The PR 736 is the first of the Generation 6 dozers to be introduced to the North American market. This model was unveiled last March during Conexpo and the first units are expected to be here in the coming months. The new PR 736 is a fully hydrostatic dozer powered by a 201 HP Liebherr diesel engine / Tier 4 Final with an operating weight ranging between 44,000 and 55,000 lbs. Its diesel engine, machine control systems and electronics are designed and developed in-house by Liebherr.
The new PR 736 achieves best-in-class fuel economy
Based on its predecessor, the PR 736 comes with lots of improvements. While the hydrostatic travel pumps and motors are the same reliable components used on the PR734, the electronic controls and the engine are new.
The PR 736 features a newly designed 4-cylinder Liebherr engine with a 427 in3 (7.0 Liter) displacement – an engine displacement larger than many 6-cylinder engines used in this class ““ achieving best-in-class fuel economy. Fuel efficiency is improved by up to 6% under heavy loads and even greater fuel savings are observed when using the ECO mode under light and medium applications. The ECO-mode is a fuel-efficiency control system developed by Liebherr to optimize the engine speed without compromising power and performance.
Liebherr Electronics – Machine Control Systems
The electronic control management system developed by Liebherr monitors the load condition on the machine and the operator commands to adjust the drive train accordingly. This includes the variable pumps, motors and the engine power. Under standard load conditions the engine runs at a different horsepower rating than it does under heavy load conditions. This is a fully automatic process controlled by the Liebherr built-in electronics without the operator noticing anything except the good pushing performance while having outstanding fuel efficiency.
New Liebherr Engine- Tier 4 Final/Stage IV
Generation 6 Dozers feature Tier 4 Final Liebherr diesel engines. To comply with the latest emissions standards Liebherr has developed its own common rail fuel injection system that uses multiple injections per work cycle. This enables the new Liebherr engine to meet the new Tier 4 final standards without using a Diesel Particular Filter (DPF) while providing important benefits to the customer. The main benefit is that the engine will never have to go into active or passive regeneration therefore the machine will be fully operable at all times (machines that use engines with DPF require to be inoperable while in active regeneration ). Another advantage for the customer is the reduced fuel consumption. The removal of the DPF eliminates the need for high exhaust gas temperatures which was normally achieved by injecting additional fuel depending on the application.
New Standards in Operator Comfort
In addition to the new developments on the drive train, Liebherr has also given high priority to the cab design to enhance the overall comfort and safety of the machine.
Generation 6 dozers achieve outstanding visibility by integrating the ROPS structure into the cab itself rather than mounting an external ROPS bar. Components such as the exhaust stack are placed in line with the A-pillar of the cab for a clear and unobstructed view to the front. Additionally, the new cab has wider doors for easier access and better visibility to the blade.
Generation 6 dozers feature ergonomically designed and adjustable T-handle style joysticks with thumb pads for additional functions.
The safety lever is no longer necessary on the Generation 6 dozers. Liebherr now uses a seat-switch combined with a parking brake release switch. The parking brake automatically applies and self-releases depending on the travel commands. Analog gauges on the dash were replaced by a modern touch screen which is part of the Liebherr machine control system. The intuitive navigation menu allows the operator to monitor several machine parameters such as fuel level, fuel consumption or coolant temperature and also allows the operator to save custom-settings (e.g., the ECO mode, automatic engine shutdown). It also allows the operator to change aggressiveness of the hydrostatic drive train by adjusting the response to joystick travel and steering commands.
Improvements to the exterior of the machine include a larger size sprocket for reduced and more equal wear and the optional 6-way blade. The 6-way blade is also manufactured by Liebherr and uses angled cylinders for unmatched rotating power.
To improve the serviceability of the machine, Liebherr has improved the access to critical service points. The PR 736 has a hydraulically tilt-able cab like its predecessor but now also has a swing out fan for great access to the cooling package.
Additionally, each Liebherr Generation 6 dozer is compatible with blade control technologies from any of the major suppliers and can be ordered GPS ready from the factory. This allows customers to use their preferred system.
