Chapter 6 of 9

Bus mechanics

40 questions from the official bank with the right answer, in the order of the manual.

A test on this chapter Cards of this chapter

No. 10
In an independent vehicle that has air brakes, the time of air containers filling should not be longer than?
1. AThree (3) minutes for pressure increase from 0% to 65% of the maximum pressure.
2. BThere is no limit, provided that the air containers be filled.
3. CTen (10) minutes for pressure increase from 0% to 65% of the maximum pressure.
Right answer: A. An official question of the Ministry, in its official translation.
No. 14
What is function of the primary shaft in the gear-box?
1. AThrough the clutch it is driven by the engine.
2. BThrough the central shaft and the joints it drives the driving wheels.
3. CIt is driven by the central shaft and drives the secondary shaft.
Right answer: A. An official question of the Ministry, in its official translation.
No. 16
The rev-counter of some buses has yellow, green and red scales (areas of revolution indications). Where will the pointer be when the engine’s performance is good and the fuel consumption is limited?
1. AYellow scale.
2. BGreen scale.
3. CRed scale.
Right answer: B. An official question of the Ministry, in its official translation.
No. 17
The rev-counter of some buses has yellow, green and red scales (areas of revolution indications). Where will the pointer be when the fuel consumption is excessive in relation to the output engine power?
1. AYellow scale.
2. BGreen scale.
3. CRed scale.
Right answer: C. An official question of the Ministry, in its official translation.
No. 18
What is the function of the auxiliary shaft in the gear-box?
1. AIt is driven by the engine through the clutch.
2. BIt drives the driving wheels through the central shaft and joints.
3. CIt is driven by the primary shaft and drives the secondary shaft.
Right answer: C. An official question of the Ministry, in its official translation.
No. 21
The wheel anti-lock braking system (ABS):
1. APrevents differential locking on bends.
2. BPrevents wheel sliding during acceleration.
3. CPrevents wheel locking when braking (on a wet road).
Right answer: C. An official question of the Ministry, in its official translation.
No. 26
What is the range of the lowest permissible pressure of compressed air in a pneumatic braking system?
1. AAbout 5-6 bar.
2. BAbout 9-10 bar.
3. CAbout 14-15 bar.
Right answer: A. An official question of the Ministry, in its official translation.
No. 27
In a suspension system with air, what is the use of the high pressure circuit:
1. AIt supplies additional air to, and increases the pressure in the air springs, when the car is being loaded, so as to maintain it steady.
2. BIt maintains the pressure in the air springs steady.
3. CIt supplies air to the servo-mechanisms of the vehicle.
Right answer: A. An official question of the Ministry, in its official translation.
No. 30
The carbon monoxide (CO) is a pollutant contained mainly in combustion products of a:
1. ADiesel-engined car.
2. BPetrol-engined car.
3. CElectric-engined car.
Right answer: B. An official question of the Ministry, in its official translation.
No. 32
In a fully synchronized gear-box:
1. AAll gears change in a synchronized way.
2. BAll gears change in a synchronized way, except for the first gear.
3. CAll gears change in a synchronized way, except for the reverse.
Right answer: C. An official question of the Ministry, in its official translation.
No. 33
How do pistons transfer the pressure created by the mixture explosion to the crankshaft?
1. AThrough the camshaft.
2. BThrough the valve tappers.
3. CWith the help of the connecting rod.
Right answer: C. An official question of the Ministry, in its official translation.
No. 34
The aim of the connecting rod is:
1. ATo transfer the kinetic energy of the piston to the crankshaft.
2. BTo connect the piston with the camshaft.
3. CTo open and close the inlet and exhaust valve.
Right answer: A. An official question of the Ministry, in its official translation.
No. 35
On a tyre 175/70 R 15 87T, size 15 indicates:
1. AThe external diameter of the tyre in inches.
2. BThe diameter of the wheel-rim in inches.
3. CThe height of the tyre tread in inches.
Right answer: B. An official question of the Ministry, in its official translation.
No. 36
The sulphur dioxide (SO2) is a pollutant contained in combustion products of a:
1. APetrol-engined car.
2. BDiesel-engined car.
3. CGas-driven car.
Right answer: B. An official question of the Ministry, in its official translation.
No. 37
What does a four-stroke diesel-engine suck during induction stroke:
1. AA mixture of diesel oil and air.
2. BOnly diesel oil.
3. COnly air.
Right answer: C. An official question of the Ministry, in its official translation.
No. 38
What is the aim of the central driving shaft, if the engine is in the front and the driving wheels are at the back?
1. ATo drive the front wheels.
2. BTo transfer the motion from the differential to the gear-box.
3. CTo transfer the torque from the gear-box to the driving wheels.
Right answer: C. An official question of the Ministry, in its official translation.
No. 40
The oxidizing catalytic converter in buses:
1. AFacilitates the exhaust gases outlet.
2. BReduces pollution emitted by the exhaust pipe.
3. CIncreases engine horsepower.
Right answer: B. An official question of the Ministry, in its official translation.
No. 41
Piston’s compression springs are designed:
1. ANot to allow combustion gases to escape to the crankcase.
2. BNot to allow the lubrication oil to reach the combustion chamber.
3. CTo lubricate the piston-cylinder surfaces.
Right answer: A. An official question of the Ministry, in its official translation.
No. 43
The braking system with compressed air (air brakes) is used in buses, because:
1. AVehicle driving is more comfortable.
2. BThe hydraulic braking system does not suffice for slowing down the vehicle.
3. CThe external wear of the piping and the other mechanisms of the air brakes is rare.
Right answer: B. An official question of the Ministry, in its official translation.
No. 45
In a four-stroke diesel-engine, when the crankshaft completes two revolutions, how many revolutions does the camshaft perform:
1. AOne revolution.
2. BTwo revolutions.
3. CFour revolutions.
Right answer: A. An official question of the Ministry, in its official translation.
No. 46
The centrifugal pump of the water of the cooling system is driven by:
1. AThe crankshaft through a belt.
2. BThe camshaft with special gears.
3. CThe camshaft through a belt.
Right answer: A. An official question of the Ministry, in its official translation.
No. 47
The lubrication of engine bearing surfaces of modern cars is performed:
1. ABy oil injection.
2. BBy compulsory oil circulation.
3. CBy a mixed system.
Right answer: B. An official question of the Ministry, in its official translation.
No. 48
The hydraulic steering system is used in buses so as to:
1. AReduce the effect of driver’s muscular effort at turning.
2. BIncrease the effect of driver’s muscular effort at turning.
3. CIncrease tyre grip on the road.
Right answer: B. An official question of the Ministry, in its official translation.
No. 50
The air compressor:
1. ASucks the air, compresses and introduces it into the air containers.
2. BSucks the air and sends it to the suspension system.
3. CSucks the air and sends it to the cooling system.
Right answer: A. An official question of the Ministry, in its official translation.
No. 52
The servo-brake with compressed air applies to:
1. AA mechanical braking system.
2. BA hydro-pneumatic braking system.
3. CAn electrical braking system.
Right answer: B. An official question of the Ministry, in its official translation.
No. 53
The oil springs are designed:
1. ATo lubricate the distributor.
2. BNot to allow the lubrication oil to reach the combustion chamber.
3. CNot to allow the combustion gases to escape to the crankcase.
Right answer: B. An official question of the Ministry, in its official translation.
No. 54
The shock absorbers (amortisseur) are mechanisms which:
1. AMake car’s driving stable.
2. BControl and absorb fast the springs’ oscillations when the wheels meet a roughness on the road.
3. CConnect car frame with the tyres.
Right answer: B. An official question of the Ministry, in its official translation.
No. 57
The automatic pressure regulator is a mechanism of the braking system which:
1. ARegulates automatically the pressure in the brake cylinders according to vehicle’s loading.
2. BProduces the required compressed air.
3. CDistributes the air to more than one circuit.
Right answer: A. An official question of the Ministry, in its official translation.
No. 58
The centrifugal water pump of engine’s cooling system:
1. ASucks the cooling fluid from the radiator’s upper water space and sends it with natural flow to engine’s cylinder casings.
2. BSucks the cooling fluid from the radiator’s lower water space and sends it with pressure to engine’s cylinder casings.
3. CWith the help of the thermostat it sucks the cooling fluid and sends it to cylinder casings.
Right answer: B. An official question of the Ministry, in its official translation.
No. 62
What is the aim of the exhaust brake?
1. AThrift in fuel consumption.
2. BReduction of the use of footbrake during vehicle movement on a downhill.
3. CEngine relief.
Right answer: B. An official question of the Ministry, in its official translation.
No. 63
In a bus fitted with a braking system with compressed air (air brakes), where should the driver direct their attention mainly?
1. ATo the way the brakes act.
2. BTo the indications of the manometers on the dashboard.
3. CThe way the footbrake pedal goes down when pressed.
Right answer: B. An official question of the Ministry, in its official translation.
No. 64
Which of the following components are driven by the camshaft:
1. AThe crankshaft.
2. BThe fan.
3. CThe inlet and exhaust valve.
Right answer: C. An official question of the Ministry, in its official translation.
No. 65
Which is the normal water circulation in the cooling system?
1. ARadiator - water jackets - water pump - thermostat -radiator.
2. BRadiator - thermostat - water jackets - water pump -radiator.
3. CRadiator - water pump - water jackets - thermostat -radiator.
Right answer: C. An official question of the Ministry, in its official translation.
No. 66
At least how many are the internal lighting circuits of a bus?
1. AOne (1).
2. BTwo (2).
3. CThree (3).
Right answer: B. An official question of the Ministry, in its official translation.
No. 67
What does the oil manometer on dashboard of a bus show?
1. AHydraulic brakes oil pressure.
2. BEngine oil pressure.
3. CSump oil quantity.
Right answer: B. An official question of the Ministry, in its official translation.
No. 68
At least how many exterior rear-view mirrors should a bus have?
1. ATwo (2).
2. BThree (3).
3. CFour (4).
Right answer: A. An official question of the Ministry, in its official translation.
No. 69
Which is the basic function of the differential?
1. ATo differentiate the revolutions of one driving wheel from the other.
2. BTo increase the number of revolutions of the driving wheels in relation to those of the central driving shaft.
3. CTo change driving direction by 40 degrees.
Right answer: A. An official question of the Ministry, in its official translation.
No. 70
The danger switch that every bus has, designed to limit the risk of fire when the vehicle is stopped, cuts off:
1. AFuel supply.
2. BThe circuit of internal danger lighting.
3. CThe circuit of central electrical door locking.
Right answer: A. An official question of the Ministry, in its official translation.
No. 73
Why, when you press the accelerator pedal, is the power produced by a diesel engine increased?
1. ABecause the inlet valve opens more.
2. BBecause more diesel goes to the fuel injectors.
3. CBecause current of greater intensity goes to the sparkling plug.
Right answer: B. An official question of the Ministry, in its official translation.
No. 78
Which is the function of the silencer of the exhaust pipe:
1. ATo decrease the speed of exhaust gases outlet so as to reduce noise.
2. BTo decrease the speed of exhaust gases outlet so as to reduce fuel consumption.
3. CTo decrease the speed of exhaust gases outlet so as to warm up the interior of the vehicle.
Right answer: A. An official question of the Ministry, in its official translation.

In an independent vehicle that has air brakes, the time of air containers filling should not be longer than?

What is function of the primary shaft in the gear-box?

The rev-counter of some buses has yellow, green and red scales (areas of revolution indications). Where will the pointer be when the engine’s performance is good and the fuel consumption is limited?

The rev-counter of some buses has yellow, green and red scales (areas of revolution indications). Where will the pointer be when the fuel consumption is excessive in relation to the output engine power?

What is the function of the auxiliary shaft in the gear-box?

The wheel anti-lock braking system (ABS):

What is the range of the lowest permissible pressure of compressed air in a pneumatic braking system?

In a suspension system with air, what is the use of the high pressure circuit:

The carbon monoxide (CO) is a pollutant contained mainly in combustion products of a:

In a fully synchronized gear-box:

How do pistons transfer the pressure created by the mixture explosion to the crankshaft?

The aim of the connecting rod is:

On a tyre 175/70 R 15 87T, size 15 indicates:

The sulphur dioxide (SO2) is a pollutant contained in combustion products of a:

What does a four-stroke diesel-engine suck during induction stroke:

What is the aim of the central driving shaft, if the engine is in the front and the driving wheels are at the back?

The oxidizing catalytic converter in buses:

Piston’s compression springs are designed:

The braking system with compressed air (air brakes) is used in buses, because:

In a four-stroke diesel-engine, when the crankshaft completes two revolutions, how many revolutions does the camshaft perform:

The centrifugal pump of the water of the cooling system is driven by:

The lubrication of engine bearing surfaces of modern cars is performed:

The hydraulic steering system is used in buses so as to:

The air compressor:

The servo-brake with compressed air applies to:

The oil springs are designed:

The shock absorbers (amortisseur) are mechanisms which:

The automatic pressure regulator is a mechanism of the braking system which:

The centrifugal water pump of engine’s cooling system:

What is the aim of the exhaust brake?

In a bus fitted with a braking system with compressed air (air brakes), where should the driver direct their attention mainly?

Which of the following components are driven by the camshaft:

Which is the normal water circulation in the cooling system?

At least how many are the internal lighting circuits of a bus?

What does the oil manometer on dashboard of a bus show?

At least how many exterior rear-view mirrors should a bus have?

Which is the basic function of the differential?

The danger switch that every bus has, designed to limit the risk of fire when the vehicle is stopped, cuts off:

Why, when you press the accelerator pedal, is the power produced by a diesel engine increased?

Which is the function of the silencer of the exhaust pipe: