Longitudinal Vehicle Dynamics Part 1

Question 1

72) 4 gears, instead of 5 influence leading to:
a) Lower consumption;
b) High performance;
c) Depends on the gear ratio.

Answer 1

c) Depends on the gear ratio.

Question 2

73) At fixed delivered power:
a) It is more convenient to use the engine at low chocking (close to the curve of maximum power); b) It is more convenient to use the engine at high chocking (close to the curve of maximum power);
c) The chocking doesn’t interfere with the assessment of convenience.

Answer 2

a) It is more convenient to use the engine at low chocking (close to the curve of maximum power);

Question 3

74) At equal delivered power, for the consumption, it’s more convenient:
a) Low chocking (the kilometric consumption, instead, usually improves at long gears, with a lot of (low) chocking);
b) High chocking;
c) The chocking doesn’t interfere with the assessment of convenience.

Answer 3

a) Low chocking (the kilometric consumption, instead, usually improves at long gears, with a lot of (low) chocking);

Question 4

75) To adopt 5 gear ratios instead of 4:
a) Improves the acceleration characteristics of the vehicle;
b) Can improve the acceleration characteristics of the vehicle;
c) Improves the acceleration a characteristic of the vehicle, but it’s necessary to consider the gear shifting time.

Answer 4

c) Improves the acceleration a characteristic of the vehicle, but it’s necessary to consider the gear shifting time.

Question 5

76) The hourly consumption is measured in:
a)
g
CVh ;

b)
dm3
kWh ;

c)
dm3
s
.

Answer 5

b)
dm3
kWh ;

Question 6

77) The consumption by travelled distance unit is obtained by multiplying the hourly consumption by: a) The inverse of the travelling speed;
b) The travelling speed;
c) The travelling speed and the fuel’s specific heat capacity.

Answer 6

a) The inverse of the travelling speed;

Question 7

78) The consumption Q(V ) by distance unit:
a) Increases with the speed;
b) Decreases with the speed;
c) Has a minimum at increasing the speed.

Answer 7

c) Has a minimum at increasing the speed.

Question 8

80) The greatest contribution, beyond that of the mass, for the calculation of the translating apparent mass is due to:
a) The engine inertia;
b) The wheels inertia;
c) The transmission inertia.

Answer 8

a) The engine inertia;

Question 9

81) The main factor that influences the transmissible power:
a) Weight;
b) Slippery road;
c) Torque at the driving axle.

Answer 9

b) Slippery road;

Question 10

82) The clutch’s maximum torque:
a) Is approximately equal to the one of the engine;
b) Is greater than the one of the engine;
c) Is smaller than the one of the engine.

Answer 10

b) Is greater than the one of the engine;

Question 11

83) The efficiency of the clutch is the ratio between:
a) The dissipated energy at the clutch and the energy provided by the engine;
b) The energy provided to the vehicle and the energy dissipated at the clutch;
c) The energy provided to the vehicle and the energy provided by the engine.

Answer 11

c) The energy provided to the vehicle and the energy provided by the engine.

Question 12

84) The efficiency of the clutch is important to:
a) Overheating (only after repeated starts);
b) Mechanical resistance;
c) Friction components consumption.

Answer 12

c) Friction components consumption.

Question 13

85) The efficiency of the clutch:
a) Is close to 0.5;
b) Is approximately equal to 1;
c) Is lower than 0.5.

Answer 13

c) Is lower than 0.5.

Question 14

86) The value of the acceleration in first gear increases by decreasing the transmission ratio: a) Always;
b) Only up to a certain value;
c) Never.

Answer 14

b) Only up to a certain value;

Question 15

87) The acceleration of the vehicle increases the maximum transmissible power for adherence reasons if: a) The vehicle is FWD;
b) The vehicle is RWD with hg null;
c) The vehicle is RWD with hg different from 0.

Answer 15

c) The vehicle is RWD with hg different from 0.

Question 16

88) The influence of the acceleration over the transmissible power for reasons of adherence is as greater as:
a) The greater is the ground slope;
b) The greater is the center of gravity height;
c) The highest is the longitudinal grip coefficient.

Answer 16

b) The greater is the center of gravity height;

Question 17

89) The translating apparent mass is:
a) Variable with the speed;
b) Constant;
c) Constant, if the gear ratio is fixed.

Answer 17

c) Constant, if the gear ratio is fixed.

Question 18

90) The maximum transmissible power at high speed is greater for:
a) FWD;
b) RWD;
c) 4WD.

Answer 18

c) 4WD.

Question 19

91) The practice of tracing only two curves X f and X rrelative to the minimum and maximum
loads is more realistic in the case of a passenger vehicle (normal or sportive) or in the case of an industrial vehicle?
a) Industrial vehicle.

Answer 19

a) Industrial vehicle.

Question 20

92) The maximum speed for adherence reasons is obtained intersecting:
a) The available power at the wheels with the power needed for motion;
b) The available power at the wheels with the transmissible power at the wheels; c) The power needed for motion with the transmissible power at the wheels.

Answer 20

c) The power needed for motion with the transmissible power at the wheels.

Question 21

93) The curves Q (V ) present a minimum at rather low speed, and that last is found in a zone at which
the engine works:
a) Very chocked with low efficiencies;
b) With high chocking;
c) With low chocking.

Answer 21

a) Very chocked with low efficiencies;

Question 22

94) At the alternating engine with controlled ignition, the efficiency decreases:
a) With increasing the delivered power at low regime;
b) With decreasing the delivered power at high regime;
c) With decreasing the delivered power.

Answer 22

c) With decreasing the delivered power.

Question 23

95) At the A linear term of the formula of the power needed for motion is inserted: a) The ground slope contribution;
b) The (static) rolling resistance contribution;
c) Both.

Answer 23

c) Both.

Question 24

96) At the B linear term at the velocity of the formula relative to the power needed for motion, is present: a) The ground slope contribution;
b) The quadratic term of the rolling resistance (dynamic);
c) Both.

Answer 24

b) The quadratic term of the rolling resistance (dynamic);

Question 25

97) With respect to the graph
PMAX
mg V MAX

are more economical the isolated vehicles or those with trailer?

Answer 25

a) Those with trailer.

Question 26

98) If the power and velocity are fixed, it is convenient to choke (for the specific consumption): a) Little;
b) A lot;
c) Doesn’t matter.

Answer 26

a) Little;