Fuel evaporative emission control system

As of 2021, the number of fuel vehicles in China has reached 307 million.As the service life of a car increases, the fuel system ages and leaks are prone to occur.

Therefore, it is imperative to add the sealing test of the fuel evaporative emission control system to the routine testing items of motor vehicles!

According to the national standard GB18285-2018, fuel evaporation testing is only applicable to testing during registration and annual inspection of fuel vehicles; it is not applicable to the production line of new vehicles, nor is it applicable to testing by fuel tank cap manufacturers.

Partial interpretation of national standard GB18285-2018

Article 11 of the national standard GB18285-2018 clearly stipulates that this standard will be implemented from May 1, 2019.The original text is as follows:

11 standard implementation

11.1 This standard will be implemented from May 1, 2019.Periodic vehicle environmental inspections nationwide should be conducted using the simple working condition method specified in this standard. For vehicles that cannot use the simple working condition method, the double idle method specified in this standard can be used.

    11.1.1 Off-line inspection of new production vehicles will be implemented from November 1, 2019.

    11.1.3 The specific time for nationwide implementation of the limit b specified in this standard will be announced separately by the ecological environment department of the State Council.

11.2 From the date of implementation of this standard, the existing relevant local emission inspection standards will be abolished.

11.3 This standard is supervised and implemented by the ecological environment department of the State Council.

*The fuel evaporation detection system has not been officially implemented as of July 13, 2022.The specific implementation date is to be announced by the ecological and environmental protection department;

Appendix E2.1 of the national standard GB18285-2018 stipulates detailedoil inlet pressure test standards:

E.2.1 Oil inlet pressure test

E.2.1.1 The fuel evaporative emission control system stabilizes the initial pressure at 3500+250Pa for 120 seconds. If the pressure loss exceeds 1500Pa, the test result will be unqualified.The fuel evaporation control system should be separated from the fuel inlet and the hose clamp between the fuel tank and the activated charcoal canister.

E.2.1.2 Fast pass During the 20 to 120 second measurement period, if the pressure measured at any time exceeds the calculated result of the following formula, a fast pass decision can be made for the pressure test.

Appendix E2.2 of the national standard GB18285-2018 stipulates detailed Fuel tank cap test standard:

E.2.2 Fuel tank cap test

E.2.2.1 Pressure loss test

The pressure loss method has a 1L space at the top of the fuel level, and the pressure at startup is specified as 7000+250Pa. If the pressure loss exceeds 1500Pa during the 10-second test, the fuel tank cap test fails. E2.2.2 Leakage flow test

Under the condition of 7500Pa, the leakage flow should not exceed 60mL/min. The leakage rate measured by the flow method should be converted to the leakage rate under the standard state (23℃, 101.35kPa). If the leakage rate exceeds 60mL/min under the condition of 7500Pa, the fuel tank cap test fails.

Optimization of standards by local governments

 Heruis' solution

Instrument used for testing: HG-01 fuel evaporation detector

Specification parameters

1. Differential pressure detection method can eliminate the impact of ambient temperature on the stability of test results;

2. The sealing ring of each connector has a 2W life guarantee; it will automatically remind you to replace the sealing ring when it expires; to prevent the sealing ring from aging and affecting the stability of the test results.

3. The air storage tank stores the air source pressure in it to avoid the impact of external air source fluctuations on the air source pressure, and can reduce the temperature of the compressed air to the same as the ambient temperature;

Reason for choosing Hirays

HG-01 Advantages

• The detection accuracy can reach 0.1pa;

• The detection data can be saved for 15 years;

• Hirays fuel evaporation detector is highly integrated;

• Three major measures to ensure high stability of test results;