HYBRID COMBUSTION MODE OF INTERNAL COMBUSTION ENGINE AND CONTROLLER THEREOF, INTERNAL COMBUSTION ENGINE, AND AUTOMOBILE

Abstract

A hybrid combustion mode of an internal combustion engine and a controller thereof, an internal combustion engine, and an automobile. The hybrid combustion mode of an internal combustion engine comprises: directly injecting fuel in a cylinder, using ignition combustion control when the internal combustion engine is started, and increasing the inlet temperature and inlet pressure by using a turbocharger; using homogeneous charge compression ignition combustion mode when the internal combustion engine is run, and except when the engine flames out, opening all throttles, not performing exhaust relief control on the turbocharger, increasing filled gas amount by using the turbocharger, and increasing the combustion temperature and pressure of a tail end of a cylinder compression stroke; and when the internal combustion engine is low in load, or when it cannot be determined, through the temperature of a water tank and the inlet pressure behind the throttle, that a compression ignition condition is met, switching a combustion control mode from ignition to compression ignition, if a compression ignition state can be switched to smoothly, maintaining the compression ignition combustion mode, and if the compression ignition state cannot be switched to smoothly and therefore the rotation speed of the engine decreases abnormally, quickly recovering the ignition combustion control mode. Cool start of low-octane gasoline internal combustion engine in a low-temperature environment can be implemented.

Claims

1. A method for operating an engine capable of a hybrid combustion mode, the method comprising: directly injecting a fuel into a cylinder; selecting a low octane number gasoline as the fuel with a Research Octane Number (RON) of 20 to 69; operating the engine running under a non-homogenous combustion compression ignition (NHCCI) mode comprising: directly injecting the low octane number gasoline into the cylinder during a compression stroke in which a piston moves from the BDC to the TDC; the ignition timing of the engine depending on the injection time of the low octane number gasoline into the cylinder by diffused compression ignition, and the combustion of a mixture of the low octane number gasoline and air is a stratified combustion; the NHCCI mode can work in all speed range of the engine without a speed limit; the NHCCI mode can work in all load range of the engine without a load limit; when the engine is cold that a temperature of the engine is not greater than a predetermined temperature, starting up the engine under a homogenous combustion spark ignition (HCSI) mode; the predetermined temperature of the engine varies with ambient temperature out of the engine; when the engine is hot that the temperature of the engine is greater than the predetermined temperature, starting up the engine under NHCCI mode, not relying on the use of high temperature exhaust gas; determining that a condition of NHCCI mode is not met and maintaining run of the engine at an additional cycle under HCSI mode, if the temperature of the engine is not greater than the predetermined temperature; determining that the condition of NHCCI is met, if the temperature of the-engine is greater than the predetermined temperature; changing the mode from HCSI mode to the NHCCI mode when the condition of NHCCI mode is met, and maintaining run of the engine at NHCCI mode; and changing the mode from NHCCI mode to HCSI mode when the condition of NHCCI mode is no longer met.

2. The method of claim 1, further comprising: starting up the engine under the HCSI mode; determining that the condition of NHCCI mode is not met and maintaining run of the engine at an additional cycle under HCSI mode, if at least one of the temperature of the engine is not greater than a predetermined temperature, the speed of the engine is not greater than a predetermined speed; the load of the engine is not greater than a predetermined load, and an intake pressure of a throttle valve is not greater than a predetermined pressure, and a combination thereof; determining that the condition of NHCCI mode is met, if the temperature of the engine is greater than the predetermined temperature, and the speed of the engine is greater than a predetermined speed; and the load of the engine is greater than a predetermined load, and the intake pressure of the throttle valve is greater than the predetermined pressure, and the combination thereof; in the speed range of the engine, the NHCCI mode has no upper speed limit; in the load range of the engine, the NHCCI mode has no upper load limit; changing the mode from HCSI mode to NHCCI mode when the condition of the NHCCI mode is met, and maintaining run of the engine under the NHCCI mode; and changing the mode from NHCCI mode to HCSI mode when the condition of NHCCI mode is no longer met.

3. The method of claim 2, further comprising selecting a high-octane gasoline fuel with a research octane number of equal or greater than 89, or the low octane gasoline fuel with a research octane number of 20 to 69 as the fuel for the engine during operation of the engine.

4. The method of claim 2, wherein the engine further comprises a turbocharger, or a mechanical super-charger, or a combination thereof.

5. The method of claim 2, wherein the engine further comprises a cylinder of a normal compression ratio of equal or greater than 17, and selecting a gasoline fuel with a research octane number in the range of 40-69 as the fuel during operation of the engine under the hybrid combustion mode.

6. The method of claim 2, wherein the engine further comprises a cylinder of a normal compression ratio in the range of 12-17, and selecting a gasoline fuel with a research octane number of equal or less than 40 as the fuel during operation of the engine under the hybrid combustion mode.

7. An electronic control unit (ECU) configured to operate an engine in a hybrid combustion mode, wherein operation in the hybrid combustion mode comprises: directly injecting a fuel into a cylinder; selecting a low octane number gasoline as the fuel with a Research Octane Number (RON) of 20 to 69; operating the engine running under a non-homogenous combustion compression ignition (NHCCI) mode comprising: directly injecting the low octane number gasoline into the cylinder during a compression stroke in which a piston moves from the BDC to the TDC; the ignition timing of the engine depending on the injection time of the low octane number gasoline into the cylinder by diffused compression ignition, and the combustion of a mixture of the low octane number gasoline and air is a stratified combustion; the NHCCI mode can work in all speed range of the engine without a speed limit; the NHCCI mode can work in all load range of the engine without a load limit; when the engine is cold that a temperature of the engine is not greater than a predetermined temperature, starting up the engine under a homogenous combustion spark ignition (HCSI) mode; the predetermined temperature of the engine varies with ambient temperature out of the engine; when the engine is hot that the temperature of the engine is greater than the predetermined temperature, starting up the engine under NHCCI mode, not relying on the use of high temperature exhaust gas; determining that a condition of NHCCI mode is not met and maintaining run of the engine at an additional cycle under HCSI mode, if the temperature of the engine is not greater than the predetermined temperature; determining that the condition of NHCCI is met, if the temperature of the-engine is greater than the predetermined temperature; changing the mode from HCSI mode to the NHCCI mode when the condition of NHCCI mode is met, and maintaining run of the engine at NHCCI mode; and changing the mode from NHCCI mode to HCSI mode when the condition of NHCCI mode is no longer met.

8. The ECU of claim 7, wherein operation in the hybrid combustion mode further comprises: starting up the engine under the HCSI mode; determining that the condition of NHCCI mode is not met and maintaining run of the engine at an additional cycle under HCSI mode, if at least one of the temperature of the engine is not greater than a predetermined temperature, the speed of the engine is not greater than a predetermined speed; the load of the engine is not greater than a predetermined load, and an intake pressure of a throttle valve is not greater than a predetermined pressure, and a combination thereof; determining that the condition of NHCCI mode is met, if the temperature of the engine is greater than the predetermined temperature, and the speed of the engine is greater than a predetermined speed; and the load of the engine is greater than a predetermined load, and the intake pressure of the throttle valve is greater than the predetermined pressure, and the combination thereof; in the speed range of the engine, the NHCCI mode has no upper speed limit; in the load range of the engine, the NHCCI mode has no upper load limit; changing the mode from HCSI mode to NHCCI mode when the condition of the NHCCI mode is met, and maintaining run of the engine under the NHCCI mode; and changing the mode from NHCCI mode to HCSI mode when the condition of NHCCI mode is no longer met.

9. The ECU of claim 8, further comprising selecting a high-octane gasoline fuel with a research octane number of equal or greater than 89 as the fuel for the engine during operation of the engine.

10. The ECU of claim 9, further comprising a fuel selection switch that is configured to allow a selection of two or more types of gasoline fuels for the engine.

11. The ECU of claim 8, wherein a fuel selection switch is configured to select the gasoline fuel directly injected into the cylinder from a high-octane gasoline fuel with a research octane number of equal or greater than 89, and the low-octane gasoline fuel with a research octane number (RON) of 20 to 69.

12. The ECU of claim 11, further configured to switch operation of the engine between the hybrid combustion mode and a second HCSI mode; wherein the low octane number gasoline with a research octane number of 20 to 69 is directly injected into the cylinder during operation in the hybrid combustion mode; wherein the high-octane gasoline fuel with a research octane number of equal or greater than 89 is directly injected into the cylinder during operation in the second HCSI mode.

13. The ECU of claim 12, wherein the cylinder of the engine comprises a normal compression ratio of 9-11, or a normal compression ratio of 11-17.

14. An engine adopting the control method required by claim 1, wherein the cylinder of the engine has a normal compression ratio of 9-22.

15. The engine comprising the ECU of claim 8, wherein the cylinder of the engine is configured to gain a realized compression ratio of 15-21 with at least one of turbocharger and mechanical supercharger, and the combination thereof.

16. The engine comprising the ECU of claim 8, wherein the engine comprises a turbocharger and a mechanical supercharger; wherein the cylinder of the engine is configured to gain a realized compression ratio of equal or more than 17 by manipulating the cylinder with a normal compression ratio of equal or less than 11 through supplying the cylinder with an intake pressure of equal or high than 1.7 atmospheric pressure (kg/square centimeter) with the turbocharger; wherein the cylinder of the engine is configured to gain a realized compression ratio of equal or more than 17 by manipulating the cylinder with a normal compression ratio of equal or less than 11 through supplying the cylinder with an intake pressure of equal or high than 1.7 atmospheric pressure (kg/square centimeter) with a mechanical super-charger when the intake pressure is less than 1.7 atmospheric pressure (kg/square centimeter) by the turbocharger.

17. The engine of claim 14, further comprising an electric heating plug.

18. An automobile comprising the ECU of claim 8, further comprising a non-transitory computer readable medium with instructions recorded thereon; wherein the instructions are configured to program the ECU.

19. The automobile comprising the ECU of claim 8, further comprising a fuel selection switch; wherein the fuel selection switch is configured to select a gasoline fuel from a high-octane gasoline fuel with a research octane number of equal or greater than 89, and a low-octane gasoline fuel with a research octane number of 20 to 69.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] While particular embodiments of the invention have been shown and described below, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

[0066] For further illustrating the invention, experiments detailing a method for achieving a hybrid combustion mode of an internal combustion engine are described below. It should be noted that the following examples are intended to describe and not to limit the invention.

EXAMPLE 1

[0067] A direct injection gasoline engine comprising a turbocharger and having a compression ratio of 10 (or 9.6, or 10.5, or 11) is equipped with a vehicle-mounted device capable of controlling the hybrid combustion mode (for a vehicle-mounted device of a common vehicle, for example, an electronic control unit, only the spark ignition combustion mode is provided, without compression ignition mode). At the initiating stage of the engine, the spark ignition mode is employed, and the air intake volume is regulated by a throttle valve. The fuel-air ratio is controlled at about 14.7 as possibly. After the temperature of the engine rises and the turbocharger works normally thereby improving the upstream intake pressure of the throttle valve, the compression ignition combustion mode is activated, and the decompression valve of the turbocharger is shut down or abolished, so that the maximum inlet pressure and maximum air intake flow of the turbocharger are all used for aeration. When the temperature of the water tank reaches 90 C., the ambient temperature is over 10 C., and the intake pressure reaches over 1.7 kg/square centimeter, the vehicle (engine) having a compression ratio of 10 can utilize gasoline having an octane number of less than or equal to 30 (specific octane number gasoline should be determined according to different types of vehicles, and cannot be determined only by the compression ratio of the engine) to achieve the compression ignition mode, thereby greatly improving the thermal power conversion efficiency of the engine.

[0068] Existing vehicles have a compression ratio of around or over 10. The method of the invention can be used to update the computer program of the existing vehicles thereby providing the vehicles with a hybrid combustion mode, thus saving the fuel consumption, and reducing the carbon dioxide emissions.

[0069] To ensure the reliability of the compression ignition, and apply the compression ignition combustion mode before the upstream intake pressure of the throttle valve reaches 1.7 kg/square centimeter, the octane number of the gasoline can be further reduced, for example, employ gasoline having an octane number of 20, 15, 10, or 0.

[0070] In this example, when the engine works at a low load, the turbocharging effect leaves much to be desired. When the upstream intake pressure is less than 1.7 kg/square centimeter, the engine is ignited through a spark ignition mode.

[0071] When the ambient temperature is much lower, or the gasoline has a much higher octane number, or the waste gas is insufficient due to a low load thereby producing low intake pressure, during the shift of the combustion mode from the spark ignition to the compression ignition, the rotational speed of the engine should be carefully observed to detect whether the compression ignition is achieved. If the compression ignition fails, the rotational speed of the engine will decrease abnormally, the spark ignition combustion mode should be adopted immediately, until the above three conditions for the compression ignition combustion mode are all satisfied.

[0072] Because the compression ratio of the conventional engine cylinders is low thereby resulting in unsatisfactory thermal power conversion efficiency, the technical solution of this example is just a transition. Newly-produced vehicles, without any doubt, should employ engines having high compression ratio (for example, 17-22 12-14, or 14-17) so as to make full use of low octane gasoline.

[0073] To ensure the smooth transition of existing engines, a controller (or an electronic control unit) comprising two sets of engine management modes is disposed in the engines. The controller comprises a transfer switch to select one of the two management modes. When the transfer switch points to the mixed or low octane gasoline, the engines or vehicles are ignited through a hybrid combustion mode. When the transfer switch points to the spark ignition or high octane gasoline, the engines or vehicles are conventional engines or vehicles ignited spark ignition combustion mode.

[0074] The controller or electronic control unit comprising two sets of engine management modes can enable a common vehicle (or engine) to consume conventional gasoline, or to consume low octane gasoline whereby transforming the conventional vehicle into a dual-fuel vehicle (or engine).

EXAMPLE 2

[0075] A direct injection gasoline engine comprising a turbocharger and having a compression ratio of 18 is provided and the computer program thereof is modified (for a vehicle-mounted device of a common vehicle, only the spark ignition combustion mode is provided, without the compression ignition mode). At the initiating stage of the engine, the spark ignition mode is employed, and the air intake volume is regulated by a throttle valve. After the temperature of the engine rises and the turbocharger works normally thereby improving the upstream intake pressure of the throttle valve, the compression ignition combustion mode is activated, and the decompression valve of the turbocharger is shut down or abolished, the throttle valves are completely opened, that the maximum intake pressure and maximum air intake flow of the turbocharger are all used for aeration. The gasoline having an octane number of 40 is consumed.

[0076] Experiments show that, when the ambient temperature is at minus 14 degrees (experiments show that the limiting application temperature can reach at minus 50 degrees (50 C.)), the engine can be ignited by a spark ignition combustion mode for normal start. When the water tank temperature reaches 60 C., the ambient temperature is 14 C., and the intake pressure is over 1.1 kg/square centimeter, the combustion mode of the engine can shift from a spark ignition mode to a compression ignition mode. Thus, the thermal power conversion efficiency of the engine is greatly improved. When the engine runs at idle state or at low load, the engine can also be ignited by a compression ignition mode. When the engine is still active (the water tank temperature is over 60 C.), the spark ignition mode can be omitted and the compression ignition mode can be directly introduced. When the water tank temperature is 20 C. and the spark ignition mode is employed at the initiating stage, the fuel consumption is 0.9 liter/hour at the idle state. When the water tank temperature is 90 C. and the engine runs through a compression ignition mode, the fuel consumption is 0.5 liter/hour at the idle state. Obviously, a large amount of fuel is saved.

EXAMPLE 3

[0077] A gasoline engine (used for vehicle) comprising a mechanical supercharger is provided with a compression ratio of 10 (or 9.6, or 10.5 or 11). In the initiating stage, the mechanical supercharger supplies compressed air having a pressure of above 1.7-1.9 kg/square centimeter for the cylinder.

[0078] To modify the computer program of the engine, so that the injection timing(location) occurs when the piston reaches close to the top dead center with an angle of 16 degrees (the injection timing varies with the changes of the working conditions and load), and the throttle valves are completely opened. The electronic ignition timing is postponed to the working stroke when the piston has passed the top dead center with an angle of between 5 and 15 degrees. Thus, a conventional gasoline engine consuming high octane number gasoline is transformed into a compression ignition low gasoline engine. The compression ignition low gasoline engine can consume low octane gasoline having an octane number of less than 30 under an ambient temperature of over 20 C. to achieve cold start.

[0079] If the computer program of the compression ignition low gasoline engine is updated to have a hybrid combustion mode, the engine can achieve cold start under an ambient temperature of over minus 20 C. (20 C.).

[0080] If a novel electronic control unit (soft ware and hard ware) comprising a fuel selection switch and two engine management modes, that is, a conventional spark ignition mode and a hybrid combustion mode, is employed to substitute the electronic control unit (vehicle) of a conventional engine, the (vehicle) engine can consume both common gasoline and low octane gasoline, with no need to change the physical structure of the (vehicle) engine.