When operating in a cruising condition, LogixDrive reduces to a minimum the lube oil quantity in the rear axle (valve closed/reservoir filled with oil).
In high-torque (climbing), braking or low speed conditions, higher lube level is required so the oil quantity is increased by opening a valve to empty the reservoir.
Using laser welding technology for building axles makes the differential case extremely rigid, allowing for higher torque capacity, weight savings and improved durability.
Meritor – a leading global supplier of drivetrain, mobility, braking and aftermarket solutions for commercial vehicle and industrial markets – is developing what it says is the industry’s first intelligent axle system – the LogixDrive.
The system actively “thinks” using a performance logic system, enabled by an electronic control unit with dedicated sensors measuring temperature, speed, braking and torque conditions to optimize axle efficiency, said Fabio Santinato, Meritor’s chief engineer, axles engineering, for Europe. The LogixDrive utilizes the Meritor lube management system to actively apply or reduce axle lubrication based on current truck performance and driving conditions.
Fleet Maintenance was one of a select group of North American trucking industry publications to get an inside look at LogixDrive during a visit to Meritor’s axle plant in Cameri, Italy, last week.
LogixDrive is the first application of electronics on axles by Meritor.
Power loss in axles
LogixDrive addresses the two main areas of power loss in axles: gear and bearing friction and oil churning due to gear rotation, Santinato explained. Adding or reducing lubricant on the gear set during the vehicle’s operation improves efficiency and fuel savings, as well as reduces lubrication breakdown.
LogixDrive can increase fuel savings from 0.5 to 0.8 percent without any need for a driver interface, and parasitic energy loss reductions of up to 50 percent compared with previous generation axles.
LogixDrive employs sensors to measure oil temperature and combines that with torque and speed information to reduce lubrication in high-speed/low-torque conditions or increase lubrication in low-speed/high-torque conditions. The lube oil is stored in a reservoir built inside the axle housing.
When the oil is not needed, the teeth of crown gear churns oil into an opening at the top of the reservoir. A normally open valve at the bottom of the reservoir is pneumatically closed to contain the oil.
When the stored lube oil is required for high-torque (climbing), braking or low-speed conditions, the valve opens pneumatically and the oil drains through gravity.
In high-torque (climbing), braking or low speed conditions, higher lube level is required
When full, the reservoir holds about 5 liters of oil, lowering the oil level in the axle from 12 liters to 7 liters.
Linehaul trucks operate in cruising condition for 80 percent to 90 percent of the time, Santinato noted, and do not require a lot of oil in the rear axle. The greater the amount of oil, the greater the “oil splash” (oil churned up by the drive gears) in the axle housing, resulting in more parasitic horsepower loss.
When at cruising speeds, LogixDrive reduce the oil quantity in the rear axle (valve closed/tank filled with oil) to a minimum. The lower oil level around crown-gear results in reduced churning losses. That improves axle efficiency for reduced truck fuel consumption.
The system is failsafe and will open in the event of a system failure.
LogixDrive was developed for the Meritor 17X single reduction hypoid drive axle that was designed for on-highway applications and European linehaul operations.
The system is being prepared for Meritor’s 17X EVO rear axle – the evolution of 17X axle with higher efficiency, superfast ratios and expanded capability to 50 tons. It is a global platform that was launched with Volvo in late 2013.
LogixDrive will also be applied to the 18X – a rear axle intended for fast and heavy long-haul operations.
Laser welding technology
The 17X and 18X axles both feature a number of technical improvements, including laser welding technology, noted Marco Bassi, senior director, Europe and South America engineering, for Meritor.
This technology makes the differential case extremely rigid, allowing for higher torque capacity, he said. Laser welding eliminates 38 bolts in comparison with its predecessor and results in significant weight savings.
Additionally, there are is greater efficiency and better gear integration which yields improvement in durability.
The axles’ ring gear-to-case and case-to-case joints are also laser-welded
Prototypes of the Meritor LogixDrive are currently being field tested in Europe. The system could be introduced into the U.S. first because fleets are more concerned with fuel efficiency that those in Europe.
Santinato said that with LogixDrive there is the potential for an axle-monitoring system to improve oil performance and drain interval frequency.