Take a fuel sample from some convenient point upstream of the filter/water separator. Allow the fuel to settle for a few minutes in a glass container and inspect for cloudiness (an indication of water), algae (jellylike particles floating on the surface), and solids. Placing a few drops of fuel between two pieces of glass will make it easier to see impurities. If fuel appears contaminated, drain and purge the system as described below.
Assuming that the fuel is clean and water-free, the most important quality is its cetane value, which can be determined with fuel hydrometer. A good No. 2 diesel has a specific gravity of 0.840 or higher at 60 degree Farenheit. No. 1 diesel can reduce power outputs by as much as 7% over No. 2 fuel. Blending the two fuels, a common practice in cold climates, results in correspondingly less power.
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There are common engine malfunction that usually occurs, either its because of human cause or because of engine durability it self, or probably because of engine spare part duration that need to be replaced.
Some engine malfunction usually indicated by uncommon engine behavior such as unable to start the engine, smoke cause of fuel contribution, speed loss, and many others that will be explained as below:
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Normally, installation is a bolt-on proposition, but things become complex when engines or transmissions are not as originally supplied.
Operators often judge a truck’s power, or lack of it, by how fast the truck runs. In other words, operators look at maximum rated horsepower available at full governed rpm. But expected road speeds may be unrealistic. For example, numerically low axle ratios can, up to a point, increase top speed, but at the cost of reduced acceleration and less startability, a term that is defined below.
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Diesel fuel is a middle distillate, slightly heavier than kerosene or jet fuel. Composition varies with the source crude, the refining processes used, the additive mix, and the regulatory climate.
EPA regulations apply only to sulfur content and to cetane number/aromatic content. Other fuel qualities, such as lubricity, filterability, and viscosity, are left to the discretion of the refiner. As a general rule, large truck stops provide the best, most consistent fuel.
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Industrial diesel engines come out of a conservative design tradition. High initial costs, weight, and moderate levels of performance are acceptable trade offs against early failure. The classic diesel is founded on heavy, fine-grained iron castings, liberally reinforced with webbing and aged prior to machining.
Buttressed main-bearing caps, pressed into the block and often cross-drilled, support the crankshaft. Pistons run against replaceable liners, whose metallurgy can be precisely controlled.
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A current strategic objective for the automotive application of the four-stroke, gasoline engine is a substantial improvement in fuel consumption while meeting the required levels of pollutant emissions and engine durability.
The improvement of passenger car fuel economy represents a very important goal that will determine the future use of SI engines instead of the small, high-speed, diesel engines.
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In summary, the preparation of the fuel-air mixture is one of the most important processes in ensuring a successful GDI combustion system. The spray-air-wall interaction and the spray-induced air motion all must be well examined in order to optimize the mixture formation process. Some of the guidelines for an optimal mixture preparation strategy are summarized as follows.
• Spray characteristics:
o appropriate cone angle to insure good air utilization for early injection;
o appropriate fuel mass distribution within the cone to avoid fuel wetting of the cylinder wall and the piston crown outside of the bowl; Read the rest of this entry »
As is the case for diesel combustion, the fuel spray characteristics are of significant importance to direct-injection gasoline combustion systems. Parameters such as the spray cone angle, mean drop size, spray penetration, and fuel delivery rate are known to be critical, and the optimum matching of these parameters to the airflow field, piston bowl geometry and spark location usually constitute the essence of a GDI combustion system development project.
In contrast, the primary fuel spray characteristics of a port fuel injector generally have much less influence on the subsequent combustion event, mainly due to the integrating fuel effects of the residence time on the closed valve, and due to the secondary atomization that occurs as the induction air flows through the valve opening.
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Horsepower is the ability to perform work over time. In 1782, James Watt, a pioneer developer of steam engines, observed that one mine pony could lift 550 lb of coal one foot in one minute. Torque is the instantaneous twisting force applied to the crankshaft. In the English-speaking world, we usually express torque as pounds of force applied on a lever one foot long.
The two terms are related:
Horsepower = torque x 2pi x rpm. Revolutions per minute is the time component.
Torque = displacement x 4pi x bmep.
The latter term, brake mean effective pressure, is the average pressure applied to the piston during the expansion stroke.
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Modern SI engines mix air and fuel in the intake manifold by way of one or more low-pressure (50-psi or so) injectors. A throttle valve regulates the amount of air admitted, which is only slightly in excess of the air needed for combustion. As the throttle opens, the injectors remain open longer to increase fuel delivery. For a gasoline engine, the optimum mixture is roughly 15 parts air to 1 part fuel. The air-fuel mixture then passes into the cylinder for compression and ignition.
In a CI engine, air undergoes compression before fuel is admitted. Injectors open late during the compression stroke as the piston approaches tdc. Compressing air, rather than a mix of air and fuel, improves the thermal efficiency of diesel engines. To understand why would require a course in thermodynamics; suffice to say that air contains more latent heat than does a mixture of air and vaporized fuel.
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