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RBSE Prav Voc Automotive study materials
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RBSE Prav Voc Automotive practice questions

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Question 1Automotive Engine Systems and Principles

In a four-stroke diesel engine, which stroke immediately follows the power stroke?

  1. Injection stroke
  2. Exhaust stroke Correct answer.
  3. Intake stroke
  4. Compression stroke

Explanation

The four-stroke cycle runs intake, compression, power, then exhaust. After the piston is driven down by combustion, it rises again and pushes burnt gas out through the open exhaust valve, so the exhaust stroke comes directly after the power stroke.

Question 2Automotive Engine Systems and Principles

What is the primary function of the flywheel on an engine crankshaft?

  1. To open and close the intake valves
  2. To store rotational energy and smooth out speed fluctuations Correct answer.
  3. To cool the exhaust gases before release
  4. To filter the engine lubricating oil

Explanation

The flywheel has high rotational inertia, so it absorbs energy during the power stroke and releases it during the other strokes. This keeps the crankshaft turning smoothly between power impulses and carries the engine through idle.

Question 3Automotive Engine Systems and Principles

A technician measures a cylinder bore that is 0.06 mm larger than the standard dimension and the service limit is 0.05 mm. What is the correct interpretation?

  1. The measurement error is acceptable because 0.01 mm is negligible
  2. The bore is within limits and can be reused as is
  3. The bore is undersized and requires a thicker piston
  4. The bore exceeds the wear limit and requires reboring or replacement Correct answer.

Explanation

The measured oversize of 0.06 mm is greater than the permitted maximum of 0.05 mm, so the cylinder has worn beyond its service limit. Continued use would cause poor ring sealing, blow-by and oil consumption, so the block must be rebored or replaced.

Question 4Automotive Engine Systems and Principles

Which component converts the reciprocating motion of the piston into rotary motion of the crankshaft?

  1. Pushrod
  2. Camshaft
  3. Timing chain
  4. Connecting rod Correct answer.

Explanation

The connecting rod links the piston to the crankshaft journal and swings through an arc as the piston moves. This geometry converts straight-line piston travel into crankshaft rotation and transmits the combustion force.

Question 5Automotive Engine Systems and Principles

In a petrol engine, what is the purpose of the throttle valve in the intake system?

  1. To regulate the mass of air entering the engine and thereby control power output Correct answer.
  2. To maintain constant fuel pressure at the injectors
  3. To atomise the fuel before it reaches the cylinder
  4. To prevent backfire in the exhaust manifold

Explanation

The throttle plate restricts intake airflow, so the driver controls how much air-fuel mixture reaches the cylinders and therefore engine power. Modern systems measure that airflow and meter fuel to match it.

Question 6Automotive Engine Systems and Principles

An engine has a compression ratio of 9:1 and a swept volume of 400 cm³ per cylinder. What is the clearance volume?

  1. 40 cm³
  2. 45 cm³
  3. 50 cm³ Correct answer.
  4. 44.4 cm³

Explanation

Compression ratio equals (swept volume + clearance volume) divided by clearance volume. Solving 9 = (400 + V)/V gives 9V = 400 + V, so 8V = 400 and V = 50 cm³.

Question 7Automotive Engine Systems and Principles

What is valve overlap in a four-stroke engine?

  1. The period when both intake and exhaust valves are open together around top dead centre Correct answer.
  2. The amount the valve lifts off its seat
  3. The clearance gap between the rocker arm and valve stem
  4. The angle by which the camshaft lags the crankshaft

Explanation

Overlap occurs near the end of the exhaust stroke and start of the intake stroke, when the intake valve has begun to open before the exhaust valve fully closes. It uses gas inertia to improve cylinder filling and scavenging.

Question 8Automotive Engine Systems and Principles

Why is a turbocharger more effective than a belt-driven supercharger at high altitude?

  1. It cools the intake charge without any intercooler
  2. It uses exhaust energy that is largely independent of ambient air density Correct answer.
  3. It is driven by the crankshaft and therefore scales with engine speed
  4. It increases the compression ratio of the engine mechanically

Explanation

A turbocharger recovers energy from the exhaust gas stream, so it can raise intake pressure even when ambient air is thin, subject to the pressure ratio it can produce. A belt-driven supercharger must be spun by the engine and its boost falls with ambient density.

Question 9Automotive Engine Systems and Principles

What does the term valve clearance refer to in an overhead-valve engine with mechanical lifters?

  1. The distance the valve spring is compressed
  2. The space between the valve guide and the valve stem
  3. The gap between the rocker arm and the valve stem tip Correct answer.
  4. The gap between the valve face and valve seat

Explanation

Valve clearance is the small gap in the valve train, usually measured between the rocker arm and valve stem tip. It allows for thermal expansion so the valve still seats fully when the engine is hot.

Question 10Automotive Engine Systems and Principles

A diesel engine produces white smoke continuously after warm-up. Which cause is most consistent with this symptom?

  1. Excessive injection advance
  2. High engine oil level
  3. Late injection timing or low compression Correct answer.
  4. Rich air-fuel mixture from a blocked air filter

Explanation

White smoke from a warm diesel usually indicates unburnt fuel vapour, often from retarded injection timing or insufficient compression heat to ignite the charge. Checking timing and compression is the logical diagnostic path.

Question 11Automotive Engine Systems and Principles

Which of these is the main purpose of the cooling system in an internal combustion engine?

  1. To reduce the octane requirement of the fuel
  2. To keep metal temperatures within a range that maintains clearances and lubricant integrity Correct answer.
  3. To increase the compression ratio when the engine is cold
  4. To warm the fuel so it vaporises more readily

Explanation

Combustion produces large heat loads, and the cooling system holds metal and oil temperatures in a safe band. This preserves running clearances, prevents oil breakdown and avoids detonation from overheated surfaces.

Question 12Automotive Engine Systems and Principles

What is the function of the thermostat in a liquid-cooled engine?

  1. To regulate coolant flow so the engine reaches and holds operating temperature Correct answer.
  2. To release pressure from the cooling system
  3. To switch the radiator fan on and off electrically
  4. To circulate coolant through the heater matrix only

Explanation

The thermostat is a temperature-sensitive valve that stays closed while the engine is cold, allowing rapid warm-up, then opens to route coolant through the radiator. It therefore holds the engine near its design operating temperature.

Question 13Automotive Engine Systems and Principles

A wet-liner engine differs from a dry-liner engine in which respect?

  1. The liner cannot be replaced during overhaul
  2. The liner is made of aluminium rather than cast iron
  3. The liner is in direct contact with the coolant Correct answer.
  4. The liner is pressed into a blind bore with no coolant contact

Explanation

A wet liner has its outer surface exposed to coolant, sealed at top and bottom by O-rings or gaskets. A dry liner sits in a bore and transfers heat through the parent metal without touching coolant.

Question 14Automotive Engine Systems and Principles

During a compression test on a petrol engine, one cylinder reads much lower than the others, but adding a few drops of oil raises the reading. What does this indicate?

  1. Worn piston rings or cylinder bore Correct answer.
  2. A burnt exhaust valve
  3. A sticking intake valve
  4. A leaking head gasket

Explanation

Oil temporarily seals the gap between rings and bore, so if the reading improves the leakage is past the piston rings. Valve or gasket leakage would not be corrected by oil because those paths are not sealed by it.

Question 15Automotive Engine Systems and Principles

What is the primary role of the engine lubrication system beyond reducing friction?

  1. To raise the compression pressure in the cylinder
  2. To carry heat away from bearings and clean wear particles to the filter Correct answer.
  3. To increase the octane rating of the fuel
  4. To provide hydraulic pressure for the brake system

Explanation

Oil forms a film that separates moving surfaces, but it also transports heat from bearings and carries metallic debris to the filter. These cooling and cleaning duties are essential to bearing life.

Question 16Automotive Engine Systems and Principles

Why must the oil pressure relief valve open at a set pressure?

  1. To open the oil filter bypass during normal warm running
  2. To regulate the oil temperature at 90 degrees Celsius
  3. To keep the oil level constant in the sump
  4. To prevent excessive pressure from damaging seals and filters when the oil is cold Correct answer.

Explanation

A cold engine makes the oil viscous, so the pump can generate very high pressure. The relief valve diverts excess flow back to the sump to protect seals, galleries and the filter from rupture.

Question 17Automotive Engine Systems and Principles

Which statement correctly describes the difference between indicated power and brake power?

  1. Indicated power is the power developed in the cylinder, while brake power is what remains at the flywheel after friction losses Correct answer.
  2. Brake power is always greater than indicated power
  3. Indicated power excludes the pumping losses of the exhaust stroke
  4. Indicated power is measured at the flywheel and brake power at the piston

Explanation

Indicated power is derived from the pressure acting on the piston during the cycle, whereas brake power is the useful output measured at the flywheel. The difference between them is friction and pumping loss, known as friction power.

Question 18Automotive Engine Systems and Principles

What is the effect of advancing the ignition timing too far on a spark-ignition engine?

  1. Fuel consumption improves because more work is extracted
  2. Peak cylinder pressure occurs too early, causing knock and possible piston damage Correct answer.
  3. The exhaust valve opens earlier to release pressure
  4. The engine runs cooler because combustion is completed sooner

Explanation

Too much advance starts combustion well before top dead centre, so peak pressure arrives while the piston is still rising. This raises peak temperature and pressure, producing detonation and mechanical stress on pistons and bearings.

Question 19Automotive Engine Systems and Principles

In a common-rail diesel injection system, what determines the injection pressure?

  1. The camshaft lobe profile only
  2. The engine coolant temperature sensor
  3. A high-pressure pump feeding a shared rail with an electronic pressure control valve Correct answer.
  4. The spring tension inside each injector nozzle

Explanation

A common-rail system separates pressure generation from injection timing: a high-pressure pump charges the rail, and a control valve or metering unit holds the target pressure. The electronic control unit then commands each injector to open.

Question 20Automotive Engine Systems and Principles

A vehicle with a turbocharged petrol engine has low power and blue-grey smoke from the exhaust. Which fault best fits these symptoms?

  1. Faulty coolant temperature sensor
  2. Worn clutch friction plate
  3. Failed turbocharger shaft seal allowing oil into the intake or exhaust Correct answer.
  4. Leaking intake manifold gasket admitting unmetered air

Explanation

A failed shaft seal lets pressurised oil pass into the turbine or compressor housing, where it burns and produces blue-grey smoke. Loss of boost control and oil fouling of the intake also reduce power.

Question 21Automotive Engine Systems and Principles

What is the purpose of an intercooler in a turbocharged engine?

  1. To increase the density of the compressed intake charge Correct answer.
  2. To cool the exhaust gas before it reaches the turbine
  3. To reduce the pressure of the intake charge
  4. To cool the engine oil returning to the sump

Explanation

Compressing air raises its temperature, which lowers density and increases knock risk. An intercooler removes that heat so more air mass enters each cylinder, improving power and combustion quality.

Question 22Automotive Engine Systems and Principles

Which component in a distributor-type ignition system triggers the ignition coil to fire at the correct moment?

  1. The pickup coil or contact breaker acting with the rotor Correct answer.
  2. The ignition condenser
  3. The spark plug suppressor cap
  4. The ballast resistor

Explanation

The pickup coil or contact breaker generates a signal as the distributor shaft rotates, and this signal switches the primary circuit to collapse the coil field. The rotor then distributes the high voltage to the correct plug.

Question 23Automotive Engine Systems and Principles

Why is a diesel engine generally more thermally efficient than a petrol engine of similar size?

  1. It uses a higher compression ratio and unthrottled air supply Correct answer.
  2. It has a richer air-fuel mixture at all loads
  3. It uses a spark plug to control combustion precisely
  4. It burns fuel at a lower peak temperature

Explanation

High compression raises the expansion ratio and extracts more work from the burnt gas, while the absence of a throttle reduces pumping losses. Together these raise thermal efficiency compared with a throttled spark-ignition engine.

Question 24Automotive Engine Systems and Principles

What does the term scavenging mean in a two-stroke engine?

  1. The opening of the reed valve under crankcase pressure
  2. The mixing of oil with petrol for lubrication
  3. The process of removing burnt gas and filling the cylinder with fresh charge Correct answer.
  4. The ignition of the charge by the spark plug

Explanation

Scavenging is the flow of fresh charge through the cylinder that pushes burnt gas out of the exhaust port. Good scavenging improves power and reduces emissions, while poor scavenging leaves residual gas behind.

Question 25Automotive Engine Systems and Principles

A four-cylinder four-stroke engine has a bore of 80 mm and a stroke of 90 mm. Using pi = 3.1416, what is the approximate total swept volume?

  1. 1448 cm³
  2. 1810 cm³ Correct answer.
  3. 226 cm³
  4. 905 cm³

Explanation

Single-cylinder swept volume is pi/4 times bore squared times stroke, which is 0.7854 x 6400 mm² x 90 mm, about 452,400 mm³ or 452 cm³. Multiplying by four cylinders gives roughly 1810 cm³.

Question 26Automotive Engine Systems and Principles

In a four-stroke spark-ignition engine, which valve is open during the exhaust stroke?

  1. The intake valve only
  2. The exhaust valve only Correct answer.
  3. Both the intake and exhaust valves
  4. Neither valve; both remain closed

Explanation

During the exhaust stroke the piston moves from bottom dead centre to top dead centre and pushes burned gases out through the open exhaust valve. The intake valve is closed during this stroke so that fresh charge is not expelled. Valve overlap, where both valves are briefly open, occurs only around top dead centre between the exhaust and intake strokes.

Question 27Automotive Engine Systems and Principles

A four-stroke engine has a stroke of 100 mm and a connecting rod length of 200 mm. At top dead centre, what is the approximate piston position relative to the crankshaft centreline?

  1. 50 mm above the crankshaft centreline
  2. 250 mm above the crankshaft centreline
  3. 300 mm above the crankshaft centreline Correct answer.
  4. 100 mm above the crankshaft centreline

Explanation

At top dead centre the crank throw and connecting rod are in a straight line, so the piston pin height equals the crank radius plus the rod length. The crank radius is half the stroke, 50 mm, and adding the 200 mm rod gives 250 mm. The 300 mm figure would apply only if the full stroke were added instead of the crank radius.

Question 28Automotive Engine Systems and Principles

Which statement best explains why a diesel engine does not require a throttle valve in the intake system?

  1. The diesel cycle always runs leaner than the petrol cycle at every operating point
  2. A throttle would prevent the glow plugs from reaching operating temperature
  3. Load is controlled by the quantity of fuel injected, so the intake charge remains essentially unthrottled Correct answer.
  4. Diesel fuel ignites only when the intake air is above atmospheric pressure

Explanation

In a diesel engine, power output is regulated by the mass of fuel injected per cycle, and the engine draws nearly the same air mass at a given speed regardless of load. Throttling the intake would create a pumping loss without helping mixture preparation, because the fuel is injected directly into the cylinder near top dead centre. This unthrottled operation is a major reason for the diesel's higher part-load efficiency.

Question 29Automotive Engine Systems and Principles

A four-cylinder four-stroke engine has a bore of 80 mm and a stroke of 90 mm. Using pi = 3.1416, what is the approximate total engine displacement?

  1. 452 cm³
  2. 1448 cm³
  3. 1810 cm³ Correct answer.
  4. 724 cm³

Explanation

Displacement per cylinder equals the bore area times the stroke: pi times 4.0 cm squared times 9.0 cm, which is about 452.4 cm³. Multiplying by four cylinders gives approximately 1810 cm³. The other figures correspond to one cylinder or to using the bore as a radius instead of a diameter.

Question 30Automotive Engine Systems and Principles

A technician is checking the valve train of a four-stroke engine and finds that the camshaft rotates at half the speed of the crankshaft. Which statement explains why this speed ratio is required?

  1. Each valve must open once per crankshaft revolution to keep pace with every piston stroke.
  2. The camshaft speed is set by the oil pump drive and has no fixed relation to the crankshaft.
  3. Each valve must open once every two crankshaft revolutions so that the full four-stroke cycle is completed. Correct answer.
  4. The camshaft must turn faster than the crankshaft so the valves can close before ignition.

Explanation

A four-stroke cycle needs two complete crankshaft revolutions (720 degrees) to pass through intake, compression, power and exhaust, and each valve opens only once in that cycle. Driving the camshaft at half crankshaft speed therefore gives one valve event per two crank revolutions, correctly synchronised to piston position.

Question 31Automotive Transmission, Steering, and Suspension Systems

In a manual gearbox, which component allows the driver to engage different gear pairs while the input shaft keeps turning?

  1. The differential cage
  2. The final drive pinion
  3. The propeller shaft yoke
  4. The synchronizer assembly Correct answer.

Explanation

The synchronizer (baulk-ring) assembly equalizes the rotational speed of the gear and the output shaft before the dog teeth mesh, so gears can be selected without crashing. The other listed parts transmit torque but play no role in speed matching during a shift.

Question 32Automotive Transmission, Steering, and Suspension Systems

A clutch is described as 'slipping' during acceleration. Which condition most directly explains this symptom?

  1. Air trapped in the hydraulic release line
  2. Excessive free play at the clutch pedal
  3. Insufficient clamping force between the pressure plate and friction disc Correct answer.
  4. A worn pilot bearing in the crankshaft

Explanation

Slipping means the friction disc cannot transmit full engine torque, which happens when the pressure plate springs apply too little clamp load or the friction lining is worn thin. Pedal free play and trapped air cause incomplete release (drag), not slip, and a pilot bearing affects spigot support only.

Question 33Automotive Transmission, Steering, and Suspension Systems

In a torque converter, which element is connected to the turbine and drives the gearbox input shaft?

  1. The impeller
  2. The stator
  3. The turbine hub Correct answer.
  4. The lock-up piston

Explanation

The turbine is splined to the turbine hub, which drives the gearbox input shaft. The impeller is driven by the engine, the stator redirects fluid to multiply torque, and the lock-up piston merely couples the turbine to the cover at cruise.

Question 34Automotive Transmission, Steering, and Suspension Systems

A vehicle with a worn inner CV joint typically produces which symptom?

  1. A shimmy felt through the steering wheel at 80 km/h
  2. A rhythmic clunk that worsens during acceleration on full lock Correct answer.
  3. A grinding noise only when the brakes are applied
  4. A steady hum that rises with road speed regardless of throttle

Explanation

Worn inner CV joint balls and races clunk under torque reversal and at high steering angles because clearance allows the joint to snatch. A constant hum points to a wheel bearing, shimmy to wheel balance, and brake-only grinding to the braking system.

Question 35Automotive Transmission, Steering, and Suspension Systems

Which statement correctly describes the function of a differential in a rear-wheel-drive vehicle?

  1. It converts rotational motion into linear motion for the suspension
  2. It allows the outer wheel to rotate faster than the inner wheel during a turn Correct answer.
  3. It multiplies engine torque by a fixed ratio before the gearbox
  4. It locks both half-shafts together whenever torque is applied

Explanation

During a turn the outer wheel travels a longer path, so the differential planet gears let the two half-shafts rotate at different speeds while still sharing torque. Torque multiplication before the gearbox is not its role, and it does not lock the shafts or convert motion to linear form.

Question 36Automotive Transmission, Steering, and Suspension Systems

A rack-and-pinion steering gear has excessive free play at the steering wheel before the road wheels respond. Which adjustment is most appropriate?

  1. Tighten the rack guide (yoke) preload Correct answer.
  2. Increase the tyre inflation pressure
  3. Replace the steering column universal joint
  4. Reduce the caster angle

Explanation

Free play at the wheel before road-wheel response is usually caused by excessive clearance between the rack and pinion, corrected by adjusting the rack guide preload to specification. Tyre pressure and caster do not remove mechanical lash, and the column joint is a separate wear point.

Question 37Automotive Transmission, Steering, and Suspension Systems

Which alignment angle is defined as the forward or backward tilt of the steering axis in the side view?

  1. Included angle
  2. Toe-in
  3. Camber
  4. Caster Correct answer.

Explanation

Caster is the side-view tilt of the steering axis and governs straight-line stability and self-centring. Camber is the inward or outward lean of the wheel in front view, toe is the difference in track at the front and rear of the tyres, and included angle combines camber with kingpin inclination.

Question 38Automotive Transmission, Steering, and Suspension Systems

A customer reports that the steering wheel pulls to the right on a straight, level road. Which cause is most consistent with this complaint?

  1. Excessive positive caster on the left front wheel
  2. Excessive negative camber on the right front wheel
  3. Too much positive camber on the left front wheel Correct answer.
  4. Equal toe-in on both front wheels

Explanation

A wheel with more positive camber tends to roll outward, so extra positive camber on the left pushes the vehicle to the right. Unequal caster causes a pull toward the side with less positive caster, and equal toe settings do not create a directional bias.

Question 39Automotive Transmission, Steering, and Suspension Systems

Which component in a MacPherson strut suspension serves both as a spring seat and as the upper steering pivot?

  1. The strut bearing (top mount bearing) Correct answer.
  2. The lower ball joint
  3. The anti-roll bar link
  4. The track control arm bush

Explanation

The strut top mount contains a thrust bearing that carries the spring load and allows the strut to rotate as the wheels steer. The lower ball joint is the lower pivot, while the anti-roll bar link and control arm bush do not carry spring load or permit steering rotation.

Question 40Automotive Transmission, Steering, and Suspension Systems

A coil spring on a front strut is found to be broken at its lowest coil. Which consequence is most likely if the vehicle continues in service?

  1. The damper rod will seize immediately
  2. The anti-roll bar will disconnect from the strut
  3. The broken end can rotate and puncture the tyre sidewall Correct answer.
  4. The wheel alignment will self-correct as the spring settles

Explanation

A broken lower coil can rotate and its sharp end may contact and cut the tyre sidewall, which is a serious safety risk. Alignment will not self-correct, the damper is a separate component, and the anti-roll bar link is not dependent on spring integrity.

Question 41Automotive Transmission, Steering, and Suspension Systems

Which type of suspension layout uses a transverse leaf spring acting as both spring and upper locating member?

  1. Multi-link with air springs
  2. Trailing-arm with torsion bars
  3. Double-wishbone with coil springs
  4. Transverse leaf-spring independent suspension Correct answer.

Explanation

Some independent suspensions, notably certain front and rear layouts, use a transverse leaf spring that also helps locate the hub carriers. Double-wishbone, trailing-arm and multi-link designs use coil, torsion bar or air springs respectively.

Question 42Automotive Transmission, Steering, and Suspension Systems

A telescopic shock absorber is being checked on the bench. Which observation indicates it should be replaced?

  1. It has a dead spot followed by sudden free movement in one direction Correct answer.
  2. It has free play in the upper rubber bush
  3. It extends smoothly with even resistance and no oil seepage
  4. It shows a light film of oil around the top seal

Explanation

A dead spot followed by a sudden loss of resistance means the valving or gas charge has failed and damping is inconsistent. Even resistance with no seepage is normal, a light film is acceptable, and bush play is a mounting issue rather than damper failure.

Question 43Automotive Transmission, Steering, and Suspension Systems

What is the primary purpose of the anti-roll (stabilizer) bar in a vehicle suspension?

  1. To dampen wheel hop during braking
  2. To resist body roll by linking the left and right suspension members Correct answer.
  3. To adjust the ride height when loaded
  4. To increase the spring rate in a straight line

Explanation

The anti-roll bar is a torsion spring connecting the left and right sides; it twists only when one side moves relative to the other, so it resists body roll in cornering. It does not change straight-line spring rate, adjust ride height or damp wheel hop.

Question 44Automotive Transmission, Steering, and Suspension Systems

A vehicle with a hydraulically assisted rack-and-pinion system has heavy steering at idle that improves as engine speed rises. Which fault is most likely?

  1. A leaking steering rack end seal
  2. A worn outer track rod end
  3. A slipping power steering pump drive belt Correct answer.
  4. A seized steering column lock

Explanation

Assistance that improves with engine speed points to the pump not delivering enough pressure at low rpm, commonly a slipping drive belt or a worn pump. A seized column lock would prevent steering entirely, a rack seal leak would cause fluid loss, and a track rod end affects play rather than effort.

Question 45Automotive Transmission, Steering, and Suspension Systems

In an electric power steering (EPS) system, which input does the control module use to determine the amount of assist?

  1. The brake pedal position and throttle angle
  2. The gearbox output speed and clutch position
  3. The coolant temperature and oil pressure
  4. The steering torque sensor signal and vehicle speed Correct answer.

Explanation

The EPS module reads the torque sensor to detect driver effort and the vehicle speed signal to reduce assist at high speed for stability. Coolant, oil pressure, brake and clutch signals are unrelated to steering assistance.

Question 46Automotive Transmission, Steering, and Suspension Systems

A power steering system uses a rotary control valve. What happens when the driver turns the wheel while the engine is running?

  1. The valve increases the pump displacement
  2. The valve bypasses the pump back to the reservoir only
  3. The valve directs pressure to one side of the piston to assist the turn Correct answer.
  4. The valve closes all fluid ports and locks the rack

Explanation

Turning the wheel twists the torsion bar and shifts the rotary valve, opening pressure to one side of the rack piston while opening the other side to return. It does not lock the rack, bypass fluid only, or change pump displacement.

Question 47Automotive Transmission, Steering, and Suspension Systems

Which condition would cause a vehicle to have excessive toe-out on the front wheels?

  1. A leak in the power steering return line
  2. Bent steering arms or a worn rack inner joint Correct answer.
  3. An overinflated tyre on one side
  4. A worn upper strut mount bearing

Explanation

Toe is set by the steering linkage, so a bent steering arm or worn rack inner joint changes the effective track and produces toe-out. Fluid leaks, tyre pressure and a strut bearing do not alter the toe setting in a repeatable way.

Question 48Automotive Transmission, Steering, and Suspension Systems

Which of the following best describes the purpose of the kingpin inclination (steering axis inclination) in a modern suspension?

  1. To reduce steering effort and improve straight-line stability Correct answer.
  2. To increase the track width during cornering
  3. To provide a mounting point for the anti-roll bar
  4. To set the ride height of the vehicle

Explanation

Kingpin inclination (steering axis inclination) tilts the steering axis inward at the top so the tyre contact patch sits closer to the axis, reducing steering effort and helping the wheels self-centre. It does not change track width, mount the anti-roll bar or set ride height.

Question 49Automotive Transmission, Steering, and Suspension Systems

A four-wheel-drive vehicle has a transfer case with a viscous coupling. What is the primary function of the coupling?

  1. To disengage the front axle during braking
  2. To lock both axles rigidly whenever the vehicle stops
  3. To reduce engine torque to the rear axle only
  4. To allow a speed difference between front and rear axles while transmitting torque Correct answer.

Explanation

A viscous coupling in a transfer case allows the front and rear axles to turn at different speeds while transmitting torque through the silicone fluid shear. It does not lock rigidly, bias torque only to the rear, or disengage during braking.

Question 50Automotive Transmission, Steering, and Suspension Systems

Which component in a manual transmission prevents the driver from selecting two gears at the same time?

  1. The input shaft bearing
  2. The reverse idler gear
  3. The shift interlock (shift rail detent) mechanism Correct answer.
  4. The gearbox breather

Explanation

Shift interlock mechanisms on the shift rails or selector forks lock out other gears once one is engaged, preventing simultaneous engagement. Bearings, the reverse idler and the breather perform different functions.