Automobile Cooling System

All automobile need a cooling system for their machine, if there is no cooling system heat transfer from fuel combustion will too hot for the machine. In high temperature, all steel and lubrication oil will damage. Several parts will change the form because of their expansion.

On the internal combustion engine the temperature as long on operation can reach temperature of 2500oC. On the side of this combustion room, metal temperature can reach 600oC, so that why engine need of cooling system. Because on this temperature all part and lubrication oil can damage vastly.

There are two cooling system on automobile:

1. By blowing of air into the combustion machine (available in motorcycle)
2. By pumping of water into the surround of machine and then cooled that water in the radiator using a fan. (available on car)

Machine part that is placed on the front usually cool by water, and machine parts that locate on the back of car sometime cooled by air. Air cooling system usually have high noise.

Cooling system in general using two methods:

1. Direct cooling system (using air cooling system)
2. Indirect cooling system (using combination of water cooling system and air cooling system)

Electronic Speedometer

On the speedometer can be seen about what the speed is and how many km have been reaching by the car. The speed is pointed by needle and traveled distance is showed by odometer (mechanic display). Electronic circuit is put in indicator pulse changed from the transducer become form is needed by to move two parts. Beside the motor speed, other component on the odometer parts is mechanical; the speed of motor drive is signed by transducer pulse from electronic circuit, move odometer and meter the traveling of the gear.

Speedometer parts are divided into: electronic circuit that can change a transducer pulse into low voltage current and moving coil meter. The needle is moved by low voltage current that is supplied by electronic circuit. These speedometer part is placed on the instrument panel and connected that is printed on tree low voltage current terminal.

Reduction Gear
This part same as on mechanical speedometer but the pinion is suited with transducer driver.

Transducer
The transducer is change rotation moving into electronic pulse through magnetic rotation and micro contact room effect. Transducer is moved by reduction gear and placed on the back of transmission room. Tree cable and terminal are used for connecting the transducer on the electric circuit.

Water Cooler Temperature Indicator

Water cooler temperature indicator consist of: switch on contactor, low voltage stabilizer, indicator and sender and relay.

a. Indicator or Measure Unit
This unit uses the same type as oil pressure on the machine and have a little different;
Have temperature symbol that is printed on the dial indicator or lens glass.
The lamp only will turn on when the machine too hot
To test the lamp circuit when the starter on

b. Sending Unit
Sender unit is bolted on the cylinder head in the maximum temperature cooling, identification sign or temperature range is placed on the body to differ between bimetal contactor type and micro wax type and termistor type.

c. Relay
Relay is used on the several purposes to test the lamp circuit when the contactor is on start position. Relay is placed on the relay panel under the machine cap, and relay have four terminal to make connected to lamp circuit.

Connection order from component meter type same as the pressure oil that is shown by dash dot on the circuit diagram.

Sending Unit

Sender is installed on the machine block “point close” of channel oil pump on the left side in order to show the maximum oil pressure. Sender type is determined by indicator that indicates the pressure and stick on the block body.

There are many kind of sender type available: switch type, thermal bimetal type, and variable resistance.

Switch Type:

1. Using with lamp
2. Contact set operate using diaphragm
3. One contact connected to the lamp using low voltage terminal
4. Other contact connected to the lamp mass through the machine

Thermal Bimetal

1. Use with thermal bimetal size
2. Consist of contact set, a piece of bimetal, heater coil and diaphragm
3. Diaphragm will change the power in the thermal bimetal and make the electric current changed
4. This connected to the circuit through low voltage terminal, and the body is connected to mass on the machine

Variable Resistance Type

1. Using with moving coil size or digitally supplied.
2. This rheostat can use a wiper arm or piczoresistor type
3. Diaphragm moving will change resistance or cause the voltage of low voltage circuit changed
4. One low voltage terminal is used for measured circuit and two for digital supply, the body is connected to the mass on the machine.

The next are the relationship of thermal bimetal component size order.

Oil Pressure Indicator

Oil pressure indicator is divided into several parts: ignition contactor, voltage stabilizer, and indicator and transmission unit.

Voltage Stabilizer

The goal of this unit provides a stable voltage. To avoid any fault result, voltage is keep about a half of voltage filling system. This system needs a unit that sensitive to high temperature (thermal) or heat or electronic type (solid state type). Thermal is contains of contact unit, bimetal and small heater coil.

Solid state type consisted of several resistor and Zener diode, this is installed in the printed circuit board.

Indicator

Indicator install on the instrument panel or dashboard in order easy to monitor by driver. This instrument consisted of: Lamp, measurement unit, and digital display.

Function of Lamp indicator:

• As a signal lamp of low oil pressure
• Usually use low power about 2 – 4 watt
• Usually installed with red plastic lens with oil symbol, or word “Oil”, printed and lighted with small lamp.
• Lamp holder is placed/located on the circuit board and connected on the circuit

Measurement Indicator:

• Needle pointer and scale number that pointed current oil pressure
• Oil symbol or word “OIL” is printed above needle pointer
• This make a coil move using bimetal type
• Two terminal interconnected using printed circuit from the back of instrument panel

Digital Display

• Display that is shown an oil pressure on letter or drawing
• This is LED type (light emitting diode) or vacuum fluorescent display (VED)
• Using a microprocessor that receive input signal from various sender and pointed an output signal needed.

The next article about Transmission Unit or Sender