Automotive Drive System Developments

Supplementary Drive System


 Functional Description – Overview

The BMP team has developed an invention to provide short term additional motive force to any wheeled device with driven wheels.

In many applications, wheeled vehicles are designed to provide drive to only a limited number of the wheels in contact with the ground. In most cases this is a consequence of minimising cost, weight or complexity in the vehicle.

This simplified drive system provides a suitable solution for most scenarios that these vehicles experience. In situations where additional drive is required, the simplified drive system is unable to provide the necessary tractive force to enable the vehicle to proceed, resulting in a restricted range of operation or a bogged vehicle. The traditional solution requires the vehicle’s owner to acquire a different vehicle, once installed with multiple driven wheels. In this case a more complex and heavy drive system is installed to provide the additional traction, even though the additional support is only required in limited situations for a small percentage of the operational life of the vehicle.

The invention provides a mechanism to provide additional drive to one or more additional wheels for a short period of time thereby avoided the added complexity and weight of a specifically designed multi-drive vehicle.

Scenarios where the additional motive force could be utilised include:

  • Providing additional traction on uneven, lose or slippery conditions
  • Accelerating the vehicle when heavily loaded
  • Initial movement for stationary
  • Assisting the vehicle on climbing



In addition, the invention provides a further benefit of enabling motive force to be applied to one or more of the wheels of a towed vehicle (trailer-bogie or additional axles on a single or multiple trailers). The benefit of this further benefit is that the trailer becomes a short term driven vehicle reducing the load on the towing vehicle and thereby avoiding problems associated with towing an unaided vehicle on difficult ground.

A further additional advantage of the invention is the ability of additional motive force to be applied in either direction with an adjustable level of support to the main vehicle.

A further additional benefit of the invention is the ability of the invention to provide a degree of braking. The additional braking effort can be adjusted, but provide the benefit of supplementing the main vehicle’s braking system, which in turn may allow greater vehicle, or trailer, weights to be employed safely while meeting the relevant regulations.

A further additional benefit of the invention is to provide a degree of energy recovery during braking, thereby replenishing the Local Storage Unit(s), or other energy storage devices on the main vehicle, the trailer or both.



The invention incorporates four main components:

  • Local energy storage unit
  • Central motor unit
  • Energy transfer and charging system
  • Control system


A simplified schematic of the invention, in elevation view is presented in Figure 1, while a functional description of each component is provided below.

Figure 1: Simplified schematic of the invention (elevation view)




Local Energy Storage Unit(s)

The Local Energy Storage Unit(s) provide a means of accumulating energy from the main vehicle’s engine, or the locally driven wheel(s), and storing the energy until required. Additionally, the storage unit(s) are able to release the stored energy at the rate required by the overall system to provide the additional motive force required.

The Local Energy Storage Unit(s) are designed to be replenished with stored energy during the normal operation of the vehicle. Further, the storage units are designed to release and replenish the stored energy many times during the life of the main vehicle.

An alternative configuration of the invention includes the addition of a supplementary engine, such as a donkey engine, to provide the energy required by the Local Energy Storage Unit(s). The justification for this supplementary engine is to increase the rate of replenishment of the energy stored in the Local Energy Unit(s) and so enable the invention to provide additional motive force for longer periods or more frequently than could be achieved by relying on the main vehicle’s engine alone.

The number and size of the Local Energy Storage Unit(s) can be adjusted to suit the requirements of the vehicle operator.

Central Motor Unit(s)

The Central Motor Unit(s) provide rotational energy to the Energy Transfer and Charging System. The Central Motor Unit(s) are powered by energy received from the Local Energy Storage Unit(s).

Energy Transfer and Charging System (s)

The invention includes Energy Transfer and Charging System(s). The Energy Transfer and Charging System(s) are mounted to provide drive to the individual wheel hub(s), and receive power from the Central Motor Unit(s). The resultant energy is sufficient to rotate the wheel under the load conditions in a way specified by the Control System.

The Energy Transfer and Charging System(s) are designed to convert the power from the Central Motor Unit(s) into a form suitable to the range of operation of the vehicle. The Energy Transfer and Charging System(s) can cope with a wide range of operational speeds without significant loss of efficiency or operational effectiveness.

Further, the Energy Transfer and Charging System(s) are able to provide energy back to the Local Storage Unit(s) during periods of the operational cycle when the drive is not required to be directed to the driven wheel(s).

Control System

The Control System is an electronic system designed to regulate the operation of the overall system. The Control System will receive inputs from the vehicle operator, the main vehicle’s management system and the component of the invention. The Control System will use these inputs to regulate the behaviour of the invention to optimise its performance.

The Control System output will be based on the vehicle operator’s input and will be coordinated with the operating conditions of the main vehicle. The degree of additional motive force can be adjusted to suit the particular scenario being experienced. The Control System will be able to communicate with the main vehicle to provide an optimised response from the invention. The operating conditions in the main vehicle to be monitored include: vehicle speed, engine speed, throttle position, wheel speed sensors, engine fault codes amongst others. The Control system will adjust the performance of the invention by monitoring the Energy Transfer and Charging System(s) behaviour, in particular rotational speed and direction, and adjust the operation of the Central Motor Unit(s) and Energy Transfer and Charging System(s) to provide the optimised performance of the system.

The Control System will also monitor the condition of the Local Energy Storage Unit(s) to support the continued operation of the invention, provide updated status of the invention to the main vehicle operator and the ongoing safety of the component parts.


 Schematics of Examples of the Invention

Main Vehicle Only




Vehicle with Trailer