Two-stroke engine
AssigneeAndreas Stihl
InventorsMichael Wissmann, Harald Schliemann
Life of this patent
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Abstract
The invention is directed to a control system for a two-stroke engine for limiting a control quantity thereof such as the rotational speed. For this purpose, a pressure line including a valve is connected to the crankcase and leads to a pneumatic controlling member which is responsive to a mechanical or electrical signal (vibrations or electric pulse from the ignition system). By means of suitable transmission means, the movement of the controlling member is transmitted to the carburetor throttle, for example.
Claims26
A two-stroke engine equipped with a control device to control an operating condition of the engine, the engine comprising:
- a crankcase subjected to continuously alternating underpressure and overpressure conditions;
- signal means for providing a signal indicative of a predetermined value of the operating condition of the engine to be controlled;
- an output actuator connected to said control device for adjusting said operating condition;
- pneumatic actuating means responsive to a change in pressure therein for acting on said output actuator so as to cause the latter to adjust said control device to control said operating condition;
- pressure connecting means for connecting said pneumatic actuating means to said crankcase;
- and,
- valve means responsive to said signal for acting on said pressure connecting means so as to cause said pressure change to occur in said pneumatic actuating means.
A two-stroke engine equipped with a carburetor controlled by a throttle flap, the engine comprising:
- a crankcase subjected to continuously alternating underpressure and overpressure conditions;
- signal means for providing a signal indicative of the rotational speed of the engine to be controlled;
- an output actuator connected to said throttle flap of the engine for adjusting the speed thereof;
- pneumatic actuating means responsive to a change in pressure therein for acting on said output actuator so as to cause the latter to adjust the position of said throttle flap thereby changing the speed of the engine;
- pressure connecting means for connecting said pneumatic actuating means to said crankcase;
- and,
- valve means responsive to said signal for acting on said pressure connecting means so as to subject said pneumatic actuating means to one of said pressure conditions thereby causing said pressure change therein.
A two-stroke engine equipped with a carburetor controlled by a throttle flap, the engine comprising:
- a crankcase subjected to continuously alternating underpressure and overpressure conditions;
- signal means for providing a signal indicative of the rotational speed of the engine to be controlled;
- an output actuator connected to said throttle flap of the engine for adjusting the speed thereof;
- pneumatic actuating means responsive to a change in pressure therein for acting on said output actuator so as to cause the latter to adjust the position of said throttle flap thereby changing the speed of the engine;
- a pressure conduit for connecting said pneumatic actuating means to said crankcase;
- check valve means connected into said conduit for passing only waves to said pneumatic actuating means developed by said underpressure condition;
- and,
- venting valve means connected to said pneumatic actuating means for responding to said signal to supply air to said pneumatic actuating means so as to cause said pressure change.
Dependencies are inferred from the claim text.