Power management system for street sweeper

A power management system for a street sweeper comprising:

• a variable speed engine for transporting the street sweeper and for powering sweeping components of the street sweeper, said engine being operable within either an idle speed range and a full speed range;
• an engine speed sensor coupled to the engine for providing engine speed information to a control unit;
• a hydraulic pump powered by the engine;
• a vacuum fan motor powered by the hydraulic pump;
• an electric proportional valve coupled between the hydraulic pump and the vacuum fan motor, said valve for selectively restricting a flow rate of hydraulic fluid to the vacuum fan motor;
• and
• the control unit operatively coupled to the engine speed sensor and the proportional valve, said control unit receiving the engine speed information from the engine speed sensor and communicating a control signal to the proportional valve to control the flow rate of hydraulic fluid to the vacuum fan motor as a function of engine speed.

A street sweeper comprising:

• an engine for transporting a vehicle and for powering a sweeping mechanism and a vacuum system;
• an engine speed sensor coupled to the engine for providing engine speed information to a control unit;
• a hydraulic pump operatively coupled to the engine;
• a hydraulic vacuum fan motor powered by the hydraulic pump;
• a main cylindrical pickup broom coupled to the vehicle;
• a debris conveyer for transporting debris from the pickup broom to a debris collection hopper;
• a gutter broom operatively coupled to the vehicle;
• an electric proportional valve coupled between the hydraulic pump and the vacuum fan motor, said valve for selectively restricting a flow rate of hydraulic fluid to the vacuum fan motor;
• and
• the control unit operatively coupled to the engine speed sensor and the proportional valve, said control unit receiving the engine speed information from the engine speed sensor and communicating a control signal to the proportional valve to control the flow rate of hydraulic fluid to the vacuum fan motor as a function of engine speed.

A method of managing engine power for a street sweeper, said street sweeper including a variable speed engine, a sweeping mechanism powered by the engine and including a main pickup brush, a vacuum system including a hydraulic vacuum fan motor, an engine speed sensor coupled to the engine for providing engine speed information to a control unit, a hydraulic pump coupled to the engine, an electric proportional valve coupled between the hydraulic pump and the vacuum fan motor, said valve for selectively restricting a flow rate of hydraulic fluid to the vacuum fan motor, and the control unit operatively coupled to the engine speed sensor and the proportional valve, said control unit receiving the engine speed information from the engine speed sensor and communicating a control signal to the proportional valve to control the flow rate of hydraulic fluid to the vacuum fan motor as a function of engine speed, said method comprising the steps of:

• (a) operating the engine at a first selected engine speed;
• (b) communicating engine speed information from the engine speed sensor to the control unit;
• (c) selecting a proportional valve setting from among a group of valve settings;
• (d) communicating a control signal from the control unit to the proportional valve, said control signal associated with the proportional valve setting selected in step (c);
• (e) adjusting the proportional valve in response to the signal communicated in step (d) in order to adjust a flow of hydraulic fluid to the vacuum fan motor;
• and
• (f) repeating steps (a) through (e) with the engine operating at a second engine speed in order to manage engine power.

A power management system for a surface maintenance machine, said system comprising:

• a variable speed engine for transporting the surface maintenance machine, said engine operating within one of an idle speed range, an intermediate speed range, and a full speed range;
• a hydraulic pump powered by the engine;
• a vacuum system including a hydraulic vacuum fan motor powered by the hydraulic pump;
• an engine speed sensor coupled to the engine for providing engine speed information to a control unit;
• an electric proportional valve coupled between the hydraulic pump and the vacuum fan motor, said valve for selectively restricting a flow rate of hydraulic fluid to the vacuum fan motor;
• and
• the control unit operatively coupled to the engine speed sensor and the proportional valve, said control unit receiving the engine speed information from the engine speed sensor and communicating a control signal to the proportional valve to control the flow rate of hydraulic fluid to the vacuum fan motor as a function of engine speed.