Cooling and Lubrication Systems Exercises

     1. Please answer the following four questions

    1)Define the major parts of a cooling system.

    2) Identify the main function of lubricating system，and the main components.

    3) Identify working principle of the cooling system.

    4) Identify how the lubricating system works.

    1. Translate the following sentences into Chinese

    1) The fan's activity is not always necessary, and it takes power from the engine tospin. For this reason a thermostatic control，or fan clutch, is often used to reduce drivetorque when it isn't needed (variable-speed fan)．

    2) A different type of fan uses centrifugal force to move its flexible plastic blades，byflattening them when the engine rpm is high (flexible-blade fan)．The less angle the bladeshave, the less power they use. The idea of these units is to save horsepower and reducethe noise the fan makes.

    3) A fan can have from four to six blades to suck the air through the radiator. Oftenthe radiator has a shroud for the fan to keep it from recirculating the same hot air that hascollected behind the radiator. Many fans have irregularly spaced blades to reduce resonant noise.

    4) Another function of the expansion tank is to remove air bubbles from the coolingsystem. Coolant without air-bubbles is much more efficient than coolant with air bubbles，because it absorbs heat much faster. The advantage of the expansion tank is that while thelevel of coolant contained in it rises and falls，the radiator is always full.

    5) Automatic Lubrication System consists of a timer/ controller, a reservoirpump，a supply line, metering valves & injectors as well as feed lines. Each of its components hasa unique function which plays a pivotal role in lubricating the part or point of applicationin/on the machine.

    6) One of the functions of the engine lubrication system is to maintain a positive andcontinuous oil supply to the bearings. Engine oil pressure is high enough to get the oil tothe bearing with sufficient force to produce adequate oil flow for proper cooling. Normalengine oil pressure range is from 207 to 414 kPa while the hydrodynamic film pressuresdeveloped in the high-pressure areas of the engine bearing may be over 6，895 kPa.