Diesel Engine

History Rudolf Diesel had discovered the diesel engine in year Year Engine Development 1673 Engine concept developed （ Huygens,Holland ） 1766 Steam Engine discovered （ Watt,Britain ） cycle Otto cycle （ Otto,Dutch ） 1881 Discovering of 2 cycle engine （ Clerk,Britain ） 1886 Discovering of gasoline engine, actual use （ Daimler,Dutch ） 1892 Discover of diesel engine, actual use （ R.Diesel,Britain ） 1900 Passenger usage of gasoline and diesel engine （ Britain ， Dutch, America ） 1903 Improvement of gasoline engine to fly first airplane （ Wright,America ） 1909 Mass production of vehicles engine （ Ford,America ） 1914 Passenger use of airplane engine 1936 Discover of jet engine （ F.Whittle,Britain ）

What is Diesel Engine A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber during the final stage of compression. This is in contrast to a petrol (gasoline) engine or gas engine, which uses the Otto cycle, in which a fuel/air mixture is ignited by a spark plug.internal combustion engineignition combustion chambercompressionpetrol (gasoline) enginegas engineOtto cyclespark plug Diesel engines are manufactured in two stroke and four stroke versions.two strokefour stroke Use in locomotives, large trucks and electric generating plants. In the 1930s, they slowly began to be used in a few automobiles. Since the 1970s, the use of diesel engines in larger on-road and off-road vehicles in the USA increased.automobilesoff-road vehicles As of 2007, about 50 percent of all new car sales in Europe are diesel.

Diesel Cycle

Diesel Fuel Diesel engines can operate on a variety of different fuels, depending on configuration, though the eponymous diesel fuel derived from crude oil is most common. diesel fuelcrude oil Good-quality diesel fuel can be synthesised from vegetable oil and alcohol. Biodiesel is growing in popularity since it can frequently be used in unmodified engines, though production remains limited.vegetable oil alcoholBiodiesel Petroleum-derived diesel is often called petrodiesel if there is need to distinguish the source of the fuel.

Diesel Injection A vital component of diesel engines is a mechanical governor which regulates the idling speed and maximum speed of the engine by controlling the rate of fuel delivery. The system use a combination of springs and weights to control fuel delivery relative to both load and speed.governor Source:

Diesel Injection Modern, electronically controlled diesel engines control fuel delivery by use of an electronic control module (ECM) or electronic control unit (ECU). The ECM/ECU receives an engine speed signal, as well as other operating parameters such as intake manifold pressure and fuel temperature, from a sensor and controls the amount of fuel and start of injection timing through actuators to maximize power and efficiency and minimize emissions. Controlling the timing of the start of injection of fuel into the cylinder is a key to minimizing emissions, and maximizing fuel economy (efficiency), of the engine.ECUactuatorsfuel economy Source:

Common-rail D.I. To improve the combustion, the fuel must be injected at a very high pressure, so high that normal fuel injectors cannot achieve. In common-rail system, the fuel pressure is implemented by a strong fuel pump. The high-pressure fuel is fed to individual fuel injectors via a common rigid pipe (hence the name of "common-rail"). In the current first generation design, the pipe with stand the pressure as high as 1,350 bar. New common-rail engine cuts fuel consumption by 20%. Doubles torque at low engine speeds and increases power by 25%. It also brings a significant reduction in the noise and vibrations. Greenhouse gases (CO 2 ) is reduced by 20%. NOx, (CO) emissions are reduced by 40%. Unburnt hydrocarbons (uHC) reduced by 50%. Particle emissions reduced by 60%.

Piezoelectric Injector Piezoelectricity is the ability of some materials (notably crystals and certain ceramics, including bone) to generate an electric potential in response to applied mechanical stress.crystalsceramicsboneelectric potentialstress made of piezo crystals to control the injection valve. The piezo crystals expand within an electrical field. The electronically controlled piezo actuator switches five times as fast as a solenoid.. allow for precise measurement of fuel injected lead to reduction in harmful combustion products.

Diesel Combustion

Diesel Petrol Comparison DescriptionSI EngineCI Engine Basic cycleOtto cycle or constant volume heat addition cycle Diesel cycle or constant pressure heat addition cycle. FuelGasoline, a highly volatile fuel. Self-ignition temperature is high. Diesel oil, a non-volatile fuel. Self- ignition temperature is comparatively low. Introduction of fuel A gaseous mixture of fuel and air is introduced during the suction stroke. A carburetor is necessary to provide the mixture. Fuel is injected directly into the combustion chamber at high pressure at the end of the compression stroke. A fuel pump and injector are necessary. Load controlThrottle controls the quantity of mixture introduced. The quantity of fuel is regulated in the pump. Air quantity is not controlled.

Diesel Petrol Comparison DescriptionSI EngineCI Engine IgnitionRequires an ignition system with spark plug in the combustion chamber. Primary voltage is provided by a battery or a magneto. Self-ignition occurs due to high temperature of air because of the high compression. Ignition system and spark plug are not necessary. Compression ratio 6 to 10. Upper limit is fixed by antiknock quality of the fuel. 16 to 20. Upper limit is limited by weight increase of the engine. SpeedDue to light weight and also due to homogeneous combustion, they are high speed engines Due to heavy weight and also due to heterogeneous combustion, they are low speed engines Thermal efficiency Because of the lower CR, the maximum value of thermal efficiency that can be obtained is lower. Because of higher CR, the maximum value of thermal efficiency that can be obtained is higher. WeightLighter due to lower peak pressures.Heavier due to higher peak pressures.