Interpretation of payment instrument

What devices or procedures can be considered as payment instrument as per Art. 4(14) of PSD2.

The Central Bank of Member State A as competent authority (CA) in Member State A has received several notifications based on the Article 37 of PSD2. In those cases, CAs need to make a decision if a given solution meets the requirements of limited network exclusion. However to apply an exclusion first that solution should fall under the definition of one of the payment services described in PSD2. Mostly, it is issuing of payment instruments and/or acquiring of payment transactions. Therefore, the question occurred that a given solution (eg. a fuel card) based on the business model can be considered as payment instrument hence the CAs should consider the application of an exclusion. In the case of a given multinational oil company - as per the statement of the company - the fuel cards are not used for initiating the payment transaction, in other words there is no payment order given with the card itself, but there is an identification and an “authorisation” of the fact whether the oil company issued the fuel card has a deferred payment agreement with the card holder. After a certain period, a formal invoice is issued and the settlement of the invoice is done via a regular credit transfer.