BENDIX BW1837 User's Manual
Contents
1. Next screw and lock the potentiometer in place torque to 25 inch pounds 5 The sleeves lock into the body of the potentiometer for easy removal and reassembly Test 3 Perform the following Operational Test before installing the electronic treadle OPERATIONAL TEST Note for Cummins potentiometers only The optimum output amp switch points should be achieved when the idle voltage equals the set voltage or set resistance written on the potentiometer Use the test circuit shown in Figure 8 a Check that the electronic treadle mounting plate is securely attached to a smooth flat surface in such a way that does not twist the unit b Connect the potentiometer or position sensor to the volt meter and power supply as shown in Figures 6 7 or 8 depending on the model Note The power supply needs to be 5 VDC Do not exceed this voltage c Verify that the closed throttle idle output voltage asa percentage of supply voltage is within the limits listed in Figure 2 For example with a supply voltage of 5 volts for the Caterpillar potentiometer in its closed throttle position read between 0 5 to 1 0 volts 10 20 of supplied voltage d Depress the treadle to its full throttle position The output voltage as a percentage of supply voltage should be within the limits listed in Figure 2 For example with a supply voltage of 5 volts for the Caterpillar position sensor in its open throttle position read between 3 75 to 4 5 v2. OUTPUT VOLTAGE OV CLOSED THROTTLE OPEN OPEN THROTTLE FULL FIGURE 3 OUTPUT VOLTAGE As the potentiometer rotates its resistance changes This way the potentiometer can react to the driver s request for engine power through the ET S or ET S2 treadle by changing resistance The resulting change of voltage is sensed by the electronic engine controller The electronic treadle receives its supply voltage from the engine control unit If the driver does not request engine power the treadle is in the idle position This condition is also referred to as Closed Throttle In this state the potentiometer returns the minimum percentage of supply voltage to the engine control unit see Figure 2 As the driver depresses the treadle the electronic treadle output voltage increases see Figure 3 The potentiometer allows an increased amount of its supply voltage to return to the engine control unit which in turn increases the engine s speed In the full or Open Throttle position the driver has depressed the treadle to its furthest possible point This is the state of least potentiometer resistance The electronic treadle returns the maximum percentage of supply voltage to the engine control unit see Figure 2 PREVENTIVE MAINTENANCE Important Review the warranty policy before performing any intrusive maintenance procedures An extended warranty may be voided if intrusive maintenance is performed during thi
3. applications and systems Components with stripped threads or damaged parts should be replaced rather than repaired Do not attempt repairs requiring machining or welding unless specifically stated and approved by the vehicle and component manufacturer Prior to returning the vehicle to service make certain all components and systems are restored to their proper operating condition BW1837 2004 Bendix Commercial Vehicle Systems LLC All rights reserved 6 2004 Printed in U S A
4. as shown on the label within 10 Ohms Next while holding the potentiometer at the set resistance screw and lock the potentiometer in place torque to 25 inch pounds 5 The sleeves lock into the body of the potentiometer for easy removal and reassembly Test 2 Where the potentiometer has no label but has engraved set voltage shown The Cummins potentiometer on the electronic treadle has an integral idle validation switch It also has a set voltage value marked on the cover which needs to be used to properly install the potentiometer The drive slot in the potentiometer should engage with the drive tang at the end of the drive shaft Next rotate the potentiometer until the hole in the metal sleeve matches the mounting holes on the actuator base Loosely screw the potentiometer in place but do not tighten Construct the test circuit following the circuit diagram shown in Figure 8 To make the test circuit connect the test load resistor 47 000 Ohms and a capacitor 01 MicroFarads across pins 3 and 4 of the potentiometer Then connect a voltmeter to the lead ends of the test circuit Next connect a 5 volt power supply to the potentiometer at pin 4 APS ground and pin 5 supply voltage Caution Sensor may be damaged if supply exceeds 5 volts Now the installer should read the set voltage value marked on the potentiometer Rotate the potentiometer until the voltmeter reads the same voltage as shown on the potentiometer within 02 volts
5. may damage the paint finish 2 Inspect the treadle and mounting plate for severe corrosion pitting or cracks Replace as necessary Superficial corrosion and or pitting is acceptable 3 Inspect the cable assembly for loose or frayed wires potentiometer clockwise until the first set of mounting physical damage or any contaminants on the connec holes align Secure using two screws torque to 25 5 tors Replace as necessary in lbs b For Caterpillar Position Sensor Aligning the drive ASSEMBLY slot the position sensor engages the drive tang at the 1 Securely clamp the treadle mounting plate end of the drive shaft see Figure 4 Rotate the position 2 a For Detroit Diesel Potentiometers Align the drive sensor clockwise until the first set of mounting holes slot and engage the potentiometer the drive tang at the align Secure using two screws torque to 20 2 in end of the drive shaft see Figure 4 Rotate the Ibs DIGITAL POTENTIOMETER 1_ PC NO ON THIS SURFACE POWER SUPPLY 9 16 VDC PIN C 300 000 OHM RESISTOR GROUND TESTLOAD AL i iN 8 _uJ i POTENTIOMETER VOUT OUTPUT Closed Throttle open Range 7 18 VREF INPUT Open Throttle full Range 74 84 FIGURE 6 ELECTRICAL TEST SCHEMATIC FOR THE DETROIT DIESEL CONNECTOR Closed Throttle open Range 10 20 Open Throttle full Range 75 90 PINA VREF INPUT 2000 OHM 5 RESISTOR PEDAL POSITION PIN B SENSOR 0 VOU
6. All other repairs require replacement of the ET S or ET S2 treadle Refer to Figure 5 throughout the procedures Treadle Removal ET S Treadle Position the treadle on its side with the potentiometer fac ing up Remove the small retaining ring 3 and small nylon washer 4 that hold the treadle on to the treadle arm and set aside for the assembly process After the washer is removed pull the treadle off carefully releasing the pres sure from the treadle spring 7 Set the spring 7 nyliner bearing 6 and the treadle aside for the reassembly pro cess Inspect rubber treadle cover replace if necessary ET S2 Treadle Position the treadle assembly on its side with the poten tiometer facing down Remove the small retaining ring 3 and the nylon washer 4 from the treadle pivot pin Remove the pivot pin from the treadle assembly Gently release the tension on the treadle spring 7 while removing the treadle from the treadle arm Remove the nyliner bear ing 6 from the treadle arm Potentiometer Removal Secure the mounting plate Important Do not clamp the assembly by the treadle actuator body or base since overclamping may cause the casting to be distorted Remove the two screws 2 that secure the potentiometer 1 to the actuator base The potentiometer 1 can then be lifted away from the drive shaft CLEANING AND INSPECTION 1 Use suitable solvent to clean all metal parts note that mineral spirits
7. T PWM OUTPUT CABLE 47 000 OHM 5 RESISTOR POSITION SENSOR PIN C Y GROUND Caterpillar output voltage is Pulse Width Modulated FIGURE 7 ELECTRICAL TEST SCHEMATIC FOR THE CATERPILLAR CONNECTOR 4 Vs SUPPLY VOLTAGE Closed Throttle open Range 5 17 Open Throttle full Range 70 81 LOCK TAB V3 LOGIC HIGH AT IDLE IDLE VALIDATION SWITCH PEDAL POSITION SENSOR TEST LOAD 47000 OHM V2 LOGIC LOW AT IDLE IVS GROUND GROUND POTENTIOMETER SET VOLTAGE AND PC NO SHOWN HERE 4 APS GROUND FIGURE 8 ELECTRICAL TEST SCHEMATIC FOR THE CUMMINS CONNECTOR c For Cummins Potentiometers Test 1 Where the set resistance and voltage is shown on a label The Cummins potentiometer on the ET S and ET S2 treadle has an integral idle validation switch It also has a set resistance value marked on the cover which needs to be used to properly install the potentiometer The drive slot in the potentiometer should engage with the drive tang at the end of the drive shaft Next rotate the potentiometer until the hole in the metal sleeve matches the mounting holes on the actuator base Loosely screw the potentiometer in place but do not tighten Connect an ohmmeter to pins 3 APS output and 4 APS ground as shown in Figure 8 Now the installer should read the set resistance value marked on the label Rotate the potentiometer until the ohmmeter reads the same resistance
8. TREADLE ACTUATOR BODY MOUNTING ae ACTUATOR BASE CONNECTOR TREADLE POTENTIOMETER MOUNTING ET S TREADLE ee FIGURE 1 ET S AND ET S2 ELECTRONIC TREADLES DESCRIPTION The ET S and ET S2 treadles are engine compartment bulkhead mounted electronic treadles On electronically controlled diesel engines the electronic treadle fulfills the same function as a conventional mechanical throttle However rather than transmitting a mechanical force to the engine governor the electronic treadle controls engine speed by supplying a variable electrical voltage to the engine s electronic controller The main components of the EI S and ET S2 treadles are a mounting plate suspended treadle potentiometer variable resistor actuator body and base The selected potentiometer chosen for a specific engine application provides the electrical link to the engine control system OPERATION The electronic treadles provide smooth graduated throttle control through the function of its potentiometer variable resistor The drive shaft of the cam follower assembly transfers any movement of the treadle to the potentiometer POTENTIOMETER MOUNTING PLATE TREADLE PIVOT PIN TREADLE ET S2 TREADLE CLOSED THROTTLE IDLE OPEN OPEN THROTTLE FULL FIGURE 2 OUTPUT VOLTAGE AS A PERCENTAGE OF SUPPLY VOLTAGE 74 90 75 90 70 81 8V CATERPILLAR e 5V ET S TREADLE
9. g portion of the nyliner bearing with the tangs of the treadle spring 7 point ing toward the ET S2 treadle body The short tang should rest on the top side of the treadle arm Align the treadle arm and treadle spring with the recess in the underside of the treadle 4 Insert the pivot pin from the potentiometer side of the ET S2 treadle assembly through the treadle treadle arm nyliner bearing 6 and spring 7 Secure with the nylon washer 4 and retaining ring 3 5 Make sure the ET S2 treadle has smooth even treadle movement 6 Install the ET S2 treadle on the vehicle see ET S amp ET S2 Treadle Installation ET S amp ET S2 TREADLE INSTALLATION 1 Using the mounting hardware set aside install the assembled electronic treadle on the vehicle Torque to between 85 and 110 Ib in 2 Reconnect the cable connector by plugging it into the potentiometer s integral connector and pushing until the lock tab snaps into place WARNING PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH When working on or around a vehicle the following general precautions should be observed at all times 1 Park the vehicle on a level surface apply the parking brakes and always block the wheels Always wear safety glasses 2 Stop the engine and remove ignition key when working under or around the vehicle When working in the engine compartment the engine should be shut off and the i
10. gnition key should be removed Where circumstances require that the engine be in operation EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving rotating leaking heated or electrically charged components 3 Do not attempt to install remove disassemble or assemble a component until you have read and thoroughly understand the recommended procedures Use only the proper tools and observe all precautions pertaining to use of those tools 4 Ifthe work is being performed on the vehicle s air brake system or any auxiliary pressurized air systems make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle If the vehicle is equipped with an AD IS air dryer system or a dryer reservoir module be sure to drain the purge reservoir 5 Following the vehicle manufacturer s recommended procedures deactivate the electrical system in a manner that safely removes all electrical power from the vehicle 6 Never exceed manufacturer s recommended pressures 7 Never connect or disconnect a hose or line containing pressure it may whip Never remove a component or plug unless you are certain all system pressure has been depleted 8 10 Use only genuine Bendix replacement parts components and kits Replacement hardware tubing hose fittings etc must be of equivalent size type and strength as original equipment and be designed specifically for such
11. olts 75 90 of supplied voltage e Make five full applications and record idle position voltage each time Verify that idle position voltages recorded do not vary by more than 4 For example for a 5 volt supply if there is any variation the difference between the high and low readings should not exceed 02 volts If the electronic treadle fails to function within its specified ranges it should be repaired or replaced with a new or genuine Bendix remanufactured unit available at any authorized parts outlet Treadle Installation ET S Treadle 1 Replace the rubber treadle cover if needed 2 Place the spring 7 on the treadle pivot pin 3 Install the nyliner bearing 6 into the treadle Note the nyliner bearing collar is placed on the treadle arm side Holding the spring in position the treadle is then in stalled The nylon washer 4 and retaining ring 3 secure the treadle into position 4 Make sure the ET S treadle has a smooth even treadle movement 5 Install the ET S treadle on the vehicle see ET S amp ET S2 Treadle Installation ET S2 Treadle 1 Position the treadle assembly on its side with the poten tiometer facing up 2 Insert the nyliner bearing 6 into the treadle arm with the collar up toward potentiometer side The nyliner bear ing 6 will protrude through the treadle arm providing a guide for the treadle spring 7 3 Place the treadle spring 7 on the protrudin
12. retaining ring for cracks or deterioration Replace as necessary ET S amp ET S2 TREADLE REMOVAL 1 Park the vehicle on a level surface and block the wheels 2 Drain the air pressure from all vehicle reservoirs 3 Disconnect the cable assembly of the potentiometer Lift the lock tab and pull the connectors until they disengage 4 Remove the electronic treadle from the vehicle set aside the mounting hardware for reassembly DISASSEMBLY Please note that the internal mechanism of the ET S and ET S2 treadle are not field serviceable and therefore individual parts or parts kits are not available for these components Disassembly may lead to malfunction of the ET S or ET S2 treadle The following instructions cover the maintenance and replacement of the potentiometer and treadle with its bearing spring etc only The instructions provided with those items should be followed in lieu of the steps presented here There are no other field serviceable parts ACTUATOR BASE 1 MOUNTING POTENTIOMETER PLATE 2 10 SCREWS 3 RETAINING PS RING By T ACTUATOR BODY TREADLE ARM SPRING ET S TREADLE PIVOT PIN PIVOT PIN 4 NYLON WASHER REPLACEABLE RUBBER COVER ET S TREADLE ONLY NYLINER BEARING 6 NYLINER N BEARING 4 gt TREADLE JS S gt ay 4 NYLON WASHER j 3 J ANE RING ET S2 TREADLE FIGURE 5 ET S AND ET S2 TREADLE EXPLODED LINE DRAWING
13. s period Because no two vehicles operate under identical conditions maintenance intervals will vary Experience is a valuable guide in determining the best maintenance interval for a vehicle GENERAL Important Visually check for physical damage to the electronic treadle such as broken or missing parts Actuate the pedal five times from stop to stop noting any binding or soft pedal response Important Note DO NOT DISASSEMBLE THE ACTUATOR BODY Replace the ET S or ET S2 treadle if there is any binding soft pedal actuation or if the nylon washers or retaining rings indicated in Figure 4 are cracked or have signs of deterioration RETAINING AM FOLLOWER y RINGS DRIVE SHAFT POTENTIOMETER NYLON WASHERS FIGURE 4 TOP SECTIONAL VIEW Perform the inspections presented atthe prescribed interval If the electronic treadle fails to function as described it should be repaired or replaced with a new or genuine Bendix remanu factured unit available at any authorized parts outlet Every 3 months or 25 000 miles or 900 operating hours 1 Remove any accumulated contaminants and visually inspect the exterior of the electronic treadle assembly for physical damage or excessive corrosion 2 Inspect electrical connections and cable assembly for signs of corrosion wear or physical damage Replace as necessary 3 Inspect treadle spring sleeve bearing nylon washer rubber treadle cover ET S treadle only and
Download Pdf Manuals
Related Search