Why Maruti Killed The Diesel Engine: Real Reason Revealed

maruti suzuki's fatal diesel engine design error

Maruti Suzuki, India’s biggest car manufacturer, offers a variety of models in the Indian market. They currently offer cars with petrol engines only. However, this was not always the case. They used to offer several models with a Fiat-sourced 1.3-litre turbo diesel engine. This engine was so popular that it was even called the national engine of India. In 2019, Maruti decided to introduce a brand-new 1.5-litre turbo diesel engine that was developed in-house. It was initially introduced in the Ciaz and later in the Ertiga. Sadly, this version was offered only for a year. As part of the BS6 transition, Maruti discontinued not just this engine but all diesel engines. What exactly happened? Why did Maruti kill the diesel engines? Let’s find out.

Why Maruti Killed The Diesel Engine: Real Reason Revealed
Maruti Suzuki 1.5 Diesel engine

Maruti had spent over five years and Rs 1,000 crore in designing and developing this new engine. Usually, when a manufacturer develops an engine, it is offered in the market for at least 15 years. However, in this case, Maruti abruptly stopped production in 2020. Officially, Maruti has been telling everyone that they discontinued the diesel engines due to diminishing demand and the higher cost of making them BS6 compliant. However, that is not the truth.

Diesel engines were extremely popular among Maruti buyers, especially in the commercial segment. When Maruti discontinued diesel engines, their market share dropped below 50 percent.

What Is the Actual Reason?

Maruti Suzuki never wanted to exit the diesel market in India. However, they were forced to do so because of a mistake they made during the development of their new engine. The reason why Maruti decided to develop an in-house diesel engine was that Suzuki Motor Corporation chairman Osamu Suzuki wasn’t happy paying high license fees to FCA.

Why Maruti Killed The Diesel Engine: Real Reason Revealed
Maruti Ertiga & Ciaz diesel

They developed the 1.5-litre E15A series diesel engine. It was an extremely refined engine and was performing well in the Ciaz and later in the Ertiga. Maruti also had plans to replace the 1.3-litre Fiat engine in the Brezza at a later stage.

However, that is when the BS6 emission norms kicked in and the manufacturer noticed an issue with the cylinder head. Usually, in petrol engines, cylinder heads come with an integrated exhaust manifold. This technology is not used in diesel engines as they are substantially cooler than the petrol ones.

As the name suggests, the exhaust manifold is a part of the cylinder head and not a separate bolt-on piece. It improves packaging and reduces weight. The engine’s water jacket absorbs heat from the exhaust gases and keeps it much cooler than a cast iron manifold. This also helps in improving fuel efficiency. While all this looks good for Maruti, they realized this was a mistake only during the BS6 transition. This one mistake cost Maruti crores and forced them to stop producing diesel engines.

What Exactly Happened?

As mentioned above, an integrated exhaust manifold is useful in a petrol engine. But, when it comes to diesel engines, which are already cooler than petrol engines, this technology is not much use. This technology carries the risk of overcooling the exhaust gases. This creates serious complications while upgrading to BS6.

To move from BS4 to BS6 norms, the exhaust after-treatment hardware has to be upgraded from a Diesel Oxidation Catalyst (DOC) to a complex Diesel Particulate Filter (DPF) and DOC system. This became a challenge for Suzuki engineers. Normally, in BS6 diesel engines, unburnt hydrocarbons are emitted in gaseous form through the ultra-fine channels of the DPF.

Why Maruti Killed The Diesel Engine: Real Reason Revealed
Maruti Suzuki Maruti Ciaz 1.5 Diesel

However, in Suzuki’s diesel engine, the exhaust gases were overcooled and they were actually in liquid form. The hydrocarbons can’t pass through the DPF in liquid form. This gets trapped in the DPF. The DPF has a ceramic-based substrate which can handle temperatures of around 1000 degrees Celsius during regeneration. However, in Suzuki’s case, the temperature was way more than what it could handle, and that was leading to hairline cracks which can damage the DPF.

Why Did This Happen?

Suzuki has expertise in petrol engines; however, they were not experts when it comes to diesel engines. When the engine was being developed, there was no need for a DPF as it was all BS4. However, by the time they realized the mistake, it was too late.

Can Maruti Rectify the Mistake?

Maruti could have rectified the mistake by redesigning the head, but they chose not to. The stricter emission norms and increasing cost of developing diesel engines were some of the reasons. Also, Maruti had lost the window of opportunity. If they had rectified the issues from the start, we would still have had diesel Maruti cars in the market.

Via: ACI