US2789802A - Coasting economizers - Google Patents

Description

April 23, 1957 No Load M. B. HEFTLER 2,789,802

COASTING ECONOMIZERS Filed Sept. 11. 1953 FIGURE l mum; 2 INVENTOR.

United State Farm COASTING ECONOMIZERS Maurice Ben Heftler, Grosse Pointe Park, Mich.

Application September 11, 1953, Serial No. 379,531

2 Claims. (Cl. 261-69) It is advisable in certain applications of gasoline engines to provide the carburetor with a device often known as a coasting economizer. This device shuts off the flow of fuel to the engine during deceleration, and thereby avoids the partial combustion that otherwise occurs. One type of such device is described in Patent Number 2,699,157. This device, like practically all devices for the purpose known in the art, is responsive to the increase in intake manifold vacuum that occurs during deceleration. It functions very well on the typical industrial engine, which has but a moderate increase in manifold vacuum as the throttle is opened from its idle position without load on the engine. Its special feature is that the rise in the suction of the fuel channel is applied to the opposite side of the diaphragm from the side that is exposed to the manifold vacuum so as to counterbalance the effect of the rise in manifold vacuum as the throttle is opened with the engine at no load.

But there are types of engines designed for other classes of service in which there is a very considerable increase in manifold vacuum as the throttle is opened without load on the engine. This increase may be so great as to obscure the relatively small increase that occurs on deceleration, and to make it quite impossible to use the deceleration increase to actuate a coasting economizer.

This invention solves the above stated problem. It provides a simple way to use a vacuum coasting economizer on an engine with a large amount of manifold vacuum increase as the throttle is opened without load on the engine. It makes it possible to achieve sensitive operation over a considerable range of throttle positions and amounts of deceleration.

Figure l is a schematic drawing of the pneumatic system involved in this invention.

Figure 2 is a graph of the vacuums involved in this device.

Referring to Figure l, the intake manifold of the engine is shown by 1, on which the carburetor is mounted, the venturi of which is shown by 2. The main nozzle 3 discharges into the venturi. The air flow through the carburetor is controlled by the throttle 4. The vacuum responsive part of the coasting economizer is shown by 5. Increase in vacuum is used to shut off the fuel during deceleration by admitting air through passage 12 into the conventional idle circuit 13--14 in sufiicient quantities to reduce the vacuum existing on idle fuel jet 15 to below its threshold value. This is the method used in Patent 2,699,157. The fuel could also be shut ofl? by having the diaphragm 13 actuate a needle valve in the emulsion channel, as shown in Patent 2,751,201. Chamber 5 is connected, through channels 6 and 7, to the inlet manifold 1; chamber 5 is also connected, through channels 6 and 9, to a port 10 in the wall of the carburetor bore located with respect to the throttle plate 4 in such a way that port 10 is exposed to manifold vacuum when the throttle is in the idle position and exposed to vacuum between the throttle plate and venturi when the throttle is opened to about quarter throttle. The pneu- Z,789,8 02 Patented Apr.. 23, 1 957 'ma'tic' characteristics of the connection betweenchainber *Sand manifold -1-is fixed by -a suitable restrictions at the junction of channels 6 and 7; likewise the pneumatic characteristics of the connection between chamber 5 and port 10 is fixed by a suitable restriction 11 at the junction of channels 6 and 9. The restrictions 8 and 11 may of course be omitted if the channels 7 and 9 are of suitable bores and lengths.

This invention is applicable to engines that have a large increase in manifold vacuum at no load as the speed is increased from idle. It is not needed otherwise. The need increases as the steepness of the manifold vacuum curve increases. High duty engines, such as used for aircraft, for racing, and for some military purposes, have a large increase in manifold vacuum as the throttle is opened from idle at no load. This results from the timing of the valve events that gives highest power at full throttle.

The vacuum obtained from channel 7, which is connected to the manifold, is modified by vacuum obtained from port 10. A graph of these individual vacuums involved is shown in Figure 2, taken at no load. The manifold vacuum is labeled V7 and it will be noted that it increases as the speed increases; the vacuum in port 10 is labeled V10 and has the opposite characteristic of decreasing as the speed increases. The ideal vacuum for actuating a coasting economizer would be one which neither increases nor decreases as the speed is increased at no load. Such an ideal vacuum is obtained by blending vacuums V7 and V10, the blending being accomplished by connecting both vacuums to a common channel 6 through suitable restrictions 8 and 11; and the result is a vacuum V6 which is practically level at on load over a wide speed range. As load is applied, all the vacuum readings become smaller, and as load is reduced, such as by deceleration on coasting, or overdriving the engine by the vehicle, all the vacuum readings are increased. The vacuum in channel 6 is useful for controlling the action of a coasting economizer because it is a function of engine load and relatively insensitive to changes in throttle position or engine speed, within the speed range in which coasting economizer action may be desired.

I claim:

1. A coasting economizer for a carburetor of an internal combustion engine, including a vacuum responsive fuel flow control valve, a vacuum chamber, and means for p0- sitioning said valve as a function of the vacuum in said chamber, a communicating passage between said chamber and the intake manifold, a second communicating passage between said chamber and a port in the throttle bore of the carburetor located so that said port is on the manifold side of the throttle when the throttle is in the idle position and on the atmospheric side of the throttle when the throttle is open, and means for regulating the vacuums supplied to said chamber through said passages, whereby the resultant vacuum in said chamber has a substantially stable value over a range of throttle positions.

2. A coasting economizer for a carburetor of an internal combustion engine having a throttle, said coasting economizer including a fuel fiow control valve, a vacuum chamber and means for positioning said valve as a function of the vacuum in said chamber, said chamber having a pneumatic connection to the intake manifold and a second pneumatic connection to the intake manifold when the said throttle is closed and to a source of lower vacuum when said throttle is open, and means for regulating the vacuums supplied to said chamber through said connections, whereby the resultant vacuum in said chamber has a substantially stable value over a range of throttle positions.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Hoof Aug. 27, 1940 Leibing Sept. 17, 1940 Olson Mar. 9, 1943 4 Strebinger Nov. 2, 1948 Mallory Oct. 23, 1951 Grifion Aug. 18, 1953 Boller Nov. 10, 1953 Anderson Jan. 5, 1954

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