Method and apparatus for converting an alcohol into a motor fuel mixture

Abstract

A method and apparatus for converting an alcohol into a fuel mixture which consists of alcohol, ether and water and is suitable for operating a combustion engine, in particular an internal combustion engine in a motor vehicle, converts the alcohol into the fuel mixture in a reactor at a suitable reaction temperature. The mixing ratio of alcohol fraction, ether fraction and water fraction in the fuel mixture is adjusted by controlling at least one reaction parameter of a reaction taking place in the reactor.

Claims

1. An apparatus, comprising: a reactor that converts an alcohol into a fuel mixture by a reaction, the fuel mixture consisting of alcohol, ether, and water, and being suitable for operating a combustion engine; a heating device that heats the alcohol before the alcohol enters the reactor; a control device that adjusts a mixing ratio of an alcohol fraction, an ether fraction, and a water fraction in the fuel mixture by adjusting at least one reaction parameter of the reaction taking place in the reactor, wherein the control device adjusts the at least one reaction parameter taking into account a first measurement signal indicating an operating parameter of an exhaust-gas aftertreatment system and a second measurement signal indicating an operating parameter of the combustion engine including at least one of speed, load, acceleration, cylinder pressure, and knocking.

2. The apparatus according to claim 1, wherein the heating device consists of an exhaust-gas heat exchanger for heating and a second heat exchanger with air or liquids as a transfer medium for cooling, at least one of the exhaust-gas heat exchanger and the second heat exchanger is controllable by the control device to control the heat transfer to the alcohol flowing therethrough.

3. The apparatus according to claim 1, wherein the at least one reaction parameter is the reaction temperature or the reaction pressure in the reactor, and wherein the second heat exchanger is disposed between the exhaust-gas heat exchanger and the reactor and uses the ambient air or a liquid to cool the alcohol heated in the exhaust-gas heat exchanger to at least one of a temperature and pressure value suitable for the reaction taking place in the reactor.

4. The apparatus according to claim 3, further comprising at least one sensor that measures the reaction temperature and the reaction pressure in the reactor and transmits the measured values as measurement signals to the control device.

5. The apparatus according to claim 1, further comprising at least one of a cylinder pressure sensor and a knocking sensor on the combustion engine that transmits measurement signals to the control device as operating parameters of the combustion engine, the control device adjusting at least one of the heating of the alcohol to be converted and the pressure in the reactor based on the measurement signals.

6. The apparatus according to claim 5, wherein the control device adjusts at least one of the heating of the alcohol to be converted and the pressure in the reactor based on the speed and load of the combustion engine.

7. The apparatus according to claim 1, wherein the control device adjusts at least one of the heating of the alcohol to be converted and the pressure in the reactor based on the speed and load of the combustion engine.

8. The apparatus according to claim 1, wherein the combustion engine is an internal combustion engine in a motor vehicle.

9. The apparatus according to claim 1, wherein the second measurement signal indicates the speed of the combustion engine.

10. The apparatus according to claim 1, wherein the second measurement signal indicates the cylinder pressure of the combustion engine.

11. The apparatus according to claim 1, wherein the second measurement signal indicates knocking of the combustion engine.

12. The apparatus according to claim 1, wherein the second measurement signal indicates the load of the combustion engine.

13. The apparatus according to claim 1, wherein the second measurement signal indicates the acceleration of the combustion engine.

14. The apparatus according to claim 1, wherein the at least one reaction parameter is the reaction temperature or the reaction pressure in the reactor.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows a schematic depiction of an apparatus for converting an alcohol into a combustion engine fuel mixture according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(2) The apparatus has a tank 1 which contains an alcohol (methanol or ethanol for example) which is fed by a first pump P1 through a heating device 2 to a reactor 3. In reactor 3, the alcohol is converted at a suitable reaction temperature into a motor fuel mixture which is fed via a chamber 4 and a second pump P2 to a combustion engine 5. The combustion engine 5 is for this equipped with injection nozzles 6 to 9, via which the motor fuel mixture is injected into the combustion chambers of combustion engine 5.

(3) The apparatus depicted in FIG. 1 can more particularly be disposed in a motor vehicle with a diesel engine as combustion engine 5.

(4) In order that the motor fuel mixture supplied to combustion engine 5 has a mixing ratio of its alcohol, ether and water fractions which is suitable for combustion engine 5, heating device 2 heats the alcohol before entry into reactor 3 to a suitable temperature therefor. The process of heating is controlled by a control device 10 according to two or more operating parameters. Measurement signals representing different operating parameters are sent for this via measurement signal lines 11 to 13 to the control device 10 from sensors provided in reactor 3 and on combustion engine 5. The reaction temperature and the reaction pressure are received by control device 10 from reactor 3 as measurement signals on which the mixing ratio of alcohol, ether and water in the motor fuel mixture depends. Moreover, a knocking sensor 14 and a cylinder pressure sensor 15 send corresponding measurement signals to the control device 10 which together with further operating state signals, for example speed n, load and acceleration, characterize the current operating state of combustion engine 5. On the basis of these operating parameters of combustion engine 5, control device 10 can determine a suitable mixing ratio for the motor fuel mixture and effect an appropriate adjustment to the reaction in reactor 3.

(5) Heating device 2 in the depicted exemplary embodiment consists of an exhaust-gas heat exchanger 16 and an air heat exchanger 17. An exhaust-gas line 18 leads from combustion engine 5 through the exhaust-gas heat exchanger 16 and, inside the exhaust-gas heat exchanger 16, heats the alcohol likewise directed through the exhaust-gas heat exchanger 16. The heated alcohol passes from the exhaust-gas heat exchanger 16 to the air heat exchanger 17, where ambient air flowing therethrough can be used to cool the alcohol down to a desired temperature. Both the exhaust-gas heat exchanger 16 and the air heat exchanger 17 can be controlled heat exchangers, facilitating controlled heat transfer. For instance, a bypass control in exhaust-gas heat exchanger 16 can be used to ensure that only a certain proportion of the exhaust-gas stream is used to heat the alcohol flowing therethrough. In the case of air heat exchanger 17, controlled cooling of the alcohol flowing therethrough is possible by control device 10 controlling, for example, the air throughput through the air heat exchanger 17.

(6) It will be appreciated that a different heat transfer medium, such as water or oil (not depicted here), can also be used for heat exchanger 17 in place of air.

(7) The pressure in the reactor can be varied using control elements as well as the temperature. One way to do this is by changing the methanol quantity pumped by pump P1, for example by changing the speed or lift or by means of a variable throttle disposed on the suction side of pump P1. A further way is to use a pressure control valve on the pressure side of pump P1 to adjust the pressure in the reactor irrespective of the reactor temperature.

(8) The motor fuel mixture produced in reactor 3 can, if necessary, be aftertreated or intermediately stored in a chamber 4 downstream of reactor 3.