Isuzu F Series

One reason why Isuzu has been leading the sales leader board for 27 consecutive years is the company’s on-going commitment to market research. By closely listening to the Australian transport community, the brand is constantly re-aligning its product portfolio with the market to ensure all research and development efforts are issue-focused and applicable to real life.

Operational efficiency is one crucial focus area that has been coming up time and again as part of that process, prompting the OEM to update the medium-duty F Series range for the 2016 season and expand it with a total of 11 all-new models. To find out just how much of an impact Isuzu’s continuous improvement processes have had on the range, Prime Mover tested eight samples – each of them ballasted up to around 80 per cent of the individual GVM – in and around Brisbane.

Outwardly, each new F Series model can be recognised by an updated grille design and new badging, while the seat trim and steering wheel give away the new generation on the inside. The real change, however, occurred below the hood, where the F Series received a pair of new engines as well as a new, torque-convertor equipped automated manual transmission (AMT).

Engine one is a descendant of the first four-cylinder unit Isuzu introduced to the F series back in 2007. It has been completely redesigned for the model upgrade, with only bore and stroke remaining untouched. The result is a 5.2-litre, two-stage turbocharged and intercooled unit that is available in two power ratings – either with 210hp (154kW) and 726Nm of torque or with a 240hp (177kW)/ 765Nm package.

In applications up to 14 tonnes GVM, it will replace the six-cylinder version used previously, with Isuzu claiming it will likely end up outperforming its predecessor. Our multi-model test can confirm the potential is certainly there: Both the low and high-pressure elements of the turbo operate broadly across the engine’s rev range to provide smooth and continuous power for take-off and the necessary grunt to climb hills when loaded. The physical size of the turbo has also been reduced, allowing for a quicker response time during low revolutions and faster availability of torque.

According to Isuzu, the lighter four-cylinder engine contributes to a lower tare weight and more payload available over the front axle, and incorporates a car-like idle-stop system (ISS) with hill-hold function that switches off the engine when the truck is stationary to reduce emissions and fuel consumption. Demanding just a few extra seconds per stop to trigger the engine restart, Isuzu says the ISS can provide fuel savings between five and 10 per cent – with the biggest difference achievable in heavy traffic conditions.

The four cylinder’s emissions comply with Japan’s PNLT standard, which is similar to Euro VI. An external injector delivers fuel to clean the Isuzu’s diesel particulate diffuser (DPD), thereby eliminating the dilution of crankcase oil by performing the regeneration process outside of the engine block.

The automated manual transmission (AMT) available in connection with the 5.2-litre unit has been upgraded to a full torque convertor, which significantly increases start-ability and driveability and replicates the take-off characteristics of a full automatic. The torque multiplication factor of 1.45:1 greatly assists in getting the wheels turning on a loaded vehicle and essentially enables the smaller engine to perform as if it was half as big again.

What’s more, lower maintenance costs can be expected as there are no mechanical clutch components to wear as found within other AMTs – the fluid solution chosen here, with its lock-up torque convertor, provides an ultra-smooth take-off under all conditions, seamless shifts at all rates of acceleration and will provide improved fuel economy. The stubby transmission selector lever incorporates a button to select between power and economy modes and another to engage first gear when starting off loaded on an uphill grade.

The second engine is a 7.8-litre six-cylinder unit that has had every aspect of its combustion process reworked to generate fewer emissions at the exhaust manifold – therefore requiring a much simpler clean-up operation within the exhaust system using a diesel oxidation catalyst. This makes the ‘6HK1’ the only medium-duty engine in the Australian market with neither a diesel particulate filter (DPF) nor selective catalytic reduction (SCR) that uses AdBlue fluid – a solution especially suitable to vocational applications that involve a lot of idle time, high PTO use and frequent stopping.

The six-cylinder F models involved in our test are all equipped with Allison’s 2500 series six-speed automatic transmission – a marriage that seems to be working well, with the transmission seamlessly selecting the gears that deliver the best torque performance. The Allison is factory-filled with synthetic fluid, which should provide a reduced whole-of-life service cost, too. There is a ‘Range’ pre-select function on the shift lever that has the transmission automatically kick back to fifth gear when over-running down-hill, which will in turn maximise the effectiveness of the exhaust brake. In our test, the feature proves so effective that the truck actually slows rather than just holding its speed, which will save money on brakes and add to overall safety.

Depending upon the specific model – and there are lots of them – the six-cylinder can be fitted with Isuzu’s own six-speed manual too, a ZF nine-speed manual or the heavier-duty Allison MD 3000 six-speed auto.

Every vehicle in our test is also equipped with Isuzu’s telematics system, which was first unveiled in late 2014 and is available in a basic version, labelled Isuzu Connect, or a more comprehensive one, named Isuzu Connect Plus. Both are based on a black box installed behind the dash panel and connected to various sensors on the vehicle that are linked with a server so that both driver and HQ can access the same data.

The introductory-level Isuzu Connect can boast features such as live locating, mechanical checking, theft alert and service reminders, and also provides some analysis of how the vehicle is driven – speeding, harsh acceleration and adherence to pre-determined, geo-fenced boundaries are all record. The Connect Plus version, meanwhile, ups the ante by adding engine management data to the mix, from clutch activation and fuel consumption through to idling time. Isuzu is quick to point out that both solutions have been developed specifically for the local Australian market – meaning they take into account local conditions and use the trusted Telstra mobile network.

Making the system broadly available across the range is likely to hit a nerve, says Isuzu, as research has shown that maximum operational efficiency cannot be achieved without a solid data foundation. As such, the depth of analysis provided by systems such as Isuzu’s can have a real and positive impact on businesses equipped and willing to put the time and effort into interpreting the data made available to them.

In combination with the new engine and transmission line-up, the new F Series therefore has all the potential to continue Isuzu’s dominance in the medium-duty market. It can combine excellent driveability, which will make drivers’ days less stressful, with modern technology that will help fleets keep costs in check. Plus, the dual environmental benefit of using less fuel and reducing emissions is quickly becoming a key selling point, too.

The story has appeared in the August edition of Prime Mover. To get your copy, click here.


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