T 1198/10 11-07-2013

Reasons for the Decision

1. The appeal is admissible.

2. Non-admittance of D11 and D12

2.1 Although the appellant argued that D11 and D12 should already be in proceedings or, if not, should then be admitted into the appeal proceedings, the Board decided not to admit these for the following reasons.

2.2 In its communication sent prior to oral proceedings, the Board had already expressed its preliminary opinion that the opposition division correctly exercised its discretion in not admitting these documents into proceedings, based on its conclusion, which was reasoned in the decision, that they were found not to be sufficiently relevant. The argument offered by the appellant that, due to the opposition division's communication prior to oral proceedings provisionally considering novelty and inventive step to be present, whereby it had needed to conduct a further search, has little relevance here. Not only does a provisional opinion by an opposition division concerning documents on file not immediately give rise to any justification for performing a search to find further documents, but the opposition division anyway did not exclude D11 and D12 merely on the basis of their filing at a late stage of proceedings, but specifically due to their lack of relevance.

Also, when considering the subject-matter of claim 1, they indeed do not disclose more features than other documents on file, in particular not "an intermediate position" and "a second position" providing specific first and second portions of exhaust gas flowing through the heat exchanger and the bypass duct.

2.3 Although D12 discloses an intermediate position ("Zwischenstellung" (col. 3, line 68)), it is not further explained how this position is to be controlled. In D11 the pressure drop is controlled digressively depending on the volume flow through the heat exchanger, and upon reaching a certain limit the flow is stopped (claims 1 and 2). This limit however is an engine temperature dependent factor (claim 3) which has no relation to the pressure drop within the heat exchanger system. These documents thus lack all relevance to the issues of novelty and inventive step with respect to the subject-matter of the claims.

In its response subsequent to the Board's communication, the appellant did not contest the correct use of discretion by the opposition division, but argued instead simply that D11 and D12 were not only relevant to novelty but also to inventive step. However, the reasons already given above are not overcome by this argument, and the appellant supplied no further reason as to why the Board's preliminary opinion on this matter should indeed be altered. Thus, the Board remains of the opinion that the opposition division exercised its discretion correctly such that D11 and D12 were correctly not admitted into the proceedings.

2.4 The appellant's further line of argument that D11 and D12 should then be admitted into the appeal proceedings because they had been filed with the grounds of appeal is also not convincing. First, documents which have not been admitted into proceedings before an opposition division on the exercise of its discretion, which is subsequently found by the Board to be a correct exercise of discretion, cannot then normally be allowed into the proceedings during appeal either (see also G7/93, Reasons 2.6), since this would otherwise defeat the object of the exercise of the opposition division's discretion not to admit them. Appeal proceedings in an inter partes case are not intended to be an opportunity simply for continued examination of an opposition, but instead are mainly to give the losing party a possibility to challenge the decision of the opposition division on its merits (see e.g. G9/91, Reasons 18).

The appellant cited T 609/99 in support of its case for admittance of D11 and D12. However, the facts of the case are quite different. In T 609/99 (see Reasons 2.2 and 2.3) the legal and factual framework of the opposition proceedings was considered not to be enlarged, as the late-filed citation related to physical principles available to the skilled person which helped to promote convergence of the debate in that case, and for that reason the Board found it unreasonable not to admit it into the proceedings. In the present case, D11 and D12 clearly go outside the legal and factual framework existing on filing the opposition and no convergence of the debate has occurred, rather new lines of attack.

Lastly, the hurdle to have documents admitted at an even later stage (in appeal proceedings) is clearly such that the documents need to be prima facie highly relevant in the sense that revocation of the patent would be highly probable if the documents were admitted. This, is clearly not the case here as already evident from item 2.2. above, where this Board anyway explained that the documents were considered even not to be more relevant than documents already on file due to the fact that no more features were disclosed in D11 and D12 compared to the documents already on file.

3. Novelty (Article 54 EPC 1973)

3.1 In respect of D4 the appellant argued that, although this document disclosed a control of the exhaust gas flowing through the heat exchanger duct and the bypass duct by different valves, the method according to claim 1 did not exclude the use of two valves. Also, the heat exchanger caused a flow restriction leading to elevated back pressure, and there were a number of sensors detecting those parameters for controlling the valves by the control electronics. Thus the skilled person reading D4 would recognize that all the steps of the claimed method were already disclosed in that prior art document.

3.2 Contrary to the appellant's assertion, the Board finds that in its decision, the opposition division concluded correctly that the method of claim 1 was novel when compared with D4. In D4 there is no explicit or implicit disclosure of monitoring by direct or indirect means a pressure drop across the heat exchanger system (feature (d)). In this regard it should be noted that the back pressure depends on several parameters such as the load of the engine and the flow distribution between the heat exchanger duct and the bypass duct, such that a change in the pressure across the heat exchanger system in the understanding of the skilled person cannot be derived from the measurement of the back pressure.

3.3 The appellant asserted that D10 related to a system for controlling the exhaust gas flow which had a structure identical to that used in the method claimed and it used the same method steps. Although the structure is similar to that shown in the patent, the Board finds that at least features (c) and (d) are not clearly and unambiguously disclosed in D10.

As regards feature (c), namely "switching the valve (10) into a first position in which the entire exhaust gas flows through the heat exchanger duct (5)", D10 discloses on page 2, lines 6 to 8 "... which method comprises progressively closing at least partially said bypass duct to divert at least a proportion of exhaust gasses through said heat exchanger ...". No indication is present that the valve is switched nor that it is brought into a fully closed position (which is required if the "entire" exhaust gas is to flow through the heat exchanger duct; a matter which was not contested). In respect to feature (d), no disclosure can be derived, either explicitly or implicitly that a pressure drop is monitored by direct or indirect means across the heat exchanger system. The appellant relied on D10 (page 1, lines 5 to 9) according to which the flow through the ducts is controlled such that the pressure upstream of the valve is at a requisite level. However, a particular pressure drop in the heat exchanger duct is not identifiable from this back pressure because it depends on the engine load and the partially closed or opened valve controlling simultaneously both the heat exchanger duct and the bypass duct and not only distributing the gas flow between those two ducts as claimed.

4. Inventive step (Article 56 EPC 1973)

4.1 The appellant's attack against inventive step started from D10 as closest prior art. However, no objective problem underlying the subject-matter claimed was formulated by the appellant. The respondent saw the problem to be solved as being the provision of a simpler method of controlling a valve in an exhaust gas heat exchanger system for a combustion engine. The Board agrees with the problem formulated by the respondent.

4.2 The appellant asserted first that the structure of the control system according to D10 was similar to that of the patent. The skilled person having general knowledge in the technical field of controls would understand the indication given in D10 that the bypass duct was at least partially closed, in the sense that it could also be completely closed (page 2, lines 6 to 7). Further, since fully closing the valve did not require closed loop control, an open loop control could be used. The introduction section in that document also clearly indicated that the upstream pressure of the valve played an important role in the control of the valve. The upstream pressure was measured by suitable means (page 7, lines 20 to 22), and in view of the availability of such sensors, the skilled person would allegedly also consider the measurement of the pressure drop across the heat exchanger as the same result would be achieved as with back pressure.

4.3 Applying the usual problem-solution approach, the Board cannot follow the appellant's argument. Even assuming that the skilled person were familiar with the different kinds of control, any indication in D10 or the further cited prior art documents is missing as to why the closed loop control used in D10 allowing the control of the valves in a variety of ways (page 7, line 14) should be replaced by a simpler open loop control without the exercise of inventive skill. Merely because two methods of control are known generally (as exemplified by D13, which was anyway not a matter of dispute per se), does not mean that one would necessarily be used to replace the other wherever desired.

According to D10 and the further cited documents D1 to D9 relating to the control of valves in exhaust gas heat exchanger systems, none of these indicates monitoring a pressure drop across the heat exchanger. Even assuming that the back pressure caused by the rising flow resistance within the heat exchanger necessarily had some influence on the total back pressure upstream of the control valve, no direct conclusion in respect of the pressure drop across the heat exchanger can be drawn from that resulting change in the back pressure because there are further parameters having influence on the back pressure. Consequently none of the prior art cited teaches the monitoring of the pressure drop across the heat exchanger either directly or indirectly, let alone for the specific control purpose as claimed.

In regard to the appellant's attack against inventive step regarding D1 and D2, the Board had already stated in its communication issued before oral proceedings, with reference to Article 12(2) RPBA, that it had been presented with no express argument by the appellant in regard to the reasons given in the decision under appeal as to why this finding was incorrect. No reply was made by the appellant in that regard either in writing or at the oral proceedings. The Board thus confirms its provisional view that it concurs with the opposition division on this matter.

Therefore the Board concludes that the method according to claim 1 has to be considered as involving an inventive step. The dependent claims relate to particular embodiments of the invention and the Board has been given no reason independent to the argument against claim 1 as to why those claims could not also be maintained as granted.