Transcript cruise control system

CRUISE CONTROL SYSTEM
SREEKANTH KOMMULA
12071A0377
Department Of Mechanical Engineering
It is an emerging automobile technology which allows the motor
vehicle to automatically control its speed , by taking over the
throttle of the car, to maintain a steady speed as set by the
driver.
Working
• The cruise control system controls the speed of the car by
adjusting the throttle position.
• It actuates the throttle valve by a cable connected to an
actuator , instead of pressing a pedal.
• The throttle valve controls the power and speed of
the engine by limiting how much air the engine takes in.
• Two cables are connected to a pivot that moves the
throttle valve.
One cable comes from the accelerator pedal, and one
from the actuator.
• When the cruise control is engaged, the actuator moves
the cable connected to the pivot, which adjusts the
throttle; but it also pulls on the cable that is connected to
the accelerator pedal.
System components
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Vehicle's Speed Sensor (VSS)
Mounted to the transmission and
provides a low voltage AC signal to the
CCM, which converts the AC signal to a
pulse width modulated DC signal,
which is sent to the CCM @ 4000
pulses per mile.
Cruise Control Module (CCM)
It has to do three things.
1. It remembers the speed we set and
stores it until we change it or turn off the
ignition.
2. It takes the speed signal from the
VSS and compares it to the set speed.
3. It sends pulse signals to the actuator.
Actuator
It actually moves the throttle linkage (most often vacuum operated)
as directed by the CCM until the set speed has been achieved. It
then maintains this speed by controlling the amount of vacuum.
Brake Switch
The cruise control release switch and stop lamp switch,
mounted on the brake pedal bracket, are used to disengage the
cruise control system when the brake pedal is pressed. This is
accomplished by interrupting the flow of current to the CCM.
The cruise speed of the vehicle at brake actuation will be
stored in the CCM memory.
Clutch Switch
In addition to the brake switch, a vehicle with a manual
transmission has a switch very similar to the brake switch and
disengages the cruise control system when the clutch pedal is
depressed.
Throttle Linkage
The actual mechanical connection between the cruise control
actuator and the engine throttle.
OPERATION
The cruise control system
usually has buttons:
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Cruise off
Set +/Resume
Cruise control in Mahindra XUV 500
TECHNOLOGICAL ADVANCEMENT
Adaptive Cruise Control
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Conventional cruise controls
are not always practical when
driving in moderate traffic.
Some modern vehicles
have adaptive cruise control
(ACC) systems, which is a
general term meaning improved
cruise control. These
improvements can be automatic
braking or dynamic set-speed
type controls.
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The key difference between conventional cruise control and ACC is
being able to adjust the gap distance .
When a vehicle ahead of us enters our lane or a slower vehicle is
ahead in the same lane, the vehicle speed will adjust automatically to
maintain a preset gap distance.
Gap distance settings based on the driving style:
1.
Sporty Gap
2.
Normal Gap
3.
Comfort Gap
TYPES
Automatic Braking Type
This uses either a radar or laser setup to allow the vehicle to keep
pace with the car it is following. Some systems also
feature forward collision warning systems, which warns the
driver if a vehicle in front gets too close suddenly.
Dynamic Set Speed Type
This uses the GPS position of speed limit signs, from a database.
Some are modifiable by the driver such that driver input is
shared, improving the database for all users.
COLLISON WARNING WITH
BRAKE SUPPORT
ADVANTAGES
• Usefulness for long drives
• Reduces driver fatigue
• Improves comfort
• Better fuel efficiency.
• Unconsciously violating speed
limits
• Accidents can be reduced
DISADVANTAGES
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Downhill which is steep enough to
accelerate with an idling engine.
High Cost.
Not for heavy traffic.
Encourages the driver to become
careless.
Dangerous in slippery roads.
Cannot respond directly to the
traffic signals.
CONCLUSION
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Current system ranges 150 meters can stop and slows if any
obstruction.
Fully autonomous car is probably not viable in the foreseen future.
Near by vehicles would be in constant communication with each
other and act co-operatively.
It will probably take decades, but car accidents may eventually
become rare.