DE2107302C - Decompression device to facilitate the start of two-stroke internal combustion engines - Google Patents

Description

.Start process a connection from the pressure chamber of the sucked mixture back into the suction line.

a flushing lift pump into the atmosphere so that the filling is reduced.

is cash. characterized in that the compression resistance of the scavenging air pumpc

the scavenging air pump is a crankcase pump; it is not affected.

and the device through the decompression * - German patent specification 253 141 shows a de-

valve (4. 11) is formed. λ not an outward compression arrangement. at the during the Anh-i-

opening back sleep. cntil is. that the connection movement of both the working cylinder and.!; ..

in the event of overpressure in the crank case (1), the purge air pump opens continuously with the atmosphere. and closes at negative pressure, and that the actuation remains to switch off the starting resistance

gungsorgan (7. 8) the Dekompressionsveniil after Instead, it can also be provided that only d>.

the mentioned part of the starting process in the closing scavenging air pump connected to the atmosphere i-i

holds position. ~ "But that means that the scavenging air pipe is true

2. Decompression device not fully compliant with the starting process of ck'r function 1. characterized in that the loading 25 is connected.

actuating element with a hold-down device (4) for From IJjA.-Patent 2 773 4.N9 it is Ix

the non-return designed as a flap valve. with two-stroke internal combustion engine :! with crank

cooperates valve, the hold-down box pump a valve in a connection between

can be brought into two end positions and at least see the inside of the crankcase and the atmosphere the one direction of movement by e..ie crank 30 as a non-return valve that can be opened to the outside.

or curve or an eccentric (8) or the like. The voltage of a valve in

is influenced, the or the spring pushing its closed position arbitrarily

management organ is controlled. is adjustable. so that the valve is predetermined in the case of

3. Decompression device after Ante maximum of the pressure ii. the crank case Claim 1, characterized in that the valve 35 opens. However, it is also provided that dL til is spring-loaded in the closing direction and fuel supply from the pressure in the crankcase ahd that a mechanical transmission of motion is essential. The reduction in crankcase pressure that connected to the starting device of the engine during starting thus causes verdening Actuator on the valve in opening- minimizing the fuel supply during the other Direction acts. 40 lassens. Such a dependency is undesirable.

4. Decompression device as instructed! during fuel cranking Claim 3. characterized in that the start is required.

device consists of a rope start arrangement. After all, it is with a two-stroke internal combustion engine!) which is provided with a switch-off point for the rope with crankcase pumps known, a decompresist, which is so arranged. that when stretching the 45 sion in the crankcase through a throttle duct! to Rope at least partially reach the closing force required by the main pump chamber of the crank the valve is relieved in such a way that it verunter box pump with a Nepen pump room the overpressure in the crankcase opens. binds. The decompression effect of this throttle

5. Decompression device after the canal is greatest at low speed and Claim 3, characterized in that the 50 disappears at higher speeds. If only Starting device from an electric starter to decompression during starting ermotor with an electromechanical contact is desired, such a device is suitable There is a device that does not work with the actuating device, since it is always an active element at low speeds connected is. will sam.

6. Decompression device according to An 55 The invention is therefore based on the object Claim 2 and 3, characterized in that the one decompression device of the initially ge-Stijrtvorrichtung of the engine of a type mentioned above, by means of which the goes back to the device for introducing pressurized gas into the engine compression in the scavenging air pump cylinder consists. Starting resistance is reduced, but by the

60 Function of the purge air pump during starting

is not turned off completely. Furthermore,

seeks that the decompression action only during

of the starting process and not always at low

The invention relates to a decomprcs- speeds occurs.

sieve device to facilitate the start of two 65 The solution according to the invention is that

Cycle internal combustion engines with a decompression - the scavenging air pipe is a crankcase pump and

valve for intermittently keeping the device open by the Dekompressionsventii

Connection to the atmosphere is established during a part. which has an outward opening back

<f

.ien.

-! on

. _rdcn.

Hilasveiiiil is. that the connection opens when overpressure and that the actuating member the Dek.iiiip: -, .- ior, svcntil μ de- after said part: ü - ,,;,; ",," hlie _{in ^Sc::} -; holds RECOVERY.. ^

Q _{l (} · c'iiiidungsgeinäß 1 oue kam-, ■ · ■.> ..- hj m combination with an IX-k "i: ipr _l .-- o ::.; ..! -..-.- ,!. _ul , _i . _{i on the} sinner as well as without a -Heil ud..r independent of such aii ^ e .-. u:;:. et> _: <! en. The latter-: -t then of importance who ·:,.: .-; · \ lotor with a · compressed gas S'arv.orp.iuup .: ·,.; -.; -, "· ;.;. · ... where '-: ■! Zv linde; als Druvkk ..: ni _; n .: -. _-. <. "-I-.dei _w i _r j. I :: ■ die Starthewegu.ig eüv ^ e ;;: .:. - ^ -oü but aii-- " ^: '' another start; · ;.! · -.:·-. _ ·":. ■■. e-idhir S-Mn. b ·. ■ ^: ice-wise with ai N. ■ '■■■■ ..-', ■■.: ■. ..- .. -; j _c , ^ j _ncr - ivn arrangement becomes - .., - ■: v .. ie j _;!> Se! ⁿ he actuation ■: ■. ■ .-; ■■: ■ ;.,;.; ._ .. _m . pres-i · - '<drawn ι- ■■■ . ■ · ..; _i: \ / \ UEN / Jer al - '''' ° zvv or d :: - k .. :: .. ■ · .. · ■ _{v... llbe} j (]: through the flute r. ;; ■■ ., ■, .-. mui .-- ,, becomes. '· ■' ■ the motor mitteK.! -. τ .N-- i .- ' , Uüi 'antiehi-. Will. Hin Motor: pn J.' · :. v.:r!·

motor ΝΠ also with .- ::; er. ■ ':> ■■. . _{; Πν} sv'SteiT .-. 'Measured the Erfmdune: · ■ · .. wöbe: i ", zvveckiform'uepv. I- ..' · .: wende:: ie with the same M: · ... .. Can be operated rigidly. Below - ^: below α ünen. Without the. Motor -.being broken - ce- ~ -..: Still. - the restoration ::, -.- ^! By -n -. Can a manu. '■ · ■■■ .. ■; scher -chaltkonlakt for die-c \. .... -.:·■ In the S: notor this becomes u ·;) n: ..; ■ _: - , of the motor .her some compression.:.: ■, m _; . _; .: m of the star! ^1. ■. ■ .-. ifs saved, which means the M:.;.: .. ^ -ehonted ■ ' icrell seen is hei ^ ■ -. · _; , _: ,., · ^: · _ _{.; ι;} !;, _. from (i- used Startv- qri. ■! ■ ::. i-iü .tlic -Jn -Eesp :: ^T '-as in particular then.; ■■;: ej ^ h ;; i..her \' orlei!! ■ - '-Vcnη only one bi- _; -. _:; ),:,. -: ner ^ i.uaelle zur Veriui:.: ^r ig sielu.

H ^ execution example! dci! : i :: i:! u ;; L is used in folee :; in by reference: Ui "d e /e-.e'viniii: ^ eschri.i : i. Ls shows

Fi'- .. i die DekompressHHisanof.jiii! "^ Üeinäß der IZrfin. '! :: i; · including control unit m 1 \> μ i / orr aipioiektiiui, Γ ;;: 2 the arrangement uemäi.i Lii :. i u \ Veiukalprojeki ': "ii and

f-'i _ ■ ί the arrangement in a rope projection. The arrangement shown in FIG. 1 is mounted on an end wall of the crankcase 1 of a two-stroke engine, the crankshaft 2 of which is protruded by a lurker in the end wall; -.in the. In the front wall of the crankshaft there is a continuous channel 3 (I-ig. 3) with a (Minting, with which a valve body 4 cooperates to open and close the channel between the interior of the crankcase and the environment. The valve body is firmly seated at the end of a curved arm 5, which is mounted pivotably up and down in a bearing 6 and at its other end has a cam button? which interacts with a cam disk 8 on a shaft 9. The valve body presses due to the action of a spring 10 between the arm and the crankcase but on the outside on a rubber pipe 11 against the CX opening and seals periodically because the button and cam are in contact by means of the plate against the duct opening. If the valve body and the plate are separated, the plate is against the Ötnunsi nesogen and the duct closed. If there is overpressure in the crankcase, the plate is pressed outwards by the opening Channel neötTnet and the crankcase is vented. This shows how the valve works during a start-up process. During the upward movement of the piston, a negative pressure is created in the crankcase, which is maintained by closing the valve, so that a cast mixture is blown from the carburetor into the crankcase, which gas is emptied through channel 3 when the piston is moved downwards as a result of oiling the valve. As a result, the approval of the gas from the carburetor is already in motion at the beginning of the start, which is an important Bediiiiiunii for the Lrfo ^: the start attempt. since from then on the compression starts again and the gas is blown into the cylinder in place. During the time in which it is active, the valve has the function of a non-return valve in the crankcase wall with the opening path directed outwards from the crankcase. The control element shown in the drawing, which keeps the valve closed after its time has expired. will now be described in more detail.

The control unit has a revolution counter that starts at the same time as the crankshaft closes turning begins. The counter consists of a driver 12 on the end of the crankshaft and one with Teeth 21 provided dental arch 13 on a slidable and pivotable plate 14 one protruding from the crankcase front wall Pin 15 is mounted. The bore 16 for the storage of the plate 14 is an elongated hole so that the toothhogen in and outside of F.ingrili with the driver can be moved. The shift towards the driver is achieved by turning the shaft 9 Done clockwise, save in the holder 17 is lurked on the crankcase and provided with three radially advancing wings 18, of which in the functional phase shown in the drawing, one with the bar 19 on the circular arc Outer edge 20 of the plate 14 cooperates. During this rotation of the shaft 9 of about 1 / s one full turn the cam comes into engagement with the cam switch 7. so that the valve Il biginn. to act as a flap valve. The cam is a circular disc with three recesses k so placed with respect to the wings 18 are that the course button slides on a curve when at the same time a wing against the bar beats.

When the engine is started, the procedure is as follows: The shaft 9 is rotated, preferably with the aid of an actuating element not shown. For example, a pulley for the starter cord in a cord starter or a hand crank or ein.w Startschlussis, so that the wing closest to the bar 19 guides the plate as far as possible to the right in FIGS. The wing is kept pressed against the bar by means of the actuating member during the entire take-off process. As the crankshaft rotates, the driver advances one tooth 21 for each revolution, and the plate is pivoted about the pin 15 through a corresponding angular amount. If the one outer end of the disc 14 to the

When the driver approaches, the edge of the wing slides of the bar 19. and the axis 9 is driven by the actuator by another approximately Ve turn turned. The curve truck now slides into a recess in the cam disc, whereby the valve body is pressed against the rubber plate 11, so that the channel 3 during the remains closed and the engine starts afterwards. A tension spring 22 between the plate 14 and a point on the crankcase pulls the plate back into its left end position and swivels it back (Fig. 1), the dental arch on the driver located in the recess passes by. At the next start, the axis 9 is rotated again by one Ve revolution, so that the next wing 18 comes into contact with the strip 19.

The control member shown can also be used to advantage for controlling a pressurized gas starting device the rotation of the shaft 9 is applied in stages for the control of a Valve of a proportioning element or the like in such a starting device. This control for the The supply of pressurized gas is carried out synchronously with the control of the crankcase valve. To be well-defined To obtain angular positions on the shaft 9, the arrangement is provided with a stop element 23, which cooperates with the wings 18 and which consists of projecting parts of a disc, which is attached to the shaft 9 next to the cam. This is done by means of a resilient one-way clutch 24 connected to a control shaft 25, which in turn is connected to the actuator for the arrangement connected. The stop member 23 is on a pin projecting from the crankcase 26 pivotably arranged and has two protruding arms 27,28, of which the first with a voi the wings 18 and the other with a control pin 29 on the outside of the control axis 25 gc listening coupling part cooperates. Who this part is rotated (approximately '/., Turn) the pin 29 pivots the arm 27 out of the wing disc, and this together with the shaft 9 and cure vcnscheibe is by Ve turn from one in de

ίο One-way clutch contained spring rotated so that the closest wing of the wing disc hits the bar ΊΙ9. Figs. 1 and 2 show this Position where the control axis Vj is rotated one revolution and is held in this position while the starting device is working. When one end of the groin (the dental arch and the groin are symmetrical in relation to on the center line of the plate 14 to make the take-off in both directions possible) the wing disc reached, the ledge leaves contact with the wing and the disk continues to rotate Ve turn. Since the control axis is then turned back, the wing disc is prevented from moving back to go to the rear edge of the wing, which now strikes the outside 20 of the bar. the

The leading edge: the wing is hooked by the arm 27, which goes back to the swiveled-in position, whereupon the position of the wing disc is fixed. When using a power other than pressurized gas, which is introduced into the cylinder, the arrangement described can be supplemented or modified for the decompression also in the Cylinder during takeoff. A special valve or the said valve for propellant gas can can be applied and controlled with an organ similar to that described above.

1 sheet of drawings

Claims (1)

1 2 of the Startvoniangs and with an actuator claims: for ά ~ * decompression valve. whereby a Vornch- is provided. by which during the 1. Dckompressionseinrichtun «to the starter part of the ~~ start process a connection from the pressure from two-stroke internal combustion engines with a scavenging air pipe into the atmosphere Dekompressionsvemil to be immiuieren- adjustable. . . keeping open a connection to the Atrno- The German patent specification 676 (K) I shows em D- spherical compression valve on the working cylinder during part of the "starting process" and with an actuator for the Dekom internal combustion engine, which after the visual lifting Jc-. compression valve, where. ne device in front of the inlet valve at low speeds, i.e. in particular see is. through which during the part of the special also when touching, part of the eye