1. Home
2. Environment
3. Environmental Programs
4. ecoTRANSPORT
5. ecoFREIGHT
6. Road
7. Automatic and Automated Transmissions

Automatic and Automated Transmissions

Automated and automatic transmissions have many benefits, including possible fuel savings, and can contribute to driver retention.

Important obstacles stand against the adoption of innovative technologies, of which one of the most important is the lack of practical information coming from independent sources. The objective of these fact sheets is to inform those in the trucking industry about new and emerging advanced technologies that have been tested through the Energotest program (run by FPInnovations), which can help increase fuel efficiency and, at the same time, reduce the environmental impact of freight transportation in Canada.

Description

Fleets started to turn to automated and automatic transmissions in the 1990s, primarily with the goals of attracting new drivers, reducing maintenance costs and, in the case of automatic transmissions in off-highway applications, increasing traction. Both types of transmissions eliminate shifting, but in different ways. Automated transmissions are constant mesh transmissions that use a clutch. They are similar to manual transmissions, except that the gear selection is done automatically using an electronic controller and hydraulic or pneumatic actuation. An automatic transmission has a torque converter instead of a clutch. Thus, it offers a range of torque multiplication and a continuously variable ratio, as well as automatic gear selection and uninterrupted torque to the drive wheels during shifting. Some transmissions have sensors for measuring changes in road grade, and can skip one or two gears at a time using combinations that a driver might never use.

One of the best ways to reduce fuel consumption is to have the engine working in its optimum rpm range for fuel efficiency. Automatic and automated transmissions minimize the time spent outside of this optimum range or “green band”.

Automatic transmissions have an additional advantage: power has to “drop out” when a manual or automated transmission shifts, but with an automatic transmission, the power remains smooth throughout. This is very advantageous, particularly for traction in on/off road applications, as well for the steady operation of all types of trucks in start-and-stop traffic.

According to Allison Transmission, in North America the market share of heavy-duty vehicles with automatic transmissions increased from less than 1% in 2001 to 10% in 2005. For automated transmissions, Arvin Meritor estimated the total market share at 10% and Eaton Corporation estimated it at 14%. Eaton Corporation reports that they sold more than 150 000 units in North America. The FleetSmart Program of Natural Resources Canada conducted a study in 2001 on automatic and automated transmissions for the heavy truck market. It concluded that carriers surveyed for the study had no negative performance aspects to report and the energy performance of a heavy truck with an automatic or automated transmission is either superior or identical to that of conventionally equipped vehicles.

FPInnovations conducted two studies between 2004 and 2007 aimed at providing information to the forestry transportation sector on the impact of automatic transmissions on operational performance. The results of these studies indicated that automatic transmissions can minimize the influence of the driver’s shifting ability on fuel efficiency and reduce the impact of driver fatigue. Furthermore, there was no significant difference in fuel consumption between the performance of an automatic transmission vehicle and that of a manual transmission vehicle. Traction advantages were also anecdotally reported by many users of automatic transmission.

Scope of Application

Automated and automatic transmissions are friendlier to beginners and easier to train on. They reduce driver fatigue and stress by allowing drivers to concentrate on operating the vehicle safely instead of shifting gears, particularly in difficult road conditions, and consequently contribute to driver retention. Fleets should examine their drivers’ behaviours behind the wheel when evaluating the benefits of introducing automatic and automated transmissions.

Return on Investment

FPInnovations conducted an SAE-TMC Type II fuel consumption test to evaluate the influence of the transmission on driver performance during the day, using an automatic transmission vehicle as the test vehicle and a manual transmission vehicle as the control vehicle. The test results showed that during the test day, the degradation in driver performance with the manual transmission truck translated into a 2.9% relative increase in fuel consumption when compared with the automatic transmission truck.

However, many experts believe that in the Class 8 long-haul segment, the market share for automatic and automated transmissions will be eventually limited because of the additional costs involved, which range from $4 000 for an automated transmission to $10 000 for an automatic transmission. Although in the past automated and automatic transmissions did not add resale value, experts have noticed a big change recently.

Consequently, the return on investment cannot be “automatically” applied to any situation, because an automated or automatic transmission may make the worst manual driver perform as well as the best performers, but good manual drivers will probably not see huge improvements, if any, in fuel efficiency.

Specification Considerations

When spec’ing an automatic or automated transmission, other components of the vehicle should be also reviewed for optimizing performance, cost, and weight, such as engine size, differential ratio, or drive shaft size.

Regulatory Issues

There are no specific regulatory requirements, but automatic and automated transmissions increase tare weight and marginally reduce payload allowance. However, some automatic transmissions lessen tare weight because a smaller drive shaft and engine may be used.

Maintenance Considerations

Manufacturers and many fleets claim that automated and automatic transmissions offer lower maintenance costs and increased fuel economy.

Fleets are reporting that the incidence of mechanical failures decreases dramatically with automatic transmissions, even though an increase in the number of failures in electronic components was noticed. However, electronic repairs are less costly than mechanical ones.

References

Carme, R. 2005. Performance evaluation of Allison Transmission’s automatic transmission in a forestry context. Forest Engineering Research Institute of Canada (FERIC), Pointe-Claire, QC. Advantage Report 6(14).

Cullen, D. 2007. The automatic answer. Fleet owner, November 1, 2007.

Gelinas, T. 2007. Shifting demands. Fleet equipment, September 2007.

Kilcarr, S. 2002. Transmission trends. Fleet owner, June 1, 2002.

Kilcarr, S. 2006. Shifting for fuel efficiency. Fleet owner, February 2006.

Natural Resources Canada (NRCan). 2001. Technical evaluation of automatic-type transmissions for the heavy truck market. Office of Energy Efficiency, FleetSmart Program, Ottawa, Canada.

Surcel, M.-D.; Michaelsen, J.; Carme, R.; Brown, M. 2007. Performance evaluation of heavy-duty vehicles equipped with automatic transmissions and powertrain adaptive systems in forestry transportation. SAE 2007-01-4212. SAE 2007 Commercial Vehicle Engineering Congress and Exhibition, Rosemont – Chicago, IL.

Date modified:

2012-03-12

Primary navigation