Cat’s new CT13 engine

Cat’s new 12.4-litre engine is based on the Navistar MaxxForce power plant and has had considerable input from Caterpillar itself rather than just a yellow paint job. The combination of technologies has proved effective in almost two million kilometres of testing as well as our no-time-pressure drive along the New England Highway from Brisbane to Newcastle.

The CT13 is a new, yet proven, combination that has supplanted the previous Cat C13 ACERT 13-litre engine. The Carbon Graphite Iron (CGI) lightweight block is ribbed for additional strength and provides an engine that is 40 per cent stiffer, has a tensile strength that is 75 per cent higher and a 200 per cent fatigue resistance advantage over traditional grey cast iron blocks, yet is able to be around 220 kilograms lighter than a standard cast iron equivalent. That’s an important weight saving right over the front axle.

According to Cat, the choice of engine materials assists in reducing in-cab noise and vibration by 30 per cent over the previous model. In addition, the CT13 goes down a different path from most other big bore diesels by not having coolant or lubricant flow between the top of the wet sleeved block and the cylinder head and instead has separate flow paths for the fluid. This innovation creates a much stronger block and the ability for more precise engine temperature control.

The alloy radiator is 1,429 square inches in size and additional airflow is electronically engaged via a viscous hub Horton fan when required. The engine seemed to stay around the 80-degree mark with the fan only kicking in on the long pulls – even on a 30-degree day. Mounted in front of the coolant radiator is another alloy intake charge air cooler that again contributes to the efficiency of the CT13 engine.

Other technology employed includes an inter-cooler to reduce the temperature of the inlet air charge between the twin sequential turbochargers and the large after-cooler that is required to cool the proportion of the exhaust gases that are returned into the combustion process to meet the current Australian emission regulations.

As with other EGR engines, this technology of the Cat CT13 engine means there is no requirement for the after-treatment injection of urea (AdBlue) to meet ADR 80-03 emissions requirements. Instead, the Cat CT13 high-pressure common rail injection and its unique dual turbo setup compliment redesigned steel pistons to ensure that combustion of the fuel air mix is maximised. The engine is controlled by a single Engine Control Module, which has increased computing power to continuously calculate the optimum fuel/air mix to achieve maximum power and efficiency. There are less electrical connections than on the C13 ACERT and most of the engine’s wiring loom is encased in foam protection.

Rated at 475 horsepower at 1700 rpm and developing a maximum of 1700 foot/pounds of torque at just 1200 rpm, the CT13 has ample torque to allow for shifting at lower revs to minimise fuel consumption and with maximum torque made at such low rpm maintains the ability to ‘hang on’ when approaching crests.

A three stage Jacobs engine brake is standard and proved to be effective, especially when the engine was pushing 1900-2000 rpm. Downshifting to keep within that rev range ensured that the service brakes were not touched used even on the steepest decents such as Moonbi coming into Tamworth, yet inside the cab with the windows up there was little increase in noise level.

For our trip, the New England Highway was in need of, and in places getting some, urgent attention following weeks of heavy rains that created damage to large sections of the surface. The situation had been made worse due to the much higher traffic load due to the coastal Pacific Highway route experiencing some flood related closures in the weeks leading up to our assessment.

For our assessment drive, the CT13 power Cat was a CT610 day cab, pulling a new Kennedy side tipper loaded with ballast. An 18-speed overdrive Eaton is standard equipment while the test vehicle was fitted with the Eaton UltraShift Plus automated manual transmission, which is a standard offering from the US at a reasonable cost premium and is was controlled by a push button module solidly mounted to the engine cover.

Let’s face it, this cab and transmission combination would probably be much more suited to the Western Ring Road or the M5 West, but it didn’t disappoint on the roller coaster that is the New England Highway. With the transmission in ‘manual’ mode and shifting up at 1900 and down at 1600 rpm, it was no chore to keep the CT13 engine at its sweet spot and to exploit the momentum of the vehicle.

With maximum torque being produced at such low revs, the Cat could also be allowed to run all the way down to 1100 rpm and hold there on a steady incline and recover its breath quickly once over the apex.

At highway speeds, selecting ‘auto’ mode produced pretty much the same gear shift results as manually over-riding them, and the Cat engineering people informed us that the transmission had been programmed specifically to do just that in this case. Other programs can be readily introduced to suit the specific tasks of an operator. Essentially, using auto around town and manual mode on the highway will probably produce the best fuel economy figures.

The Meritor diffs contained the taller 3.91:1 gear sets, with the options available being 4.1:1 or even 4.3:1. Rear suspension can be a choice of Hendrickson HAS 460-65 or Hendrickson Primaax PAX 460, both of which meet the Australian road friendly requirements.

The test vehicle was equipped with one of SBG Telematics’ ProCon units that provided the fuel figures for the trip of 1.988 kilometres per litre, which is a good result considering the circumstances of this particular journey that involved a lot of roadworks. An operator experienced in both the truck and the route could expect to easily better 2.1 km/litre, especially when considering that this truck had just 4,000 kilometres on its odometer.

The Cat CT610 truck with the C13 ACERT engine has been reviewed previously by Prime Mover, but it is worthwhile revisiting a few non-engine related details for the purpose of this story.

Thre are are in excess of 500 Cat trucks at work in Australia and operators’ feedback so far has indicated that the aerodynamic design of the CT610 cab is widely acknowledged to assist in reducing fuel consumption. The Australian specific mirrors also have a curved surface on the front side, which would contribute to the low wind noise experienced in the cab, even with the electrically operated windows in the down position.

Aesthetically, the CT610 has nothing to be ashamed of and its distinctive grille makes it stand out on the highway. Inside the cab, the instrument cluster in front of the driver looks sporty and tough and the optional leather Gramag air suspended driver and passenger seats include integrated seat belts and add a level of practical luxury. An appreciated innovation with the air seats (including the high back vinyl National air seats that are standard equipment) is the location of the air relief valve under the dash that is another reduction in cab noise.

The instruments also include a LCD screen for on-board diagnostics. The test truck featured a local ‘standard option’ media centre that incorporated audio, GPS and Bluetooth and was well positioned for the driver’s vision and input.

The Cat truck network in Australia confounded many in the industry by selling out their entire initial stock of 540 units of various specifications. It seems a shame that some of that momentum has been lost due to production facility issues brought about by the restructure of Navistar in the USA. However, the new CT13 engine should be well received here and sales will be resumed once the new stock currently on order becomes available over the next few months.

Leave a Reply

  1. Australian Truck Radio Listen Live
Send this to a friend