CN107084057B - A device and method for controlling fuel supply of CNG dual fuel vehicle - Google Patents

Abstract

The present invention provides a device for controlling fuel supply of a CNG dual-fuel vehicle, the device includes a fuel injection pulse width acquiring device for acquiring a fuel injection signal sent by an engine cylinder, wherein the fuel injection signal includes a fuel injection pulse The width value and the engine electronic control unit are used to judge whether to switch the fuel from CNG fuel according to the fuel injection pulse width value when the vehicle is in a condition of large power demand. The method includes: acquiring a fuel injection pulse width value of a fuel injection signal sent by an engine cylinder; when the vehicle is in a condition with a large power demand, judging whether to switch the fuel from the CNG fuel to the fuel injection pulse width value according to the fuel injection pulse width value. gasoline fuel. The method adopted by the present invention to automatically switch to the fuel mode at a necessary stage of driving not only makes the dual-fuel vehicle better in power, but also naturally consumes a certain amount of fuel, thereby avoiding the inability to consume a large amount of fuel for a long time to bring the engine question to come.

Description

A device and method for controlling fuel supply of CNG dual fuel vehicle

technical field

The present invention relates to the field of engine electronic control, in particular to a device and method for controlling fuel supply of CNG dual-fuel vehicles.

Background technique

CNG dual-fuel vehicles are basically used in taxis in areas with rich gas resources. In such applications, drivers often rely entirely on CNG fuel, and gasoline is only used for starting, so that the gasoline in the fuel tank is constantly volatilized, and the gum Continuous accumulation often causes the injector to be blocked and makes the engine work unstable. At the same time, the quality of gasoline in the fuel tank is getting worse and worse. In the worst case, the vehicle will not be able to start, and the user often does not realize the problem and will only return to the 4S shop for repair, which will increase the user's car cost unnecessarily. It also affects the reputation of the model.

When the driver accelerates rapidly and wants to obtain the maximum speed, the fuel demand of the engine per cycle is the largest. At this time, switching to the fuel state can not only improve the dynamic performance of the vehicle, but also the large-flow fuel injection cycle just achieves that we use gasoline from time to time. The purpose of flushing the fuel injector, so as to avoid the fuel injector being blocked by the deposited gum. The judgment of the driver's need to accelerate rapidly or to obtain the maximum speed can be simply attributed to the judgment of the fuel injection pulse width, thus completing the identification of the switching timing with a simple judgment.

SUMMARY OF THE INVENTION

In order to solve the problem of rapidly switching the fuel supply mode of CNG dual-fuel vehicles under the condition of large power demand, the present invention provides a device and method for controlling the fuel supply of CNG dual-fuel vehicles, which can be used during driving. In a necessary stage, the problem of insufficient vehicle power due to the low utilization efficiency of a certain fuel is prevented by switching the fuel to another fuel; A control method for reliable protection of equipment in the fuel system.

An object of the present invention is to provide a device for controlling the fuel supply of a CNG dual-fuel vehicle, which includes CNG fuel and gasoline fuel, for controlling the automatic switching of fuel in the non-starting phase of the vehicle , the device includes:

an injection pulse width acquisition device, used for acquiring an injection signal sent by an engine cylinder, where the injection signal includes an injection pulse width value;

The engine electronic control unit is configured to judge whether to switch the fuel from CNG fuel to gasoline fuel according to the fuel injection pulse width value when the vehicle is in a condition of large power demand.

Further, the engine electronic control unit is configured to switch the fuel from CNG fuel to gasoline fuel when the fuel injection pulse width value is greater than a first preset value.

Further, the engine electronic control unit is configured to switch the fuel from gasoline fuel to CNG fuel when the fuel injection pulse width value is smaller than a second preset value;

Wherein, the first preset value is greater than the second preset value.

Further, the device also includes:

a gasoline storage tank for storing said gasoline fuel;

CNG storage tanks for storing said CNG fuel; and

an oil level sensor for detecting the oil level of the gasoline fuel in the gasoline storage tank.

Further, the engine electronic control unit is configured to switch the fuel from the CNG fuel to the CNG fuel when the current fuel is CNG fuel and the oil level is not zero while the fuel injection pulse width value is greater than the first preset value. Switch to gasoline fuel.

Further, the engine electronic control unit is configured to, when receiving a signal to switch the fuel from gasoline fuel to CNG fuel, wait a preset time before processing the signal.

Further, the engine electronic control unit is configured to control the fuel to be CNG fuel when the vehicle is in a non-starting phase and is not in a condition of high power demand.

Another aspect of the present invention provides a method for controlling the fuel supply of a CNG dual-fuel vehicle, including CNG fuel and gasoline fuel, for controlling the automatic switching of fuel during the non-start phase of the vehicle , the method includes the following steps:

obtaining the fuel injection signal sent by the engine cylinder, where the fuel injection signal includes the fuel injection pulse width value;

When the vehicle is in a condition of high power demand, it is determined whether to switch the fuel from CNG fuel to gasoline fuel according to the fuel injection pulse width value.

In particular, the engine electronic control unit is configured to switch the fuel from CNG fuel to gasoline fuel when the fuel injection pulse width value is greater than a first preset value.

In particular, the engine electronic control unit is configured to switch the fuel from gasoline fuel to CNG fuel when the fuel injection pulse width value is less than a second preset value;

Wherein, the first preset value is greater than the second preset value.

One aspect of the present invention provides an apparatus for controlling fuel supply of a CNG dual-fuel vehicle, which can prevent a certain The low efficiency of fuel utilization results in insufficient vehicle power and other engine-related problems.

Further, another aspect of the present invention provides a method for controlling the fuel supply of a CNG dual-fuel vehicle, the method utilizes the engine electronic control unit according to the received actual fuel injection pulse width signal of the gasoline fuel unit. The value is compared to a reference threshold to quickly and easily select how the vehicle is fueled.

The above and other objects, advantages and features of the present invention will be more apparent to those skilled in the art from the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

Hereinafter, some specific embodiments of the present invention will be described in detail by way of example and not limitation with reference to the accompanying drawings. The same reference numbers in the figures designate the same or similar parts or parts. It will be understood by those skilled in the art that the drawings are not necessarily to scale. In the attached picture:

1 is an exemplary structural diagram of an apparatus for controlling fuel supply of a CNG dual-fuel vehicle according to an embodiment of the present invention;

FIG. 2 is a flowchart of a control method of the exemplary apparatus shown in FIG. 1 for controlling fueling of a CNG dual-fuel vehicle.

Detailed ways

FIG. 1 is an exemplary structural diagram of an apparatus for controlling fuel supply of a CNG dual-fuel vehicle according to an embodiment of the present invention. Dual-fuel vehicles generally refer to two sets of fuel supply systems, one of which supplies natural gas or liquefied petroleum gas, and the other that supplies fuel other than natural gas or liquefied petroleum gas. The two fuel supply systems supply the cylinders according to a predetermined ratio Fuel, in-cylinder mixed combustion vehicles, such as CNG gasoline dual fuel vehicles, or CNG diesel dual fuel vehicles. The main fuel of such vehicles is CNG, and gasoline generally only plays a role in ignition. The structural parameters of this type of engine are hardly changed, and it can be flexibly switched between the two operating conditions of pure combustion of gasoline and simultaneous combustion of CNG and gasoline. At present, dual-fuel mainly refers to vehicles that use gasoline and CNG as fuel, which cannot be used at the same time. Either gasoline or CNG is used. Due to the obvious advantages of natural gas vehicles in terms of emissions, compared with gasoline vehicles, natural gas vehicles emit almost zero particulate matter, and the emissions of NOx, CO and HC are also significantly reduced, so natural gas vehicles are of great significance in improving air quality.

Despite this, there are still some problems in the use of natural gas vehicles. In the application of taxis in areas with rich gas resources, drivers often rely entirely on CNG fuel, and gasoline is only used for starting, so that the gasoline in the fuel tank is constantly volatilized. The continuous accumulation of gum often causes the injector to be blocked and makes the engine work unstable. At the same time, the quality of gasoline in the fuel tank is getting worse and worse. In the worst case, the vehicle will not be able to start, and the user often does not realize the problem and will only return to the 4S shop for repair, which will increase the user's car cost unnecessarily. It also affects the reputation of the model.

The CNG dual-fuel car is made by adding a set of "CNG conversion system" on the basis of retaining the original car's fuel supply system. That is to say, a dual-fuel vehicle is based on retaining the gasoline and diesel fuel supply systems, plus a set of gas supply systems.

In one embodiment of the present invention, FIG. 1 shows a device for controlling the fuel supply of a CNG dual-fuel vehicle, which may generally include an engine 1, an engine electronic control unit 2, a fuel injection pulse width acquisition Device 3 , gasoline storage tank 4 , CNG storage tank 5 and oil level sensor 6 . It should be noted that the engine 1 of the present invention also includes parts associated with air intake and air discharge, and generates power through gasoline fuel and CNG fuel.

The gasoline tank 4 supplies gasoline fuel to the combustion chamber of the engine 1 . The gasoline storage tank 4 includes all means for supplying and controlling gasoline fuel. For example, the gasoline storage tank 4 may include a gasoline tank, a fuel line for supplying gasoline, and a gasoline injector for injecting gasoline.

The CNG tank 5 supplies CNG fuel to the combustion chamber of the engine 1 . The CNG storage tank 5 includes all means for supplying and controlling CNG fuel. For example, the CNG storage tank 5 includes a CNG fuel tank, a fuel line for supplying CNG fuel, a CNG injector for injecting CNG fuel, a vaporizer for vaporizing CNG fuel in a liquid state, and a mixer for mixing CNG fuel and air.

The gasoline storage tank 4 may adopt a gasoline multi-point injection method in which the air and gasoline fuel are mixed and then injected into the combustion chamber of the engine 1 or a gasoline direct injection method in which the gasoline fuel is directly injected into the combustion chamber of the engine 1 .

The fuel injection pulse width obtaining device 3 is defined to obtain the fuel injection signal sent by the engine cylinder, and the fuel injection signal includes the fuel injection pulse width value; the fuel injection pulse width value is defined as every time the engine electronic control unit controls the fuel injector The length of time for the injection. For example, when the vehicle is rapidly accelerating or the vehicle is expected to obtain the maximum speed, the actual value of the fuel injection pulse width sent by the fuel injection pulse width acquisition device 3 to the engine electronic control unit 2 is compared with the reference threshold to determine whether the vehicle switches fuel model.

The engine electronic control unit 2 includes signal generation logic for controlling the injection timing and quantity of gasoline fuel and CNG fuel.

The oil level sensor 6 is used to detect the oil level of gasoline fuel in the gasoline storage tank 4 .

FIG. 2 is a flowchart of a control method of the exemplary apparatus shown in FIG. 1 for controlling fueling of a CNG dual-fuel vehicle. In one embodiment, the control method determines the manner of fuel supply according to the following steps:

Step S1: the engine electronic control unit 2 uses gasoline fuel as the starting fuel, specifically, the engine electronic control unit 2 provides the gasoline fuel to the combustion chamber of the engine 1 through the gasoline storage tank 4, and thus executes the vehicle start;

Step S2: The engine electronic control unit 2 switches the gasoline fuel to the CNG fuel in the vehicle. Specifically, the engine electronic control unit 2 switches the gasoline fuel in the gasoline storage tank 4 to the CNG fuel in the CNG storage tank 5, thereby converting the fuel into the CNG fuel. The CNG fuel is supplied to the combustion chamber of the engine 1; the vehicle uses the CNG fuel as the driving fuel for driving the vehicle;

Step S3: the engine electronic control unit 2 switches the CNG fuel to the gasoline fuel under the condition that the power demand of the vehicle is relatively large;

Step S4: The engine electronic control unit 2 judges whether the amount of oil in the gasoline storage tank is zero under the condition that the power demand of the vehicle is relatively large, so as to carry out the next operation. The specific conditions for the judgment are:

When the amount of oil in the gasoline storage tank is zero, return to step S2, and the engine electronic control unit 2 controls the vehicle to continue driving the vehicle with CNG fuel;

When the amount of oil in the gasoline storage tank is not zero, perform the next step of this step;

Step S5: The engine electronic control unit 2 executes this step when the power demand of the vehicle is relatively large and the oil quantity in the gasoline storage tank in step S4 is not zero, and the specific conditions for judgment are:

When the actual value of the fuel injection pulse width is greater than the first preset value, execute the next operation;

When it is not satisfied that the actual value of the fuel injection pulse width is greater than the first preset value, return to step S2, and the engine electronic control unit 2 controls the vehicle to continue driving the vehicle with CNG fuel;

Step S6: The engine electronic control unit 2 enters a condition where the vehicle has a large power demand, and at the same time satisfies the condition that the amount of oil in the gasoline storage tank in step S4 is not zero and the actual value of the fuel injection pulse width in step S5 is greater than the first preset value. Execute this step below, at this time the vehicle fuel is switched to gasoline;

Step S7: Under the condition that the engine electronic control unit 2 switches the vehicle fuel to gasoline when the vehicle enters a working condition with a large power demand, if the following conditions are met:

When the actual value of the fuel injection pulse width is less than the second preset value, return to step S2, at which time the engine electronic control unit 2 controls the vehicle to drive the vehicle with CNG fuel;

When the actual value of the fuel injection pulse width does not satisfy the condition of being smaller than the second preset value, step S6 is continued, and the vehicle driving fuel is still gasoline at this time.

In particular, in order to avoid repeated switching, it should be set that the first preset value in the above steps is greater than the second preset value.

One aspect of the present invention provides an apparatus for controlling fuel supply of a CNG dual-fuel vehicle, which can prevent certain problems by switching the fuel to a fuel different from the driving fuel at a necessary stage in the driving process. The low utilization efficiency of a fuel results in insufficient vehicle power and other engine-related problems.

Another aspect of the present invention also provides a method for controlling the fuel supply of a CNG dual-fuel vehicle, the method utilizes the engine electronic control unit according to the received actual value of the fuel injection pulse width signal of the gasoline fuel unit and a reference threshold value comparison, so as to quickly and easily select the fuel supply method of the vehicle.

The method adopted by the present invention to automatically switch to the fuel mode at a necessary stage during driving not only improves the power performance of the dual-fuel vehicle, but also naturally consumes a certain amount of fuel, thereby avoiding the long-term use of CNG fuel to bring about the engine. series of issues.

By now, those skilled in the art will recognize that, although various exemplary embodiments of the present invention have been illustrated and described in detail herein, the present invention may still be implemented in accordance with the present disclosure without departing from the spirit and scope of the present invention. The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. a kind of device that the fuel for controlling CNG dual-fuel vehicle is supplied, for controlling the vehicle in the non-start up stage When fuel automatic switchover, the CNG double fuel includes CNG fuel and Fuel Petroleum, and described device includes:

Fuel injection pulsewidth acquisition device, for obtaining the fuel injection signal of cylinder transmission, the fuel injection signal includes oil spout arteries and veins Width values；

Engine electronic control unit, for when the vehicle is in the larger operating condition of power demand, according to the fuel injection pulsewidth Value judges whether fuel switching to Fuel Petroleum by CNG fuel.

2. the apparatus according to claim 1, wherein the engine electronic control unit is configured in the fuel injection pulsewidth The fuel is switched into Fuel Petroleum by CNG fuel when value is greater than the first preset value.

3. the apparatus of claim 2, wherein the engine electronic control unit is configured in the fuel injection pulsewidth The fuel is switched into CNG fuel by Fuel Petroleum when value is less than the second preset value；

Wherein, first preset value is greater than second preset value.

4. device according to any one of claim 1-3, wherein described device further include:

Gasoline tank, for storing the Fuel Petroleum；

CNG storage tank, for storing the CNG fuel；With

Fuel level sensor, for detecting oil level of the Fuel Petroleum in the gasoline tank.

5. device according to claim 4, wherein the engine electronic control unit is configured in the fuel injection pulsewidth Value be greater than the first preset value while, meet Current fuel be CNG fuel and the oil level be not zero condition when by fuel by CNG fuel switches to Fuel Petroleum.

6. device according to claim 4, wherein the engine electronic control unit is configured to receive will be described When fuel is switched to the signal of CNG fuel by Fuel Petroleum, a preset time is waited to reprocess the signal.

7. device according to claim 6, wherein the engine electronic control unit is configured to be in the vehicle Non-start up stage and when being not at the larger operating condition of power demand, controlling the fuel is CNG fuel.

8. a kind of method that the fuel for controlling CNG dual-fuel vehicle is supplied, for controlling the vehicle in the non-start up stage When fuel automatic switchover, the CNG double fuel includes CNG fuel and Fuel Petroleum, and described method includes following steps:

The fuel injection signal that cylinder is sent is obtained, the fuel injection signal includes fuel injection pulsewidth value；

When the vehicle is in the larger operating condition of power demand, judge whether to fire fuel by CNG according to the fuel injection pulsewidth value Material switches to Fuel Petroleum.

9. according to the method described in claim 8, wherein, being judged whether fuel according to the fuel injection pulsewidth value by CNG fuel Switching to Fuel Petroleum includes: to switch to the fuel by CNG fuel when the fuel injection pulsewidth value is greater than the first preset value Fuel Petroleum.

10. according to the method described in claim 9, wherein, also being wrapped after the fuel switches to Fuel Petroleum by CNG fuel It includes: the fuel being switched into CNG fuel by Fuel Petroleum when the fuel injection pulsewidth value is less than the second preset value；

Wherein, first preset value is greater than second preset value.