FIELD OF THE INVENTION

The present invention relates to machines having power systems that include an internal combustion engine.

BACKGROUND TO THE INVENTION

Machines such as material processing apparatus conventionally include a diesel engine, an electrical system and a hydraulic system. The diesel engine may provide mechanical power to a main processing unit, for example a crusher, of the apparatus, and also to the wheels or tracks in cases where the apparatus is mobile. The diesel engine may power the electrical system via an alternator, and may also power the hydraulic system via a hydraulic pump and hydraulic motor.

For environmental reasons, it is desirable to reduce the use of internal combustion engines, and in particular diesel engines. However, because of the typical power requirements of some material processing apparatus, replacing the diesel engine with electrical motors, or using a conventional diesel-electric hybrid system, can be cost prohibitive and/or impractical.

It would be desirable to mitigate the problems outlined above.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a machine comprising: a mechanical transmission system coupled to a mechanical load; an internal combustion engine coupled to the mechanical transmission system; an electrical system; at least one motor-generator coupled to the electrical system and to the mechanical transmission system, wherein, in at least one mode of operation, said electrical system is configured to deliver electrical power to said at least one motor-generator, said at least one motor-generator being configured to generate mechanical power from said electrical power and to deliver said mechanical power to the mechanical transmission system to drive said mechanical load.

In preferred embodiments, said electrical system is connectable to an external electricity supply, and wherein in at least one of said at least one mode of operation, said electrical system is configured to deliver electrical power from said external electricity supply to said at least one motor-generator. Preferably, said external electricity supply is a mains electricity supply.

Preferably, in at least one other mode of operation, said internal combustion engine is configured to deliver mechanical power to said at least one motor-generator via said mechanical transmission system, said at least one motor-generator being configured to generate electrical power from said mechanical power and to deliver said electrical power to the electrical system.

Optionally, in at least one of said at least one other mode of operation, said internal combustion engine delivers mechanical power to said mechanical load via said mechanical transmission system.

In preferred embodiments, the machine is operable in a first mode of operation in which said internal combustion engine delivers mechanical power to said mechanical load via said mechanical transmission system, and in which said internal combustion engine delivers mechanical power to said at least one motor-generator via said mechanical transmission system, and in which said at least one motor-generator generates electrical power from said mechanical power and delivers said electrical power to the electrical system. Optionally, the machine is mobile and comprises at least one wheel or track for conveying the machine along a ground surface, the electrical system comprising at least one electric motor for driving said at least one wheel or track, and wherein in said first mode of operation said electrical system is configured not to run said at least one electric motor.

Optionally the machine is mobile and comprises at least one wheel or track for conveying the machine along a ground surface, the electrical system comprising at least one electric motor for driving said at least one wheel or track, and wherein the machine is operable in a second mode of operation in which said internal combustion engine delivers mechanical power to said at least one motor-generator via said mechanical transmission system, said at least one motor-generator generating electrical power from said mechanical power and delivering said electrical power to said at least one electric motor. Preferably, in said second mode of operation said mechanical transmission system is configured not to supply mechanical power to said mechanical load.

Optionally, the machine is operable in a third mode in which said electrical system is connected to an external electricity supply and said electrical system delivers electrical power from said external electricity supply to said at least one motor-generator, said at least one motor-generator generating mechanical power from said electrical power delivering said mechanical power to the mechanical transmission system to drive said mechanical load. Optionally the machine is mobile and comprises at least one wheel or track for conveying the machine along a ground surface, the electrical system comprising at least one electric motor for driving said at least one wheel or track, and wherein in said third mode of operation said electrical system is configured not to run said at least one electric motor.

In typical embodiments, said at least one motor-generator comprises first and second motor-generators.

Typically, the electrical system includes an AC-AC electrical power conversion system, preferably an AC-DC-AC power conversion system, connected to said at least one motor-generator. In said at least one mode of operation, said power conversion system may be configured to convert AC electrical power received from an external electricity supply, preferably a mains electricity supply, to AC electrical power for said at least one motor-generator.

Optionally, in said at least one other mode of operation, said power conversion system is configured to convert AC electrical power generated by said at least one motor-generator to AC electrical power for said electrical system.

Said at least one motor-generator typically comprises more than one motor-generator, and said power conversion system may comprise a respective electrical power converter connected to each motor-generator.

In preferred embodiments, said power conversion system comprises an electrical power converter connected to a main circuit of said electrical system, said main circuit preferably being connectable to an external power supply.

In preferred embodiments, said power conversion system is an AC-DC-AC power conversion system comprising at least one AC-DC/DC-AC power converter connected to said at least one motor-generator, and an AC-DC/DC-AC power converter connected to a main circuit of said electrical system, and wherein the respective DC side of each converter are connected together.

Preferably said power conversion system is an AC-DC-AC power conversion system, and one or more battery is connected to the DC side of said power conversion system to provide electrical power to said DC side.

In preferred embodiments said machine is a material processing apparatus and said mechanical load comprises a material processing unit, for example a crusher.

Another aspect of the invention provides a material processing apparatus comprising: a mechanical30transmission system coupled to a mechanical load; an internal combustion engine coupled to the mechanical transmission system; an electrical system; at least one motor-generator coupled to the electrical system and to the mechanical transmission system, wherein, in at least one mode of operation, said electrical system is configured to deliver electrical power to said at least one motor-generator, said at least one motor-generator being configured to generate mechanical power from said electrical power35and to deliver said mechanical power to the mechanical transmission system to drive said mechanical load.

Other advantageous aspects and features of the invention will become apparent to those ordinarily skilled in the art upon review of the following description of a specific embodiment and with reference to the accompanying drawings.

