Technical Documents - Documentos Técnicos: INTERNAL COMBUSTION ENGINES
An engine is a device that converts heat energy into mechanical energy to perform work. An internal combustion engine is any engine in which fuel is burned within its body (fig. 1-1).
Figure 1-1 . Basic elements of an engine. |
The combustion that occurs within the cylinders produces energy. This energy moves the parts of the engine that drives the equipment. Air and fuel are two elements needed to produce heat energy in an engine. Oxygen in the air is evenly mixed with the fuel and is vaporized. This mixture allows for quick and even burning. The chemical process that occurs when the air and fuel mixture in the cylinder is ignited is known as combustion. An engine uses both reciprocating motion and rotary motion to transmit energy. Four parts of the engine work together to convert reciprocating motion into rotary motion. These four parts are as follows: a cylinder, a piston, a connecting rod, and a crankshaft (fig. 1-2). |
Figure 1-2.-Piston and crankshaft. |
The piston and cylinder are matched parts, fitted closely to allow the piston to glide easily with little clearance at the sides within the cylinder. The top of the cylinder is closed and has a space for the combustion chamber. The connecting rod transmits the up-and-down motion of the piston to the crankshaft.
|
The crankshaft has a section offset from the center line of the shaft so that it “cranks” when the shaft is turned (fig. 1-3).
Figure 1-3.—Piston to crankshaft relationship.
Figure 1-4.—Piston positions.
ENGINE CYCLE
When the piston is at the highest point in the cylinder, it is in a position called top dead center (TDC). When the piston is at its lowest point in the cylinder, it is in a position called bottom dead center (BDC) (fig. 1-4). As the piston moves from top to bottom or from bottom to top, the crankshaft rotates exactly one half of a revolution. Each movement of the piston from top to bottom or from bottom to top is called a stroke; therefore, the piston completes two strokes for every full crankshaft revolution.
For an engine to operate, the following sequence of events must occur:
- INTAKE: A combustible mixture is pulled into the cylinder.
- COMPRESSION: The combustible mixture is compressed into a smaller space.
- POWER: The compressed combustible mixture is ignited causing it to expand, producing power.
- EXHAUST: The burnt gases are removed from the cylinder.
The engine repeats this sequence of events over and over again to produce sustained power. One complete series of these events in an engine is called a cycle. Engines have either a four-stroke cycle or a two-stroke cycle; most engines operate on the four-stroke cycle.
Four-Stroke Cycle Gasoline Engine.
In the four-stroke cycle gasoline engine, there are four strokes of the piston in each cycle: two up and two down (fig. 1-5). The four strokes of a cycle are as follows: intake, compression, power, and exhaust. A cycle occurs during two revolutions of the crankshaft.
|
A- Intake stroke |
B- Compression stroke |
|
C- Power stroke |
D- Exhaust stroke |
INTAKE STROKE. — The intake stroke begins at top dead center, and as the piston moves down, the intake valve opens. The downward movement of the piston creates a vacuum in the cylinder, causing a fuel and air mixture to be drawn through the intake port into the combustion chamber. As the piston reaches bottom dead center, the intake valve closes.
COMPRESSION STROKE.— The compression stroke begins with the piston at bottom dead center and rising up to compress the fuel and air mixture. Since both the intake and exhaust valves are closed, there is no escape for the fuel and air mixture, and it is compressed to a fraction of its original volume. At this point, the fuel and air mixture is ignited.
POWER STROKE.— The power stroke begins when the fuel and air mixture is ignited, burns and expands and forces the piston down. The valves remain power stroke ends as the piston reaches bottom dead center.
EXHAUST STROKE.— The exhaust stroke begins when the piston nears the end of the power stroke and the exhaust valve is opened. As the piston moves upward towards top dead center, it pushes the burnt gases, resulting from the ignition of the fuel and air mixture, out of the combustion chamber and through the exhaust port. As the piston reaches top dead center, ending the exhaust stroke, the exhaust valve closes, and the intake valve opens to begin the intake stroke for the next cycle.
|
|
|
Briggs & Stratton Extended Life Series Intek V-Twin Engine with Electric Start 26 HP, 1in. x 3 5/32in. Shaft, Model# 44Q777-0127-G1
$849.99
The Briggs & Stratton 27 HP Extended Life Professional Series™ V-Twin Engine is a powerful choice for OEM and replacement use. The engine is designed with easy maintenance points and longer-lasting components to save time and money over the long run. Premium engine offers world class power, performance and reliability, with features like Magnetron electronic ignition, a large dual-barrel carburetor and an advanced debris management system. Engine Displacement (cc): 724, Start Type: Electric, Application: Commercial mowers, zero-turn-radius Mowers, and lawn tractors, Engine Type: Extended Life series V-Twin OHV, Rated Power (HP): 27, Shaft Output: Vertical, Shaft Diameter (in.): 1, Shaft Length (in.): 3 5/32, Shaft Keyway (in.): 1/4, Shaft End Tapped (Diameter (in.)/Threads per inch): 7/16-20, Shaft Rotation (From PTO Shaft Side): Counterclockwise, Bearing Type: Plain, Cylinders (qty.): 2, Cylinder Bore: Cast iron, Bore x Stroke (in.): 3.12 x 2.89, Cooling System: Air coole... [Read more]
Brand: Briggs & Stratton
|
Briggs & Stratton Intek Snow Horizontal Engine 7.5 HP, 1in. x 2 27/64in. Shaft, Model# 12D412-0009-E1
$429.99
Briggs & Stratton 205cc Intek Snow Horizontal Engine. Intek engines are designed and built to provide the highest level of performance and power available. Compact OHV design increases engine efficiency and valve life. Aluminized Lo-Tone muffler offers superior sound reduction and corrosion resistance. This engine has large displacement for increased torque and easy removal of wet heavy snow. Freeze resistant recoil starter provides smooth easy starts. Ergonomically designed rewind handle and controls for easy use in cold, snowy weather. Computer optimized snow hood maintains constant carburetor and engine temperatures to optimize cold-weather performance and prevent freeze-up. U.S.A. Displacement (cc): 205, HP: 7.5, Application: Snow blower, Torque (ft./lbs.): 9.0, Shaft Output: Horizontal, Engine Type: Snow-OHV, Start Type: Recoil, Shaft Dimensions Diameter x L (in.): 1 x 2 27/64, Mounting Base L x W (in.): 6.38 x 3.12, Bolt Circle (in.): 3 5/8, PTO Height (in.): 4.17, Shaft K... [Read more]
Brand: Briggs & Stratton
|
Briggs & Stratton Powerbuilt Vertical Engine with Electric Start 12.5 HP, 1in. x 3 5/32in. Shaft, Model# 219707-0026-E1
$579.99
Briggs & Stratton 12.5 HP Powerbuilt OHV Vertical Engine. Overhead valve design runs cooler and cleaner, delivering more power, longer engine life and improved fuel economy. Improved breather system lowers oil consumption and reduces emissions. U.S.A. Engine Displacement (cc): 344, Start Type: Electric, Application: Riding lawn mowers and lawn tractors, Engine Type: Power built OHV, Rated Power (HP): 12.5, Shaft Output: Vertical, Shaft Diameter (in.): 1, Shaft Length (in.): 3 5/32, Shaft Keyway (in.): 1/4, Shaft End Tapped (Diameter (in.)/Threads per inch): 7/16-20, Shaft Rotation (From PTO Shaft Side): Counterclockwise, Bearing Type: Plain, Cylinders (qty.): 1, Cylinder Bore: Cast iron, Bore x Stroke (in.): 3.44 x 2.26, Cooling System: Air cooled, Air Cleaner Type: Automotive type pleated paper air filter, Fuel Tank: Not included, Fuel Type: Gasoline, Oil Capacity (qt.): 1.5 (48 oz.), Lubrication System: Splash, Low Oil Alert: No, Ignition System: Electronic, Governor System: M... [Read more]
Brand: Briggs & Stratton
|
Husqvarna Garden Tractor - 726cc Kawasaki Engine, 54in. Deck, Model# LGT24K54
$2,399.99
Husqvarnas Yard Tractor offers premium performance with quality results. The compact size makes it easy to maneuver and require less space for storage. Features such as a fender-mounted cutting height adjustment system between 1 1/2in. to 4 1/2in, an adjustable seat, an ergonomic steering wheel and step-through design make this tractor simple and comfortable to use. U.S.A. Engine: Kawasaki, HP: 24, Engine Model: FR591, Cutting Width (in.): 54, Cutting Height (in.): 1 1/2-4, Start Type: Electric, Transmission: Hydro, Blade Engage Control: Lever, Deck Lift: Lever, Turning Radius (in.): 16, Blades (qty.): 3, Fuel Capacity (gal.): 4, Forward Speeds: Variable, Reverse Speeds: Variable, Max. Forward Speed (MPH): 5 1/2, Max. Reverse Speed (MPH): 2 1/2, Frame Construction: Steel channel, Deck Construction: Stamped steel, Steering Type: Sector and pinion, Brakes: Disc, Front Tire Size (in.): 15, Rear Tire Size (in.): 20, Cooling: Air, Folding Armrests: No, Dimensions L x W x H (in.): 69 1/4 ... [Read more]
Brand: Husqvarna
|
|
Husqvarna Zero-Turn Mower - 725cc Kohler Engine, 54in. Deck, Model# RZ5424
$2,999.99
Husqvarnas Residential-Series Zero-Turn Mower offers all the maneuverability, efficiency and convenience of a professional mower in a package perfect for any homeowner. Expect true zero-turn mower performance with twin maintenance-free integrated transmissions, heavy-duty front casters and a rugged steel tube frame. Conveniently placed controls, foam-padded steering levers and an adjustable seat make this mower easy and enjoyable to use. U.S.A. Engine: Kohler, HP: 24, Engine Displacement (cc): 725, Engine Model: Courage, Cutting Width (in.): 54, Cutting Height (in.): 1 1/2-4, Cutting Styles: Mulch, rear bag, side discharge, Start Type: Key, Transmission: Hydrostatic, Blade Engage Control: Manual, Deck Lift: Manual, hand-operated, Turning Radius (in.): 0, Blades (qty.): 3, Fuel Capacity (gal.): 3 1/2, Forward Speeds: Variable, Reverse Speeds: Variable, Max. Forward Speed (MPH): 6 1/2, Max. Reverse Speed (MPH): 3 1/2, Frame Construction: Welded steel, Deck Construction: Stamped steel,... [Read more]
Brand: Husqvarna
|
Husqvarna Push Mower - 160cc Honda GCV Engine, 21in. Deck, Model# 7021P
$289.99
This efficient Husqvarna Push Mower features a compact design, making it easy to maneuver in tight spaces and three cutting systems: collection, mulch and side discharge. The handle folds for easy storage and transportation. Double ball-bearing wheels ensure smooth operation and durability. Offers 4-point, 9 position cutting height adjustment for varying lawn conditions. U.S.A. Engine Displacement (cc): 160, Start Type: Recoil, Drive: Push, Cutting Width (in.): 21, Engine: Honda, Engine Model: GCV160, Rated Power (HP): 4.4, Torque (ft./lbs.): 6.9 at 2,500 RPM, Deck Material: Steel, Discharge: Side, rear bag, Cutting Height (in.): 1 1/4-3 1/2, Cutting Styles: Mulch, rear bag, side discharge, Bagger Volume (bushels): 2, Fuel Tank Capacity (qt.): 1.2, Front Tire Size (in.): 8, Rear Tire Size (in.): 12, Dimensions L x W x H (in.): 40 x 25 1/4 x 17 3/4 Dependable 160cc Honda GCV engine 3-in-1 deck has three cutting systems: side discharge, rear bag and mulching Extra-large 2-bushel bag f... [Read more]
Brand: Husqvarna
|
Husqvarna Yard Tractor - 724cc Briggs & Stratton Engine, 48in. Deck, Model# YTH23V48
$1,799.99
Husqvarnas Yard Tractor offers premium performance with quality results. The compact size makes it easy to maneuver and require less space for storage. Features such as a fender-mounted cutting height adjustment system between 1 1/2in. to 4 1/2in, an adjustable seat, an ergonomic steering wheel and step-through design make this tractor simple and comfortable to use. U.S.A. Engine: Briggs & Stratton, HP: 23, Engine Displacement (cc): 724, Engine Model: 44, Cutting Width (in.): 48, Cutting Height (in.): 1 1/2-4, Start Type: Electric, Transmission: Hydro, Blade Engage Control: Lever, Deck Lift: Lever, Turning Radius (in.): 16, Blades (qty.): 3, Fuel Capacity (gal.): 3, Forward Speeds: Variable, Reverse Speeds: Variable, Max. Forward Speed (MPH): 5 1/2, Max. Reverse Speed (MPH): 2 1/2, Frame Construction: Steel channel, Deck Construction: Stamped steel, Steering Type: Sector and pinion, Brakes: Disc, Front Tire Size (in.): 15, Rear Tire Size (in.): 20, Cooling: Air, Folding Armrests... [Read more]
Brand: Husqvarna
|
Husqvarna Self-Propelled Lawn Mower - 173cc Kohler XT-7 Engine with Electric Start, 22in. Deck, Model# XT722FE
$329.99
This Husqvarna self-propelled lawn mower makes mowing the lawn a walk in the park. The 22in. blade is powered by a 173cc Kohler XT-7 engine with electric start. U.S.A. Not for sale in California. Engine Displacement (cc): 173, Start Type: Electric with recoil backup, Drive: Self- propelled, Transmission: Front wheel, Cutting Width (in.): 22, Engine: Kolher, Engine Model: XT-7, Torque (ft./lbs.): 7, Deck Material: Steel, Discharge: Side, rear bag, Cutting Height (in.): 1 1/2-3 1/2, Cutting Styles: Mulch, rear bag, side discharge, Cutting Speeds: Variable, Bagger Volume (bushels): 2, Fuel Tank Capacity (qt.): 1.04, Front Tire Size (in.): 8, Rear Tire Size (in.): 8, Dimensions L x W x H (in.): 36 1/4 x 25 1/4 x 20 3/4 3-in-1 mulch with 2-bushel rear bag and side discharge Electric start [Read more]
Brand: Husqvarna
|
|
Husqvarna Self-Propelled Lawn Mower - 173cc Kohler XT-7 Engine with Electric Start, 22in. Deck Model# XT722FE
$349.99
This Husqvarna self-propelled lawn mower makes mowing the lawn a walk in the park. The 22in. blade is powered by a 173cc Kohler XT-7 engine with electric start. CARB approved. U.S.A. Engine Displacement (cc): 173, Start Type: Electric with recoil backup, Drive: Self-propelled, Transmission: Front wheel, Cutting Width (in.): 22, Engine: Kohler, Engine Model: XT-7, Torque (ft./lbs.): 7, Deck Material: Steel, Cutting Height (in.): 1 1/2-3 1/2, Cutting Styles: Mulch, rear bag, side discharge, Cutting Speeds: Variable, Bagger Volume (bushels): 2, Fuel Tank Capacity (qt.): 1.04, Front Tire Size (in.): 8, Rear Tire Size (in.): 8, Dimensions L x W x H (in.): 38 1/2 x 24 x 20 3/4 3-in-1 mulch with 2-bushel rear bag and side discharge CARB approved Electric start [Read more]
Brand: Husqvarna
|
Husqvarna Rear Tine Tiller - 14in. Tilling Width, 205cc Briggs & Stratton Engine, Model# CRT900-CA
$599.99
This Husqvarna Rear Tine Tiller is ideal for homeowners preparing large flowerbeds and vegetable gardens. Its 12in. dia. counter-rotating tines allow deep soil penetration for better bed preparation. Powered by a reliable Briggs & Stratton engine with forward and reverse gears for improved maneuverability. U.S.A. Application: Tilling, Working Width (in.): 14, Engine: Briggs & Stratton, Engine Type: 900 OHV series, Displacement (cc): 205, Torque (ft./lbs.): 9, Overall Width (in.): 15 1/2, Tines (qty.): 8, Tine Type: Bolted, Height Range (in.): 7, Tire Size (in.): 13 x 5 x 6, Disc Diameter (in.): 12, Disc Thickness (in.): 0.203/0.250, Depth (in.): 6 Counterweight increases the weight on the wheels for improved balance and safer operation Power forward and reverse for easy operation and transport 13in. dia. x 5in.W agricultural tires have heavy treads for good grip in cultivated or muddy soil The easy-adjust drag bar provides balance in different working conditions Powerful OHV... [Read more]
Brand: Husqvarna
|
Husqvarna Dual-Stage Snow Thrower - 24in. Clearing Width, 208cc SnowKing Engine, Model# 924HV
$799.99
This Husqvarna Dual-Stage Snow Thrower moves heavy snow with a sturdy two-stage auger/impeller system and a 24in. clearing width. Powered by a premium 208cc SnowKing engine and guided with single-hand controls that allow the operator to rotate the chute or adjust deflector angle while the wheels and auger are engaged. Youll be ready to take on any storm that Mother Nature delivers. U.S.A. Product Style: Walk behind, Drive System: Chain, Blower Type: Two stage, Start Type: Electric, Clearing Width (in.): 24, Engine: SnowKing, Gross Torque: 9.00 ft-lbs, Throw Distance (ft.): Up to 65, Forward Speeds: 6, Reverse Speeds: 2, Auger Type: Standard, Discharge Chute Rotation (deg.): 180, Discharge Chute Material: Steel, Impeller Size (in.): 12, Engine Displacement (cc): 208, Intake Height (in.): 23, Tire Size (in.): 16 x 5, Headlight: Yes 208cc SnowKing premium engine provides power to handle the snow 24in. clearing width removes more snow with each pass 16in. x 5in. tires work in all snow c... [Read more]
Brand: Husqvarna
|
Whelen Engineering Guardian Strobe Mini Light Bar - Magnetic Mount, Model# G7MA
$239.99
The Whelen Engineering Guardian strobe mini light bar provides up to 480 flashes per minute. U.S.A. Light Type: Strobe, Light Color: Amber, Mount Type: Magnetic, Connector Type: Cigar plug, Housing Material: Polycarbonate, Flashes Per Minute: 480, Flash Patterns (qty.): 1, Bulbs Per Light (qty.): 2, Lights Included (qty.): 1, Mounting Hardware Included: No, Power Cord (ft.): 10, Dimensions L x W x H (in.): 17 5/15 x 7 x 6 1/4 SAE J1318 Class 1 certified (amber) Includes 2 remote strobe heads with built-in power supply 120 CometFlash. with half-sized diamond mirror provides 480 flashes/minute High/low intensity control Standard 12V/24V DC Swivel mount with 3 suction cups securely holds light to windshield, minimizing flashback to driver Can change flash patterns via push-button on back of unit [Read more]
Brand: Whelen Engineering
|
|
|
|
|
