54. As was discussed in the first part of the meeting on the previous day, the modular structure of the draft has been suggested, providing three different type of approvals:
1) approval of a HDDF retrofit system;
2) approval of a HDDF retrofitted engine; and
3) approval of a HDDF retrofit vehicle regarding the installation of a retrofit HDDF engine.

The main text includes scope, general provisions and general definitions. All specific topics regarding the three different (above mentioned) approvals have been moved to the appropriate Annexes in the first draft text produced by AEGPL.

55. The group expressed concerns about possible loopholes with respect to R49 when approving a HDDF retrofitted engine and HDDF retrofit vehicle with a retrofitted HDDF engine. Since the most important part is related to HDDF retrofit systems, the group decided to delete Annex 2 and Annex 3 from AEGPL proposal and to develop Annex 1. Future meetings will focus on and complete the discussion on HDDF retrofit systems. The group agrees to take the AEGPL text as starting point for further development.

56. The Annex 1 (HDDF Retrofit systems) of AEGPL proposal was presented. Mr. Castagnini explained the difference between updated text and previous versions.

57. Specific retrofit systems definitions (definitions applicable only to HDDF retrofit systems) were moved from the main text to Annex 1, in order to avoid confusion with other type approvals. The requirements to allow parent engines not meeting the baseline emissions would be enforced. OBD data should be monitored and no detected malfunction shall be active. The group recognized the difficulties of finding an existing engine that meets the emission limits, especially if the engine was certified to a previous emission level than the current Euro level. But the importance of having the engine fulfill the baseline emission limit is clearly recognized. The group agrees to find a solution to this challenging problem.

58. A general discussion took place about the ability to find a diesel engine in compliance with the emissions limits and the impacts of performing a conversion to dual-fuel, as well as how to include this in regulatory language (if possible). System suppliers spend a great deal of money and energy trying to find compliant engines that can be converted if they are going to improve the emissions over diesel. There are a variety of solutions possible but in this forum there was general brainstorming solutions proposed. For example, Mr. Bleuler (TUV) proposed to allow wider engine family definitions in order to reduce the difficulties of finding parent engines that are in compliance with baseline emission limits.

59. AEGPL: If it is agreed that the original emission limits must be maintained (or improved) in the dual-fuel mode even when the parent engine is not compliant in the diesel mode, AEGPL asked to evaluate the possibility, in these cases, to allow for some tolerance of the limits in line with those accepted during COP or ISC (to be investigated). In addition, creating a less stringent engine family definition would ease the practical problems faced by retrofit system manufacturers when searching for compliant diesel engines.

60. Annex 1: OBD requirements have been defined. Since there is no communication between the ECU and dual-fuel ECE, a switch back to diesel mode is prescribed in case of any detected malfunction.

61. Annex 1: Extension of the application range requires a simplified test sequence that can be performed either on a representative engine equipped with the HDDF retrofit system or on a vehicle equipped with the representative engine and the HDDF retrofit system (to be defined).

62. Annex 1: Installation manual shall consist of two parts: 1) describing the HDDF retrofit system and a list of components; and 2) installation instructions for the specific vehicle. This installation of the manual for the parent vehicle must be
supplied to the regulatory authority

63. Annex 1: End user manual informs the end-user about the characteristics and safety features of the installed HDDF retrofit system.

64. Other Annexes will be defined over time after the completion of Annex 1.

65. Written remarks received from AECC, John May. Annex 1, 3.1 were discussed (AECC was not able to be present at the meeting). “If the parent engine is not equipped with one or more devices listed above, engines with these devices are
allowed.” "In this case they should not be allowed to be part of the same engine family.” Mr. Dekker indicates that, in the light of their experience, sometimes a retrofitted engine in dual-fuel mode performs worse in the presence of EGR than in
absence, for instance. More discussion on the family definition is required.

66. Furthermore AECC mentioned in their written comments that they agree with the possibility to consider CH4 as a GHG contributor.

67. Annex 1: 6.3.2 Limit values and relevant pollutants for ESC and ETC cycles: that this needs to be clearer that this applies to the emissions both before and after retrofitting; that the manufacturer cannot be allowed to choose whether or not to include deterioration; and durability of the retrofitted system should have to be demonstrated, rather than simply taking assigned deterioration factors (DFs). There was a broad and general discussion of this issue.

68. AEGPL explained its proposal: The application of DF’s and the testing with deteriorated components (aged after a durability test as in REC) have to be an alternative in order to avoid a double durability burden. This is based on the consideration that R. 49 DF’s (05 and 06 series of amendments) in the dual-fuel mode have been confirmed to be identical to those applied in diesel mode. In other words, the language for the OEMs allows them to choose to include deterioration factors, so why not the retrofitters as well?

69. Discussion: if the concern regards the guarantee that the retrofit system is generically durable, the respect of endurance testing and requirements set out in R67/01 and R 110 could be already satisfactory. As for environmental aspects, that observation offers also an alternative solution to the application of DF’s: engine emission tests could be carried out fitting gas components aged in accordance with R67/01 or R 110 endurance tests. But this requires further discussion. There are concerns about the complication and the cost of the testing protocols that would be imposed on retrofit suppliers.

70. Mr. Rijnders indicated that the AECC remarks are valid and further discussion will be required.