Internal combustion engines with external mixture formation and compensation vessel for avoiding re-ignition

Abstract

Internal combustion engines having an external mixture formation and compensation tank for avoiding reignition. An internal combustion engine is provided having an external mixture formation including at least one exhaust system, at least one intake system, the intake system including at least one intake manifold, at least one throttle valve, at least one mixture forming device, at least one compensation tank, and at least one air filter.

Claims

1. An internal combustion engine with external mixture formation comprising: an exhaust system; and an intake system, the intake system including an intake manifold, a throttle valve, a mixture forming device, a compensation tank and an air filter, the compensation tank being provided upstream from the throttle valve, the compensation tank forming an air volume upstream of the mixture forming device and downstream of the air filter and being configured for relieving a backfire pressure wave, wherein the compensation tank has a stepped design, wherein the stepped design defines a fluidic bottleneck between an inlet and an outlet of the compensation tank.

2. The internal combustion engine as recited in claim 1 wherein the throttle valve is situated between the intake manifold and the mixture forming device.

3. The internal combustion engine as recited in claim 1 wherein the mixture forming device is a gas mixer.

4. The internal combustion engine as recited in claim 1 wherein the mixture forming device is a carburetor.

5. The internal combustion engine as recited in claim 1 wherein the compensation tank is made of a thermally conductive material.

6. The internal combustion engine as recited in claim 1 wherein a ratio of an inlet of the compensation tank to an outlet of the compensation tank is approximately 58/80.

7. The internal combustion engine as recited in claim 1 wherein the mixture forming device and the compensation tank are connected via a flexible tube element.

8. The internal combustion engine as recited in claim 1 wherein a flow rectifier is situated between the compensation tank and the mixture forming device.

9. The internal combustion engine as recited in claim 1 wherein the flow rectifier is made of a metal mesh and/or a knitted metal and/or a comb-like extruded profile.

10. A method for operating the internal combustion engine as recited in claim 1 comprising: providing the compensation tank for receiving hot combustion gases in a backfire that are mixed with non-combustible fresh air in the compensation tank.

11. The internal combustion engine as in claim 1 wherein the fluidic bottleneck is defined by a first step on a first side of the compensation tank and a second step on a second side of the compensation tank that is opposite of the first side.

12. An internal combustion engine with external mixture formation comprising: an exhaust system; and an intake system, the intake system including an intake manifold, a throttle valve, a mixture forming device, a compensation tank and an air filter, the compensation tank including, on a first side thereof, a compensation tank inlet, a compensation tank outlet and at least one step on an outer surface of the compensation tank between the compensation tank inlet and the compensation tank outlet, wherein the compensation tank includes, on a second side opposite the first side, at least one further step on the outer surface of the compensation tank.

13. The internal combustion engine as recited in claim 12 wherein the compensation tank inlet has a larger diameter than the compensation tank outlet.

14. The internal combustion engine as recited in claim 12 wherein the compensation tank includes two compensation volumes connected by a fluidic bottleneck provided at the at least one step.

15. The internal combustion engine as recited in claim 12 wherein the compensation tank includes a fastening area fixed in the at least one step.

16. An internal combustion engine with external mixture formation comprising: an exhaust system; and an intake system, the intake system including an intake manifold, a throttle valve, a mixture forming device, a compensation tank and an air filter, the compensation tank including, on a first side thereof, a compensation tank inlet, a compensation tank outlet and at least one step on an outer surface of the compensation tank between the compensation tank inlet and the compensation tank outlet, wherein the compensation tank includes a fastening area fixed in the at least one step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is explained in greater detail below on the basis of exemplary embodiments illustrated in the drawings.

(2) FIG. 1 shows an internal combustion engine including a flow rectifier and a compensation tank upstream from the carburetor.

(3) FIG. 2 shows an internal combustion engine including a compensation tank upstream from the carburetor.

(4) FIG. 3 shows a step-shaped compensation tank.

(5) FIG. 4 shows temperature and pressure characteristics in the intake manifold without the compensation tank.

(6) FIG. 5 shows temperature and pressure characteristics in the intake manifold including the compensation tank.

(7) FIG. 6 shows a comparison in tabular form with and without a compensation tank.

DETAILED DESCRIPTION

(8) In FIG. 1, an internal combustion engine 7 is illustrated including a flow rectifier 3 and a compensation tank 4 that are situated in the flow direction upstream from carburetor 2. The intake air aspirated by internal combustion engine 7 passes by air filter 5 to then enter compensation tank 4 designed in a step-shaped manner via compensation tank inlet 8 (FIG. 3). The intake air present in compensation tank 4 enters flow rectifier 3 via compensation tank outlet 9 (FIG. 3), whose diameter is larger than that of compensation tank inlet 8. Flow rectifier 3 includes a flow rectifier housing and a flow rectifier insert. The flow rectifier insert is a close-meshed metal lattice. In one alternative specific embodiment, the flow rectifier insert is a comb-like extruded profile. The flow rectifier insert is preferably made of a thermally conductive metal, such as copper or aluminum.

(9) FIG. 2 shows an internal combustion engine 7 including a compensation tank 4 that is situated in the flow direction of the intake air upstream from carburetor 2. The intake air aspirated by internal combustion engine 7 passes by air filter 5 to then enter compensation tank 4 designed in a step-shaped manner via compensation tank inlet 8 (FIG. 3). The intake air present in compensation tank 4 enters carburetor 2 via compensation tank outlet 9 (FIG. 3), whose diameter is larger than that of compensation tank.

(10) In FIG. 3, a step-shaped compensation tank 4 in the form of an air intake box is provided. Compensation tank 4 includes a compensation tank inlet 8 and a compensation tank outlet 9. The outer surface of compensation tank 4 has a step-like design between compensation tank inlet 8 and compensation tank outlet 9, a fastening area 10 for fastening compensation tank 4 to the internal combustion engine being provided in the first step from compensation tank inlet 8 in the direction of compensation tank outlet 9. The outer surface of compensation tank 4 has step-like design on the side opposite compensation tank inlet 8 and compensation tank outlet 9, a fastening area 10 for fastening compensation tank 4 to the internal combustion engine being provided in each step. The housing of compensation tank 4 is made of a thermally conductive material, for example metal. The overall volume of the compensation tank is between 2 liters and 5 liters. The diameter ratio of compensation tank inlet 8 of the compensation tank to compensation tank outlet 9 is approximately 58/80. In one specific embodiment (not illustrated), the outer surface of compensation tank 4 between compensation tank inlet 8 and compensation tank outlet 9 only has one step, and compensation tank 4 essentially includes two compensation volumes that are connected with the aid of a fluidic bottleneck in the area of the step. This specific embodiment of compensation tank 4 has a volume of approximately 3 liters.

(11) FIG. 4 shows the temperature and pressure characteristics in the intake manifold plotted over time without the compensation tank illustrated in FIG. 2.

(12) In FIG. 5, the temperature and pressure characteristics in the intake manifold including the compensation tank are illustrated over time on the internal combustion engine from FIG. 5. Here, it becomes apparent that the temperature as well as the pressure in the intake manifold are reduced when a compensation tank is used.

(13) FIG. 6 shows a comparison in tabular form of the pressure and temperature values in the intake manifold of the same engine with and without a compensation tank.

LIST OF REFERENCE NUMERALS

(14) 1 throttle valve

(15) 2 carburetor/gas mixer/mixture forming device

(16) 3 flow rectifier

(17) 4 compensation tank

(18) 5 air filter

(19) 6 intake manifold

(20) 7 engine

(21) 8 compensation tank inlet

(22) 9 compensation tank outlet

(23) 10 fastening area