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VDA OEM Safety concept for R744-A/C-systems in passenger cars working group of VDA OEMs.

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Presentation on theme: "VDA OEM Safety concept for R744-A/C-systems in passenger cars working group of VDA OEMs."— Presentation transcript:

1 VDA OEM Safety concept for R744-A/C-systems in passenger cars working group of VDA OEMs

2 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG2 Safety barriers in the refrigerant cycle Safety requirements for the cabin, focus on evaporator Basic requirements Safety targets Content Standard R744-air-conditioning-system Safety requirements engine compartment Secondary safety measures / e.g. odorization Summary

3 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG3 Standard R134a vs. R744-A/C-system with high pressure relief device Compressor Accumulator Internal Heat Exchanger Evaporator Expansion device P/T Sensor Combined module Condenser Gascooler low pressure relief device

4 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG4 Basic requirements –Based on standardized R744-systems and components according to relevant standards (e.g. SAE J-doc) –Applicable from manually to automatically controlled AC-systems –Applicable to all car segments

5 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG5 Safety targets –To protect driver from loss of concentration and reaction –To protect all passengers from health problems –To protect persons (service personnel included) outside the vehicle from injury acc. Safety-Study of Risa Safety Analysis Ltd., VDA Wintermeeting 2002.

6 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG6 Safety barriers in the refrigerant cycle: Pressure and temperature limits Max. operating temperature 165°C short time 180°C (less 5 min.) Max. switch-on pressure 9,5 MPa Min. switch-on pressure 2,5 MPa Max. release pressure (high side) 17 MPa below SAE J639 Max. release pressure (low side) 13 MPa below SAE J639 Max operating (cut off) pressure 14 MPa Max. working pressure 13,3 MPa

7 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG7 Safety barriers in the refrigerant cycle –Limitation of discharge pressure and temperature –Pressure relief devices on high and low pressure side –Material strength to protect components against breaking and bursting according to SAE J639 –Compressor switch-on depending on pressure and temperature

8 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG8 Safety requirements for the cabin –No servicable refrigerant-side connection fitting inside the cabin –Mechanical fixing of the evaporator in- and outlet pipe inside the HVAC-unit –Safe evaporator –Low pressure side relief device

9 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG9 Definition of the “safe evaporator” –Fundamental safe, i.e. no breaking or bursting under any possible operating condition –Complete and further enhanced quality assurance for - design and testing (wall thickness, material and corrosion properties) - production (well known, industrialized, reliable flat tube design) - storage and transport - assembly and final inspection –Regular inspection of fulfilling introduced production standards and worker certification –Definition of leakage rates and leakage behavior

10 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG10 Safe evaporator: planning and design –Material selection –Definition of proper evaluation tests regarding increased safety aspects –Robust design of the evaporator and its in- and outlet pipe –Fundamental design

11 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG11 Safe evaporator: production –Full-automatic brazing of evaporator core, including in- and outlet pipe, in approved process –Life cycle test for each evaporator design: e.g. - pressure-impulse-test - corrosion-test - leak-test - burst-test –100%-leak test of evaporators in vacuum chamber at 9 MPa –100% leakage and functional testing of the final assembled HVAC units

12 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG12 Safe evaporator: transport and assembly –Full monitoring of storing and transport - at supplier - from supplier to OEM - at OEM –Proper assembly - cockpit mounting - connection of pipes - evacuation, charge and test of the refrigerant cycle - 100% functional test at end of line

13 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG13 Safety requirements for the engine compartment –Protective gear mandatory (goggles, gloves) –Special designed refrigerant connection fittings for a safe pressure release according SAE standards –High pressure side relief device –Service by trained personel only –Warning label to prevent DIY –R744 AC-loop components according SAE standards –Definition of maximum R744 charge on label –Service equipment and proceedings according SAE st.

14 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG14 Safe system superiority to secondary safety measures –VDA OEMs prefer safe designed systems more than “state of the art” components without enhanced safety through design, process and testing improvements –Design and production of the AC-loop has to avoid any hazardous failure => components according J-SAE –In case that SAE standards and design rules cannot be guaranteed, VDA OEM recommend secondary safety measures (Several possibilities)

15 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG15 Odorized R744 as possible secondary safety measure –Odorization of non smelling hazardous gases is state of the art (e.g. natural gas, liquefied gas, CO 2 for stationary fire extinguishers) –Odorization is an accepted safety measure by legislator and population since decades –Important criteria for selection: - Already accepted odorant for natural gas application Approved warning agent with field experience in handling and chemical properties - Odor different to any other smelling agent in car

16 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG16 Chemical properties of odorant (Odor S-Free©) –US and German MSDS available –Type approval as warning agent according E DIN –Main compounds are widely used acrylates (raw material in chemical industry, several tons/a) –Possibility to ventilate due to: - Zero ODP and GWP (EPA Paper „Draft Analysis of 1999 TRI Data) - Sulfur free –Certified for gas application according German standard DVGW An ISO certification is expected for 2008

17 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG17 Type approval and warning level for odorants –Definition: Warning level for odor is the medium odor intensity, at which every person with average possibility to smell and average physiological condition surely can detect the odorant. (Odor level 3) –Additional statistical tests: 113 testing persons evaluated the smell impression of Odor S-Free© in comparison to THT and TBM. The smell impressions have been similar. To quote: “ … Odor test carried out at the University of Karlsruhe proved the warning character of the sulfur-free odorant in direct competition with sulfur containing odorants and showed that this odor is well distinguishable from every day smells.“

18 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG18 Status of testing –Oil compatibility approved (high ppm for water and odorant) –Durability and long term chemical stability of odorant approved –Approval of no chemical reaction between odorant and R744 –Short term compressor tests showed no negative effects to materials of compressor –Compatibility between desiccant and odorant approved

19 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG19 Remaining issues –Design and testing - Long term compressor durability with odorized R744 - Final material compatibility with elastomers in AC-loop - Finalized purity standard for R744 odorized –Production - Infrastructure concept for R744 odorized in plant –Service - Supply chain for aftersales supply with R744 odorized - Purity standard with container and fitting definition

20 VDA OEM safety concept for R744-A/C-systems in passenger cars Tiger Team meeting 2008St. Wiedemann BMW AG20 Summary –FMEA according international standards of SAE J1739 and J2773 Safety Analysis –Applicable to - all car segments and - all A/C-systems according SAE standards –“safe evaporator” to protect driver and passengers –Appropriately higher safety than today –Basis is standard R744-A/C-system with safety installations to protect persons in and outside the car


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