Dictionary of technical terms (Mercedes-Benz C-Class W201)

A

ABS (Anti-lock braking system)

A system, usually electronically controlled, that prevents wheels from locking during braking by reducing the brake fluid pressure at the wheels.

Emergency brake

A braking system independent of the main hydraulic braking system that can be used to slow or stop a vehicle when the main brakes fail, and to hold the vehicle stationary when the brake pedal is released. Typically has a lever that is mechanically linked to the front or rear brakes by cables and linkages. Also known as a handbrake or parking brake.

Adsorber

An element of the environmental protection system designed to prevent fuel vapors from entering the atmosphere: contains activated charcoal granules to retain fuel vapors in the engine fuel supply system.



Ampere (A)

A unit of measurement for electric current. One A is the current flowing through a resistance of 1 ohm with a voltage difference of 1 V across its ends.



Anaerobic compactor

A substance used to prevent bolts and screws from loosening.

Anaerobic - means it does not require oxygen to activate. Loctite brand sealant is widely used.

Anti-seize compound

A coating that reduces the risk of sticking of connections that are exposed to high temperatures, such as exhaust manifold bolts and nuts.



Antifreeze

Substance (usually ethylene glycol), which is mixed with water and used in the car's cooling system to prevent the coolant from freezing in the winter. Antifreeze also contains chemical additives to prevent corrosion and rust, which would tend to clog the radiator and coolant passages and reduce the efficiency of the cooling system.

Asbestos

A natural fibrous mineral with high thermal resistance, commonly used in brake lining materials.

Asbestos is hazardous to health and dust created by brake systems should not be inhaled or swallowed.

B

Beating

Radial or axial movement of the rim or end face of a rotating part relative to a fixed point due to inaccuracy in its manufacture or improper fit on the shaft.

Electronic control unit

A computer that controls (for example) the ignition and fuel injection systems or the anti-lock braking system.

IN

Drive shaft

Any shaft that transmits torque. Usually referred to as a half shaft in front-wheel drive vehicles.



Bleeding valve

A valve or shut-off screw on a brake slave cylinder, caliper, or other hydraulic component that opens to allow air to escape from the hydraulic system. Sometimes called a nipple.

Phillips screw

A type of screw that has a head with a cross-shaped slot instead of a longitudinal slot. It requires a corresponding type of screwdriver.

Air purifier

A metal or plastic housing containing a filter element that cleans the air entering the engine from dust and dirt.



Airbag (cushion) of safety

Inflatable bag hidden in the steering wheel (on the driver's side) or in the glove box (from the passenger side). In a frontal collision, the bags inflate, protecting the driver and front passenger from impact with the steering wheel or windshield.



Volt (V)

A unit of measurement of voltage in an electric circuit. A voltage of 1 V is formed at the ends of a 1 Ohm resistance when a current of 1 A flows through it.

Intake manifold

A pipeline with channels through which the working mixture (carburetor engine and throttle body injection engine) or air (diesel engine) are supplied to the valves in the cylinder head.

Release bearing

A thrust bearing in a clutch that is moved axially by the action of the clutch pedal and acts on the release levers or on the petals of the diaphragm spring to disengage the clutch. Starter interlock switch On vehicles with automatic transmission, a switch that prevents starting unless Neutral or Park is engaged.

Exhaust manifold

A pipe with multiple passages through which exhaust gases leave the engine's combustion chambers and enter the exhaust pipe.



Viscosity

A quantity that characterizes the resistance of a liquid to flow.

G

Torsional vibration damper

A device designed to reduce vibrations when the crankshaft rotates. Can be installed in the crankshaft pulley.

Generator

An element of the electrical equipment of a car that converts mechanical energy into electrical energy. It is driven by the crankshaft via a belt drive. It is used to recharge the battery, operate the ignition system and electrical devices.





Sealant

A liquid or paste used to prevent leakage in a joint. Sometimes used in conjunction with a gasket.

Hydraulic pusher

A tappet that uses hydraulic pressure from the engine's lubrication system to maintain zero clearance (constant contact) with camshaft and valve stem. Automatically adjusts to changes in valve stem length as it heats up. Hydraulic tappets reduce valve noise.

d

Oxygen sensor

A device installed in the exhaust manifold of an engine that detects the oxygen content of the exhaust gases and converts this information into an electrical current. Also known as a lambda probe. Overhead valve engine An engine with valves located in the cylinder head, but with the camshaft located in the engine block.

Overhead cam engine

An engine with the camshaft(s) located on the cylinder head.

Diagnostic code (fault code)

A digital code generated by the electronic engine management system when a fault occurs. This code can be read via the diagnostic module and used to determine which part of the system may be at fault.

Disc brake

A brake that includes a rotating disc that is compressed by brake shoes. Friction converts the energy of a moving vehicle into heat.



Spacer (washer)

A thin spacer used to adjust the axial clearance or relative position between two parts. Adjustment is made by changing the thickness of the spacer.

3

Plug

A metal part in the form of a disk or plate that closes the hole in the casting through which the molding mixture is removed. In cast parts of the engine body, such plugs also act as safety elements that reduce the likelihood of damage when the coolant freezes.

Gap

The distance between two parts. For example, between a piston and a cylinder, between a bearing and a journal, etc.

Valve clearance

Clearance between valve stop (end of the valve stem) and a rocker arm or tappet. Valve clearance is measured when the valve is closed.

Starting from an external source

Starting a car engine with a discharged or weak battery, from a charged battery by connecting the batteries with large-section wires. Sprocket A wheel with teeth that engage with a chain or toothed belt.

AND

Indicator

A device or light on the dashboard used to monitor the status of vehicle systems. An indicator with a movable pointer and scale divisions is called an analog indicator. An indicator with a numerical display of information is called a digital indicator.

Tool for measuring runout and backlash.

Spark gap

The distance between the center and side electrodes in a spark plug. Also refers to the gap between contacts in the breaker assembly in a conventional contact ignition.



Plain Bearing Clearance Gauge



A thin plastic thread, available in various sizes, used to measure clearances. For example, to measure the clearance in a plain bearing, place the thread across the journal of the bearing. Assemble and disassemble the bearing: the width of the crushed strip will indicate the clearance between the journal and the bearing.

TO

Carburetor

A device that mixes fuel and air in the proper proportions to produce the required power from a spark-ignition internal combustion engine.



Cardan shaft

A long, hollow tube with universal joints at the ends that transmits torque from the transmission to the differential on rear-wheel drive, front-engine vehicles. Universal joint A double hinged joint for transmitting rotation at an angle. A universal joint consists of two U-shaped forks and a cross-shaped joint called a cross.



Crankshaft housing

The lower part of the engine block in which the crankshaft rotates.

Catalytic converter

A device in the exhaust system, installed in the muffler, that converts some particularly harmful components of the exhaust gases into less harmful ones.



Valve

A device through which a flow of liquid or gas passes, the amount of which can be controlled by a moving part that opens, closes, or partially closes one or more passages. The moving part of such a device is also called a valve.

Exhaust gas recirculation valve

Valve for passing exhaust gases into the intake manifold.



Allen's Key

Hex key for loosening bolts with hexagonal socket.

Crankshaft

The main shaft of the engine, located along the entire length of the crankshaft housing, and having cranks to which the connecting rods are attached.



Shoe brake

The brake is a metal drum located inside the wheel. When the brake pedal is pressed, curved brake shoes are pressed against the inside of the drum to slow or stop the car.



Compression

Decreasing the volume and increasing the pressure and temperature of the gas.

Lock-nut

A nut that holds another nut, usually used for adjustment, in the desired position.

Main bearings

Bearings in which the crankshaft rotates in the engine crankcase. In an in-line engine, the number of main bearings is usually one more than the number of cylinders. Main bearings are usually made in the form of bores in the crankcase, into which liners are placed, coated on the inside with an antifriction material with a low coefficient of friction.

Rocker arm

A two-arm lever that swings on an axle or journal. In an overhead valve engine, the rocker arm transmits the movement of the pushrod to the valve stem. Crown nut An elongated nut with through slots on the top to secure the nut to a bolt or stud from loosening.



"Crocodile"

A long spring metal clamp with teeth. Used for temporary connections to the electrical network.

L

Headlight lamp

An older headlight design that combines the reflector, lens, and filament into a hermetically sealed unit. When the filament burns out or the lens cracks, the entire unit must be replaced.

Backlash

Movement due to clearance between two parts. In the case of a crankshaft, the distance the crankshaft can move back and forth in the cylinder block.

M

Flywheel

A massive disk that accumulates the energy of impulses during working strokes in the cylinders. On cars, the flywheel is attached to the crankshaft to smooth out uneven rotation.

Multimeter

An electrical measuring instrument capable of measuring voltage, current, and resistance. Also known as a tester.

Fan clutch

Hydraulic transmission that allows maintaining the desired fan speed at variable engine speed.

ABOUT

Pressure limiter

A hydraulic control valve that limits the pressure in the rear brakes during emergency braking to prevent the wheel from being completely braked.

Load dependent pressure limiter

A control valve for the brake hydraulic system that functions similarly to a pressure limiter but also takes into account the rear axle load.

Nitrogen oxides

The primary toxic pollutant emitted by gasoline and diesel engines at high temperatures. Ohm A unit of electrical resistance. A resistance of 1 ohm produces a voltage drop of 1 volt when a current of 1 amp is passed through it.

Ohmmeter

A measuring device for determining electrical resistance.

Ignition timing

The angle through which the crankshaft must rotate to bring the piston to top dead center, usually expressed as a number of degrees, at the moment when ignition of the mixture occurs.

Axis

The shaft on which the wheel rotates or which rotates together with the wheel. Also - the beam which connects two wheels of the car. The axle which also transmits torque to the wheels is called the drive axle.



Folding washer

A washer designed to prevent spontaneous loosening or loosening of nuts securing units and parts by bending a special tongue of the washer onto the edge of the nut.

P

Partition

A part of a car body that separates the engine compartment from the passenger compartment.

(Article text obtained from the website: MercedesMan.ru)

Fuse box

An electrical device that protects a circuit from accidental overload. A typical fuse contains a low-melting wire that is calibrated to melt at a certain amount of current (amperes) and disconnect the circuit it is protecting.

Fusible link

A circuit protection device consisting of a conductor surrounded by heat-resistant insulation. The conductor has a diameter smaller than the wire it is protecting, so it acts as the weakest link in the circuit. Unlike a blown fuse, a broken fusible link must be cut from the wire to be replaced.

Plain bearing

A unit that ensures easy rotation of the shaft in the housing and does not allow their relative radial displacement. Usually made in the form of a cylindrical bore in the housing, into which a bushing or insert made of antifriction material with a low friction coefficient is inserted. A plain bearing usually requires good organization of lubrication under pressure. An example is the crankshaft bearings of an engine.



Half shaft

The rotating shaft that transmits torque from the final drive mechanism to the drive wheel is usually mounted in the driven rear axle.

Cylinder firing order

The order in which the mixture is ignited in the engine cylinders, starting with the first cylinder.

Auxiliary unit drive

A belt drive designed to drive auxiliary units such as the generator, water pump, power steering pump, air conditioning compressor, etc. from the crankshaft pulley.



Longitudinal inclination of kingpin

The angle of installation of wheels, which determines the tilt of the kingpin axis in the longitudinal plane. The longitudinal tilt angle of the kingpin is considered positive when the top of its axis is tilted back.

Bleeding brakes

Procedure for bleeding air from the hydraulic brake drive system.



Pad

Any thin, soft material - usually cork, cardboard, asbestos, or soft metal - installed between two metal surfaces to provide a good seal. For example, a cylinder head gasket is installed at the joint between the block and the cylinder head.



Spring ring

A ring-shaped clamp for preventing longitudinal movement of cylindrical parts and shafts. The inner spring ring is installed in a recess (groove) in the housing, the outer spring ring is inserted into a recess (groove) on the outer surface of the cylindrical shaft.

R

Radiator

A heat exchange device that provides heat transfer from liquid to air, designed to reduce the temperature of the liquid in the cooling system of an internal combustion engine.

Camshaft

A rotating shaft on which a series of cams are located that operate the engine's valve mechanisms. The camshaft may be chain or belt driven.

Rack and pinion steering mechanism

A steering system in which the steering shaft has a pinion at the end that engages with a rack. When the steering wheel is turned, the pinion turns and moves the rack to the left or right. This movement is transmitted through the steering rods to the steered wheels.

Adjustment

The process of fine-tuning the operation of an engine, including replacing certain parts, to achieve the best possible performance.

Camshaft Drive Belt

The toothed belt that rotates the camshaft. A belt break while the engine is running can cause serious consequences. Gas recirculation The removal of a portion of the exhaust gases to the engine inlet for re-burning in order to reduce harmful emissions into the atmosphere.

Rotor

The rotating part of any device (for example, a generator).

A turbocharger rotor is an assembly that includes a compressor wheel, shaft, and turbine wheel.

The distributor rotor is the rotating part of the ignition distributor that alternately connects the center electrode on the distributor cap to the high-tension spark plug wires and directs the high voltage from the ignition coil winding to the proper spark plug.

WITH

Welding

Joining two parts by heating and melting the metal in the weld area.

Free play

Pre-action travel. The "free movement" in a linkage or assembly, between the start of force application and the actual movement. For example, the distance a brake pedal will travel before the piston in a brake master cylinder begins to move.

Serpentine drive

An engine accessory drive that uses one wide, long belt that wraps around all the pulleys instead of several short belts.



Engine management system

A computer that controls fuel injection and ignition.

Compression ratio

The ratio of the volume of the cylinder when the piston is at bottom dead center to the volume of the cylinder when the piston is at top dead center.

MacPherson strut

A type of front suspension system invented by Earl MacPherson at Ford in England. In its original form, the lower control arm is formed by a simple horizontal link to the anti-roll bar. A long strut is mounted between the body and the steering knuckle, combining a coil spring and shock absorber into a single unit. Many modern so-called MacPherson struts use a conventional A-shaped arm as the lower support and do not rely on an anti-roll bar.

Support

The stationary part of the disc brake, which covers the disc and guides the brake pads. The caliper also contains the working hydraulic cylinders of the brake system with pistons that press the brake pads against the disc during braking.

Electrical wiring diagram

A drawing showing the components and wires of a vehicle's electrical system using standardized symbols.

Wheel alignment

The difference in distances between the end surfaces of the wheels at the front and rear. If this distance at the rear is greater than at the front, the toe-in is called positive, if the opposite is true, then it is negative. Toe-in is usually important for the front (controlled) wheels. On rear-wheel drive vehicles, a small amount of positive toe-in is necessary to compensate for the forces tending to push the wheels apart so that the front wheels are parallel when driving. On front-wheel drive vehicles, a small amount of toe-in is usually set (negative convergence).

T

Thermostat

A temperature-controlled valve that regulates the flow of coolant between the engine block and the radiator to maintain the optimum engine temperature. A thermostat is also used in some air cleaners that are temperature-controlled.

Pusher

A cylindrical part that transmits movement from the cam to the valve stem either directly or through a rocker arm.

Brake lining

A component made of friction material with a high coefficient of friction. The brake lining is glued or riveted to a steel base, together with which it forms the brake shoe.

Brake shoe

A component of a disc or drum brake that is pressed against the surface of the disc or drum connected to the wheel and is designed to reduce the speed or stop the vehicle. A brake shoe usually has a base made of steel in the shape of the link being stopped (flat for a disc brake and crescent-shaped for a drum brake), to which a brake lining made of friction material is glued or riveted. Brake drum A component of the brake that rotates with the wheel and is acted upon by the brake shoes to stop the vehicle.

Brake disc

The part of the brake that rotates with the wheel and is acted upon by the brake shoes to stop the vehicle.

Tracer

Stripes of a different color applied to the insulator of a wire to distinguish that wire from another wire with an insulator of the same color.

Turbocharger

A device with a gas turbine and a centrifugal compressor, driven by exhaust gases, to increase the air pressure in the intake manifold. Typically used to increase engine power with the same cylinder displacement.

U

Impact puller

A special puller that is screwed or attached to a part, such as a shaft or bearing. The puller rod has a massive blank that can slide along the rod. At the free end of the rod there is a stop that the blank hits, releasing the part being removed.

Sealing ring

A type of seal made from a special rubber-like material. When assembling a unit, to ensure a reliable seal, the ring is placed in a groove in which it is compressed by the attached part.

Sh

Air cleaner filter element

The main element of the air cleaner, usually made of porous paper, through which all air entering the engine passes.

X

Coolant

Any substance used to remove heat in an air conditioning system. For many years, the most common refrigerant was R-12; however, manufacturers have recently begun using the less toxic substance R-134a, which is less harmful to the ozone layer of the atmosphere.

Honing

Abrasive tool for correcting small deviations in bore cylindricity or differences in engine cylinder diameters, brake cylinders, etc.

C

Coil spring

A coil made of elastic steel, available in various sizes. It is used in many vehicle components, such as an elastic element in the suspension, in the valve mechanism.

Sh

Ball bearing

A unit that provides easy rotation of the shaft in the housing and its fixation relative to the housing in the radial and axial directions. The bearing consists of an inner and outer ring with steel balls between them.

Constant velocity joint

A type of universal joint that does not exhibit speed variations due to changes in torque transmission angle. Connecting rod bearing A bearing that connects the lower end of a connecting rod to the crank of an engine crankshaft. Usually made as a plain bearing.

Calipers

A precision measuring instrument that measures internal and external dimensions. Not as precise as a micrometer, but more convenient.

SCH

Probe

A thin strip or blade of hard steel of a certain thickness is used to determine the gaps between parts.

E

Electronic fuel injection control system

A computer-controlled fuel injection system that distributes fuel to injectors located in each intake port of the engine.