QC/T 727-2007Instruments for automobiles and motorcycles (English PDF)

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°C~28°C 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 °C. 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.