JPS6045742B2 - Internal combustion engine braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for braking or reducing the speed of an internal combustion engine.

This device is particularly useful in large motor vehicles as an adjunct to the normal braking mechanism to reduce the speed of the motor vehicle. Such a need is particularly required by heavy-duty motor vehicles in order to share the burden of customary brakes. The need for this assistance arises when the vehicle descends a long steep slope or in the event of brake failure. It is already known in the internal combustion engine art that engines powering relatively large motor vehicles, such as heavy haul trucks or the like, can be equipped with auxiliary braking systems. Typically, such devices convert the engine from a power source to a braking source whenever such supplemental braking is required. Generally, this is accomplished by modifying the engine exhaust and/or intake timing in such a way as to change the movement of the piston from a relatively small power loss to a large power loss when engine braking occurs. Absorption of such power uses the principle of an air compressor. That is, when braking is required, the piston acts on the air trapped in the cylinder of the engine. Such devices are currently sold by the Jacob Manufacturing Company of West Hartford, Conn., under the trade name JakeBrake. Similar devices are shown in the following US patents: U.S. Patents No. 2139090 (Lisholm), No. 2995890 (Dolza), No. 34265
No. 23 (Schutlaub), No. 343966 (Jyoons), No. 3585976 (Rider entry No. 359195)
Tan (Cubis), No. 3744464 (Soltau),
and No. 3333405 (Haviland). A particular improvement according to the practice of the invention relates to a modified turbine of a turbocharger, which operates with an engine equipped with such an auxiliary braking device. The turbine has pivotally mounted convex or variable angle blades, these elements act when braking is desired, thereby increasing the speed of the compressor driven by the turbine and forcing a larger volume of air to flow than the other. This results in entrapment in the cylinder.
Any variable geometry turbine that produces a higher rotational speed of the turbocharger during braking can be used. In order to carry out the invention, it is only necessary that the amount of air supplied into the cylinders of the engine when braking is required is greater compared to the amount of air supplied by constant geometry turbine action. is necessary. Modifying the turbine in this manner generally does not affect the operation of the auxiliary brake system valve timing mechanism. In the diagram, number 10 indicates an internal combustion engine, such as a diesel engine, and conventional auxiliary braking operates on the principle that the engine is trapped in a cylinder, effectively converting the trapped air into a power absorption device. Equipped with any of the following equipment. Such devices are well known in the art, as mentioned above, and are designated by the numeral 12. Exhaust manifold is number ζ14
The turbine 1 of the turbocharger 18 is shown as
Supply to 6. The turbocharger is of conventional construction and includes a shaft 20 driven by a turbine, which drives a compressor 22. The high pressure output of the turbine is connected to pipe 24.
to the intake manifold 26 of the engine 4.
All of the above-described elements shown in FIG. 1 are known in the art. Briefly, when auxiliary engine braking is required, a dynamic brake 12 or other similar arrangement is installed on the engine in such a way that power must be supplied to the engine by rotation of the engine's crankshaft. Altering the normal operation of the valve and/or exhaust valve, thereby compressing the air within the cylinders of the engine. For example, when a heavy automobile powered by such an engine descends a long slope, power is extracted from the rotation of the automobile's wheels to rotate the crankshaft and compress the air. FIGS. 2 and 3 each illustrate a variable geometry turpin, so named because adjustments or changes in its internal geometry or structure cause changes in its performance. Such a turbine is suitable as the turbine 16 of the turbocharger 18. Figure 2 is Angel (A
1 illustrates such a turbine formed in accordance with U.S. Pat. No. 2,944,786 to M. The pivoted blades 30 swing toward and away from the radial inlet turbine inlet 32, thereby varying the velocity of the inlet gas supplied to the turbine wheel 34.
FIG. 3 shows another variable geometry turbine, constructed in accordance with British Patent No. 214,423 of 1924. In this latter type of turbine construction (well known in the turbine art), unidirectional adjustment of the blades 38 causes an increase in the velocity of the gas delivered to the turbine wheel. Thus, with any variable geometry turbine arrangement, the speed of the turbine wheels can be increased, with a corresponding increase in the speed of the compressor wheel, while creating a greater pressure in the intake manifold 26. The resulting larger amount of air is supplied into the cylinders of the engine. FIG. 4 shows an increase in the braking action of the engine arrangement shown in FIG. 1, which is achieved by implementing the present invention.

The left part of the abscissa illustrates the engine braking action by the device 12. Curve 1 shows the magnitude for braking action without a variable geometry turbine. Curve ■ is the magnitude of the braking action due to the increased air volume in the cylinders of the engine brought about by increasing the speed of the compressor wheel by means of a variable geometry turbine as shown in FIG. 2 or 3. shows. It can be seen that the braking action or braking force is significantly increased due to the large amount of air in the cylinders of the engine. Without a variable geometry turbine, compressor speed would decrease with decreasing positive engine power. Variable geometry turbines are
This reduction in engine power is compensated for by increasing the velocity of the engine exhaust gases delivered to the turbine wheel.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a diesel engine with a variable geometry turbocharger. 2 is a plan view of a variable geometry turbine that may be used with the turbocharger of FIG. 1; FIG. FIG. 3 is a plan view of another variable geometry turbine that may be used with the turbocharger of FIG. 1; FIG. 4 is a curve showing the relationship between turbocharger speed and engine power. 10... Internal combustion engine, engine, 14...
・Exhaust manifold, 16...Turbine, 18...
...Turbocharger, 20...Shaft, 22
...Compressor, 24...Pipe line, 26...
Intake manifold, 30... blade, 32... inlet, 34... turbine wheel, 38...- blade.

Claims (1)

[Scope of Claims] 1. An engine includes a turbocharger, the turbocharger includes a turbine coupled to an exhaust port of the engine, and further includes a compressor driven by the turbine, the output side of the compressor being connected to an intake manifold of the engine. powering the motor vehicle, including a mechanism in which the engine changes its normal valve sequence such that when braking is desired, the engine acts as an air compressor and brakes the motor vehicle powered by the engine. In an internal combustion engine braking system suitable for A braking device for an internal combustion engine, characterized in that it functions as an air compressor. 2. The turbine of the turbocharger is of the radial entry type, said means being formed by blades pivotally mounted in the inlet passage of the turbine, the movement of the blades reducing the area of the turbine inlet passage and reducing the flow of gas passing into the holes of the turbine. Braking device according to claim 1, characterized in that it increases the speed. 3. Claim 1, characterized in that the turbine comprises a plurality of adjustable blades around the circumference of the turbine wheel, adjustment of the blades in one direction increasing the velocity of gas passing to the turbine wheel. Braking device described in .