, status adjustment, etc. can be done manually or automatically in two modes of operation.
According to the installation method, the control panel of the diesel generator set can be divided into the one-piece type and split type. A split control panel means that the unit and the control panel are placed separately, and the control system and main switch are installed in the control panel. The integrated control panel is composed of two parts: an automatic control panel and a switch panel. The automatic control panel (installation control) is fixed on the top of the generator set through a shock-absorbing pad, and the switch panel (installation of the main switch) is installed on the side of the generator set.
The control screen can be divided into instrument type and LCD digital type according to the display mode of the diesel generator set. With the development of electronic technology, the current control screens equipped by diesel generator set manufacturers are all LCD digital display control screens. The advantage is that the parameters and faults of the unit can be viewed intuitively.
At present, the main control panel modules of diesel generator sets on the market include British Deep Sea (DEEP SEA), Czech Republic (COMAP) Wilson’s independent control panel, and now all manufacturers have developed their own control systems.

What are the automatic switching cabinet, and the cabinet and its function?

Answer: Automatic switching cabinet The automatic switching cabinet is also called the dual power supply cabinet. It acts as a bridge between the diesel generator set power, the mains power, and the load. The automatic switching cabinet can ensure that when the mains power supply fails, the generator set automatically starts to complete the power supply conversion within the set time (3S~10S), and realizes the power supply to the load. When the mains power is restored, it automatically switches to the city. Electric power supply.
Parallel cabinets When multiple diesel generators sets supply power to the same load, to ensure the reasonable distribution of loads, the reliability of power supply, and the operating economy of the unit, the power of multiple diesel generator sets must be connected in parallel. At this time, parallel cabinets must be equipped. . When different AC power supplies need to be connected in parallel to the same load, the AC power must meet the following conditions: the same phase sequence, the same voltage, the same frequency, and the same phase.

Types of batteries

Answer: In the diesel generator set, we used lead-acid batteries that can be divided into two categories, namely dry-charged batteries and maintenance-free batteries two species.
<1> Dry-charged battery: Its full name is the dry-charged lead-acid battery. Its main feature is that the negative plate has a high power storage capacity. In a completely dry state, it can save the obtained power within two years. Just add electrolyte and wait for 20-30 minutes before use. Its main advantages are stable voltage and low price; its disadvantages are low specific energy (that is, electric energy stored per kilogram of battery), short service life, and frequent routine maintenance.
<2> Maintenance-free storage battery: Due to its structural advantages, the maintenance-free storage battery consumes very little electrolyte and basically does not need to be supplemented with distilled water during its service life. It also has the characteristics of shock resistance, high-temperature resistance, small size, and small self-discharge. The service life is generally twice that of ordinary batteries. There are also two types of maintenance-free batteries on the market: the first is that the electrolyte is added once at the time of purchase and does not require maintenance (addition of supplementary fluid) after use; the other is that the battery itself has been filled with electrolyte and sealed up when it leaves the factory. , The user cannot add refill at all.
Lead-acid batteries are available in 2.4 volts, 4 volts, 6 volts, 8 volts, 12 volts, and 24 volts series, with capacities ranging from 200 mAh to 3000 amp-hours. Generally, diesel generator sets use 12V or 24V batteries to start.

What are the accessories of the standard diesel generator set?

Answer: The accessories of the general standard diesel generator set mainly include: batteries, battery connection cables, bellows, mufflers, elbows, fasteners, etc.

What are the environmental protection projects of diesel generator sets?

Answer: When the diesel generator set is in operation, the black smoke and sulfur dioxide of the exhaust gas are inevitable, and the noise of the engine room is still above 98dB ( A ). If left unchecked, the high-decibel noise and black smoke emitted will pollute the surrounding environment. According to the requirements of the environmental protection department, environmental protection treatment of the diesel generator room is required, which mainly includes the following projects:
To remove black smoke, reduce sulfur dioxide and nitrogen oxides on the exhaust gas of generator sets;
Carry out comprehensive treatment of sound insulation, sound absorption, noise reduction, and vibration reduction in the computer room;
Silencing the air intake, exhaust, and smoke exhaust systems of the generator set.

Application of diesel generator sets in modern high-rise buildings and large buildings

Answer: Although in recent years, with the continuous establishment of hydropower, firepower, wind power, and other power stations in our country, most cities have sufficient mains power supply capacity, at any time, to ensure the fire protection requirements of large buildings, the mains is destroyed There is enough power to meet the needs of power outages or emergency power supplies in emergencies. Therefore, the use of diesel generator sets as emergency power supplies is an ideal choice in recent decades.

What is common power and standby power?

Answer: The design of each diesel generator set has a certain power range, and there is a certain difference in power between diesel engine and alternator. Their design makes the diesel generator set not exceed a certain power value. When the power exceeds the power, the diesel engine cannot increase the power or the excessive power causes the engine to be damaged. Therefore, it is very important to distinguish between common power and standby power.
Common power refers to the continuous power supply of non-constant load, there is no limit to the annual operating time, and it is allowed to run within 10% of overload for 1 hour every 12 hours.
Standby power refers to a continuous power supply for non-constant loads. At this time, the generator has been adjusted to the highest allowable power. Overload operation is not allowed at any time, and only continuous operation is allowed to accumulate no more than 1 hour within 12 hours.