When The Car Doesn't Work

BEFORE a car needs repairs, the owner should check the car's manual to see if maintenance is needed. Failure to care for the car, and ignoring the initial warning signs (funny noises, problems that "fix themselves", etc) will produce more extensive and costly damage in the long run. I. Starting Problems Problems encountered in starting are usually due to the condition of the battery (clicking noises, no sound or slow grinding). These problems can often be solved by jump starting or charging the battery. If there is no response after trying these cures, it will probably be necessary to get experienced help or have your car inspected and serviced by a professional. II. Moving Problems 1. Problems with the engine hesitating, cutting out, being weak, or having difficulty with the idling should all be carefully inspected by an experienced mechanic. Overheating may be due to a need for additional coolant in the radiator or a need to unload excess weight (as when pulling a trailer). Turn off all accessories; i.e., the air conditioner. If this doesn't help, get professional help. 2. Transmission problems should always be inspected for repair or adjustment by a professional mechanic. If the car is driveable, drive slowly and carefully to the nearest service facility. If in doubt about driving the car, call a tow truck. III. Stopping Problems: When the brakes fail to hold, or if they squeal, grab or drag, they should be inspected and cared for at a specialized brake shop. When the problem is due to worn tires, the tires should be replaced at once before damaging other, more expensive elements of the car.

Windshield Washers

All cars use an electric pump-operated windshield washer with a positive displacement washer pump. On some, the motor is placed in the washer reservoir, while on others, it is driven by a wiper motor. When the pump is attached to the wiper motor, the four lobe cam starts a spring-loaded follower, but the pump does not operate all the time that the wiper motor is running. This is because the pumping mechanism is locked out and pumping action occurs. A plunger is pulled toward the coil, allowing the ratchet pawl to engage the ratchet wheel, which begins to rotate, one tooth at a time. Each lobe of the cam starts the follower. The follower moves the piston actuator plate and piston away from the valve assembly and compresses the piston spring, creating a vacuum in the pump cylinder through the intake valve. As the high point of each cam lobe passes the follower, the piston spring expands, forcing the piston toward the valves. This pressurizes the washer solution so it flows out the exhaust valves to the spray nozzles.

Crash and Safety Features

What actually happens in a collision? The first part of that answer is that there are two collisions. The first collision occurs when the vehicle runs into another object. The second collision is when the occupant(s) hit the inside of the car. Neither a seat belt nor an air bag can do anything about the first collision, but they can be a great help to you in the second collision. They can minimize the impact between you and the interior of the car. Safety belt use is more than a personal right. Injuries and fatalities resulting from motor vehicle accidents are reflected in the rising costs of auto and health insurance, and costs to employers in the form of lost days at work. The taxpayer also loses by having to support emergency medical response teams and social programs for the disabled. Excuses, excuses! 1. "Seat belts are too uncomfortable." Of course, in a car accident -- without your seat belt -- you would smash into the steering column, slam into the dashboard, or crash through the windshield. This too, can be very uncomfortable. 2. "Seat belts wrinkle my clothes." Sometimes. Sitting also wrinkles clothes. Wearing clothes wrinkles clothes. Flying through a windshield REALLY wrinkles clothes. 3. "Only nerds wear seat belts." Really? It turns out that -- without seat belts -- nerds, jocks, cheerleaders, "A" students and average students would all fly through the windshield at the same rate. 4. "I'm a good driver." Nice as that is, good drivers can get hit by bad drivers, drunk drivers, or other good drivers with mechanical failures. Very few people intend to have accidents. 5. "Seat belts restrict my freedom of movement." This is true. Without your seat belt, you have all the freedom in the world -- to crash into your windshield, to slam into your car's interior, or to be thrown from your car and slide along the pavement. Freedom is great. 6. "It's too embarrassing to ask friends to use their seat belts." In 1984, 46,000 people died in car accidents. That same year, not one person died of embarrassment. Safety in car design was recognized as being important even in the earliest cars. In recent years, however, it has become a fundamental subject in its own right. Active safety measures have been designed to reduce the likelihood of a car being involved in an accident in the first place, while passive safety measures assume that a collision is inevitable and then aim to reduce the severity of the injuries to the road users involved. Until the late 1800's the British had a 2 mph speed limit for cars. There was an excellent reason for this. It was also required, for safety's sake, that each car carry two passengers with a third person walking in front. The job of the third person was to walk in front of the car to warn everyone that it was coming!

Classification by Drive Method

Vehicles can be classified by the position of the
engine and drive wheels, and the number of drive
wheels.
FF (Front-engine, Front-drive)
Because a FF vehicle does not have a propeller
shaft, a spacious interior can be realized, thus
achieving excellent comfort.
FR (Front-engine, Rear-drive)
Because a FR vehicle has a good weight
balance, it excels in controllability and stability.
MR (Midship-engine, Rear-drive)
Because a MR vehicle has a good weight
balance on the front and rear axles, it excels in
controllability.
4WD (4-Wheels Drive)
Because a 4WD vehicle drives with four
wheels, it can operate under poor conditions in
a stable manner. Its weight is greater than that
of other types of vehicles.

Some Details of Car Engine

The basic components of an internal-combustion engine are the engine block, cylinder head, cylinders, pistons, valves, crankshaft, and camshaft. The lower part of the engine, called the engine block, houses the cylinders, pistons, and crankshaft. The components of other engine systems bolt or attach to the engine block. The block is manufactured with internal passageways for lubricants and coolant. Engine blocks are made of cast iron or aluminum alloy and formed with a set of round cylinders.

The upper part of the engine is the cylinder head. Bolted to the top of the block, it seals the tops of the cylinders. Pistons compress air and fuel against the cylinder head prior to ignition. The top of the piston forms the floor of the combustion chamber. A rod connects the bottom of the piston to the crankshaft. Lubricated bearings enable both ends of the connecting rod to pivot, transferring the piston’s vertical motion into the crankshaft’s rotational force, or torque. The pistons’ motion rotates the crankshaft at speeds ranging from about 600 to thousands of revolutions per minute (rpm), depending on how much fuel is delivered to the cylinders.

Fuel vapor enters and exhaust gases leave the combustion chamber through openings in the cylinder head controlled by valves. The typical engine valve is a metal shaft with a disk at one end fitted to block the opening. The other end of the shaft is mechanically linked to a camshaft, a round rod with odd-shaped lobes located inside the engine block or in the cylinder head. Inlet valves open to allow fuel to enter the combustion chambers. Outlet valves open to let exhaust gases out.

A gear wheel, belt, or chain links the camshaft to the crankshaft. When the crankshaft forces the camshaft to turn, lobes on the camshaft cause valves to open and close at precise moments in the engine’s cycle. When fuel vapor ignites, the intake and outlet valves close tightly to direct the force of the explosion downward on the piston.

Two Stroke Engine

By suitable design it is possible to operate an Otto-cycle or diesel as a two-stroke or two-cycle engine with a power stroke every other stroke of the piston instead of once every four strokes. The power of a two-stroke engine is usually double that of a four-stroke engine of comparable size.

The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke. In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinder wall that are uncovered by the piston at the end of its outward travel). In the two-stroke cycle, the fuel mixture or air is introduced through the intake port when the piston is fully withdrawn from the cylinder. The compression stroke follows, and the charge is ignited when the piston reaches the end of this stroke. The piston then moves outward on the power stroke, uncovering the exhaust port and permitting the gases to escape from the combustion chamber.

How to work Turbo Charger

The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons.
The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin.
On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.
In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts, and it allows the shaft to spin without much friction.
There are many tradeoffs involved in designing a turbocharger for an engine. In the next section, we'll look at some of these compromises and see how they affect performance.

About Valve Seals

The valve seal is a unit that goes over the end of the valve stem. It keeps excess oil from getting between the valve guide and the valve stem.

Semiconductors and Diodes

Semiconductors are made from material somewhere between the ranges of conductors and nonconductors. Semiconductors, basically, are designed to do one of three things: (1) stop the flow of electrons, (2) start the flow of electrons, or (3) control the amount of electron flow. A semiconductor diode is a two-element solid state electronic device. It contains what is termed a "P" type material connected to a piece of "N" material. The union of the "P" and "N" materials forms a PN junction with two connections. The "anode" is connected to the P material; the "cathode" is connected to the N material. A diode is, in effect, a one-way valve. It will conduct current in one direction and remain non conductive in the reverse direction. When current flows through the diode, it is said to be "forward biased." When current flow is blocked by the diode, it is "reverse biased." When a diode is reverse biased, there is an extremely small current flow; actually, the current flow is said to be "negligible." When the P and N are fused together to form a diode, it can be placed in a circuit. The P material is connected to the positive side of the battery and the N material is connected to the negative side of the battery. Connected in this manner, current will flow. If connected in the reverse manner, current will not flow.

Worm and Tapered Peg Steering

The manual worm and tapered peg steering gear has a three-turn worm gear at the lower end of the steering shaft supported by ball bearing assemblies. The pitman shaft has a lever end with a tapered peg that rides in the worm grooves. When the movement of the steering wheel revolves the worm gear, it causes the tapered peg to follow the worm gear grooves. Movement of the peg moves the lever on the pitman shaft which in turn moves the pitman arm and the steering linkage.

Windshield Wipers

There are three types of motors that can be used for windshield wipers. The permanent "magnet" motor has two ceramic magnets that are cemented to the field frame and does not use field windings. It needs less energy than the other types of motor design, but the switch must be wired in series, creating many areas of resistance. The "shunt wound" motor provides a very consistent speed, but doesn't provide much torque upon starting. The "compound" motor wiper has a strong starting torque and provides consistent speed, but it is the most expensive. Most cars have an intermittent wiper system, which permits the driver to select a delayed wipe that operates only every few seconds. A representative wiper/washer unit is the wiper assembly, which incorporates a depressed park system that places the wiper blades below the hood line in the parked position. The relay control uses a relay coil, relay armature, and switch assembly. It controls starting and stopping of the wiper through a latching mechanism. An electric washer pump is mounted on the gear box section of the wiper. It is driven by the wiper unit gear assembly.

Window Winding Mechanisms

There are two types of window winding mechanisms; hand cranked and power. Hand cranks work two ways. With "window winders," the crank turns a "sector gear" that pivots a pair of arms. The arms raise the "window carrier" and the glass. Some cars have fixed glazing
oors so that the window cannot go up or down. The other type of window crank is a tape mechanism. It winds up a ladder-like tape made of plastic links. The plastic links are wound on to or off a spool to raise or lower the glass. The tape mechanism was introduced in 1980 GM cars. It saves weight and space. Its parts will not corrode when rainwater gets into the door, and it needs no lubrication. First introduced in 1946, power windows use a small electric motor inside the door. The motor turns the crank that raises the window. Door and vent windows are made of laminated "safety" plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic even when shattered.