Description: The essence of the invention is the wood chipper drive rotational speed control system with a spark ignition engine equipped with the object detection sensor in the chipper's feed channel and a controller that regulates the angular position of the carburetor throttle flap. In this system, the throttle controller is connected to a stepper motor, which works with the speed control lever. The lever is connected to a centrifugal mechanism regulating the position of the throttle flap in the carburetor by means of a strand. According to the invention, the preferred solution is when the carburetor, through a pressure reducer, is supplied with LPG gas or CNG gas. The benefits of the used solution, confirmed by scientific research, include: • reduction of fuel consumption and emission of toxic exhaust gases, • reducing operator stress resulting from operating costs, • automatic regulation of rotational speed (maintenance-free).
Increased awareness of the risks associated with exceeding the emission standards of harmful compounds in the air, especially in large cities, forces politicians and local authorities to take radical pro–ecological measures. One such direction is the reduction of anthropogenic harmful emissions in cities, and the other is the natural purification of these areas by developing green urban infrastructure. Trees in such areas, which absorb fumes, dust and noise, must undergo agriculture processes, i.e. cutting or pruning. The waste generated in the form of branches is processed by working machines. Processing mechanisms rely on their comminution to facilitate further transport, storage, composting or energy extraction processes. These machines are most often driven by internal combustion engines that consume non–renewable energy sources and emit harmful exhaust gases. They are dangerous especially for operators of these machines and for the immediate environment. Reducing the energy consumption of wood shredding processes and limiting the quantitative exhaust emissions generated by mobile shredding machines indicates the need to modify their design. For this purpose, it is necessary to interfere in the structure of the system and the algorithm for controlling the chipper's propulsion unit. Without taking such measures despite meeting the approval standards, which are much less stringent than in the case of motor vehicles, it will not be possible to limit the harmful effects of shredding machines on human life and health. The authors note that mobile shredding machines adapt to operating conditions in a limited way. Therefore, a decision was made to conduct development work in this direction. The goal of the developed constructions is to achieve high ecological and economic effects through the use of developed solutions based on innovative injection systems, adaptive systems responding to current working conditions and the use of alternative fuels. The solution in accordance with the patent application P.433586 reduces fuel consumption and the quantitative emission of exhaust gas from shredding machines, characterized by periodically variable work. Additionally, it can be powered by alternative fuels: LPG and CNG or biofuels. It can also work with innovative fuel injection systems for this type of drive (small engines). The closest solution to the invention is the system described in patent description P.423369 (also developed by the authors). The system uses an object detection sensor in the chipper's feed channel, which works with the air damper controller that changes the angular position of the damper flap. The control in this system takes place without detecting the engine load. In the course of research, it has been shown that controlling the rotational speed, while taking into account its changes resulting from the load on the system, allows to achieve additional benefits. Benefits of the used solution: a) regarding the change in rotational speed due to the branch in the feed channel: reduction of fuel consumption, reduction of quantitative emission of toxic exhaust gases, reduction of operator stress resulting from operating costs, automatic changea of rotational speed (maintenance-free); b) regarding the change of rotational speed due to the load: ensuring work with maximum power or torque of the machine, in the case of shredding machines insufficient torque during cutting of the branch stops the cutting mechanism, the system responds to the load delay lowering the risk of blocking the cutting mechanism and increases the machines ability to work under load, e.g. enabling the shredding of more branches at the same time, the load-responsive system reduces the likelihood of stopping the working unit resulting from overloading, the system positively affects the productivity of the machine, because the reaction to the reduction in rotational speed resulting from the load is reduced ensuring optimal processes production; Su
Organisation: Poznan University of Technology, Faculty of Mechanical Engineering, Machine Design Institute
Innovator(s): WARGUlA Lukasz, KUKLA Mateusz, WIECZOREK Bartosz, KRAWIEC Piotr