Introduction
The Indian Patents Act, 1970 states the inventions that are not eligible to be patented in India under Section 3. Section 3(m) states, a “mere scheme or rule or method of performing mental act or method of playing game [is not an invention].” Recently, in Robert Bosch Limited v. Deputy Controller of Patents and Designs1 , the Madras High Court discussed key aspects of patentability under Section 3(m), particularly concerning claims related to a method of preheating and controlling a temperature of fuel injected into a combustion engine. This blog provides a detailed case analysis of the judgement.
Details of the Case
| Details | Description |
| Case Title | Robert Bosch Limited v. The Deputy Controller of Patents and Designs |
| Date of Judgment | March 25, 2025 |
| Court | Madras High Court |
| Application Number | 201944047460 |
| Reason for Refusal | Invention not making any product, a pure method which is merely theoretical in nature, fell under Section 3(m) |
| Parties to the Case | Petitioner: Robert Bosch LimitedRespondent: The Deputy Controller of Patents and Designs |
| Equivalent Citation | CMA(PT)/1/2024 |
| Author of the Judgment | Hon’ble Justice Mr. Senthilkumar Ramamoorthy |
For reference, rejected claim 1 of the application is quoted below:
“A method of preheating and controlling the temperature of fuel injected into a combustion engine, comprising: an electronic fuel injection control unit in the engine, at least one fuel-heating device (3) positioned in contact with the fuel; at least one fuel-heating control unit (6) connected by means of at least one data connection to the electronic injection control unit (9), and electrically connected to at least one fuel-heater (3), where the fuel-heating control unit (6) controls the operation of at least one fuel heater (3); characterized by comprising the stages of: turning on the heating system; measuring an initial temperature of the fuel (tinc) upstream of the heater (3); measuring an ambient temperature (tamb); reading a target temperature of the pre-heated fuel (tpre) downstream of the heater; comparing…”
Issues before the Court
Whether the claimed invention is excluded from patent protection under Section 3(m) of the Indian Patents Act, 1970?
Contentions of the Appellant
The Appellant contended that the Controller’s impugned order is invalid due to a lack of application of mind, arbitrary reasoning, and a failure to evaluate the information presented on the record, rendering it unsustainable in law. Appellant claimed that this rejection of the patent application was primarily based on the incorrect judgement that the claimed invention comes under the exclusion under Section 3(m) of the Patents Act of 1970, without a proper analysis of its technical merits of the invention.
Contentions of the Respondent
The Respondent contended that the claimed invention is in respect of a method claim and is theoretical in nature since it does not make any product.
The Respondent in his rejection order had held, “the applicant has not developed any part in the fuel system but developed a method of controlling temperature of the fuel before injecting it into the engine in order to raise the efficiency of the engine. The applicant has only developed a methodology but not carried out any modification in the already existing working of the engine. According to him if we can preheat the fuel (based on the temperature difference between fuel in the engine and outside temperature) to a desired temperature, we can increase the efficiency of the engine. It may be so, that by following step of instructions of the alleged invention one can achieve desired/ enhanced efficiency of the fuel engine. Hence industrial applicability may be there, but Applicant is not making any product. The method he is claiming is merely theoretical in nature and not getting any product out of this.”
Observation and Decision of the Court
The Court clarified that Section 3(m) of the Indian Patents Act, 1970, is intended to exclude mere schemes, rules, or methods of performing a mental act or playing a game. If the respondent’s interpretation were accepted, all method claims would be excluded, contradicting the Patents Act, which allows both product and process claims.
Upon reviewing independent claim 1, which pertains to a method for pre-heating and controlling the temperature of fuel injected into a combustion engine, the court found that it involves a set of inventive steps and cannot be seen as just a mental act. Accordingly, the court held that said invention does not fall within the scope of Section 3(m) of the Indian Patents Act.
However, the Court maintained that the lack of inventive step objection was raised in the hearing notice and must still be examined. Consequently, the matter was remanded for reconsideration under the following terms: First, a different Controller, not the one who issued the impugned order, must conduct the reconsideration of the application to avoid biasness of the case. Second, the reconsideration must focus only on objections other than Section 3(m) that were outlined in the hearing notice. Third, the Appellant must be given a reasonable opportunity to present arguments before a reasoned decision is issued within four months from the date of receipt of the impugned order.
Our Analysis and Conclusion
The Controller’s refusal of the patent application under Section 3(m) appears to stem from a fundamental misapplication of the provision. Section 3(m) excludes only “a mere scheme or rule or method of performing mental act or method of playing game.” It does not exclude all method claims or technical processes. The phrase “mere method” refers to non-technical, abstract, or mental processes. However, the Controller misinterpreted this provision to apply broadly to a method that, while not yielding a product per se, involved a clearly defined technical process implemented through hardware and control logic.
The Controller’s reasoning was that because the invention did not “make any product” and only provided a “methodology,” it was merely theoretical. However, this ignores Section 2(1)(j) that accept process (or method) claims as patentable subject matter, provided they are novel, inventive and capable of industrial application. Moreover, the applicant provided detailed steps, sensor-based measurements, power calculations, and interactions with engine components—none of which resemble a mere mental act. Furthermore, the assertion that “no product is made” is legally irrelevant to the patentability of a method claim. Process patents are not required to yield a tangible product; rather, they must demonstrate a novelty, inventiveness and industrial applicability, all of which were sufficiently demonstrated.
The Madras High Court rightly identified this flaw. Justice Senthilkumar Ramamoorthy clarified that Section 3(m) should not be stretched to exclude all method claims, as doing so would undermine the very structure of the Patents Act, which recognizes both product and process patents. The Court correctly found that the claimed invention is a technical process and not a mental act. Therefore, Section 3(m) was not applicable.
This ruling is significant because it reinforces the principle that method claims are not per se excluded under Section 3(m). The judgment offers stronger clarity, ensuring that technical methods are assessed on their merits and not arbitrarily excluded based on an overly narrow interpretation of statutory exclusions.
References
- [1] CMA(PT)/1/2024 ↩︎