1. Overview of the Diesel Engine Operation National Biodiesel Board Diesel Technician Training Program February 2010
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5. The diesel engine: first patented in 1892 The Diesel engine was initially Intended to run on coal dust. Rudolph Diesel (1858 – 1913) Diesel demonstrated his engine at the Exhibition Fair in Paris, France in 1898. This engine was fueled by peanut oil - the "original" biodiesel.
6. The first Diesel race car placed 13 th in the Indianapolis 500 because it never stopped to refuel…
7. The American public looked to diesel fuel which was more efficient and economical and they began buying diesel-powered automobiles. Diesel vehicle popularity In the 70s due to Oil crisis This surge of diesel sales in American ended in the 1980's.
16. Current Modern fuel injector design- The fuel injection systems on the John Deere PowerTech Plus engines operate at 29,000 psi Photos compliments of the National Alternative Fuel Training Consortium
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21. A diesel fuel injection system employing a common pressure accumulator, called the rail, which is mounted along the engine block. The rail is fed by a high pressure fuel delivery pump. The injectors, which are fed from the common rail, are activated by solenoid valves. The solenoid valves and the fuel pump are all electronically controlled. Also known as CRD, Common Rail Diesel Technology Common Rail Injection
22. Common Rail Diesel Injection pressures are much higher: 24,000- 36,000 PSI In the common rail injection system the injection pressure is independent from engine speed and load. Therefore, the injection parameters can be freely controlled. Usually a pilot injection is introduced, which allows for reductions in engine noise and NOx emissions. This system operates at 27,500 psi (1900 BAR). The injectors use a needle-and-seat-type valve to control fuel flow, and fuel pressure is fed to both the top and bottom of the needle valve. By bleeding some of the pressure off the top, the pressure on the bottom will push the needle off its seat and fuel will flow through the nozzle holes.
Heat engine Greg Pahl’s book gives a good overview of historical account of diesel engine development
Submitted for patent in 1894 Engine exploded and almost killed Rudolf First successful diesel engine operation in 1897 Patent awarded in 1898
Take care with some newer glow plugs not to touch the ceramic electrode, Oil residue may can premature damage Don’t test new CDI 2.8l glow plugs with 12 volts- they are 7 volts
Bosch injection pump & Yanmar injection pumps An Injection Pump is the device that pumps fuel into the cylinders of a diesel engine or less typically, a gasoline engine. Traditionally, the pump is driven indirectly from the crankshaft by gears, ch ains or a toothed belt (often the timing belt ) that also drives the crankshaft on overhead-cam engines (OHC). It rotates at half crankshaft speed in a conventional four-stroke engine. Its timing is such that the fuel is injected only very slightly before top dead-centre of that cylinder's compression stroke. It is also common for the pump belt on gasoline engines to be driven directly from the camshaft. Because of the need for positive injection into a very high-pressure environment, the pump develops great pressure - typically 15,000 PSI or more on newer systems. This is a good reason to take great care when working on diesel systems; escaping fuel at this sort of pressure can easily penetrate skin and clothes, and be injected into body tissues with serious consequences. Earlier diesel pumps used an in-line layout with a series of cam-operated injection cylinders in a line, rather like a miniature inline engine. The pistons have a constant stroke volume, and injection volume (ie, throttling) is controlled by rotating the cylinders against a cut-off port that aligns with a helical slot in the cylinder. When all the cylinders are rotated at once, they simultaneously vary their injection volume to produce more or less power from the engine. Inline pumps still find favour on large multi-cylinder engines such as those on trucks, construction plant, static engines and agricultural vehicles. For use on cars and light trucks, the rotary pump or distributor pump was developed. It uses a single injection cylinder driven from an axial cam plate, which injects into the individual fuel lines via a rotary distribution valve. Later incarnations such as the Bosch VE pump vary the injection t iming with crank speed to allow greater power at high crank speeds, and smoother, more economical running at slower revs. Some VE variants have a pressure-based system that allows the injection volume to increase over normal to allow a turbocharger or supercharger equipped e ngine to dev elop more power under boost conditions. All injection pumps incorporate a governor to cut fuel supply if the crank speed endangers the en gine - t he heavy moving parts of diesel engines do not tolerate overspeeding well, and catastrophic damage can occur if they are over-revved. Mechanical pumps are gradually being phased out in order to comply with international emissions directives, and to increase performance and economy. Alternatives include common rail diesel systems and unit direct injection systems. These all ow for higher pres sures to be developed, and for much finer control of injection volumes compared to mechanical systems.
2.8L Jeep Liberty 24,000 PSI Multi pilot fuel injection- 1 or 2 before main injection
VGTC- low speeds, movable vanes expand for additional air boost High speeds, vanes retract to limit boost
EGR cooler on 2.8L jeep liberty
Prime indicator of Diesel fuel quality * Ability to auto-ignite * Inverse of gasoline’s octane More saturates - increases cetane # soy (48-52) yellow grease (60-75)
Measured by viscometer * Motor oil analogy* Low viscosity can affect leak down on inj pump plungers -> power loss Higher viscosity can affect insuff. Fuel supply -> power loss
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