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This standard is a revision of QC/T 727-2004.
The following main changes have been made with respect to QC/T 727-2004:
——the content of the product classification is modified, and the scope of instruments is redefined (Clause 3 of 2004 Edition, Clause 3 hereof);
——the minimum division value of the tachometer for automobile is modified (4.2.2 of 2004 Edition, 4.2.2 hereof);
——the content of the basic error is modified (4.5 of 2004 Edition, 4.5 hereof);
——the content of the pointer response time is modified (4.6 of 2004 Edition, 4.6 hereof);
——the heating and quenching of temperature sensor is deleted (4.7 and 5.8 of 2004 Edition);
——"comply with the requirements of 4.5" is added (4.12, 4.14, 4.16, 4.17, 4.18, 4.19 and 4.21 of 2004 Edition, 4.11, 4.13, 4.15, 4.16, 4.17.18 and 4.21 hereof);
——the temperature influence is modified (4.13 of 2004 Edition, 4.12 hereof);
——the temperature influence requirements of the thermometer are added (see 4.12.5 hereof);
——the content of the temperature influence is modified (4.13 of 2004 Edition, 4.12 hereof);
——the content of the voltage influence is modified (4.15 of 2004 Edition, 4.14 hereof);
——the content of the durability test is modified (4.20 of 2004 Edition, 4.20 hereof);
——4.20.7 of 2004 Edition is deleted;
——the “electronic components” in the note to the insulation voltage withstand test is modified to “semiconductor devices” (5.9 of 2004 Edition, 5.8 hereof);
——the "basic error test of speed meter" is modified to "basic error test of speedometer" (5.3.6 of 2004 Edition, 5.3.6 hereof);
——"the basic error and indication state are checked" is modified to "the indication state and value are checked" (5.10, 5.11.2, 5.11.3, 5.12, 5.14, 5.15, 5.16.2, 5.17 and 5.20 of 2004 Edition, 5.9, 5.10.2, 5.10.3, 5.11, 5.13, 5.14, 5.15.1.2, 5.17 and 5.21 hereof);
——“the speedometer may be taken out of the box for test immediately” is modified to “the instrument may be taken out of the box for test immediately” (5.11.3 of 2004 Edition, 5.10.3 hereof);
——the requirements for test point of the "power supply overvoltage test" are added (see 5.14);
——the content of the voltage interference is modified (4.19 and 5.16 of 2004 Edition, 4.18 and 5.15 hereof);
——the electromagnetic immunity test is added (see 4.19 and 5.16);
——the content of the test methods is modified (5.1, 5.3, 5.5, 5.7, 5.13, 5.16, 5.18 and 5.19 of 2004 Edition, 5.1, 5.3, 5.5, 5.7, 5.12, 5.15, 5.18, 5.19 and 5.20 hereof);
——the "voltage interference test" in Note 2 to sampling and grouping is modified to the "electromagnetic immunity test" (6.5.2 of 2004 Edition, 6.5.2 hereof).
This standard was proposed by and is under the jurisdiction of the National Technical Committee of Auto Standardization.
The previous edition of the standard replaced by this standard is as follows:
——QC/T 727-2004.
Instrument for automobile and motorcycle
1 Scope
This standard specifies the classification, requirements, test methods, inspection rules, marking, packaging, storage and preservation of instruments for automobile and motorcycle (hereinafter referred to as instruments).
This standard is applicable to speedometer, tachometer, fuel gauge, thermometer, pressure gauge, voltmeter and ammeter for automobile and motorcycle. It may also be referred to for instruments for other motor vehicles.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB/T 191 Packaging—Pictorial marking for handling of goods
GB/T 2423.10 Environmental testing for electric and electronic products—Part 2: Test methods—Test Fc and guidance: Vibration (Sinusoidal)
GB/T 2423.17 Basic environmental testing procedures for electric and electronic products—Test Ka: Salt mist
GB/T 2423.22 Environmental testing for electric and electronic products—Part 2: Test methods—Test N: Change of temperature
GB/T 2423.34 Environmental testing for electric and electronic products—Part 2: Test methods—Test Z/AD: Composite temperature/humidity cyclic test
GB/T 2828.1 Sampling procedures for inspection by attributes—Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 8170 Rules for Rounding Off of Numerical Values
GB/T 17619 Limits and methods of testing for immunity of electrical/electronic sub-assemblies in vehicles to electromagnetic radiation
GB/T 21437.2-2008 Road vehicles—Electrical disturbances from conduction and coupling—Part 2: Electrical transient conduction along supply lines only
QC/T 238 Storage and preservation for automotive parts
QC/T 29106 Technical specification of low-voltage electric harness for motor vehicles
3 Product classification
It is divided by function into speedometer, tachometer, fuel gauge, thermometer, pressure gauge, voltmeter, ammeter, and so on. See Table 1 for classification by implementation mode.
Table 1 Classification
Type Implementation mode
Electronic Digital
Analog
Electrical Electromagnetic
Moving magnetic
Bimetallic
Mechanical Magnetic inductive
Spring tube
4 Requirements
4.1 General requirements
4.1.1 Product documentation.
4.1.1.1 The instruments shall comply with the requirements of this standard, and shall be manufactured in accordance with the drawings and design documents approved through established procedures.
4.1.1.2 The shape, installation dimensions and markings of the instruments shall comply with the requirements of the product drawings.
4.1.1.3 The low-voltage electric harness used in the instruments shall comply with the requirements of QC/T 29106.
4.1.2 Normal operating environment conditions:
Temperature Relative humidity Air pressure
18℃~28℃ 45%~75% 86 kPa~106 kPa
4.1.3 Temperature range:
The operating temperature and storage temperature range are shown in Table 2.
Table 2 Temperature range °C
Operating temperature range Storage temperature range
Lower limit Upper limit Lower limit Upper limit
-30 65 -40 75
4.1.4 Operating voltage range:
The operating voltage range of the instruments is shown in Table 3.
Table 3 Operating voltage range V
Nominal voltage Operating voltage range
Umin Umax
12 10.8 16
24 21.6 32
4.2 Unit and division
4.2.1 For speedometer, the speed is generally expressed in km/h, and the mileage is expressed in km. The minimum division value of speed shall be no more than 10 km/h.
4.2.2 For tachometer, the rotating speed is generally expressed in r/min. The minimum division value of the tachometer for automobile shall be no more than 500 r/min, and that of the tachometer for motorcycle shall be no more than 1 000 r/min.
4.2.3 For ammeter, it is generally expressed in A. In principle, four divisions are specified: negative upper limit—negative median—zero—positive median—positive upper limit.
4.2.4 For voltmeter, it is generally expressed in V. In principle, there shall be no less than two divisions: lower limit—median—upper limit. It is also possible to use L to represent the lower voltage limit and H to represent the upper voltage limit.
4.2.5 For fuel gauge, the fuel level is expressed based on the position of its sensor float. In principle, there shall be no less than two divisions: 0 (Empty)—1/2—1 (Full). It is also possible to use E for empty, and F for full.
4.2.6 For thermometer, it is generally expressed in ℃. In principle, there shall be no less than two divisions: lower limit—median—upper limit. It is also possible to use C to represent the lower temperature limit and H to represent the upper temperature limit.
4.2.7 For pressure gauge, it is generally expressed in MPa. In principle, there shall be no less than two divisions: lower limit—median—upper limit. The intermediate pressure value is approximately 1/2 of the upper pressure limit.
4.3 Appearance
4.3.1 The protective layer shall be uniform, with no obvious defects such as bubbles, spots, rust and shedding.
4.3.2 Glass or other transparent materials shall not have scratches and refractions that affect accurate readings.
4.3.3 The graduation lines, symbols, numbers and other marks on the dial shall be clear and intact.
4.3.4 The exposed part of the instrument shall not have dazzling luster.
4.3.5 When the bimetallic instrument is out of service, its pointer shall be below or may also touch the initial graduation line; when the mechanical instrument is out of service, its pointer shall be at the stop and never deviate from the initial graduation line.
4.3.6 For speedometer, the numbers on the digital dial used to record the traveling mileage shall be completely arranged in the mileage counting window. For mechanical mileage counter, the numeral color indicating the integer mileage and the decimal mileage shall be clearly distinguishable. For digital mileage counter, the integer part and the decimal part shall be clearly distinguishable. The accumulated mileage at the time of delivery shall not exceed 10 km.
4.4 Indication state
When the signal changes stably, the pointer motion shall be smooth without jamming. For digital instruments, when the signal changes stably, the displayed value shall change accordingly and be normally displayed. At a constant angular speed, the tachometer pointer is within the range of 20% to 80% of the upper rotating speed limit of the scale, and the speedometer pointer is within the range of more than 20 km/h to 80% of the upper scale value, and the amount of swing shall be within ±1% of the upper limit.
4.5 Basic error
4.5.1 Under the environmental conditions specified in 4.1.2, the basic error of the pressure gauge shall not exceed the following:
The basic errors of the intermediate pressure and upper pressure limit of the scale of electrical pressure gauge and electronic pressure gauge with pointer are ±6% of the full arc length of the scale.
The basic errors of the intermediate pressure and upper pressure limit of the scale of mechanical pressure gauge are ±4% of the upper pressure limit of the scale.
Note: The basic error of the digital pressure gauge is agreed by the supplier and the purchaser.
4.5.2 Under the environmental conditions specified in 4.1.2, the basic error of the ammeter shall not exceed the following:
The basic error of the ammeter shall not exceed ±7.5% of the sum of absolute values of the two upper limits of the scale.
4.5.3 Under the environmental conditions specified in 4.1.2, the basic error of the speedometer shall not exceed the following:
4.5.3.1 The basic error range of the indicated speed shall comply with the requirements of Table 4.
4.5.3.2 The basic error range of the odometer shall be within 2%.
Table 4 Basic error of speedometer km/h
Indicated speed Actual speed
20 17~23
40 35~40
60 55~60
80 75~80
100 95~100
120 114~120
140 133~140
160 152~160
180 171~180
Note 1: The basic error of the speedometer at a higher speed is agreed by the user and the manufacturer.
Note 2: The error of the upper limit is not assessed.
Note 3: When the user has special requirements, the basic error may also be checked according to the enterprise standards or user requirements approved through established procedures.
4.5.4 Under the environmental conditions specified in 4.1.2, the basic error of the tachometer shall not exceed the following:
The basic error of the magnetic inductive tachometer shall not exceed ±3% of the upper limit within the range of 20% to 90% of the upper limit of the scale.
The basic error of the electronic tachometer shall comply with the requirements of Table 5.
Foreword i
1 Scope
2 Normative references
3 Product classification
4 Requirements
5 Test methods
6 Inspection rules
7 Marking, packaging, storage and preservation
