Automated power unit assembly for a commercial vehicle

An automated power unit assembly for a vehicle, of the type comprising:

• --an internal-combustion engine;
• --an injection pump for supplying fuel to said engine, said pump being provided with actuating control means, which can be controlled electrically from outside the assembly, and with adjustment means defining a lower set value corresponding to a minimum speed value for running said engine and an upper set value corresponding to a maximum speed value, above which the fuel supply to said engine is decreased;
• --a mechanical, unsynchronised gearbox;
• --a clutch interposed between said engine and said gearbox;
• --actuating means which can effect engagement and disengagement of gear ratios of said gearbox;
• --first valve means for operating said actuating means of said gearbox;
• --actuating means which can effect engagement and disengagement of said clutch;
• --second valve means for operating said actuating means of said clutch;
• --a synchronising brake acting on a member of said gearbox;
• --actuating means and associated valve means for operating said synchronising brake;
• --manual gear selection means;
• --sensor means which can detect operating parameters of said power unit assembly;
• --transducer means associated with said manual gear selection means, and
• --an electronic processor receiving input signals from said sensor means and said transducer means and adapted to generate control signals for said valve means, said processor comprising first processing means for calculating the engine speed following the engagement of a gear ratio selected by means of said manual gear selection means, and to prevent said engagement if said speed does not come within a programmed range of values, characterized in that said upper set value of said adjustment means (33) of said injection pump (6) corresponds to a speed value of said engine (2) which is above an upper limit of said programmed range of values;
• said processor (18) also comprising second processing means (60, 61, 62) for detecting an emergency operating condition of said vehicle and for enabling a gear change corresponding to an engine speed above said programmed range of values when said emergency operating condition prevails.