摘要:
Fuel injection arrangements having pneumatically driven injection pumps utilize the fluctuating crankcase pressure whereby the injection time point is fixed by the system. The injection time point can be fixed so as to depart from the course of the pressure in the crankcase if the crankcase pressure is applied to the injection pump via an opening controlled by the piston and if the pressure drop is directed to the combustion chamber via a relief opening. However, it has been shown that this kind of control produces considerable problems with respect to fast-running two-stroke engines. Accordingly, it is a feature of the invention to provide a check valve in the connection between the relief opening and the injection pump and to position this check valve so that it opens in the flow direction toward the combustion chamber. In this way, high pressures which occur as a consequence of incomplete or irregular combustions in the combustion chamber cannot have a feedback effect on the injection pump and the quantity injected is not increased in a disadvantageous manner for the next cycle.
摘要:
A pneumatically operated fuel injection pump has a work chamber which is partitioned by a membrane into a pulse chamber and a return chamber. The pulse chamber is charged with crankcase pressure from a two-stroke engine while a counterforce is built up in the return chamber which varies with rotational speed. A counterforce is developed by means of a precise pressure control in the return chamber which makes possible a highly precise injection adapted to rotational speed. For this purpose, the return chamber is connected with an adjusting volume via a throttled flow path. In addition, a leaf spring is mounted in the return chamber and is utilized as a return spring for the membrane.
摘要:
The invention relates to a two-stroke engine having an overflow channel through which an air/fuel mixture is supplied. The overflow channel is provided with a vaporization chamber having a hot wall against which fuel is injected and vaporized. The vaporized fuel is stored in the vaporization chamber and is carried into the combustion chamber of the engine by fresh air flowing in from the crankcase when the overflow channel is opened. Even at high rotational speed, a good mixture preparation is asssured.
摘要:
A hand-held working tool has a housing and an internal combustion engine arranged in the housing and comprising a crankshaft and an air filter. A tool is driven by the crankshaft of the internal combustion engine. A fan housing is attached to the engine housing and has an air inlet. A fan wheel is arranged in the fan housing and is driven by the crankshaft of the internal combustion engine to supply cooling air, sucked in through the air inlet, to the internal combustion engine. The fan housing has a bottom extending radially to the crankshaft. The bottom and a side of the fan wheel facing the bottom define a chamber in the fan housing. The bottom has a combustion air outlet. A combustion air channel is connected to the combustion air outlet and to the air filter. The combustion air outlet is axially supplying combustion air from the chamber through the combustion air channel into the air filter of internal combustion engine. The fan housing has a channel wall having a bottom portion connected to the face of the bottom remote from the fan wheel and covering the bottom partially to form a double-walled bottom. The end face portion of the combustion air channel is defined by the bottom and the bottom portion of the channel wall. In an alternative embodiment the combustion air channel is provided in a hollow beam of a support that supports the drive unit of the working tool.
摘要:
The invention is directed to a tensioning arrangement for saw chains of motor-driven chain saws which include a device for longitudinally displacing the guide bar. The clamped guide bar is released so that the adjusting arrangement can be actuated for the longitudinal displacement of the guide bar. By rotating a disc having a spiral slot, a slide piece, which is coupled to the guide bar, is displaced in the longitudinal direction. Assembly is simplified and handling facilitated when the tension in the saw chain is adjusted. This is achieved by making the slide piece on the spiral disc so that it is not released therefrom but instead is held so as to be rotationally and longitudinally displaceable. The slide piece is fixedly connected to the guide bar by using appropriate attachment devices.
摘要:
The invention is directed to a tensioning arrangement for a saw chain of a motor-driven chain saw. The saw chain runs on a guide bar mounted on the motor housing of the chain saw. The tensioning arrangement includes a rotatable disc having a spirally-shaped guide slot in which a lug of a slide piece engages. The longitudinal displacement of the guide bar is provided by rotating the disc. The guide slot in the disc extends over a rotational angle of at least 270.degree.. A still lesser slope of the guide slot is provided with a rotational angle in the range of 360.degree. to 450.degree.. The tensioning arrangement is especially suitable for adjusting the guide bar in motor-driven chain saws thereby adjusting the tension in the saw chain.
摘要:
The invention relates to compounds for producing polymethacrylimide foam materials (PMI foams) with particularly good mechanical properties, in particular with a particularly advantageous elongation at tear. The invention further relates to methods for producing, processing, and using said foam materials. In particular, the invention relates to novel materials, the propensity of which to form tears is clearly reduced in comparison to the prior art. This is tantamount to an elongation at tear that is higher in comparison to the prior art.
摘要:
A two-stroke engine has a cylinder with a combustion chamber and a reciprocating piston for driving a crankshaft. Transfer passages connect the crankcase in at least one position of the piston with the combustion chamber and open by piston-controlled transfer ports into the combustion chamber. An inlet opens into the crankcase and an outlet is provided at the combustion chamber. The engine is dividable into four sectors parallel to a longitudinal cylinder axis. The transfer port of a first transfer passage is arranged in the first sector, the outlet is arranged in the second sector, the transfer port of a second transfer passage is provided in the third sector, and the inlet is arranged in the fourth sector. Within the cylinder the first and second transfer passages, at a spacing from a separation plane between cylinder and crankcase, pass together into one of the second and fourth sectors.
摘要:
The invention relates to compositions for producing poly(meth)acrylamide foam materials having particularly reduced flammability. The present invention further relates to a method for the production, the processing and the use thereof.
摘要:
An online discussion recommendation system ranks and presents to users of a social media site discussions of interest preferably calculated through interest-matching. The discussion has many online posts. The system and method determine which post to present to the user as a sample snippet from such discussion using sentiment analysis. The sentiment of the snippet may be most polarized, sentiment matching the user's current mood, typical user sentiment, or others.