Case IH FFA - Engine Fundamentals PDF

TRACTOR FUNDAMENTALS Engines TRACTOR FUNDAMENTALS Engines Fuel Economy Environmentally Friendly All-Weather Operation Reliable, Long Life TRACTOR FUNDAMENTALS Engines Basic Engine Construction Power & Performance Features TRACTOR FUNDAMENTALS Engines Main En...

TRACTOR FUNDAMENTALS Engines TRACTOR FUNDAMENTALS Engines Fuel Economy Environmentally Friendly All-Weather Operation Reliable, Long Life TRACTOR FUNDAMENTALS Engines Basic Engine Construction Power & Performance Features TRACTOR FUNDAMENTALS Engines Main Engine Components Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Cylinder Block The foundation of the engine Also called the crankcase Built strong to contain combustion pressures in the cylinders Internal passages carry lubrication to the bearings and remove excess heat from around the cylinders TRACTOR FUNDAMENTALS Engines Cylinder Block Coolant Cylinder Jackets Cylinder Block Lubrication Passage Camshaft TRACTOR FUNDAMENTALS Engines Cylinder Block Engine cylinder blocks in agricultural tractors may be designed as either non- structural or structural. Structural block engines contain additional webbing for added strength and durability over non-structural block engines. Non-Structural Block Structural Block TRACTOR FUNDAMENTALS Engines Cylinder Block Non-Structural Block Non-structural blocks are Tractor Frame for non-Structural designed solely to be the solid Cylinder Block foundation for the engine and its internal components – not to provide structure to the vehicle. These applications require a frame, like the one shown to the right, to connect the front axle and rear housing. Non-structural block engines are typically found in high horsepower row-crop tractors. TRACTOR FUNDAMENTALS Engines Cylinder Block Structural Block Structural block engines Tractor Frame for Structural Cylinder Block are designed to be both the engine foundation and the tractor frame, providing structure for the vehicle. A structural block connects the front axle and rear housing to the engine block directly. Typically found in row crop, utility, compact, and specialty tractors. TRACTOR FUNDAMENTALS Engines Cylinder Block - Sleeveless Parent metal cylinders, or a sleeveless engine design, describe cylinders machined in the block casting itself. Sleeveless engine design Highly rigid cylinder bores Least expensive to manufacture Often found in lower horsepower row crop, utility, compact, and specialty tractors Cylinder Machined In Parent Metal of Crankcase TRACTOR FUNDAMENTALS Engines Cylinder Block – Dry Sleeve In a dry sleeve design, the block casting is oversized and thinwall replaceable sleeves are pressed into the bores. Advantage: The cylinder surface is easily replaced with no machining or loss of cylinder block material. Thin-walled Cylinder Sleeve Pressed into Bore in Crankcase TRACTOR FUNDAMENTALS Engines Cylinder Block – Wet Sleeve Thick-walled Cylinder Sleeve Inserted into Bore in Crankcase Cylinder Sleeve In Direct Contact with Coolant Sealing Rings In a wet sleeve design, the block bores are machined into the block and intersect cast-in cooling passages. Advantages: ease of replacement and highly efficient cooling Often found in high horsepower row crop and four-wheel drive tractor applications TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Cylinder Head Valves Injector Cylinder Head Intake Passage Exhaust Passage The cylinder head is installed on top of the block to close the tops of the cylinders. Intake and exhaust valves open and close the passages at the top of the cylinders. The fuel injectors are installed in the head and spray fuel into the combustion chamber. TRACTOR FUNDAMENTALS Engines Cylinder Head Engines are classified as direct injection when the fuel injectors spray fuel directly into the combustion chamber. Advantages: easier starting ability in addition to good economy, power output, and low emissions Direct Injection TRACTOR FUNDAMENTALS Engines Cylinder Head Pre-combustion Chamber Direct Injection Indirect Injection With indirect injection, a separate small chamber, or pre- combustion chamber, is cast into the head. Thorough mixing of fuel and air results from turbulence as the swirling, burning mixture travels into the cylinder. Advantages: good fuel economy and low emissions while using lower pressure and less complex fuel injection components, often quieter engines TRACTOR FUNDAMENTALS Engines Cylinder Head The cylinder head is responsible for the flow of air and exhaust into and out of the engine. A crossflow cylinder head has intake passages and exhaust passages cast into opposite sides of the head. A smoother flow of air in one direction across the head is most efficient. More oxygen in the cylinder supports clean combustion and higher power output from the engine. TRACTOR FUNDAMENTALS Engines Cylinder Head Intake Air Crossflow design Intake and exhaust on opposite sides Cooler air leads to a more dense air charge Density leads to more oxygen for more power and efficiency Exhaust Gas TRACTOR FUNDAMENTALS Engines Cylinder Head Four Valves per Cylinder increases air flow efficiencies Many engines also incorporate a 4-valve design, resulting in larger area valve openings and larger volume intake and exhaust passages. Reduced restriction air flow results in more complete evacuation of exhaust gases from the cylinder and more complete filling of the cylinder with fresh air. TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Crankshaft Main Bearing Journals Connecting Rod Bearing Journals The crankshaft converts the pistons’ back and forth movement into the rotating engine output. The crankshaft has main bearings on which it rotates in the cylinder block. Crankshaft throws are offset from the main bearings and have bearing journals for the connecting rods that are attached to the pistons. TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Pistons Piston Sealing Rings Sealing rings near the top of the piston seal the sides of the piston to the cylinder walls *View the included Piston video to watch the process! TRACTOR FUNDAMENTALS Engines Pistons As the pistons move toward the head, TRACTOR FUNDAMENTALS Engines Pistons air is compressed in the TRACTOR FUNDAMENTALS Engines Pistons combustion chamber. TRACTOR FUNDAMENTALS Engines Pistons When fuel is injected and TRACTOR FUNDAMENTALS Engines Pistons combustion occurs, the expanding gases exert force TRACTOR FUNDAMENTALS Engines Pistons on the top of the piston, forcing it down in the cylinder. TRACTOR FUNDAMENTALS Engines Pistons Connecting rods follow the linear movement of the pistons and transmit it to the rotary motion of the crankshaft, where power is delivered from the engine. TRACTOR FUNDAMENTALS Engines Pistons On many engines, a jet of oil is directed to the lower Cooling Oil side of the piston to remove Spray excess heat. The combustion chamber is often formed into the top of the piston. It is shaped to induce a high velocity swirling movement of the air and fuel air mixture after injection TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Camshaft & Valves The camshaft and valve train control the timing of the flow of air into the cylinders and exhaust gases out of the cylinder. TRACTOR FUNDAMENTALS Engines Camshaft & Valves Valve Spring Rocker Arms Pushrod Valves Cam Follower Cam Lobes Cam Shaft Timing Gears **Watch the Valve Video to view how the valves work in the cam-in-block engine design! TRACTOR FUNDAMENTALS Engines Cylinder Head Integral Cam Follower/Rocker Arm Overhead Camshaft Timing Gears On engines with an overhead camshaft, the entire valve system and camshaft are installed in the cylinder head. A series of timing gears drives the camshaft, which directly activates the valves through integral cam follower/rocker arm assemblies. Often found in high horsepower engines. TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Fuel Systems Injector The fuel system meters and delivers fuel to the cylinders, where it is sprayed in a fine mist to mix with the compressed air charge by an injector. Fuel must be pressurized at 20,000-30,000 pounds per square inch to assure atomization and mixing TRACTOR FUNDAMENTALS Engines Fuel Systems Lines to Each Injector Multi-plunger Pump System Distributor Pump TRACTOR FUNDAMENTALS Engines Fuel Systems Injectors High Pressure Common Rail High Pressure Fuel Pump TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger The engine breathes through the intake and exhaust systems working together. Naturally aspirated engines draw air into the cylinders by a vacuum created as the piston moves down in the cylinder. TRACTOR FUNDAMENTALS Engines A turbocharger pressurizes the intake Air Intake/ system. Turbocharger A turbo uses energy from an exhaust-driven turbine to drive a compressor wheel, which forces air into the engine intake. The volume of exhaust gases is in proportion to engine load and fuel delivery. Exhaust turbine side (red) drives intake compressor side (blue) The pressure of the air delivered to the engine intake is called boost pressure. The turbocharger uses energy that would be otherwise lost and adjusts boost pressure to engine load. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger It takes time to accelerate the turbocharger to maximum speed as engine load is applied. The design of a turbocharger requires a balance between providing the volume of air for high load and avoiding a lag as the turbocharger gets up to speed. Boost pressure modifying features are sometimes used to achieve that balance. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger Wastegate Turbocharger VGT Turbocharger The most common methods of balancing turbo lag and boost pressure are Wastegate Turbochargers and VGT Turbochargers. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger Wastegate Turbocharger Wastegate Wastegate turbochargers incorporate a waste gate to allow full exhaust flow to quickly accelerate the turbocharger, but then bypass some exhaust flow to reduce turbocharger speed and boost pressure at high turbine RPMs. TRACTOR FUNDAMENTALS Engines Air Intake/ VGT Turbo Turbocharger Vanes Pivot to Change Angle at which Exhaust Flow Contacts Turbine VGT = variable geometry turbocharger Adjusts the angle at which exhaust gases approach the turbine. Gases can contact the turbine at an aggressive angle to quickly accelerate the turbine, then reduce the angle to control speed and boost pressure when necessary. Late engines may use an electronically controlled variable geometry turbocharger (eVGT) for an even faster response. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger The blue line shows incorporation of a wastegate or a VGT, Reduces the degree of turbo lag on engine acceleration or load increase Maintains boost pressure at high RPMs. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger 2-Stage or Dual Turbochargers In Dual or 2-stage Turbocharging, two turbochargers are used to allow quick turbocharger response, while controlling max speed and boost pressure. Often, one of the turbochargers is wastegate or VGT and the other is fixed. TRACTOR FUNDAMENTALS Engines Air Intake/ Turbocharger Air-to-Air Aftercooler Water-to-Air Aftercooler Compressing air increases the air temperature. The lower the air temperature, the more dense the air charge entering the cylinders. The result is more power. Air-to-air aftercoolers use ambient air to remove heat from the air charge and water-to-air aftercoolers use engine coolant. TRACTOR FUNDAMENTALS Engines KNOWLEDGE CHECK Camshaft VGT Common Overhead Valve Turbo Rail Camshaft Train Check your engine components knowledge! Which engine component belongs in which box? TRACTOR FUNDAMENTALS Engines KNOWLEDGE CHECK Camshaft VGT Common Overhead Valve Turbo Rail Camshaft Train TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Four-stroke Cycle 1800 per Stroke 7200 per Cycle The combustion process produces power so the operator and tractor can do work. Process takes place in four piston strokes. Each stroke takes place over 180 degrees of crankshaft rotation, so all four strokes require two complete revolutions, or 720 degrees of engine rotation. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Intake Piston at top of stroke, Stroke starting to move downward During the intake stroke, the intake valve is opened in the cylinder head, allowing air to flow into the cylinder to fill the expanding volume in the cylinder. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Intake Intake valve opens, air Stroke flows into cylinder TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Intake Air fills cylinder at Stroke bottom of stroke TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Compression Valves closed, piston Stroke starts upward Near the bottom of the stroke, the intake valve is closed, and the compression stroke begins. The piston starts moving toward the cylinder head. Air is compressed to high pressure and the temperature rises to over 1000 degrees Fahrenheit. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Compression Air compressed in Stroke cylinder TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Compression Air compressed to top Stroke of stroke, reaches 1000+ degrees TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Power Fuel injected near top of Stroke stroke The third stroke is the power stroke. Near the top of piston travel, fuel is injected into the cylinder and mixes with the turbulent air charge in the chamber. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Power Fuel begins to burn, Stroke expands in cylinder As the air temperature is higher than the flashpoint of the fuel, the fuel ignites and begins to burn. As combustion progresses, the air charge temperature increases dramatically and expands. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Power Expansion continues as Stroke combustion is completed The pressure in the cylinder increases, which forces the piston down the cylinder. As the piston moves downward, the crankshaft is forced to rotate. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Exhaust Exhaust valve opens as Stroke piston reaches bottom of stroke The fourth and final stroke is the exhaust stroke. Near the bottom of the power stroke, the exhaust valve is opened. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Exhaust Piston starts upward Stroke with exhaust valve open, exhaust gases forced out of cylinder As the crankshaft continues to rotate after the power stroke, the piston is moved upward in the cylinder. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Exhaust Piston continued Stroke upward with exhaust valve open, exhaust gases forced out of cylinder Hot gases that remain in the cylinder after combustion are pushed upward toward the head, and flow from the cylinder through the open exhaust valve. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Exhaust Exhaust removed from Stroke cylinder, exhaust valve closed, cylinder ready for intake stroke of next cycle Near the top of the exhaust stroke, the exhaust valve closes and the intake valve opens, as another intake stroke and another full operating cycle begins. TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Intake Intake valve opens, Stroke next cycle begins TRACTOR FUNDAMENTALS Engines Four-stroke Cycle Intake Compression Power Exhaust ** Watch the 4 Cycle Video Animation to watch the entire cycle in action! TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition TRACTOR FUNDAMENTALS Engines Horsepower & Torque Engine Axle Torque Torque Torque is the turning or twisting force at the crankshaft that results as the piston is forced down the cylinder, and the connecting rod transmits the linear motion of the piston to the rotary motion of the crankshaft. The energy needed to turn the wheels and move the tractor, despite loads which resist movement, is delivered to the wheels as axle torque. TRACTOR FUNDAMENTALS Engines Horsepower & Torque Torque X RPM Horsepower = Constant Horsepower is the most common benchmark for tractor performance. Torque is a key part of the definition and calculation of horsepower. Horsepower adds time as a component, by factoring revolutions per minute, or engine RPM with torque to establish the amount of work performed in a certain timeframe. TRACTOR FUNDAMENTALS Engines Horsepower & Torque Maximum Power Torqu e Horsepower Engine is at full throttle and under low load As the engine is loaded, torque increases, while RPM decreases. When the rise in torque is offset by a greater decrease in RPM, horsepower has reached its maximum and will begin to decrease as load increases. This isn’t a bad thing! TRACTOR FUNDAMENTALS Engines Horsepower & Torque Torqu e Maximum Rise Maximum Torque Power Torqu e Horsepower While load and torque output increases beyond the max horsepower level, torque may continue to rise substantially as load continues to increase, meaning that despite reaching its max power, the increase in torque will allow the engine to “lug” down and continue carrying the load without a need to reduce the load, known as torque rise. TRACTOR FUNDAMENTALS Engines Horsepower & Torque Maximum Power Rated Power Torqu e Horsepower Horsepower = max horsepower Rated horsepower = level at which the engine can be operated continuously, optimizing engine life, power output and fuel economy. TRACTOR FUNDAMENTALS Engines Cylinder Block Cylinder Head Crankshaft Pistons, Connecting Rods Camshaft, Valves Fuel System, Turbocharger 4-Cycle Engine Operation Torque/Horsepower Definition