The Hindu Business Line : The two plugs that sparked the controversy

Chennai, Sept. 3 The feud between Bajaj Auto and TVS Motor is getting more heated with claims and counterclaims made by both the companies. But what exactly is at the heart of the whole controversy? Two spark plugs.

At a glance, the two companies’ new engines and the technologies adopted – in the Bajaj Exceed’s DTS-Si engine and the TVS Flame’s CC-VTi engine – will seem to share more than the one controversial feature over which the two-wheeler manufacturers are trading punches.

They are both 125cc class engines, both employ a kind of swirl induction or intake to improve the quality of the air-fuel mixture in the combustion chamber and both employ twin spark plugs, instead of the single spark plug that is typically employed in single cylinder engines.

What Bajaj is contending to be a violation of its intellectual property is the use of twin spark plugs in the same format, with a similar configuration, and in a similar sized engine by TVS Motor in the latter’s forthcoming new bike – the Flame.

Bajaj patented its twin spark plugs technology called Digital Twin Spark Ignition (DTS-i) after the company’s in-house R&D successfully integrated the feature first into the Pulsar’s 150cc engine. The technology was later used in the bigger engines of the Pulsar and in Bajaj’s smaller engined Discover.

Twin spark ignition has been used by innumerable automobile companies (both car and two-wheeler manufacturers) to gain from the improvement in performance, increased fuel efficiency and reduced emissions that the technology offers compared to conventional single spark ignition.

Twin spark ignition has been used in technologically advanced engines by carmakers like Mercedes Benz in cars like the M-Class SUV and even in the super luxury Maybach’s engines. BMW has used twin spark ignition in its high-end (650cc+) bikes for improving their emissions compliance and Alfa Romeo has used twin spark ignition for tweaking the performance of its cars. Even the i-DSI engine in the Honda City that is sold in India incorporates twin spark plugs per cylinder.

In the conventional single spark plug-per-cylinder set up, the air-fuel mixture in the engine’s combustion chamber is not optimally burnt. Imagine a vertical cylindrical box area as the combustion chamber with one spark plug firing on one side. There are corners and areas on the other side where the flame front created by the single spark plug will not be able to reach. As a result, power delivered is lower than optimum, unburnt fuel is wasted, and there will be higher toxic emissions.

With two spark plugs that are digitally mapped for optimum performance under varied operating conditions, twin spark ignition with two flame fronts, such as the DTS-i technology of Bajaj, enables more complete combustion. This boosts power and reduces wastage, thereby improving fuel efficiency and lowering emissions.

Bajaj says it holds the patent in the Indian market for the use of twin spark technology in small automotive engines. TVS claims that an application for revocation has been filed against this patent.