Electronic control System

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Quite a few of the new automotive safety technologies are based around computers, micro-circuitry that can sense what the car and its driver are doing and compensate for any problems that may threaten the well-being of the car and its passengers

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Safety System RoadmapSafety System RoadmapACC Adaptive Cruise ControlCWS Collision Warning SystemCMS Collision Mitigation SystemAEB Autonomous Emergency Braking

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Increasing vehicle speeds

30-80 kmph

1940 1950 1960 1970 1980 1990 2000

Fail-safe

Car like feel

Stability

Single line air brake

Dual line air brake

Load Sensing Valve

Automatic Slack Adjuster

ABS/ASR

EBS

Varying load conditions

Adjusting lining wear

Varying road conditions

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ESCACC

Commercial Vehicles Commercial Vehicles Braking Braking System TrendSystem Trend

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The main areas of changeThe main areas of changeChallenges for future trucksChallenges for future trucks

Safety Improved Stopping Distance Driver Assistance Systems Traffic Control Extended Vehicle Monitoring Accident avoidance

Environment Stronger Emission Regulations Less Fuel Consumption No Oil Emissions Reduced Noise Emission Road Protection Regulation for dangerous goods

Value & Performance Quality and reliability Less Operational Cost More pay load per Truck Less Maintenance Less OEM Cost for Production The Right Technology

Road Transportation important for the Future

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Anti lock braking system : To prevent vehicle skid in a panic braking situation and tobring vehicle to a controlled stop.

Electronic Braking Systems : It provides instantaneous brake response with immediate application and release in direct proportion to pedal pressure

Autonomous emergency braking :The autonomous emergency brake (AEB) is an active safety function for vehicles which aims to reduce the severity of a collision. An AEB performs a full brake when an accident becomes unavoidable. Even if this system cannot, in general, avoid the accident, it reduces the energy of the crash impact and is therefore referred to as a collision mitigation system

Electronic brake distribution : EBD is based on the principle that not everywheel needs to put forth the same effort into bringing the car to a stop.

Electronic stability control :

Traction control system :

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What causes wheel lock ? Brake force applied is more than the friction between the road and tyre

When do wheels lock ? Under critical braking conditions like

- braking on wet or slippery surfaces- driver panic reaction to unanticipated obstacle

What is the effect of wheel lock during braking ? When front wheels lock

- vehicle slides in the direction of motion and vehicle loses steerabiliity When rear wheels lock

- vehicle loses stability and often swings around It is impossible to steer around an obstacle with wheels locked Locked tyre burns out locally

Wheel Lock and its effect on VehiclesWheel Lock and its effect on Vehicles

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Purpose

To prevent vehicle skid in a panic braking situation and to bring vehicle to a controlled stop

Method

Detect impending wheel lock and by repeatedly modulating the brake pressure avoid wheel lock

Benefits

Improved safety Vehicle stability Vehicle steerability Controlled stopping

Improved Tyre life

ABSABS

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Electronic Control Unit

Speed SensorPolewheel

Modulator Valve

ABS Major aggregates

Cables : Frame harness: Cab harness

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Wheel Lock and its effect Wheel Lock and its effect -- Combination vehiclesCombination vehicles

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ABS Schematic Layout 4S/4M

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History of ABS :

1936: German company Bosch is awarded a patent for an Apparatus for preventing lock-braking of wheels in a motor vehicle.

1936-: Bosch and Mercedes-Benz partner - R&D into ABS 1972: WABCO partners with Mercedes-Benz, developing first ABS for trucks. 1978: First production-line installation of ABS into Mercedes and BMW vehicles. 1981: 100,000 Bosch ABS installed. 1985: First ABS installed on US vehicles. 1986: 1M Bosch ABS installed. 1987: Traction control - in conjunction with ABS - used on passenger vehicles. 1989: ABS hydraulic unit combined with standard hydraulic brake unit 1992: 10M Bosch ABS installed. 1995: Electronic Stability - in conjunction with ABS and TCS - for passenger cars. 1999: 50M Bosch ABS installed. 2000: 6 of 10 new cars on the road are ABS equipped. 2003: 100M Bosch ABS installed.

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Pressure build up

Solenoid armature in its lowest position ,opening the upper and closing the lower solenoid valve.

Pressure hold

Armature in its mid position ,closing the both solenoid valves .

Pressure reduction

Solenoid armature in its uppermost position , opening the lower solenoid valve .

Three Phases of Brake pressure Modulation

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Components Components of ABSof ABS

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The heart of ABS is hydraulic modulator which interposed between brake master & wheel cylinders and it implements commands from ECU. These commands are executed by solenoid actuated valves which regulate the pressure in the wheel brake cylinder.

Hydraulic Modulator

When the driver actuates brake pedal , pressure build up begins and during this period no current flows through the solenoid. The pressure generated by master cyl. Opens the uppermost valve against the force exerted on its return spring. Lower valve held closed by lower return spring, so the fluid from the master cyl. Flows thr. The open valve down thr. The duct on the rhs of armature and out to the wheel cyl.As soon as the wheel locks , the ABS system comes into op. and the ecu calculates the first of a series of ref. speeds , at the same time solenoid valve is fully energised to lift lower valve off its seat , so the fluid in the wheel cyl. Passes back thr. The solenoid by pass circuit , past the hydraulic accumulator and return pump cyl. And thr. The second check valve to the master cyl. as a result of which fluid pressure released in wheel cyl.

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Since the valve is able to Since the valve is able to release pressure from the release pressure from the brakes, there has to be brakes, there has to be some way to put that some way to put that pressure back. That is pressure back. That is what the pump does; when what the pump does; when a valve reduces the a valve reduces the pressure in a line, the pressure in a line, the pump is there to get the pump is there to get the pressure back up. pressure back up.

Accumulator & Return pump

The hydraulic modulator contains solenoid actuated valves, an electric motor driven cam actuated plunger type fluid return pump (transmits back to the brake master cylinder the fluid released cyclically from the brake actuation cy. during abs op.) and hydraulic accumulator chamber (function is to absorb surges that would occur as a result of sudden opening of pressure relief valve ) for each wheel brake cylinder.

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As soon as the wheel locks ABS comes into operation and the ECU calculates the ref. speed at the same time solenoid valve is fully energized to lift the lower valve off its seat and the upper valve is held on its seat by return spring.

With the lower valve open fluid in the wheel cyl. Passes back thru the solenoid bypass circuit past the hydraulic accumulator and return pump cyl. And thr. The second check valve to the master cyl. as a result of which fluid pressure released in wheel cyl.

As soon as the wheel unlock the solenoid returns to pressure build up or pressure hold position, depending upon the rate at which wheel decelerates.

To move the valve to pressure hold position , only half the maximum voltage is applied to the solenoid. consequently the armature is lifted only half way up its travel ,which is far enough to lift the upper valve until it is seated by its return spring, but not enough to open the lower valve .

This movement increases the compression in the return spring holding the upper valve on it seated against the force exerted by the hydraulic pressure generated in the master cylinder.

With both valves now seated ,the circuit to the wheel cylinder is closed and the pressure in it therefore retained at the level at which the wheel unlocked.

The rate of repetition of these control cycles varies , according to the condition of the road , from 4 to 10 cycles per second , similarly the ECU regulates , again according to the road condition , the rises and falls in pressure.

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Hydraulic Control Unit

The hydraulic control unit consists of

9 ABS hydraulic control valves

9 Electronic control unit

9 Power brake boosters

9 Brake master cylinder

9 Necessary brake tubes and hoses.

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Normal Braking System

1: Pedal, 2: Vacuum booster, 3: Tandem Master Cylinder, 4: Reservoir,

5: Disc Brake, 6: Braking Force Metering Device, 7: Drum Brake

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ABS Hydraulic system

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ABS Control Strategy

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Hydraulic Concept of ABS

return pump

inlet valve

outlet valve

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Suppose two rhs wheels on mud or ice and two lhs wheels on tarmac , when the brakes applied , the braking effect on the wheels on the tarmac is , of course , considerably greater than that of the slippery side and therefore causes a tendency to yaw. The effect is more pronounced in small vehicles than larger and heavier ones with large wheelbase. This is because the latter have greater inertia about the vertical axis so the rate of yaw is slower ,allowing the driver more time to apply steering correction to counter the tendency.

YAW Text Text

ThemeGallery is a Design Digital Content & Contents mall developed by Guild Design Inc.

ThemeGallery is a Design Digital Content & Contents mall developed by Guild Design Inc.

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FAQs

9 Will stopping distance be reduced because of ABS? is ABS better than the conventional air brake system? Should one use the brakes differently with ABS? Is ABS fail-safe? Can older vehicles be retrofitted with ABS? Will ABS work on all automobiles? Will ABS ensure stability in all conditions?

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ELECTRONIC BRAKE FORCE DISTRIBUTION

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refinements to antilock braking systems has been electronic brake force distribution, or EBD. EBD is based on the principle that not every wheel needs to put forth the same effort into bringing the car to a stop.

EBD is based on the principle that the weight being supported by the wheels of your car isn't evenly distributed. Some wheels carry a heavier load than others and will require more brake force in order to bring the car to a stop without it going out of control.

Furthermore, the amount of weight being supported by a wheel shifts during the braking process, so the amount of force necessary at each wheel can change rapidly. An EBD system can not only detect how much weight is being supported by each wheel, but change the amount of braking power sent to each wheel on an instant-by-instant basis.

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Tires work by friction. When you step on the accelerator, the friction between the tires and the road is what makes you move forward. When you step on the brake, the friction between the tires and the road is what slows you down. That's why in icy conditions it's sometimes difficult to get your car to start moving when

you want it to -- and even more difficult to make it stop.Friction is also what keeps the car moving in the direction you want it to go. When we accelerate, we often

take for granted that the car will move in the direction that the wheels are pointing; however, if there were no friction between the tire and the road the car could easily slip sideways and go out of control.

It's important for driving safety to maintain the friction between the tire and the road, yet there are a number of conditions under which this friction can be lost. One is acceleration on icy roads, as mentioned above,

but friction can also be lost if you brake too hard. The forward momentum of the car can keep it moving at a speed significantly greater than the speed at which the tires are spinning. This is called wheel lock and it's a

common cause of driving accidents. Once it happens, the tires no longer grip the pavement and the car continues to travel in the direction it was heading when the skid started.

The key to avoiding a skid is the slip ratio, the difference between the speed at which the car is moving and the speed at which the tire is rotating. Antilock braking systems (ABS) can sense the slip ratio of the

individual tires and modulate the brake force applied to each tire so that the slip ratio remains within a safe range, thereby avoiding a skid.

When a car slows down, its weight shifts forward. In a front-engine car, the extra weight up front increases the grip of the front tires while it reduces the grip of the rear tires. This makes the rear tires more likely to

lock up during braking. When the rear wheels slip, the car can begin to fishtail or even go into a spin. Traditionally, braking systems included a proportioning valve to allocate the correct amount of brake force

to the front and rear tires. However, with ABS the proportioning valve no longer provides an ideal solution to the problem.

This is where electronic brake force distribution (EBD) comes in. With EBD, a computer called an electronic control unit (ECU) determines the slip ratio of each of the tires individually. If the ECU notices that the rear

wheels are in danger of slipping, it applies less force to them while maintaining (or, if necessary, increasing) the force applied to the front wheels. EBD is also useful when the car is braking while driving around a

corner. While turning, the outer wheels of the car rotate more quickly than the inside wheels. If too much brake force is applied to the inner wheels they can lock, causing the car to oversteer and go out of control.

EBD can sense the slippage of the inner wheels and reduce the brake force on those wheels without reducing the force on the outer wheels

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The safety and regulatory hardware used by an electronic brake force distribution system is much the same as the hardware used by an antilock braking system without EBD. It's just programmed differently. For the

purposes of EBD, three different pieces of hardware are necessary: sensors that can determine the slip ratio of each wheel, valves that can modulate the amount of brake force that goes to each wheel and an electronic

control unit that can calculate the amount of force required.Speed sensors: To determine the slip ratio of a wheel, the EBD system needs two pieces of information: the speed at which the wheel is rotating and the speed of the car. If the speed at which the wheel is rotating is

slower than the speed at which the car is moving, then the wheel is slipping and a skid can result. A sensor is placed at each wheel to determine wheel speed. There is no specific sensor to measure the forward

motion of the car. Instead, the speed measurements from all four wheels are averaged to create an estimate of the vehicle's overall speed.

Brake force modulators: Brake force is applied to the wheels hydraulically, with brake fluid pumped into brake lines in such a way as to pneumatically activate the brake cylinders. The EBD system can modulate

the amount of brake fluid going to each wheel through electrically actuated valves.Electronic Control Unit (ECU): The ECU is a small computer embedded in the antilock braking system. It receives input from the speed sensors, calculates the slip ratio of the wheels, and uses the brake force

modulators to apply an appropriate amount of force to keep the slip ratio of each wheel within a reasonable range.

Most EBD systems also include a yaw sensor, which detects the rotation of the vehicle as it turns. This can be compared with the angle of the steering wheel by using a steering wheel angle sensor to detect oversteer(too much rotation relative to the angle of the wheel) or understeer (not enough rotation relative to the angle of the wheel). EBD can then correct the steering by activating one of the rear brakes. For instance, if the car

begins to understeer, the inner rear brake is activated to increase the car's rotation. If the car begins to oversteer, the outer rear brake is activated to decrease the car's rotation. The yaw sensor can also be used

in conjunction with electronic stability control (ESC) to prevent rollover accidents

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Now imagine that you're driving on an icy surface or a road slick with rainwater. Under these conditions it's really easy for your car to go into a skid. And although EBD cannot detect road conditions directly, it can deduce them from the slip ratio of the wheels and compensate accordingly. If conditions are different for each wheel -- for instance, if one wheel is on a patch of ice and the other is not -- this can be detected through the slip ratio. Although there's no magic solution to the problem of stopping a car under bad road conditions, EBD can make emergency braking under these conditions as safe as possible.

Here's another less-than-obvious benefit of EBD: When you load the trunk of your car with luggage, it changes the traction on your rear wheels, which means that more force can be applied to these wheels during braking. A standard proportioning valve wouldn't necessarily take this extra weight into account, but electronic brake distribution compensates appropriately for your car's now heavier rear end. EBD can't detect this extra weight directly, but the system becomes aware of it through its effect on the slip ratio of the tires.

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CARS ABILITY TO MAINTAIN ADHESIVE FRICTION BETWEEN VEHICLE AND PAVEMENT

DEALS MAINLY WITH LATERAL LOSS OF FRICTION DURING ACCELERATION

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WHILE BRAKING WHILE ACCELERATING WHILE TURNING

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When wheel slip occurs?

When the force applied to the tire exceeds the traction available to that tire

When wheel slip occurs?

Types of forces Longitudinal - torque applied to tire Lateral - while taking a curve

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DEALS WITH ACCELERATION RATHER THAN DECCELERATION(REVERSE OF ABS)

ALSO CALLED AS ACCELERATION SLIP REGULATION

HELPS TO LIMIT TIRE SLIP IN ACCELERATION ON SLIPPERY SURFACES

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WHEN CAR ACCELERATES FROM DEAD STOP SPEEDS UP WHILE CROSSING

ANOTHER VEHICLE

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WHEEL SPEED SENSOR MEASURE DIFFERENCES IN ROTATIONAL SPEED

DETERMINES IF THE WHEELS THAT ARE RECEIVING POWER HAVE LOST TRACTION

WHEN TCS DETERMINES THAT ONE WHEEL IS SPINNING MORE QUICKLY IT APPLIES BRAKE

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Purpose

The philosophy of ESC is not only to reduce the vehicle speed but also to compensate for vehicle over steering and under steering behavior.

Method

Single wheel braking of the towing vehicle in combination with brake application at the trailer.ESC includes additionally Roll over stability function

Benefits

Improved safety Compensates for vehicle over steering or under steering

behaviorPrevents vehicle roll over ( RSC function)

Electronic Stability control ( ESC)Electronic Stability control ( ESC)

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ESC >> ABS &TCS

ECU

SensorsSteering wheel sensorLateral acceleration sensorYaw sensorWheel speed sensor

Hydraulic Modulator

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ESC reduces the danger of skidding ESC works instantly. Improves stability during severe cornering Improves stability on low friction road surfaces Helps to correct vehicle control errors by sensing incorrect lateral

movement (or yaw) and by dynamically adjusting control to eliminate or reduce its impact

Provides overall control and monitoring of chassis systems

It cannot raise cornering limit.

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RSC Accelerometer

integrated in ABS ECU (or ESC Module)

ATC valve for drive axlebraking

-- RSC valvefor trailerbraking

ABS based Electronic Stability control ( ESC)

Full ESC RSC valves RSC valves plusplus

Sol.Valve for Sol.Valve for front axle brakingfront axle braking

Pressure sensor forPressure sensor forDrivers Brake Demand Drivers Brake Demand

Steering AngleSensor

ESC Module

RSC Accelerometer

integrated in ABS ECU (or ESC Module)

ATC valve for drive axlebraking

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ABS based Electronic stability control (ESC)

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ABS based ESC

Electronic Stability Control ESC improves vehicle safety Vehicle behaviour is measured with additional Yaw-rate- and lateral

acceleration sensors. Drivers requests are measured with steering angle sensor and brake

pressure sensor. These data are continuously processed. If vehicle does not react according drivers request and if the situation is

interpreted as critical, ESC intervenes and activates engine-control and tractor/trailer brakes.

If vehicle does not follow the curve according drivers steering, single wheel braking at the tractor supports the wanted steering thereby over-steering is compensated.

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ABS based ESC

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YAW Control on slippy roads YAW Control on slippy roads ESPESP--Video Sault St. Marie, Michigan USVideo Sault St. Marie, Michigan USVDC-PD1

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CMS means Collision Mitigation System. It is a system, that will autonomously do a partial braking in a collision immanent situation.

CMS is a new extension of ACC and is based on the current ACC sensor technology. A collision is not prevented but the energy of

the impact is reduced

The system does not brake on standing/stopped objects due to limited capabilities of the actual sensor technology.

CMS works only at higher initial speeds outside urban areas

Collision Mitigation SystemCollision Mitigation SystemAutonomous Emergency Braking Autonomous Emergency Braking

AEB means fully Autonomous Emergency Braking (maximum possible deceleration) without driver initiation and will overrule the driver in collision immanent situations if necessary to limit or prevent harm to himself or other traffic participants.

AEB may completely prevent a collision depending on the dynamic situation. The powerful nature of such a system demands for high reliability of the information about the

surrounding world.

Today's sensors do not provide such high reliability demands. Therefore redundant data gathering of different sensor concepts (e.g. Radar + video) is necessary to ensure safe operation of AEB.

The video sensor of the fusion concept will also provide LDW (lane departure warning).

CMS

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Many accidents are caused by late braking and/or braking with insufficient force. A driver may brake too late for several reasons: he is distracted or inattentive;

visibility is poor, for instance when driving towards a low sun; or a situation may be very difficult to predict because the driver ahead is braking unexpectedly. Most people are not used to dealing with such critical situations and do not apply enough braking force to avoid a crash.

Several manufacturers have developed technologies which can help the driver to avoid these kinds of accidents or, at least, to reduce their severity. The systems they have developed can be grouped under the title:

Autonomous: the system acts independently of the driver to avoid or mitigate the accident.Emergency: the system will intervene only in a critical situation.

Braking: the system tries to avoid the accident by applying the brakes..

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AEB systems improve safety in two ways: firstly, they help to avoid accidents by identifying critical situations early and warning the driver; and secondly they reduce the severity of crashes which cannot be avoided by lowering the speed of collision and, in some cases, by preparing the vehicle and restraint systems for impact.

Most AEB systems use radar or lidar-based technology to identify potential obstacles ahead of the car. This information is combined with what the car knows of its own travel speed and trajectory to determine whether or not a critical situation is developing.

If a potential collision is detected, AEB systems generally (though not exclusively) first try to avoid the impact by warning the driver that action is needed. If no action is taken and a collision is still expected, the system will then apply the brakes. Some systems apply full braking force, others an elevated level.

Either way, the intention is to reduce the speed with which the collision takes place. Some systems deactivate as soon as they detect avoidance action being taken by the driver

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Roll Stability control

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Risk of Roll Over

Risk of Roll & Yaw

Long conventional 6x4 tractorsLong wheelbase tractors - better

stabilityHeavy weight on rear axleLess add-on cost for the fleet

owner

CabOverEngine 4x2 TractorsShort wheelbase - less yaw

stability Light weight on rear axleSafe Truck Concept

supported by OE

Vehicle Stability ControlGlobal Applications

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Purpose

The philosophy of RSC is to reduce vehicle speed there by

preventing vehicle roll over

Method

If the lateral acceleration exceeds a certain level RSC controls the engine torque including its retarder and if necessary activates the drive axle brakes through the ASR differential brake valve and activates the brakes of trailer additionally through RSC valve

Benefits

Improved safety Prevents vehicle roll overEnsures vehicle stability

Roll Stability control Roll Stability control

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RSC Accelerometer

integrated in ABS ECU (or ESC Module)

ATC valve for drive axlebraking

- RSC valvefor trailerbraking

RSC Accelerometer

integrated in ABS ECU (or ESC Module)

ATC valve for drive axlebraking

ABS based Roll Stability Control ( RSC ) ABS based Roll Stability Control ( RSC ) -- ComponentsComponents

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ABS braking systemABS braking systemwith RSC Tractorwith RSC Tractor

Option: ABS-based Roll Stability Control RSC

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ABS based RSC

Roll Stability Control RSC improves vehicle safety

Vehicle behaviour is measured with lateral acceleration sensor

Drivers braking is identified by front axle wheel behaviour, no brake pressure sensor.

These data are continuously processed.

If lateral acceleration is interpreted as critical, RSC intervenes and activates engine-control and tractor/trailer brakes.

VDC-PD1

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ABS based RSC stand alone or part of ESC

ROLL CONTROL on high friction roadROLL CONTROL on high friction roadVDC-PD1

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Electronic Braking system ( EBS)

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Purpose

The purpose of EBS is to achieve a better brake response, shorter stopping distance,and vehicle stability control

Method

All the EBS parts viz Brake signal transmitter , Central module,Proportional relay valve , Modulator valve and Axle modulator are connected through a Controller area network ( CAN).

Brake by wire method Benefits

Shorter stopping distanceFaster service brake responseFull stability control Passenger car type feeling

Electronic Braking system( EBS)Electronic Braking system( EBS)

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EBS System - Layout

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EBS Components

Standard components

Trailer Control Valve

Proportional relay valve

Brake signal transmitter

ABS solenoid valve

Electronic control unit

Axle modulator

ESC module

Steering angle sensor

Options

ACC Sensor

Standard components

Back up valve

Trailer Control Valve

Proportional relay valve

Brake signal transmitter

ABS solenoid valve

Electronic control unit

Axle modulator

ESC module

Steering angle sensor

Options

ACC Sensor

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Cab mounted central ECU Brake signal transmitter with integrated sensors and activation

switches Central pressure control for the front axle Individual control at the front axle via ABS valves Axle modulator for the rear axle Separate pneumatic back-up valve for the rear axle Electro-pneumatic trailer control valve Electronic interface for trailer EBS

EBS Specification

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Electronic braking system

EBS integrates the following time functions

Anti Lock braking system Drive slip control Roll stability function Electronic stability function

Features

Brake by wire Minute pressure control Communication via Controller area network (CAN )network

Customer Benefits of EBS

Faster service braking response Passenger car type brake feeling Better stopping distance Roll Over Protection Stability control

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Adaptive Cruise control

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Purpose

The function of ACC is to avoid vehicle collisionMethod

Camera located in the head liner cluster , 77 GHz Radar fitted in the vehicle front, and 24 GHz radar fitted in the left hand side of the vehicle in the vehicle sense the movement of the object and accordingly transmit the signal to ECU which in turn applies the brake automatically there by reducing the vehicle speed

BenefitsPrevent vehicle collisionImproved fuel efficiencyEnhanced driver comfort due to stress relief in everyday driving

Adaptive Cruise control ( ACC)Adaptive Cruise control ( ACC)

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>$%&2Driver Assistance Systems Technology and ProductsDriver Assistance Systems Technology and Products

Headliner ClusterCamera Lane Departure

Warning & Lane Keeping Support

support of long range sensor

Long Range77 GHz Radar orInfrared Laser Sensor ACC Collision Warning Collision Mitigation Autonomous Emergency Braking

Side Sensors24 GHz Radar orultrasonicBlind spot detection

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>$%&2 Driver Assistance SystemsDriver Assistance SystemsAdaptive Cruise Control (ACC)Adaptive Cruise Control (ACC)

Traffic safety is ensured since the minimum distance between the vehicles are maintained.

Enhanced driver comfort due to stress relief in everyday driving

ACC leads to improved fuel efficiency since over speeding of vehicle is controlled

driveability

efficiency

safety

Three Reasons for ACC!

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Electronically Controlled Air Suspension (ECAS)

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Purpose

The function of ECAS is to provide a good suspension to the vehicle

Method

ECU constantly monitors the inputs like the height variations,axle loads, through pressure sensor, and controls the bellow pressure

Benefits

Less Air consumptionKneeling function ( easy lifting and lowering of vehicle)Control from driver seat

Electronically controlled Air suspension ( ECAS)Electronically controlled Air suspension ( ECAS)

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Conventional Air-Suspension

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Leveling valve

Air bellow

Reservoir

Simple System for Basic Functions

Air BellowsLeveling valve

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Electronically Controlled Air Suspension(ECAS)

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Reservoir

Height sensor

Air spring

Solenoid

ECU

ECU

ECAS The optimal solution for Trucks/Buses

Why ECAS ?

- Less air consumption- Easy lifting & lowering- Control from drivers seat

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ECAS 4x2 / 6x4 "Basic"ECAS 4x2 / 6x4 "Basic"

Height Sensor

Solenoid Valve

Remote Control

ECU

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ECUECU constantly monitors the inputs like height variations, axle loads through pressure sensor and controls the bellow pressures.Pressure sensorThe pressure sensor produces a voltage output which is proportional to the pressure present. This represents the axle loads on the vehicleHeight sensorA height sensor permanently evaluates the vehicle's height and send its readings to the ECU.Air BellowsDepending on the leveling valves control or height sensor signal, the air suspension bellows are designed to take up the required pressuredepending on the load carried on the vehicle.Solenoid valveThey increase,reduce or maintain the air volume in the bellowsRemote control unitBy means of the RCU the driver can influence the vehicle's level within the permissiblemaximum limits eg. Kneeling function