Throttle valve setting device

A throttle-valve setting device has, for idle adjustment, a motor setting lever (10) which displaces a throttle valve (3) and is connected via a path-dependent controlling movement-reversal device (15) to a setting member (13) of a setting motor (12). Thereby, upon activation of the setting motor (12), the setting lever (10) first swings slightly in one direction and then in the other direction to the full-load position of the throttle valve (3).

FIELD AND BACKGROUND OF THE INVENTION 
The present invention relates to a throttle-valve setting device which has 
a throttle valve setting lever which is connected to an accelerator pedal 
and actuates a throttle valve arranged, fixed for rotation, on a throttle 
valve shaft, the invention including a setting motor operating exclusively 
in the opening direction of the throttle valve against the force of a 
return spring in order to permit idling adjustment. 
Such throttle valve setting devices are provided in modern motor vehicles 
and are therefore known. 
In today's motor vehicles the internal combustion engine must produce 
different torques also upon idling. The power required, for example, 
increases when the air conditioner of a motor vehicle is to operate upon 
idling. When the internal combustion engine is cold, more energy is 
required in order to keep it operating than when the internal combustion 
engine is warm. In order to be able to keep the idling speed of rotation 
as low as possible under such different conditions, idling adjustment is 
being provided more and more generally. In such case, the throttle valve 
can be opened by means of the setting motor to a greater or lesser extent 
within a stipulated operating range without the driver having to actuate 
the accelerator pedal for this. 
The known idling controls have the disadvantage of their behavior upon 
failure of the energy actuating their setting motor. Ordinarily, the 
idling adjustment is designed in the manner that the throttle valve is 
swung, by a setting spring, into a position in which the idling speed of 
rotation reaches the upper value of the operating range available for the 
idling control. In practice, such high idling speeds of rotation induce an 
automatic transmission to enter into gear. If the idling control is 
developed in such a manner that, upon a failure of the external energy, 
the throttle valve reaches its substantially closed final position, then 
the internal combustion engine generally stalls upon idling, which is a 
nuisance and disadvantage for safety in travel. 
SUMMARY OF THE INVENTION 
It is an object of the invention to develop a throttle-valve setting device 
of the aforementioned type in such a manner than, upon failure of the 
energy of the setting motor upon idling, an average idling speed of 
rotation automatically results. 
According to the invention, for actuation of the throttle valve (3) by the 
setting motor (12), there is provided a movement-reversal device (15) 
which switches as a function of the distance. The movement-reversal device 
is mechanically connected in such a manner with a setting member (13) of 
the setting motor (12), that upon a displacement of the setting member 
(13) from its position which is the result of the return spring (5), the 
throttle valve (3) first of all swings slightly in the closing direction 
and then, upon further displacement of the setting member (13), in the 
opposite direction. 
By this development the result can be obtained that, upon a failure of the 
energy of the setting motor, the setting member is pulled by a setting 
spring into an emergency position in which the throttle valve assumes an 
average idle open position. By the operation of movementreversal device 
the result is obtained, upon the action of energy on the setting motor, 
that upon a displacement of the setting member, the throttle valve 
initially swings in one direction, then closes further and thereupon moves 
in the opposite direction until the throttle valve has reached the angle 
of opening which is maximum for the idling adjustment. Although the 
setting motor operates only in one direction, thanks to the invention, it 
is possible with the setting motor alone, by displacing its setting member 
in only one direction, first of all to close the throttle valve further 
and then, upon further displacement of the setting member, in the same 
direction, to open it further again. In this way, an optimal idling 
control is possible without there being an undesirably high speed of 
rotation of the engine or a stalling of the engine in the case of failure 
of the energy of the setting motor. 
The displacement of the throttle valve for the purpose of idling speed 
control must be superimposed on the throttle-valve displacement by the 
accelerator pedal. This can be done in simple fashion by providing a 
double-armed driver lever (4) which is connected, fixed for rotation, on 
the throttle-valve shaft (2) and urged by the return spring (5) in the 
closing direction of the throttle valve (3), against which driver lever 
(4) the throttle-valve setting lever (6) rests from one side by means of a 
driver (7) against a lever arm of the driver lever (4) and against which 
the motor-setting lever (10) rests from the other side via a driver (11) 
on the other lever arm. 
The movement-reversal device can be developed very simply from mechanical 
structural parts in that, in accordance with one advantageous feature of 
the invention, the movement-reversal device (15) has an intermediate lever 
(16) which is pivoted on the motor setting lever (10) with a toggle-joint 
lever pivot (17) and on the setting member (13) of the motor (12), said 
intermediate lever being held in the end position which results when no 
energy is acting on the setting motor (12) by a setting spring (14), 
against a stop (20) fastened on the housing between the articulation on 
the engine-setting lever (10) and the setting member (13) and in the 
manner that the motor setting lever (10) has, on the side opposite the 
stop (20), a driver (18) against which the intermediate lever (16) can be 
moved after slight swinging in the setting direction of the setting motor 
(12). 
Since the setting motor must operate against the return spring and the 
setting spring for the displacement of the throttle valve for adjusting of 
the idling, it is desirable that the force of the setting spring be as 
small as possible. This is achieved by urging the motor setting lever (10) 
and the intermediate lever (16) into the inward position by a leg spring 
(19) which is weaker than the setting spring (14) and is arranged on the 
toggle-lever pivot (17). By this development, the force of the leg spring 
no longer increases despite an increasing actuating stroke of the setting 
motor as soon as the intermediate lever rests against the driver of the 
motor setting lever. 
Another very simple embodiment of the movement-reversal device (15) has a 
bell-crank lever (21) with a first lever arm (22) against which the motor 
setting lever (10) is held, forming a tilt axis, and with a second lever 
arm (25) against which the setting member (13) of the setting motor (12) 
is held by the setting spring (14). Also, at the end of the setting member 
(13) there is provided a driver (23) which, after a short stroke, in the 
direction which results from the action of energy on the setting motor 
(12), arrives against the motor setting lever (10). 
Another particularly simple embodiment of the throttle-valve setting device 
(15) is formed by a cam (27) on the motor setting lever (10) against which 
the throttle-valve setting lever (6) rests. The cam makes it possible to 
develop the dependence between the stroke of the setting motor and the 
throttle-valve angle as desired. 
Such a setting device is constructed in very simple manner with a cam if 
the motor setting lever (10) is formed as a double-armed lever swingable 
around a shaft (26), and having a first lever arm of which the setting 
member (13) of the setting motor (12) is pivoted and a second lever arm 
which includes the cam (27). 
A precise adjustment of the throttle valve setting device can be obtained 
with a very simple structural part if the shaft (26) of the engine-setting 
lever (10) is developed as an adjustment eccentric which permits 
displacement of the motor setting lever (10).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the graph of FIG. 1, the optimal throttle-valve opening angle is plotted 
over the setting path of a setting motor. It can be noted that, upon 
actuation of the setting motor, the throttle-valve opening angle decreases 
first of all from about 5 degrees to about 0 and then increases to about 
25 degrees. The region close to 0 degrees to 25 degrees is the operating 
region in which the idling control operates. If the energy of the setting 
motor fails, then a return spring can move the setting member of the 
setting motor into an emergency position in which the throttle valve is 
open about 5 degrees. The optimal course of the characteristic curve shown 
in FIG. 1 can be obtained with the two throttle-valve setting devices 
which are shown in the following figures. 
FIG. 2 shows a throttle-valve housing 1 within which a throttle valve 3 is 
arranged in non-rotatable fashion on a rotatably mounted throttle-valve 
shaft 2. Furthermore, a double-armed driver lever 4 is arranged in 
non-rotatable manner on a throttle-valve shaft 2, said shaft being urged 
by a return spring 5 in clockwise direction and thus in the closing 
direction of the throttle valve 3. 
Below the driver lever 4, a throttle-valve setting lever 6 is arranged, 
mounted rotatably on the throttle-valve shaft 2, the lever 6 resting via a 
driver 7 from below against a righthand lever arm of the driver lever 4. 
On the lower end of the throttle-valve setting lever 6, there acts a rod 8 
which can be displaced by the accelerator pedal 9 between an idling 
position LL and a full-load position VL. If the accelerator pedal 9 moves 
from the idling position LL shown in the direction of the full-load 
position VL, then the throttle-valve setting lever 6 swings in 
counterclockwise direction. In this connection, the driver 7 swings the 
driver lever 4 in the same direction of rotation, so that the throttle 
valve 3 opens increasingly. 
A motor-setting lever 10 extends from above into the throttle valve housing 
1. This motor setting lever 10 is also mounted rotatably on the 
throttle-valve shaft 2 and has a driver 11 which rests from above against 
the left lever arm of the driver lever 4. For automatic motorized 
displacement operation of the throttle valve 3 for control the idling, 
there is provided a pneumatic-setting motor 12 which has a setting member 
13 which can be moved to the left, as seen in the drawing, by the action 
of vacuum on the setting motor 12 against the force of a setting spring 
14. There is of importance for the invention a path-dependent controlling 
movement-reversal device 15 which connects the end of the setting member 
13 with the motor setting lever 10, and by which the result is obtained 
that, upon movement of the setting member 13 to the left, the motor 
setting lever 10 is first of all swung in clockwise direction and then in 
counterclockwise direction (the sequence indicated by the position of FIG. 
3 followed by the position of FIG. 2 followed by the position of FIG. 4). 
In the case of the embodiment shown in FIG. 2, the movement-reversal device 
15 has an intermediate lever 16 which is pivoted on the end of the setting 
member and is connected by a toggle-lever articulation 17 to the motor 
setting lever 10. In the stretched position, shown in FIG. 2, the 
intermediate lever 16 lies against an upward pointing driver 18 of the 
motor setting lever 10. A leg spring 19, arranged on the toggle-joint 
articulation 17, acts on the intermediate lever 16 and the motor-setting 
lever 10 in such a manner that these two levers attempt to move out of 
their stretched position with respect to each other. 
For the operation of the movement-reversal device, it is furthermore 
important that the intermediate lever 16 rest against a stop 20 fastened 
to the housing on the side facing away from the driver 18 between the 
toggle-lever articulation 17 and the setting member 13. 
FIG. 3 shows that position of the structural parts described above which 
results when the setting motor is acted on by energy in the end position 
and, therefore, in that position in which the throttle valve 3 is open 
maximum upon the idling control. The setting member 13 is, in this case, 
moved maximally into the setting motor 12 so that the intermediate lever 
16 has been correspondingly swung to the maximum amount to the left 
against the force of the setting spring 14. Since the intermediate lever 
16 rests against the driver 18, the motor setting lever 10 concurrently 
has been swung in counterclockwise direction. The setting lever 10, by 
means of its driver 11, presses against the driver lever 4 and thereby has 
also swung the latter in counterclockwise direction against the force of 
the return spring 5 so that the throttle valve 3 has been correspondingly 
opened. 
During the idling control, the structural parts shown move between the end 
positions shown in FIGS. 2 and 3. FIG. 4 shows an emergency position which 
results upon failure of activation of the setting motor 12. In this 
position, the setting spring 14 has pulled the setting member 14 so far to 
the right, as seen in FIG. 4, that the intermediate lever 16 has been 
swung in clockwise direction slightly around the stop 20, which has led to 
an inward movement of the toggle-lever joint 17 and thus to a swinging of 
the motor setting lever 10 in counterclockwise direction. In this way, the 
motor setting lever 10 has been able, via the driver 11, to swing the 
driver lever 4 slightly in counterclockwise direction so that the throttle 
valve 3 is in a somewhat more open position than in FIG. 2. 
In the embodiment according to FIG. 5, the movement-reversal device 15 has 
a bell-crank lever 21 which is swingably mounted on the throttle-valve 
housing 1 and rests, with the end of a lever arm 22, against the 
motor-setting lever 10 which, in this embodiment, is extended out of the 
throttle-valve housing 1. The setting member 13 of the setting motor 12 
has a driver 23 on its end and, when the setting motor 12 is not acted on 
by pressure, is held by the setting spring 14 against the lever arm 25 of 
the bell-crank lever 21 so that the latter rests against a stop 24 which 
is fastened to the housing. 
If the setting motor is acted on by vacuum, then the setting member 13 
starts to move toward the left. In this way the bell-crank lever 21 swings 
in counterclockwise direction because the motor setting lever 10 presses 
against the lever arm 22 under the action of the return swing 5. The motor 
setting lever 10 thus follows the backward moving lever arm 22 toward the 
right. In this way the throttle valve 3 moves in closing direction. When 
the setting member 13 has been shifted so far to the left that the driver 
23 comes against the motor setting lever 10, the driver 23 then moves the 
motor setting lever 10 with it toward the left. In this way, the driver 
lever 4 is swung in counterclockwise direction, which leads to an opening 
of the throttle valve 3. 
In the embodiment of the invention shown in FIG. 6, the motor setting lever 
10 is developed as a double-armed lever which is swingable around a shaft 
26, developed as adjustment eccentric. The setting motor 12 is articulated 
on the lower motor-lever arm of the motor setting lever 10, as shown in 
FIG. 6, by the setting member 13. The other lever arm has, on its free 
end, a lift cam 27 which is so shaped that the motor setting lever 10 as a 
whole has the shape of a boot, the travel surface of which is formed by 
the lift cam 27. Against this lift cam there rests the throttle-valve 
setting lever 6 which is firmly connected to the throttle-valve shaft 2 
which actuates the throttle valve 3 in the throttle-valve housing 1. A 
setting spring 28 which is arranged on the setting member 13 urges the 
motor setting lever 10 in counterclockwise direction of rotation. In the 
position of the parts shown in FIG. 6, the throttle valve 3 is closed. The 
setting motor 12 must, in this case, be activated on by electric current, 
or hydraulic pressure or vacuum, depending on the construction of the 
motor 12. 
If the setting motor 12 is acted on by more current than in FIG. 6, the 
setting member 13 is increasingly pulled into the setting motor 12. The 
position which results upon maximum flow of current, in which the throttle 
valve 3 is maximally open, is shown in FIG. 7. The motor setting lever 10 
has, in this connection, swung so far in clockwise direction that its lift 
cam 27 has swung the throttle-valve setting lever 6 correspondingly in 
counterclockwise direction and now rests with a lefthand region of the 
lift cam 27 against the throttle-valve setting lever 6. 
If the electric energy of the setting motor 12 fails, then the setting 
member 13 moves a maximum amount out of the setting motor 12 as a result 
of the action of the setting spring 28, and the motor-setting lever 10 is 
swung in counterclockwise direction around its shaft 10. The position of 
the parts which results from this is shown in FIG. 8. The lift cam 27 then 
presses with a region forming the shape a shoulder, or heel of the boot, 
against the throttle-valve setting lever 6. The throttle valve 2 is opened 
slightly in this emergency position. Thus the same dependence results 
between the throttle valve angle and the setting path of the setting 
member 13 in the embodiment of FIGS. 2-5 as in the embodiment according to 
FIGS. 6-8.