This protects the service brakes and ensures they are always available. Retarders for heavy vehicles deep blue university of. Eddy current is a circular current produced along coil windings that generates both heat and resistance to movement. In addition to these safety benefits, appropriate use of an auxiliary braking system will extend the life of the service brakes, reducing cost and frequency of maintenance. The speed of the test bench may due to the variation or force. Transit bus air disc brake operation and wheels on. System structure in buses ebs braking system for buses with no. The retarder control valve is signaled to open, allowing oil to. Our company telma, over 60 years of existence and world leader in secondary electromagnetic retarders.
Review of retarder used as braking system in heavy vehicles. In addition, automobile brake system is an essential element to measure the performance of an automobile. None of the different types of brake fluids should be mixed. It was the first practical mechanism for altering on demand the valve timing on a. This will allow you to adjust the retarder system to the requirements of the customer. Antilock braking system abs and antislip regulation asr. Since the capacity of the retarder or its retarding action is directly related to its rpm, it will be most effective at higher engine and vehicle speeds. Telma induction brakes, commonly known as electrical or electromagnetic retarders, offer an endurance braking system.
Classic friction brakes can reach temperatures of up to degrees under demanding conditions such as adaptive braking on the highway or on long downslopes. This leads to a rapid reduction in braking efficiency. Air compressor and air system pressure you should be aware of common air pressure thresholds of your motorcoachs brake system. The electric retarder the electric retarder uses electromagnetic. Clutch switch is a switch that disengages the compression brake when the clutch is depressed. The shoes are pulled away from the drum by the springs when the brakes are released. When the brakes are released, all the brake actuators are exhausted immediately. The air pressure gauge tells you the adequacy of the air system. The braking torque is as high upto 500 kw, depending on the propeller shaft speed and this is about two to three times more braking power than can be delivered by the engine brake.
Telmas unique expertise in the field of induction braking systems has been built on over seventy years of presence in the market. The exhaust brake system can also reduce wear of vehicle brakes and. In a normal torque converter, vanes on the input housing which is attached to the engine crankshaft transmit power through the fluid coupling to the output shaft vanes of the torque converter, which is connected to. Control systems or parts thereof, in general or specially adapted for vehicles, for processing variables which influence the extent or duration of a braking event, for the following purposes. The pressure transducer or rotary switch sends an analog.
Just like the exhaust brake, the compression brake using the pumping action of an internal combustion engine to create braking power. Drum brake also has an adjuster mechanism, an emergency brake mechanism and lots of springs. The retarder should be regarded as an integrated part of the brake system, and it must be factory mounted as it cannot be retrofitted. Vehicle modifications to facilitate cooling of brakes. Troubleshooting common transit bus scam and air brake complaints apta btsbcrp00617. Nov 01, 2015 a retarder is a device used to augment or replace some of the functions of primary frictionbased braking systems, usually on heavy vehicles. Furthermore, brake wear control ensures that the brake. Motorcoach brake systems and safety technologies fmcsa. Auxiliary braking systems more likely to brake hard and frequently.
Brakeretarder article about brakeretarder by the free. The permanent hydrodynamic endurance brake system ensures reliable, wearfree braking. The most popular engine compression retarder is the jake brake. For adjusting wheelbraking force to meet varying vehicular or groundsurface conditions, e. Auxiliary brake system is developing rapidly, therefore, all kinds of vehicles, hydraulic retarder is one of the important auxiliary braking form. Klam electro magnetic retarder the new electronic retarder control system called ecs has many features and benefits to suite your requirements. According to the web site of the american society of mechanical engineers, brake retarders allow truckers to slow vehicles without causing additional wear to the conventional brake system. When enabled, the transmission retarder is activated by two different methods. Furthermore, brake wear control ensures that the brake paddisc wear is uniform throughout their service life. The brake retarder systems are sometimes referred to collectively as jake brakes in reference to the original device, the jacobs engine brake.
The degree of retardation can bevaried by adjusting the fill level of the chamber. It is no surprise that endurance brakes in buses and trucks are a legal requirement throughout europe. A retarder is a device used to augment or replace some of the functions of primary frictionbased braking systems, usually on heavy vehicles. Frictionbased braking systems are subject to brake fade.
The ebs optimises brake management by utilising the effects of the retarder or engine brake to reduce load on the wheel brakes. Increasing speed by 25% from 60 mph to 75 mph can double the stopping distance for both drum and disc brakes. Frictionbased braking systems are susceptible to brake fade when usedextensively for continuous periods, which can be dangerous if. This is the reason that they began requiring auxiliary braking systems on large fire apparatus. Retarder assembly how to remove retarder assembly special instructions warning. Telmas unique expertise in the field of induction braking systems has been built by more than sixty years of presence on the market, during. Working of drum brakes drum brakes work on the same principle as the disc brakes. Brake fade is a function of the type of brake system drum vs. This section addresses the application of retarders both in the downhill braking situation and. It was the first practical mechanism for altering on demand the valve timing on a truck diesel engine, thereby converting the engine to a power absorbing machine. This retarder operates on the torque converter principle. The department of highways and public works is responsible for ensuring safe and efficient public highways, airstrips, buildings and information systems. This system makes it all happen quick in an emergency, however it allows it to happen.
Hydraulic retarders are extremely quiet, often inaudible over the sound of a running engine, and are especiallyquiet in operation compared to engine brakes. Rule 32015 part 1 rule requirementsland transport rule. Road vehicles endurance braking systems of motor vehicles. Designed to be mounted on driveshafts, gearboxes or drive axles, this wide range provides solutions to a large variety of vehicle configurations. Heavyvehicle brakes 2006 is one of a series of rules that sets safety requirements and standards for systems and components in vehicles operating in new zealand. Auxiliary braking systems compression brake a compression brake system was first commercially available starting in 1961 from the jacobs manufacturing company, commonly referred to as the jake brake. Since 1946, telma has been the world leader in frictionless braking systems based on the physical principle of electromagnetic induction. Retarders serve to slow vehicles, or maintain a steady speed while traveling down a hill, and help prevent the vehicle from running away by accelerating down the hill. Engines brakes and retarders air suppressor is a device that stops air pulsations. The ecs retarder control system has a diagnostic tool that allows the driver owner to locate a failure and report. Retarders a retarder is a device used to boost or replace some of the functions of primary frictionbased braking systems, usually on heavy vehicles. The retarder pays for itself, often in less than 2 years.
The target of this thesis is to people get more information about automobile brake system and study some basic maintenance methods. On hydraulic brake vehicles there may be a rotary switch mounted with a bracket to the brake pedal. The caterpillar brake saver is the most popular retarder in this class. Telma induction braking systems dissipate the braking energy by generating eddy currents. The ecs retarder control system can be programmed and adjusted for your needs and the vehicle retarder application. The dawson city ice bridge is now open to heavy traffic up to 40,000 kilograms.
The brake power is independent of the engine temperature, and amounts to max. Transmission retarders are usually more effective than engine brakes at lower rpms. Iso 2226swg 6 retarders test procedures for type approval wd 12161. Hydraulic retarders are extremely quiet, often inaudible over the sound of a running engine, and are especially quiet in operation compared to engine brakes.
Department of highways and public works government of yukon. The braking force may vary due to retarder charactaristic. Home ordnance documents and other related manuals engine retarder system od162070117. The compressed air brake system is controlled at the compressor outlet from the group apu air processing unit, comprises an air dryer with heating, a pressure regulator, a fourway distributor and two external sockets. Automatic retarder when the automatic retarder is activated and you depress the brake pedal, the retarder and wheel brakes work together. Brake retarder a device used to decelerate a motor vehicle, principally when the vehicle is traveling on long downgrades.
The transmission retarder is enabled by a switch on the drivers console. The principle behind the engine retarder brake is that it changes the action of the exhaust valves, turning the engine into an air compressor. Brake retarders improve road safety and augment the functioning of wheel brakes. In that way, the retarders help to extend the life span. On air brake vehicles there is an air pressure transducer connected to the primary delivery line of the braking system to activate the retarder. Frictionbased braking systems are susceptible to brake fade when usedextensively for continuous periods, which can be dangerous. A joystick on the drivers console selects the amount of retardation. This feature helps to decelerate the vehicle and maintain a steady speed on declines. This system makes it all happen quick in an emergency, however it allows it to happen slow and not that aggressive in a normal stopping condition. Electrical system general the auxiliary brake control unit is microprocessor. It will take the use of your klam retarder to a new experience, taking away some of the fear factors of. This retarder system is manufactured by the jacobs manufacturing company, and their product is available for. The rotor is driven by the vehicle through its axle, propshaft, transmission and clutch and its rotation causes the retarder oil to undergo centrifugal. At the same time, transport capabilities increase due to higher average speeds.
Retarder switch on, joy stick in zero position fully forward on my coach, let off the power, no retard. Gang voith retarder 32 3750nm average engine 1600 min1 100 kw 200 kw 300. Loosen the screws from intermediate flange and remove it. Transmission retarders generate a lot of heat and their maximum braking horsepower is usually limited by the trucks cooling system. For the retarder to work as effectively as possible, the engine speed should be over 1,800 rpm. Operating principle telma induction brakes, commonly known as electrical or electromagnetic retarders, offer an endurance braking system. During this time telma managed to establish the industry standards and make a. The telma induction braking system product range includes more than 250 retarder variations for road vehicles, providing braking torques of 350 nm to 3600 nm.
First practical mechanism for braking large trucks with engine compression as they descend long, steep grades at controlled speeds. Repeated stops at 60 mph with drum brakes can double the stopping distance due to brake fade. March 2003march 2003 fire apparatus driveroperator 1afire apparatus driveroperator 1a slide 21144. They will avoid damage to the system components or serious personal injury, or both. For these purposes the retarder functions are fully integrated in the service brake operation.
It can absorb water from air, that is why we should avoid opening the cars brake fluid reservoir and the container of the brake fluid should be tightly sealed. Voith retarders are the lightest in weight among continuous brake systems. Retarders protect the service brakes, thus reducing expenditures on spare parts and maintenance. Zf intarder the zf intarder is a hydrodynamic retarder. This rule addresses heavyvehicle braking, which is one of the most important vehicle. Bus air brake system training home american public. The jake brake permits large trucks to descend long, steep grades at a controlled speed. Since more than 60 years, telma has been the world leader in friction free braking systems based on the physical principle of electromagnetic induction. As a dot 3 or dot 4 brake fluid absorbs water, its boiling point decreases.
With voith retarders, up to 90 percent of all braking actions can be performed without wear. The retarder works by absorbing energy during the compression stroke, and throwing away this energy through the exhaust valves as the piston completes its compression stroke. Ebs electronically controlled brake system in motor coaches. The performance of brake system directly affects the other properties of the vehicles. This booklet will cover the most common air brake system designs from 1975 to 2006. Retarders serve to slow vehicles, or maintain a steady. Use of engine retarder brakes engine retarder brakes are used in many heavy trucks as a supplement to the vehicles service brakes. Secondary brake systems engine retarders compression brake uses engine to brake turns engine into energy absorbing air compressor exhaust brake uses exhaust from engine to brake works opposite compression brake. Mx engine brake the mx engine brake is a hydraulically operated compression brake combined with a butterfly valve in the exhaust system. The owners advisor contract for yukons newest elementary school has been awarded to colliers project leaders. An allison transmission retarder provides secondary vehicle braking via the transmission. The retarder is an auxiliary brake and brakes the driving wheels. Biggest downfall on the hydraulic retarder is the heat absorbed by the transmission oil.
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