ISO 20574:2019 download.Road vehicles – Durability test method for starter motor for stop and start system.
3.7
battery simulator
electrical power supply equipment which simulates battery behaviour
3.8
engine mount
mechanical frame to support engine and gearbox
3.9
number of test start cycles
counted durability test start cycles
3.10
remaining brush length
length of brush alter the test
3.11
usable brush length
length of brush that is available to be consumed
3.12
initial brush length
length of brush before starting the test
3.13
vehicle manufacturer
company which designs and produces vehicles
3.14
engine manufacturer
company which designs and produces Internal combustion engines
3.15
starter motor manufacturer
company which designs and produces starter motors
3.16
cranking
condition in which the starter motor rotates the engine
3.17
overrunning
condition in which the engine rotates the starter motor pinion belore starter motor OFF
3.18
engine ECU
electronic control unit for controlling Internal combustion engine operation
3.19
starter solenoid
electromagnetic component of starter motor to move pinion and to switch electric motor
3.20
bl.control solenoid
starter solenoid which is able to control separately pinion movement and to switch electric motor
3.21
bench controller
device which is capable olcontrolling required test bench functions
3.22
nominal power
P.101n
power declared by the starter motor manulacturer corresponding to the maximum power output at the reference temperature when determined according to ISO 8856
3.23
battery Internal and line resistance
RBL
sum of power supply (battery or battery simulator) rnternal resistance and total resistance ol external line (positive and negative sides and connections)
3.24
device under test
OUT
starter motor used for durability test
3.25
change of mind CoM
start event before complete engine stall
3.26
starter motor voltage
voltage at battery terminal of starter motor
3.27
starter motor current
ISTR
current drawn by starter motor
3.28
starter motor open circuit voltage
UOSTR
voltage at starter motor terminals without electrical load
3.29
virtual starter motor voltage
UOSTRV
virtual starter motor voltage at GA derived from V.1 curve
3.30
battery internal resistance
RB
power supply (battery or battery simulator) resistance
3.31
line resistance
Rt
total resistance of external line (positive and negative sides and connections)
3.32
front end accessory drive
FEAD
equipment driven by belt which is connected to engine
3.33
starter motor temperature at control point
temperature measured at defined control point Iocaton
EXAMPLE At starter motor yoke surtace
3.34
temperature of starter motor brush
temperature measured inside of starter motor brush
3.35
pinion to ring gear axial gap dpr*
axial distance from front surface of pinion to ring gear at rest condition
3.36
starter motor input curve VI curve
straight line calculated Irom starter motor voltage vs starter motor current diagram defining staret motor input conditions
4 Planning of durability test
4.1 DetermInation of durability test types
The durability test is performed with an engine simulator or an engine, The followmg test types can be selected, See Table 1 for comparison of each test type.
1) Engine, using bench controller to control fuel/spark to specifically achieve pre-determined cranking time and overrunning time (see TabIe3).
2) Engine, using its engine ECU to control the test parameters.
3) Engine simulator, using engine waveform data provided by engine and/or vehicle manufacturers as input to simulator (for cranking time, overrunning time, or torque) (see Table 3).
4) Engine simulator, using synthetic pattern or engine simulation model where starter motor manufacturer or engine and/or vehicle manufacturers define values for torque, cranking and overrunning behaviour (see Table 3).
The following items should be specifically considered:
I) In case of engine simulator, multiple starter motors can be tested simultaneously with the same ring gear. In that case, the orientation of the starter motors deviate from those of the target application. Hence, the usage of multiple starter motors shall correspond to the test purpose (e.g. verification of brush durability but not verification of pinion and ring gear durability),
2) The starter motor manufacturer and engine and/or vehicle manufacturers should agree starter motor temperature level during the durability test. Different approaches to deline temperature level are established.
For example:
— test at maximum brush temperature defined by starter motor manu1acturer
— test at maximum brush temperature derived from vehicle real drive cycle; and
— test at an average brush temperature derived from brush temperature distributions of vehicle real drive cycle.
Each approach covers different testing purposes such as focusing on thermal stress, test duration, mechanical loads or balanced field representation.
3) The starter motor manufacturer and engine and/or vehicle manufacturers should define the test pass criteria and define test stop criteria according to Table 6.
4) Additional test conditions may be defined and shall be documented In test planning matrix.
For example:
— always using “100% new battery for every test;
— testing with maximum pinion to ring gear axial gap; and
— number and orientation of starter motors mounted to engine simulator ring gear.
6 Detailed test procedures
6.1 Test procedure
6.1.1 General
The structure of test benches are shown In Annex A. Annex and Annex C. depending If testing will be done with an engine, or an engine simulator.
The test procedure (or the durability test shall consist of four stages, shown below.
1) Installation and setup stage for engine or engine simulator,
2) Pre-check stage.
3) Test execution stage.
4) Post-processIng and reporting stage.
The procedure shall he executed stage by stage.
6.12 InstallatIon and setup stage far engine or engine simulator
In this stage, the following steps shall be conducted.
1) The engine and gearbox shalL be mounted on the appropriate engine mount.
2) The engine fluids (e.g. engine oil, coolant) shall be filled and checked according to vehicle and /or engine manufacturer specifications.
3) A dummy starter motor other than the DIJT shall be mounted to engine or engine simulator. dprg shall be set to appropriate value and verified according to Z4.
4) Before cranking the engine, a fluid leakage check shall be performed. In case a leakage Is detected, starter motor shall not be operated.
S) The measurement equipment shall be installed.
6) All electrical connections shall be installed and checked for verifying proper coupling and no damages.
NOTE Electrical connections Include digital signals, analogue signals, measurement cables and electrical power supplics.
7) To control the starter motor temperature at control point, a cooling system or cooling fan shall he installed.
B) The test bench shall be initialized. Initialization includes switch on electric equipment, boot up software and check measurement values.
9) The target parameters shall be SCL Parameters include control timings and rotational frequencies. V-I parameters and temperatures. II parameters are not matching to the agreed test setup, the parameters shall be adjusted.
10) The readiness for operation and runnability of the engine shall be checked,
6.1.3 Pre-check stage
In this stage, the following steps shall be conducted.
1) The dummy starter motor shall be changed to the calibration starter motor. The calibration starter motor Is used to calibrate the temperature control system for the test.
2) Starter motor input V-I curve shall be adjusted according (072.
3) All test conditions shall be once again checked. If test conditions are not matching to the agreed test setup, the parameters shall be adjusted according to Tab]2.
4) The starter motor cooling system (e.g. external fans) shall now be calibrated according to 71,.
5) If all steps were taken, the durability test Is ready to be executed,
6.1.4 Test execution stage
In this stage, the Following steps shall be conducted.
1) Brush length of OUT should either be measured or specified nominal brush length should be used and recorded according to 71.
2) The performance of the OUT shall be tested with agreed starter motor Input according to ISO 8856.
3) The calibration starter motor shall be changed to OUT.
4) Initial conditions shall be documented, refer to MuwzD Items,
5) All the channel list items and their data recording rates shall be verilied.
6) The durability test shall be started.
7) During test execution stage the parameters U SIR and Ri shall be checked periodically by calculating the V.1 curve, The data recording rates, and upper and lower limit shall be defined in the test planning matrix according Tahlr 2. (3/3).
The test shall be stopped when one defined test stop criteria is reached (see Table6). If criteria cannot be brought back into the defined range, the test shall be finished. Each time when the test is stopped, it shall be documented.