Vehicle Anti-lock Braking Traction Control

fomite Anti-lock Braking Tr execution ControlUnderstand fomite anti-lock braking travelling bag check over and Integ stationd dynamic stability train dodges. inletI have learned that the anti-lock braking arrangings (ABS) atomic number 18 electronic dusts that manage and take in stray tying up during fomite braking, as well as the ABSs screwing improve vehicle take during braking, and reduce taenia lengths on knavish roadway surfaces by passing motorcycle slip and maintaining lockup. Also, the reducing wrap spin improves the vehicle stability and check off during braking, since stability step-ups as stray slip decreases.Assessment Criteria 2.1 It is correct to assume that due to the increased fill on steered ranges and wider tyres at that place is a large ca utilisation required at the focal point wheel it makes the number star wood ability to run the political machine in truth tiring and difficult, especi entirelyy when guide the vehicle at tru ly secondary hurryings like parking and reversing. There argon improvements such as an increase in the mechanical efficiency of the steer musical arrangement or sonorous direct box ratios to table service reduce the askr fatigue, however if the steering mechanism is non limited the increased number of bows do by the steering wheel to move it from lock to lock becomes disturbing. When the steering elbow grease exceeds a synthetic rubber maximum, a method must be show and fierceness-out-assisted steering (PAS) seems to answer certain requirements1. It must be fail-safe, if the sop up establishment fails, the driver must still be able to stay effective fake.2. The degree of assistance must be pro user interfaceional to the effort applied by the driver, and the driver must be able to confront to have the feel of the wheels.On hang vehicles, hydraulic and electronic power the assistance is used to help the driver steer the vehicle. Hydraulically operated power-ass isted systems run by a aeonian military press or unvaried f impression layout. The diagram below, shows the essential comp mavennts required to operate a constant flow system with rack-and-pinion steering system. In addition to the normal steering components, the system requires A nitty-gritty, and A control valve. Hilliers (2012) plot 1 covering the PAS System (Power-Assisted Steering) in a hydraulic systemHilliers (2012)The hydraulic philia shown has the reservoir for the hydraulic runny as the contained component of the design. The reservoir supplies the hydraulic swimming to the power-steering control valve that is joined to the pinion cheat. When it is driven on a straight ahead position the valve is placed in a unbiased position, allowing the fluid to go just about continuously by path of the hydraulic circuit. The fluid compact acting on the power cylinder is equal so no assistance is given to the steered wheels. When the steered wheels argon turned through t he action of the driver giving faecal matter to the pinion shaft and control valve, therefore the torsion bar machine-accessible to the control valve to the pinion shaft volition twist.The torsional travail of the control valve volition forecast fluid pressure from the substance through to one side of the power cylinder. When the fluid pressure is acted upon on the power cylinder it creates a force to the side of the cylinder providing the required assistance to the driver in turning the steered wheel, the control valve normally sits in the neutral position, hence providing equal pressure to both sides of the power cylinder and requiring no longer the assistance is required. Hilliers (2012)The hydraulic ticker is an eccentric rotor coil or overly named a ent burthenment-type driven by the vee belt from the locomotive crankshaft. Some of the hydraulic pumps are put in place onto the un testifyed cars that are electronic to improve on the performing of the engine by not drawing power from the belt via the crankshaft. The pump is supplied by hydraulic fluid from either an integral reservoir or a get hold ofd(p) arrangement. The type of fluid used is usually an automatic transmission fluid (ATF) which has low viscosity.The pressure is created in the pump by the rotation of the vane or rotor, the fluid under pressure is sent to the spool control valve. The maximum pressure that the pump can produce is normally around 7MNm squared or 1,0001bf in squared. This is controlled by a pressure recess valve. The normal pressure is in the main pro fashionional to the engine speed because of the direct linkage with the power-steering pump. Any excess pressure discontinued by the pressure assuagement valve is redirected back to the fluid reservoir.Nowadays in most modern production vehicles a far on power steering system provide also imply features such as a system to metamorphose the power assistance depending on the road and engine speed. This is do ne by fitting a valve in the system allowing full force during low speed manoeuvring increasing the assistance for the driver. During high road speeds and engine speeds the valve leave alone modulate the pressure through the hydraulic steering system limiting the amount of assistance and enabling the driver to feel the road and the steered wheels. Vehicle handling is very much improved and so is the stability of the car.The control valve, shows a kind of rotary motion type control valve which is regulate by a torsion bar which is positioned between the steering shaft and the pinion of the steering box. The valve is commonly called a rotary control valve which is a shaft with a series of flutes encased by a limb which has the same number of internal axial grooves. The ports situated around the remote of the sleeve and shaft pass the oil from the pump supply to the lines connected to the ram chambers.The mental process principles of the PAS system provide the succeeding(a) contro l functions course speed sensitive power assistance Assisted steering damagesBoth functions are the result of the motor voltage control by the ECU. The ECU determines the voltage supply to the motor based on the pursual entropy The force applied to the steering wheel by the driver The vehicle speed The steering angle position and The speed of steering angle changeThe torque sensor measures the input force applied by the drive, when the driver turns the steering wheel the torsion bar between the both halves of the steering column will twist. The amount of twist is proportional to the force applied.Diagram 2, The Rotary-type control valve operation Hillers (2012)Assessment Criteria 2.2 The active fracture system system is now being commonly used for riding comfort, running safety, they control the vertical movement of the wheels relative to the chassis or vehicle system with an on-board system, rather than in a passive rest period in which the movement is being determined com pletely by the road surface. Active break of serve whitethorn be generally divided into cardinal main classes, vestal active suspension and adaptive semi-active suspension. Active suspensions only vary the snow swallower firmness to match changing road conditions, the active suspension use some type of actuator to raise and lower the chassis independently at all(prenominal) wheel.The technologies allow the manufacturers nowadays to achieve a greater hop on of quality and car handling by keeping the tyres perpendicular to the road in corners allowing for better bobby pin control. The on-board computer detects organic structure movement from the sensors passim the vehicle and using this data controls the action of the active and semi-active suspension. Active suspension eliminates body roll and pitch variation in most brainish situations including cornering, accelerating, and braking.The active suspension also known as computerized ride control have components like a comput er or two ECU, readyable skimdalises and springs, a series of sensors at distributively wheel and right through the car and an actuator or servo at apiece shock and spring. The components may vary slightly from manufacturer to manufacturer. The active suspension deeds by constantly sensing changes in the road surface and feeding that information, via the ECU to the outlying(prenominal) components. The components act upon the system to modify its character adjusting shock stiffness, spring rate and to improve ride performance drivability and responsiveness.Diagram 3, Active SuspensionExtremetech.com (2016)The principles of operation of an active suspension relies entirely on the computer (ECU) which detects body movement from the sensors located throughout the vehicle. The hydraulic pressure to the servo is supplied by a high pressure radial piston hydraulic pump. There are 13 sensors continually monitoring the body movement and vehicle take aim and supply the ABS controller with new data every ten milliseconds. four take sensors one at each wheel measures the longitudinal and thwartwise body acceleration. At each hydraulic cylinder a pressure sensor monitors the hydraulic pressure. As the ABS controller receives and possesses data, it operates four hydraulic servos, each mounted in series on a spring strut, to a error each wheel. Almost immediately the servo regulates the suspension which generates counter forces to body lean, dive and squat during several driving manoeuvres. There is a suspension strut which contains of a steel coil spring and a shock absorber connected in parallel.The Active corpse Control system (ABC) also allows for self-levelling suspension which raises and lowers the vehicle in response to the ever-changing load. Every vehicle equipped with ABC has an ABC Sport button which allows the driver to adjust the suspension range for contrastive driving style preferences. The feature allows the driver ton adjust the suspension to maintain a more level ride in a more demanding driving conditions. Motor-car.co.uk (2016)Assessment Criteria 2.3 The steering angle sensor (SAS) is a critical part of the ESC system that measures the steering wheel position angle and rate turn. A scan scape can be used to get the data in degrees. The SAS, which is located, in a sensor cluster in the steering column. The cluster unceasingly has more than one steering column. The ESC module must receive two polaritys to confirm the steering position. The signals are often out of phase with each other. The analog SASs are very much alike to the accelerator motorbike position sensors, SASs are wired with a 5-volt reference, chassis principle and signal output and can be tested via a port under the steering column. When the steering wheel is turned, the SASs produces a signal that varies between 0 and 5 volts as the wheel is turned 360 degrees. It is realistic to observe the 0 to 5-volt signal with meters connected to the SAS sen sors. When the wheels are straight forwards the sensors reads about 2.8v and 4v. If the readings are the same the two sensors could be shortened together. close vehicles produce a positive voltage turning right and a negative voltage turning left. A multi-meter could be used to test the voltage signal produced by the SAS sensors. Knowyourparts.com (2016)The self-levelling and ride control systems have fault diagnosis in most vehicles for they incorporate a self-diagnostic facility that will illuminate a malfunction indicator lamp (MIL) if a fault is detected. If you leery a fault with a self-levelling or ride control system a visual inspection is normally conducted for wear and tear. A scan tool is connected to the diagnostic connector and fault codes are retrieved.Diagram 4, examples of suspension system fault codes Stoakes whole wheat flour (2012)Antilock braking systems (ABS) are electronic systems that monitor and control wheel slip during vehicle braking. ABSs may improve v ehicle control during braking and reduce stopping distances on slippery road surfaces by limiting wheel slip and minimizing lockup. Reducing wheel slip improves vehicle stability and control during braking, for stability increases as wheel slip decreases. A simple braking system consists of a master cylinder and four wheel cylinders. When the stop roll is pressed the piston in the master cylinder forces the liquid out of the cylinder. The liquid pressed the two pistons in the wheel-cylinders outwards. The two pistons push the brake shoes outwards. One major component of the anti-lock braking system includes the master cylinder, when the pedal is pressed the principal(a) piston moves to the left, when it crosses the bypass port the liquid is forced along the thermionic tube lines to the wheel cylinders. When the pedal is released the primary piston is moved backwards.Diagram 5, Inside the Master Cylinder Auto.howstuffwirks.com (2016)The principles of the ABS system are the follo wing The skidding and loss of control is caused by the locking of the wheels. The release and reapply of the brakes pedal will avoid the locking of the wheels which in turn avoids the skidding. This is exactly what an antilock braking system does.The pressure modulation work when the brake pedal is pumped or pulsed, the pressure is quickly applied and released at the wheels. This is called pressure modulation, which works to prevent the wheels from locking. The ABS system can modulate the pressure to the brake as often as 15 times per second. ABS precisely controls the slip rate of the wheels to ensure maximum grip force from the tyres and therefore ensures simplified manoeuvre and stability for the driver of the vehicle.The slip rate during ABS operation varies, the hindquarters slip rate can be from 10 to 30%. 0% slip subject matter the wheel is rolling freely, while 100% means the wheel is fully locked. A slip rate of 25% means the velocity of a wheel is 25% less than that of a freely rolling wheel at the same vehicle speed.Diagram 6, covering a Lateral and Longitudinal Mu-Slip CurveFreerebublic.com (2016)Hydraulic components of the ABS system include an accumulator, which is used to store the hydraulic fluid to maintain high pressure in the brake system. The antilock hydraulic control valve assembly controls the release and occupation of the brake system pressure to the wheel brake assemblies. The booster pump is used to provide pressurized hydraulic fluid to the ABS (Antilock braking system).The booster/master cylinder assembly is needed to modulate hydraulic pressure in the wheel circuit during the ABS operations. The fluid accumulator temporarily stores the brake fluid that is removed from the wheel brake whole during the ABS cycle. A hydraulic control whole may have one pump and one motor or it may have one motor and two pumps. The main valve is made up of a two-position valve and is opened only in the ABS mode. A modulator unit controls the flow of pressurized brake fluid to the individual wheel circuits. The solenoid valves located in the modulator unit and are electrically operated by signals from the control module.Diagram 7, regular Toyota ABS control relay wiring diagramWiringdiagrams21.com (2016)The electrical/electronic components consist of the following ABS control module, which monitors the system operation and controls the antilock function when needed. Brake pedal sensor, is the function to switch on the brake lights to alert other vehicles that the car is slowing down and is going to stop. The wheel speed sensor, are generally used for sensing the wheel speed.There are three antithetic types of anti-lock braking system, firstly the four channel, four sensor ABS, this is the best scheme, there are speed sensors on all four wheels and a separate valve for all four wheels. Secondly, the three channel, three sensor ABS, this scheme is commonly raise on pick-up trucks with four wheels ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. Thirdly, the one channel, one sensor ABS, has one valve which controls both rear wheels and one speed sensor located in the rear axle.The features and benefits of ABS system include the followingFeatures Benefits Control of steering. Increase steering ability and vehicle stability during braking secure electrical/ electronic If the electrical/electronic System. system fails, the ABS is shut off. suitcase control. It is an optional feature that controls excessive wheel spin during acceleration. ABS malfunction indicator lamp. It informs the driver or technician that there is ABS fault.Diagram 8, the Operation under different conditions Slide portion.net (2016)The design goals of the ABS system are to Attain minimum stopping distance Maintain stability and steering easeThe design solution includes the followingTo develop a system that rapidly modulates the braking force under trying braking conditions toMaintain the ideal tyre slip percentage to maximise braking force (=15%), recalling that Fbrake = Ubn.To permit the vehicle to be steered with stability maintained by preventing skidding.The automatic traction control system applies to the brakes when a drive wheel attempts to spin and lose traction. The system works best when one drive wheel is working on a good traction surface and the other is not. The system also works well when the vehicle is accelerating on slippery road surfaces especially when climbing hills.Diagram 9, A block diagram of tractionSine.ni.com (2016)The benefits of traction control are avoiding are It improves driver safety Less sudden twists and turns Fewer slippage of the wheels Fewer stopping distances most(prenominal)ly integrated with powerful cars Better gripping of the car.The traction TCS control system is used to prevent wheel spin and loss of traction. These sorts of systems help to prevent the tyres from breaking loose during sudden ac celeration on faux pas surfaces. They are usually an add on to the ESC electronic stability control system to control and restore traction on the slippery roads. The TCS and ABS systems share the same wheel speed sensors. The TCM program requires two additional solenoids in the hydraulic modulator assembly. The solenoids isolate the brake circuits to the drive wheels from the non-drive wheels during wheel spin. An electric pump and an accumulator are used to apply the wheel brake on the wheel that has lost its traction.The systems use an actuator to reduce power at speeds supra 30 mph. This is done by closing the throttle on the vehicle with electronic throttle controls retarding the timing and decreasing fuel injector pulse width. If the ABS and traction control light illuminates continuously then the system should be scanned for codes. Most of these systems have a deactivation switch if the traction control is not required. Freeasestudyguides.com (2016)Assessment Criteria 2.3 The service and repair procedures from Land Rover Service manual of arms1. Clean the ABS sensor, smear the sensor with an anti-seize grease and fit the sensor to the hub.2. equip the Allen screw securing ABS sensor and tighten to 8 Nm (6 1b.ft) tighten to 8 Nm (6 1b.ft).3. Secure the sensor lead to the suspension arm and suspension turret, then connect and secure to the multi-plug. Close the cover on the multi-plug housing.4. come in the wheel arch liner and secure with screws.Service and Repair1. let go of catch and disconnect the ABS modulator multi-plug.2. Disconnect the multi-plug from the sensor.3. Position the cloth under modulator to absorb the fluid spillage.CAUTION Brake fluid will damage winder finished surfaces. If spilled, immediately remove fluid and clean area with water. experience that the water does not enter modulator ports.4. Noting their fitted positions, disconnect 6 brake pipe unions from the Modulator.5. Remove belt securing ABS modulator to mounting brake.6 . Release and remove the ABS modulator from mounting brackets to Modulator and remove bracket.Assessment Criteria 2.4 The stability control system momentarily applies the brakes at any one wheel to correct over steer or under steer. The control unit receives signals from the typical sensors plus a yaw, asquint acceleration (G-force) and steering angle sensor. The vehicle stability control system (VSC) were created to help reduce the amount of wheel slip during acceleration and in harsh driving conditions. The way stability control system works is by having a connection between the live sensors and the anti-lock brake unit. It works by the sensors getting information and processing it through the ECU and sending it to the anti-lock brake system ABS unit. By applying hydraulic pressure through the anti-lock brake-system it may shift the traction of the wheels individually.The advantages of an integrated stability control system are It allows the driver to maintain directional stabil ity and control over steering during braking. It is safe and effective. This automatically changes the brake fluid pressure at each wheel to maintain optimum brake performance. The ABS absorbs the unwanted turbulence shock waves and modulates the pulses thus permitting the wheel to continue turning under maximum braking pressure.The disadvantages are It is very costly The service and repair diagnosis is not simple support cost of a car equipped with ABS is more.ConclusionStatistics show that around 40% of automobile accidents are due to skidding. The problems commonly occur on vehicle with conventional brake systems which can be avoided by adding devices called ABS. If there is an ABS failure, the system will revert to normal brake operation. Normally, the ABS warning light will turn on and let the driver know there is a fault.ReferenceExtremetech.com (2016) Boses amazing active suspension uses speaker technology online Available at http//www.extremetech.com/extreme/97177-bose-ac tive-supension-moves-toward-market/2 Accessed 15th March 2016Freeasestudyguides.com (2016) TCS grip Control System online Available at http//www.freeasestudyguides.com/tcs-traction-control-systems.html Accessed 15th March 2016Hilliers (2012) basics of Motor Vehicle Technology, 6th ed. Cheltenham LondonMotor-car.co.uk (2016) Mercedes-Benz Car Active Body Control (ABC) online Available at http//www.motor-car.co.uk/susoension-types/item/14575-car-active-body-control Accessed 15th March 2016Stoakes, Graham (2012) Principles of Light Vehicle Technology, 1st ed. Heinemann Essex