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Bidding goodbye to India's 'national' diesel engine

28th Mar 2020 7:00 am

With the BS6 norms now in place, Fiat’s legendary 1.3-litre Multijet diesel is no more. Shapur Kotwal pays homage to the ‘national’ diesel engine that powered not one, not two, but an incredible 24 cars in India.

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Shanghai 2005, the spanking new Formula 1 circuit. Grey skies, murky clouds, and a haze so dense I can barely see the end of the back straight. Unlike the weather, however, my disposition is sunny. Lined up, cheek to cheek, wing mirror to wing mirror, are nothing but the finest diesel cars on the planet. Here to showcase the technical mastery of German component maker and industry backbone Bosch, the line-up includes cars from Mercedes, BMW, Audi, Peugeot, Honda, Lancia, and Volkswagen with its unit injector diesel tech.

As the day wears on and I pile on the laps, I realise two things: diesel engines are set to change forever, and, of all the heavy metal on offer, it’s the diminutive Lancia that’s the most impressive. Sure, the unit injector-based engines which VW once pioneered have a lot of torque, the Merc sings along nicely, and the big BMW 7 feels like it’s powered by a jet engine, but which one sits atop the pile? It’s the Lancia with Fiat’s little 1,248cc Multijet.

It’s just an absolute delight to drive. Yes, there is that initial bit of turbo lag, but get past that and it feels zingy, loves to rev, and has tremendous punch in the mid-range. And the claimed fueleconomy figures are just crazy. Also, and this is important, it’s the most un-diesel-like diesel I’ve ever driven.

Design and engineering

Should have known better, it was Fiat who all but invented the common-rail diesel engine as we know it today. First came the Jet Turbo Diesel (JTD) under the bonnet of the Alfa Romeo 156 with its Unijet system, and then Fiat took it a step further and introduced Multijet, which, as its name suggests, used multiple injections of diesel for every power stroke. To help with development, Fiat roped in Bosch, who eventually bought the rights to the system and helped it proliferate. The common-rail system eventually proved to be so good, almost every diesel car on sale today uses a version of Fiat’s system.

But what was is it that gave Multijet and common-rail such an uncommon advantage? Let’s start at the beginning. Diesels actually became attractive for automotive use after the introduction of the turbocharger. The advantages? Huge torque, better responses in the mid-range, and even slightly improved efficiency. Then came direct injection from truck engines, and that upped low-end torque and fuel economy even further. Direct-injection, however, made engines slow to respond due to the higher pressure needed to inject fuel directly into the cylinder head, and then because the combustion or burn became faster and more spikey, DI engines rattled more and became louder.

So, what exactly did Fiat do? Simply put, common-rail direct injection (CRDi) and Multijet use a very high-pressure injection system that fires multiple injections of fuel for every power stroke. This improves engine responsiveness and smoothens out combustion by progressively spacing out the ‘explosions’. Multiple injections and a very high rail pressure are now widespread in modern diesels, but it was the compact and affordable Fiat that democratised the CRDi tech that was once the preserve of high-end diesels.

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Make in India

The story of the Multijet in India, however, didn’t start with Fiat. The Italian carmaker could have been first off the blocks – it should have – but Fiat’s product planners at the time didn’t quite have the numbers to localise the engine and so decided to adopt a wait and watch philosophy. Suzuki, on the other hand, because of its one-time alliance with GM and Fiat, had been working on using the Multijet engine to bolster sales in Europe as early as 2004. And then, since it had the numbers in India and the supplier base, and could localise the engine, the first-gen Swift was the first car in India to get Fiat’s 1.3 Multijet, in 2007.

The combination was just lethal. With its distinctive shape, comfortable front seats, good driving manners, and 190Nm of torque, the Swift was both frugal and fun. Customers particularly liked the punchy torque delivery and petrol engine-like ‘light’ and rev-happy feel. Clearly remember that big grey rev counter, with the needle going all the way past 5,000rpm. And once you got it over 2,000rpm, that strong mid-range made driving the Swift diesel on a light throttle an absolute joy. What sealed the deal, however, was the incredible 15-17kpl in the real world, depending on conditions. Was it any wonder then that sales just went ballistic, even with the about Rs 70,000 premium over the petrol?

How did Maruti get it so right? “We just asked for the liveliest, most fun state of tune,” said a senior engineer at the company. “While the European setup would only deliver max performance if you floored the throttle, our car was tuned to respond very strongly if the driver so much as squeezed the pedal.” This is partly why the Swift diesel actually felt faster in the real world than its 0-100kph time of 13.87sec suggested, and when you drove it, even at part throttle, it just flew down the road. Maruti engineers even paid attention to how they tuned the accelerator for feel.

It was, however, a very high-tech and expensive engine, and localisation was the key to knock costs down. Suzuki invested Rs 2,500 crore in an all-new engine plant at Manesar, with localisation levels as high as 75 percent from day one. Critical (and expensive) components were sourced locally, right from day one, with the five Cs – the crankshaft, camshaft, cylinder head, cylinder block, and even the ‘cracked’ connecting rods – coming from Indian suppliers. And then Bosch soon made the fuel rail, the fuel pump and injectors in India too, taking local content up even further. Whereas Suzuki was the first to produce the engine in Manesar, Fiat kicked off Multijet production in Ranjangaon, which increased Multijet volumes further. Many of the suppliers were jointly approved, and the increased economies of scale from combined Maruti and Fiat production, made deeper localisation viable, and parts like the water pump, oil pump, and the fuel pump were locally sourced.

Fiat, however, tuned the engine differently. Performance was more measured and less urgent, the engine wasn’t as enthusiastic at higher revs, and what also made a difference was that Fiat’s cars were more solidly built; the Grande Punto diesel, for example, was around 50-odd kilogrammes heavier than the Swift diesel back in the day.

Not long after the Swift diesel was introduced came the mods and performance boxes. These took performance up substantially, the slug of torque now experienced much stronger. The fastest Swift diesels clocked 0-100 times of around 11.9sec, and many a time all you needed was a simple performance box from Pete’s. And then the 90hp version of the engine was introduced; it delivered even more performance and stronger acceleration. Maruti’s diesel Brezza actually did the 0-100 sprint in 12.96sec. Let’s not forget the Brezza weighed in at 1,195kg. The 90hp version ran a higher max rail pressure of 1,600bar versus 1,400 of the 75hp version; the engine had a variable geometry turbo, and it used modified pistons and piston rings.

Hello Tata

Possibly the biggest beneficiary of the Multijet engine was Tata Motors, and this is one of the main reasons why the company entered into a joint venture with Fiat. This masterstroke of Ratan Tata meant that Fiat’s Ranjangaon plant would be folded into a 50:50 Fiat-Tata Motors JV, and this included a 1,00,000 units capacity for the Multijet which, in addition to Fiat’s line-up, would be used in future Tata cars. There is no doubt that it was the Multijet that kept Tata Motors in the diesel race and the Indica Vista with this frugal and peppy engine, enjoyed a good run of success. The engine made money for Tata Motors too. When Maruti Suzuki utilised all of its Manesar plant’s 3,00,000 units per year engine capacity, it was forced to buy engines from the Ranjangaon JV for a hefty price!

Size is everything

The Multijet rode the diesel boom in India like no other. Cheap to manufacture, cheap to run, and cheap to maintain, this light and compact engine went on to power 24 individual models from five car manufactures. Weighing just 130kg fully dressed, components and ancillaries and all, the engine was a lightweight; and that’s despite having a cast-iron block for better heat dissipation and greater strength. What also helped was that it was a compact unit – just 50cm long and 65cm high. It was so compact that Fiat planned (but never built) a three-cylinder version of the unit. That was left to one-time partner GM; it ‘re-engineered’ the three-cylinder version and actually manufactured it here in India, and slipped it under the hood of the Chevrolet Beat (see box).

GM India also produced its own version of the Multijet at the company’s Talegaon plant. In fact, it had equal rights to this engine after the JV with Fiat ended. The engine powered several of GM’s brands, but in India, it was used for products from the stable of the SAIC-GM-Wuling alliance in China. However, the 1.3 never enjoyed the same level of success in these Chinese-based cars which were never engineered to take diesels. The complexity of integrating the engine led to quality issues which manifested itself in product recalls. GM India even turned the engine 90 degrees to a ‘north-south’ orientation to power the rear wheels of the Enjoy MPV, originally a Chinese Wuling.

This is something even Premier, Fiat’s original partner in India, did. It used the engine to power its Daihatsu Terios-based Rio, the first compact SUV in India. Needless to say, it was a massive step up from the unit it was using earlier – Peugeot’s TUD5 – and Premier found it to be “outstanding in all parameters”.

Bullet-proof

For such a complex, high-tech engine running such a high-pressure fuel-injection system, the Multijet was very reliable. Suzuki actually exported a fair number to its plant in Hungary, which were then re-exported to the rest of Europe. And its reliability record was fabulous. Maruti service heads we spoke to can’t remember ever opening the engine to deal with a problem. “It was super reliable,” said one of them, “we only had to open engines where people filled petrol by mistake”. A timing chain change at around 1,00,000km, however, was needed to keep the engine in the peak of health, a bit earlier than was recommended. Maruti service engineers also recommended changing the pulley, as “that reduced the play and allowed the engine to function with greater precision, improving both efficiency and power delivery.”

Could the 1.3 Multijet have carried on with the new BS6 norms coming in? Technically, yes; the engine exists in Euro 6 form in Europe. But Suzuki, it is said, didn’t want to pay the high license fees. So the 1.3 Multijet was actually discontinued because orders dried up. Fiat as a brand is extinct in India, GM has folded shop, Tata has its own BS6 diesel, and Maruti had its 1.5 DDiS. The latter, however, doesn’t meet the BS6 norms, yet. Should Maruti have carried on with Fiat’s 1.3 Multijet? We’ll only know the answer to that next April, when sales figures for the year are out.

All together, Fiat’s baby diesel powered nearly three million cars in India, and in the process probably saved millions of dollars in fuel costs. Do the back of the envelope calculation; it was almost always the most fuel-efficient car in its class. Marketed as the Multijet by Fiat, DDiS by Maruti-Suzuki, Quadrajet by Tata, Smartech by Chevrolet, and CRDi4 by Premier (Fiat’s original partner in India), the engine powered front-wheel-drive cars and even rear-wheel-drive cars. FCA still makes and sells the larger 2.0 Multijet in India, and it powers SUVs like the Jeep Compass, MG Hector and the Tata Harrier. But that’s a far cry from its heydays, where the 1.3 Multijet powered 16 individual models, all at the same time.

Multijet by three-fourths: GM’s 3-cylinder XSDE

When Fiat made the 1.3 Multijet, it also had plans to develop a 1.0-litre, three-cylinder version of the same engine. It, however, scrapped the idea before it got into production because it just didn’t make sense. To begin with, the engine was already so compact, it could easily be shoehorned into just about any Fiat engine bay. Weight wasn’t an issue either – the engine was already pretty light, at 130kg. And what worked against the three-cylinder wasthat the weight advantage lost by lopping off one cylinder was negated with the need for a heavy balancer shaft. A 58hp, 963cc, three-cylinder version of the Multijet engine was eventually made at an additional cost of 54 million Euros. However, it wasn’t Fiat that did the ‘re-engineering’ and tooling; it was onetime partner General Motors, who also owned rights to the engine. It wasn’t the smoothest diesel around at high engine speeds, it struggled on highways (0-100kph took 18.59sec), and packaging it under the compact bonnet of the Beat was difficult too. Still, it was fairly refined at low speeds, and for a time was the most fuelefficient car in India with an ARAI-certified figure of 25.44kpl.

5 Things you didn’t know

1. The world’s press was so impressed by the performance and fuel economy of Fiat’s 1.3 Multijet diesel it won the prestigious International Engine of the Year Award in 2005.

2. The engine was sold under many names. Multijet, of course, was the name Fiat used, but it was also sold as the DDiS by Maruti, Quadrajet by Tata, Smartech by Chevrolet, and CRDi4 by Premier.

3. There were a total of five versions of this engine. The range started with the 70hp version, we got the 75hp version and the 90hp version, and the Multijet II was even available with 95 and 105hp.

4. In its most advanced state, Fiat’s Multijet II uses up to eight injections per stroke and rail pressure as high as 2,000bar. Some of the tech can be found on the 2.0 in the Jeep Compass.

5. Other companies that used Fiat’s 1.3 Multijet diesel in differing states of tune included Alfa Romeo, Lancia, Ford, Opel, and Peugeot.

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