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4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J3053_201507 SURFACE VEHICLE RECOMMENDED PRACTICE J3053 JUL2015 Issued 2015-07 H
5、eavy Duty Truck and Bus Electrical Circuit Performance Requirement for 12/24 Volt Electric Starter Motors RATIONALE This document is intended to give the industry a design standard to define the design of the electrical circuits used in conjunction with 12/24 volt electric starting motors. The docum
6、ent will include all elements of the Electric Starter system main cranking and control circuits. 1. SCOPE The scope of this SAE Recommended Practice is to describe a design standard to define the maximum recommended voltage drop for starting motor main circuits as well as control system circuits for
7、 12V through 24V starter systems. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International,
8、 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. SAEJ544 Electric Starting Motor Test Procedure 2.1.2 ISO Publications Available from International Organization for Standardization, ISO Central Secretariat, 1
9、, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org. ISO 8856 Amendment 1 Road Vehicles-Electrical Performance of Starter Motors-Test Methods and General Requirements SAE INTERNATIONAL J3053 Issued JUL2015 Page 2 of 9 3. DESCRIPTION The electrical crank
10、ing system components in a heavy duty truck and bus include batteries, cabling, master disconnects, switches, control switches, relays, terminations and cranking motor. The starting system shall be designed in a fashion to provide the necessary engine RPM to start an engine under the most severe cli
11、matic conditions for which the system is intended. This SAE Recommended Practice is focused on the starter motor electrical circuit and its corresponding circuit components (Shown in Figure 6 - Diagram of Crank Circuit Main Cables), but engine cranking has many other variables as shown in Figure 1 t
12、hat will also influence engine cranking and starting performance. Engine manufactures may have minimum electrical system design guidelines defined to meet their engine starting requirements. These engine manufacture guidelines shall be considered by the truck and bus OE when designing the electrical
13、 crank system. Truck and bus OEs may also incorporate a holistic electrical cranking system design. For example, by reviewing the minimum operating temperature, minimum required engine cranking speed, circuit components, starting aids, and recommended oil type, the OEM may choose to deviate from rec
14、ommended circuit voltage drops: Battery Internal Resistance (Rbatt) may be reduced by applying a battery pack with a lower internal resistance, or by using ultracapacitors, or other alternative power sources (reference Fig. 6) A starting aid such as a block heater may allow the engine to crank at an
15、 internal temperature that greatly exceeds cold climate ambient. Temperature aids such as an air preheater and low viscosity oil may be used. If a truck or bus OE electrical cranking system design deviates from the defined component VDs found in table shown in Figure 7, explicit service literature s
16、hall be provided by the truck or bus OE defining the proper electrical crank system test procedure and a list of any specialized components such as specific battery chemistry. Figure 1 - Fishbone diagram SAE INTERNATIONAL J3053 Issued JUL2015 Page 3 of 9 4. COMPONENT STARTER MOTOR STRAIGHT DRIVE VS.
17、 GEAR REDUCTION & STARTER EFFICIENCY Torque per Amp - The gear reduction starters have the advantage of producing more torque for a given amount of current (see Figure 2- Chart of Torque vs. Current). So in this regard, gear reduction is “more efficient“. Efficiency - True efficiency is defined as P
18、ower Out /Power In. Gear reduction starters are more efficient than straight drive starters in the desired working range of the starter (see Figure 3 - Chart of Efficiency vs. Cranking speed) Speed vs. Voltage - For a given steady state current, speed is proportional to voltage. Both straight drive
19、and gear reduction motors are affected nearly equally in this regard. As shown in Figure 4 Chart of Engine RPM vs. Starter Voltage, the slope is basically the same for straight drive and gear reduction. Figures 2 thru 4 were created from starter performance test data. The test method used to generat
20、e this data conforms to SAE J544 and ISO 8856. (All data shown is relative to a 12 V Electrical System) Figure 2 - Chart of Starter Torque vs. Current 0204060801001201401601800 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000StarterTorque(Nm)Starter Current (amps)Torque per AmpGear Reduction
21、 vs. Straight Drive StartersStraight DriveGear ReductionTypical 15L Engine at -18C with 15W40 OilSAE INTERNATIONAL J3053 Issued JUL2015 Page 4 of 9 Figure 3 - Chart of Starter Efficiency vs. Cranking RPM Figure 4 - Chart of Cranking Speed vs. Voltage 5. COLD CRANKING ENGINE RPM /VOLTAGE / CURRENT Th
22、e bar charts in Figure 5 below are based on actual data from a cold crank test of a 13L engine with 15W40 oil at -18C fitted with a gear reduction starter motor. The crank data is based on 20 second continuous crank events. Fuel was disabled to prevent engine starting. Four different lead-acid batte
23、ry packs were tested and all were conditioned to 70% state of charge. Since temperature and oil weight were held constant for all tests, the cranking torque demanded by the engine was also constant for each test. This cold crank data clearly demonstrates that: A. Cranking speed is proportional to vo
24、ltage- voltage is relative to battery chemistry (battery internal resistance, Rbatt), but not necessarily a direct correlation to Cold Cranking Amps (CCA). As battery internal resistance increases, starter RPM will decrease as a result of lower available voltage at the starter. B. Current is proport
25、ional to torque - required cranking torque was constant for each test, therefore current remained constant despite the different battery packs and resulting voltages during cranking. 010203040506070800 25 50 75 100 125 150 175 200StarterEfficiency(%)Cranking RPMStarter Efficiency vs. RPMStraight Dri
26、veGR Manuf 1GR Manuf 2GR Manuf 30204060801001201401601802006 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11CrankingRPMVoltageSpeed per VoltGear Reduction vs. Straight DriveStraight Drive RPMGear Reduction RPMSAE INTERNATIONAL J3053 Issued JUL2015 Page 5 of 9 Figure 5 - Charts of cold crank data SAE INTERNATIONAL
27、J3053 Issued JUL2015 Page 6 of 9 6. STARTER ELECTRICAL CIRCUIT MAIN CRANKING CIRCUIT The main cranking circuit consists of the positive and negative cables, master disconnect switch and all circuit terminations (Figure 6 - Crank Circuit Diagram, Main Cables). Voltage drop measurement shall be perfor
28、med by applying the highest reasonable current load to the circuit to minimize the signal to noise ratio. Measurements should be performed quickly to minimize changes in circuit resistance due to I X R heating affects. 120 amps is the minimum recommended load to be applied for measurement purposes.
29、Figure 7 provides recommended values for VDROP/120AMPS, VDROP/500AMPS, as well as the equivalent resistance in Ohms. The starting motor circuits in motor vehicles shall be designed so that the difference between the voltage at the battery terminals and the starting motor terminals (including connect
30、ions and disconnect switch) shall not exceed those values shown in Figure 7 - Table of Main Cranking Circuit Recommended Maximum Voltage Drop. The voltage drop values are defined with a normal circuit temperature of 20 nullC (68 nullF). Figure 6 - Crank circuit diagram, main cables Main Cranking Cir
31、cuit Recommended Maximum Voltage Drop System Voltage Use Total Circuit Resistance V-drop/500 amps V-drop/120 amps Starter Output Range Max Engine Displacement 12 volt Light Duty 0.003- 0.004 - 0.36 -0.48V 0.9kw - 2.5kw 8 liter gas 3.5 liter diesel 12 volt Light / Medium Duty (LHDD) 0.002 1.0V 0.24V
32、2.2kw - 3.3kw 6 liter 12 volt Medium Duty (MHDD) 0.0012 0.6V 0.14V 2.7kw 6.8kw 9 liter 24 volt Medium Duty (MHDD) 0.002 1.0V 0.24V 4.5kw -7.3kw 13 liter 12 volt Heavy Duty (HHDD) 0.001 0.5V 0.12V 6.8kw - 8.5kw 16 liter 24 volt Heavy Duty (HHDD) 0.002 1.0V 0.24V 7.0kw - 13kw 30 liter Figure 7 - Table
33、 of main cranking circuit recommended maximum voltage drop all exceptions to this requirement shall be defined as described in section 3. SAE INTERNATIONAL J3053 Issued JUL2015 Page 7 of 9 6.1 Starter Electrical Circuit - Control Circuit Starter solenoid current draw varies widely based on the type
34、of starter engagement system. Robust control circuit design is critical to the starter engagement reliability and solenoid life. Although still important, the control circuit design for starters equipped with IMS (Integrated Magnetic Switch) is less sensitive to voltage drop based on the relatively
35、low current draw of the IMS coil ( 2 to 4 amps). For starters without IMS, the control circuit consists of the wiring from the battery power source to the magnetic switch, the magnetic switch contacts, and the wiring from the magnetic switch to the starter solenoid (see Figures 8 & 9 - Control Circu
36、it Diagrams, with and without IMS). Vehicles with electronically managed starter controls shall consider protection for inductive voltage spikes resulting from de-energizing the starter solenoid. Likewise, the system design should ensure that (if) a control relay exist on the starter, that suppressi
37、on is present on the coil of the relay which will ensure ample protection exist at the source where such inductive voltage spikes would be generated. Voltage drop measurement shall be performed by applying a current load suitable to the operating current level of the starter solenoid or IMS during t
38、he initial engagement phase. Magnetic switch shall be energized to perform total circuit voltage drop measurement. (Disconnect circuit from starter motor prior to performing measurement.) Measurements should be performed quickly to minimize changes in circuit resistance due to I2X R heating affects.
39、 Figure 10 describes several different engagement system types and provides recommended values for VDROP/100AMPS, as well as the equivalent resistance in . The starting motor control circuits in motor vehicles shall be designed so that the difference between the voltage at the battery terminals and
40、the starting motor control circuit terminals (including connections) shall not exceed those values shown in Figure 10 - Table of Recommended Control Circuit Voltage Drops. The voltage drop values are defined with a normal circuit temperature of 20 C (68 F). Figure 8 - Control circuit diagram, withou
41、t IMS (Integrated Magnetic Switch) SAE INTERNATIONAL J3053 Issued JUL2015 Page 8 of 9 Figure 9 - Control circuit diagram, with IMS (Integrated Magnetic Switch) Control Circuit Recommended Maximum Voltage Drop* System Voltage Starter Engagement System Type Typical Solenoid / IMS Pull-In Current (12 V
42、) Recommended Circuit Resistance at Typical Operating Current V-drop/100 amps 12 / 24 volt Positive Shift 20A -120A 0.050 - 0.008 1.0V 12 / 24 volt Mechanical Positive Engagement 80A - 120A 0.0013 - 0.008 1.0V 12 / 24 volt Electric Soft Start Positive Engagement (w/o IMS) 150A - 350A 0.007 - 0.003 1
43、.0V 12 / 24 volt * Electric Soft Start Positive Engagement (w/ IMS) 2A - 4A 0.500 - 0.250 N/A Resistance and voltage drop values given at 20 C (68f) Figure 10 - Table of recommended control circuit voltage drops * Most manufacturers of Soft Start type engagement systems take control of the critical
44、control circuit voltage drop requirements via an integrated magnetic switch and associated wiring as part of the starter assembly. The OEM is only responsible for a relatively low current (2A to 4A) circuit for the integrated magnetic switch control circuit. SAE INTERNATIONAL J3053 Issued JUL2015 Pa
45、ge 9 of 9 7. NOTES 7.1 Revision Indicator A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE TRUCK AND BUS ELECTRICAL SYSTEMS COMMITTEE
