CN112761803A

CN112761803A - Gas injection transient compensation method and device, vehicle and storage medium

Info

Publication number: CN112761803A
Application number: CN202110002815.3A
Authority: CN
Inventors: 王文霞; 穆大芸; 张硕; 查小辉; 曹石
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2021-01-04
Filing date: 2021-01-04
Publication date: 2021-05-07

Abstract

The application provides a gas injection transient compensation method, a gas injection transient compensation device, a vehicle and a storage medium. And if the vehicle is in the transient working condition, determining a transient correction value of the fuel gas amount according to the acceleration of the pedal, the rotating speed of the engine and the air intake amount. And correcting the gas demand according to the transient correction value to obtain the corrected gas demand. And finally, controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand. According to the method, the gas demand entering the vehicle cylinder is determined by combining the pedal acceleration, the engine rotating speed and the air inflow under the transient working condition, and the problem that the predicted gas injection quantity of the engine is inaccurate under the transient working condition is solved.

Description

Gas injection transient compensation method and device, vehicle and storage medium

Technical Field

The application relates to the technical field of vehicles, in particular to a gas injection transient compensation method, a gas injection transient compensation device, a vehicle and a storage medium.

Background

The engine adopts a gas single-point injection technology, namely, when gas enters an air injection pipe, the gas is premixed with air inflow and then enters a cylinder through an air inlet manifold. During the running of the vehicle, the injection amount of the gas changes along with the change of the vehicle speed, and the inaccurate gas injection amount can cause the performance of the vehicle to be reduced, namely the injection amount of the gas cannot meet the change requirement of the vehicle speed. In this case, it is necessary to predict the injection amount of the fuel gas.

In the prior art, the prediction of the injection amount of the fuel gas is generally based on the actual air intake amount, that is, the required fuel gas amount is calculated according to the actual air intake amount entering the cylinder and the required excess air coefficient.

However, in practical applications, when the injection amount of the gas is predicted according to the air intake amount, the system structure of the engine is complex, the engine has time delay, and the gas control is significantly delayed, so that the predicted gas injection amount is not accurate under the transient operating condition.

Disclosure of Invention

The application provides a gas injection transient compensation method, a gas injection transient compensation device, a vehicle and a storage medium, which are used for solving the problem that the predicted engine gas injection amount is inaccurate under transient working conditions.

In a first aspect, an embodiment of the present application provides a gas injection transient compensation method, including:

acquiring the acceleration of a pedal, the rotating speed of an engine and the air intake quantity of the vehicle in the running process of the vehicle;

if the vehicle is in a transient working condition, determining a transient correction value of the fuel gas amount according to the pedal acceleration, the engine rotating speed and the air intake amount;

correcting the gas demand according to the transient correction value to obtain the corrected gas demand;

and controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand.

In one possible design of the first aspect, the determining a transient correction value for the air quantity based on the pedal acceleration, the engine speed, and the air intake quantity includes:

determining a first correction value corresponding to the engine speed and the air intake quantity according to a first mapping relation obtained in advance;

determining a second correction value corresponding to the pedal acceleration according to a second mapping relation acquired in advance;

determining the transient correction value according to the first correction value and the second correction value;

the first mapping relation is the relation between the engine speed and the air intake quantity of the vehicle under the transient working condition determined according to experiments and the first correction value, and the second mapping relation is the relation between the pedal acceleration of the vehicle under the transient working condition determined according to experiments and the second correction value.

In another possible design of the first aspect, the method further includes:

and determining whether the vehicle is in a transient working condition or not according to the pedal acceleration, wherein the transient working condition comprises a rapid acceleration state or a rapid deceleration state.

In this possible design, the modifying the gas demand according to the transient modified value to obtain a modified gas demand includes:

if the vehicle is in a rapid acceleration state, increasing the transient correction value to the fuel gas demand to obtain the corrected fuel gas demand;

and if the vehicle is in a rapid deceleration state, subtracting the transient correction value from the gas demand to obtain the corrected gas demand.

In yet another possible design of the first aspect, the method further includes:

acquiring the air intake quantity of the vehicle passing through a throttle valve;

and calculating to obtain the fuel gas demand according to the air intake quantity, the excess air coefficient and the required air-fuel ratio.

In a second aspect, an embodiment of the present application provides a gas injection transient compensation device, including: the device comprises an acquisition module, a determination module and a processing module;

the acquisition module is used for acquiring the pedal acceleration, the engine speed and the air intake quantity of the vehicle in the running process of the vehicle;

the determining module is used for determining a transient corrected value of the fuel gas amount according to the pedal acceleration, the engine speed and the air intake amount if the vehicle is in a transient working condition;

the processing module is used for correcting the gas demand according to the transient correction value to obtain the corrected gas demand;

and the processing module is also used for controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand.

In a possible design of the second aspect, the determining module is specifically configured to:

In another possible design of the second aspect, the determining module is further configured to:

In this possible design, the determining module is configured to correct the gas demand according to the transient correction value to obtain a corrected gas demand, and specifically includes:

the determining module is specifically configured to:

In yet another possible design of the second aspect, the determining module is further configured to:

In a third aspect, embodiments of the present application provide a vehicle, including a processor, a memory, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the gas injection transient compensation method provided in the first aspect and each possible design as described above.

In a fourth aspect, embodiments of the present application may provide a computer-readable storage medium having stored thereon computer-executable instructions for implementing the first aspect and various possible designs to provide a gas injection transient compensation method.

In a fifth aspect, the present application provides a computer program product, which includes a computer program, when the computer program is executed by a processor, for implementing the transient compensation method for gas injection provided by the first aspect and each possible design.

The embodiment of the application provides a gas injection transient compensation method, a gas injection transient compensation device, a vehicle and a storage medium. And if the vehicle is in the transient working condition, determining a transient correction value of the fuel gas amount according to the acceleration of the pedal, the rotating speed of the engine and the air intake amount. And then correcting the gas demand according to the transient correction value to obtain the corrected gas demand. And finally, controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand. According to the method, the gas demand entering the vehicle cylinder is determined by combining the pedal acceleration, the engine rotating speed and the air inflow under the transient working condition, and the problem that the predicted gas injection quantity of the engine is inaccurate under the transient working condition is solved.

Drawings

Fig. 1 is a schematic structural diagram of a single-point injection system according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating a transient compensation principle of gas injection according to an embodiment of the present disclosure;

fig. 3 is a schematic flow chart of a first embodiment of a transient compensation method for gas injection according to an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a gas injection transient compensation device provided in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a vehicle according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first," "second," and the like in the description and in the claims, and in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or vehicle that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or vehicle.

Before describing embodiments of the present application, the terms and background related to the present application will be explained.

Single-point injection: the fuel gas is intensively injected and then is mixed with air in an air inlet pipeline of the engine without cylinder separation;

multi-point injection: the fuel gas is injected in an air inlet manifold or an in-cylinder injection of each cylinder, and each cylinder is independently controlled to inject;

excess air ratio: the ratio of the amount of air actually supplied to the fuel for combustion to the theoretical amount of air;

theoretical air-fuel ratio: under an ideal state, the ratio of the air intake quantity and the fuel gas injection quantity required by the complete combustion of the air and the fuel gas;

exhaust Gas Recirculation (EGR): part of the exhaust gases from the engine is returned to the intake manifold and re-enters the cylinders with fresh mixture. Because the waste gas contains a large amount of carbon dioxide CO₂Equal polyatomic gas, and CO₂When the gas cannot be combusted, the gas absorbs a large amount of heat due to high specific heat capacity, so that the maximum combustion temperature of the gas mixture in the cylinder is reduced, and the generation amount of nitrogen oxides is reduced.

The national six natural gas engine mainly adopts gas single-point injection, namely gas is injected in an air inlet pipe and premixed with air to enter an air cylinder through an air inlet manifold. The gas injection amount is generally predicted based on the actual intake air amount, which also provides the vehicle with better power performance during running.

Specifically, fig. 1 is a schematic structural diagram of a single-point injection system according to an embodiment of the present disclosure. As shown in FIG. 1, the system comprises air 11, a throttle valve 12, gas 13, exhaust gas recirculation 14, a mixture 15 and cylinders 16.

The cylinder 16 may include a plurality of cylinders 161, and a 4-cylinder engine is exemplified herein.

In the prior art, during intake to the cylinder 16, the air 11 is mixed with the combustion gas 13 through the throttle valve 12 and then mixed with the exhaust gas in the exhaust gas recirculation 14, and the mixed air mixture 15 passes through the intake manifold to the cylinder 16 and is combusted in the cylinder 16 to provide power to the engine.

When the vehicle is accelerating or decelerating, the throttle valve 12 is opened or closed in time according to the demand so that the change in the intake air amount of the air 11 satisfies the transient demand. And the amount of the gas 13 actually entering the cylinder 16 is controlled according to the required gas amount in combination with the conversion of the rail pressure of the gas 13 into the energization time. That is, the required amount of fuel gas can be calculated from the intake air amount of the air 11 passing through the throttle valve 12, the excess air ratio and the required air-fuel ratio, and the amount of fuel gas 13 is compensated by predicting the change of the fuel gas 13 from the pressure change of the mixture 15 at the time of the transient condition.

However, in practical applications, due to the complicated engine structure and the control lag of the gas 13, the gas 13 is injected inside the intake pipe, and when the gas is premixed with the air 11 and enters the cylinder 16 through the intake manifold, the requirement for vehicle operation cannot be met, and especially in rapid acceleration or rapid deceleration, the prediction of the injection amount of the gas 13 is not accurate due to the large control fluctuation of the excess air ratio.

Aiming at the technical problems, the technical concept of the technical scheme of the application is as follows: the inventors have found that the magnitude of the gas injection amount is mainly determined by the driver's control of the accelerator during the running of the vehicle. Therefore, the gas injection quantity can be corrected in time according to the opening and the change rate of the pedal in the driving intention of the driver, so that the problem of gas control lag is solved, and the control of the excess air coefficient under the transient state is more stable.

The technical solution of the present application will be described in detail below with reference to specific examples. It should be noted that the following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

Fig. 2 is a schematic view of a gas injection transient compensation principle provided in an embodiment of the present application. As shown in fig. 2, the schematic diagram includes: engine speed 21, air intake air quantity 22, pedal acceleration 23, first correction value 24, second correction value 25, transient correction value 26, gas demand 27, and corrected gas demand 28.

In one possible implementation, a first correction value 24 for the gas quantity is determined by taking the engine speed 21 and the air intake 22 of the vehicle, and then a second correction value 25 for the gas quantity is determined by taking the pedal acceleration 23 of the vehicle, while the vehicle is in a transient operating condition. Finally, a transient correction value 26 for the gas quantity is determined based on the first correction value 24 and the second correction value 25, and the gas demand 27 is corrected based on the transient correction value 26 to obtain a corrected gas demand 28.

Optionally, when the transient operating condition is rapid acceleration, the transient correction value 26 is a positive number; when the transient operating condition is rapid deceleration, the transient correction value 26 is negative.

Based on the schematic diagram shown in fig. 2, fig. 3 is a schematic flowchart of a first embodiment of a gas injection transient compensation method provided in the embodiment of the present application. As shown in fig. 3, the method for transient compensation of gas injection comprises the following steps:

and step 31, acquiring the pedal acceleration, the engine speed and the air intake quantity of the vehicle during the running process of the vehicle.

In this scheme, to the vehicle in-process of traveling, trample the footboard when the driver, when the intention was adjusted the speed of vehicle, for guaranteeing that the state of vehicle operation accords with driver's wish, just need to guarantee that gas and air fully react in the cylinder.

In this step, the acceleration of the pedal when the driver adjusts the speed of the vehicle according to his/her will during the running of the vehicle, the engine speed at the current time of the vehicle, and the air intake amount are obtained.

In one possible implementation, the pedal acceleration may be measured by a displacement sensor mounted at the pedal; the engine speed can be measured by a crankshaft position sensor; the air intake amount may be measured by a pressure sensor installed at the air intake port.

In the scheme, the fuel gas demand is calculated by obtaining the air intake quantity of the throttle valve of the vehicle according to the air intake quantity, the excess air coefficient and the required air-fuel ratio.

Alternatively, in a vehicle, the pedal is mainly used to control the opening degree of a throttle valve of the engine, that is, to control the air intake amount of the throttle valve. The excess air ratio is used for indicating the ratio of the air quantity actually supplied for gas combustion to the theoretical air quantity, so that the gas demand when the pedal is actuated can be determined through the excess air ratio and the air intake quantity of the throttle valve.

And step 32, if the vehicle is in the transient working condition, determining a transient correction value of the fuel gas amount according to the acceleration of the pedal, the rotating speed of the engine and the air intake amount.

In the scheme, whether the vehicle is in a transient working condition or not needs to be determined according to the acceleration of the pedal, and the transient working condition comprises a rapid acceleration state or a rapid deceleration state.

Specifically, the pedal acceleration can be measured by a displacement sensor, the magnitude of the pedal acceleration is judged, the vehicle running state is determined, and if the pedal acceleration is greater than a first preset threshold value, the vehicle is considered to be in a rapid acceleration state; and if the pedal acceleration is smaller than a second preset threshold value, the vehicle is considered to be in a rapid deceleration state. It should be noted that the first preset threshold and the second preset threshold may be set according to actual situations, and in some possible implementations, the first preset threshold and the second preset threshold may be equal or opposite numbers.

In this step, if the vehicle is in a rapid acceleration state or a rapid deceleration state, a transient correction value for the fuel amount is determined based on the pedal acceleration, the engine speed, and the air intake amount.

The transient correction value may be expressed as a gas amount that corrects the gas demand obtained in the above step to an actual gas amount.

Specifically, determining the transient correction value of the fuel gas amount according to the pedal acceleration, the engine speed and the air intake amount can be realized by the following steps:

step 1, determining a first correction value corresponding to the engine speed and the air intake quantity according to a first mapping relation obtained in advance.

In one possible implementation, the first correction value is obtained by means of a pulse-spectrum MAP based on the engine speed and the air intake amount. The first correction value represents a correction amount corresponding to the current working condition (which can be a small load or a large load) of the vehicle. Namely, the correction amounts corresponding to different working conditions are different in size.

The first mapping relation is the relation between the engine speed of the vehicle under the transient working condition, the air intake quantity and the first correction value, which is determined according to experiments.

And step 2, determining a second correction value corresponding to the pedal acceleration according to a second mapping relation acquired in advance.

In one possible implementation, the second correction value represents a magnitude degree of the pedal acceleration of the current vehicle, namely, a correction coefficient at different pedal accelerations.

The second mapping relationship is a relationship between the pedal acceleration of the vehicle under the transient condition and the second correction value, which is determined experimentally.

And step 3, determining a transient correction value according to the first correction value and the second correction value.

Specifically, the transient correction value may be obtained by multiplying the first correction value by the second correction value.

Optionally, when the degree of the rapid acceleration or the rapid deceleration is too low, that is, close to 0, the magnitude of the second correction value may be regarded as 0, which indicates that the gas demand does not need to be corrected, that is, the transient correction value is 0, and further, the obtained gas demand is the corrected gas demand.

And step 33, correcting the gas demand according to the transient correction value to obtain the corrected gas demand.

In this step, the gas demand determined from the air intake and the excess air factor is corrected based on the transient correction value, and the corrected gas demand is the gas demand suitable for the vehicle under the transient condition.

Specifically, according to the difference of the transient operating conditions of the vehicle, the correction of the fuel gas demand can be divided into the following two cases:

firstly, if the vehicle is in a rapid acceleration state, increasing the gas demand by a transient correction value to obtain a corrected gas demand;

and secondly, if the vehicle is in a rapid deceleration state, subtracting the transient correction value from the gas demand to obtain a corrected gas demand.

And step 34, controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand.

In this step, the gas introduced into the cylinders of the vehicle is controlled based on the corrected gas demand so that the amount of gas injected into each cylinder is the amount actually required by each cylinder in the transient condition of the vehicle.

In a possible implementation, when the driver operates the vehicle and accelerates, the gas demand calculated in the prior art is N, and the transient correction value obtained in the present embodiment is M, the corrected gas demand obtained according to the above steps is M + N, and an Electronic Control Unit (ECU) controls the amount of gas injected into each cylinder by the gas injection valve according to the corrected gas demand M + N.

According to the gas injection transient compensation method provided by the embodiment of the application, in the running process of a vehicle, the pedal acceleration, the engine speed and the air intake quantity of the vehicle are obtained, and if the vehicle is in a transient working condition, a transient correction value of the gas quantity is determined according to the pedal acceleration, the engine speed and the air intake quantity. And correcting the gas demand according to the transient correction value to obtain the corrected gas demand, and finally controlling the gas entering the vehicle cylinder according to the corrected gas demand. According to the method, the gas demand entering the vehicle cylinder is determined by combining the pedal acceleration, the engine rotating speed and the air inflow under the transient working condition, and the problem that the predicted gas injection quantity of the engine is inaccurate under the transient working condition is solved.

Fig. 4 is a schematic structural diagram of a gas injection transient compensation device provided in an embodiment of the present application. As shown in fig. 4, the gas injection transient compensation device includes: an acquisition module 41, a determination module 42 and a processing module 43.

The obtaining module 41 is used for obtaining the pedal acceleration, the engine speed and the air intake quantity of the vehicle in the running process of the vehicle;

the determining module 42 is configured to determine a transient correction value for the fuel amount according to the pedal acceleration, the engine speed, and the air intake amount if the vehicle is in the transient operating condition;

the processing module 43 is configured to correct the gas demand according to the transient correction value to obtain a corrected gas demand;

and the processing module 43 is further used for controlling the fuel gas entering the vehicle cylinder according to the corrected fuel gas demand.

In one possible design of the embodiment of the present application, the determining module 42 is specifically configured to:

determining a second correction value corresponding to the acceleration of the pedal according to a second mapping relation acquired in advance;

determining a transient correction value according to the first correction value and the second correction value;

the first mapping relation is the relation between the engine speed of the vehicle under the transient working condition and the air intake quantity and the first correction value determined according to experiments, and the second mapping relation is the relation between the pedal acceleration and the second correction value of the vehicle under the transient working condition determined according to experiments.

In another possible design of the embodiment of the present application, the determining module 42 is further configured to:

based on the pedal acceleration, it is determined whether the vehicle is in a transient condition, including a hard acceleration state or a hard deceleration state.

In this possible design, the determining module 42 is configured to correct the gas demand according to the transient correction value to obtain a corrected gas demand, specifically:

the determining module 42 is specifically configured to:

In yet another possible design of the embodiment of the present application, the determining module 42 is further configured to:

acquiring the air intake quantity of a vehicle passing through a throttle valve;

The gas injection transient compensation device provided by the embodiment can be used for implementing the scheme in the embodiment, the implementation principle and the technical effect are similar, and the description is omitted.

It should be noted that the division of the modules of the above apparatus is only a logical division, and the actual implementation may be wholly or partially integrated into one physical entity, or may be physically separated. And these modules can be realized in the form of software called by processing element; or may be implemented entirely in hardware; and part of the modules can be realized in the form of calling software by the processing element, and part of the modules can be realized in the form of hardware. For example, the processing module 43 may be a separate processing element, or may be integrated into a chip of the above apparatus. The acquisition module 41 is implemented similarly. In addition, all or part of the modules can be integrated together or can be independently realized. The processing element here may be an integrated circuit with signal processing capabilities. In implementation, each step of the above method or each module above may be implemented by an integrated logic circuit of hardware in a processor element or an instruction in the form of software.

Fig. 5 is a schematic structural diagram of a vehicle according to an embodiment of the present application. As shown in fig. 5, the vehicle includes: a processor 51, a memory 52 and a transceiver 53.

The processor 51 executes computer-executable instructions stored by the memory, so that the processor 51 executes the scheme in the above-described embodiments.

The processor 51 may be a general-purpose processor including a central processing unit CPU, a Network Processor (NP), and the like; but also a digital signal processor DSP, an application specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components.

The memory 52 stores computer-executable instructions, and may include Random Access Memory (RAM) and non-volatile memory (non-volatile memory), such as at least one disk memory.

Optionally, in terms of hardware implementation, the obtaining module 41 in the embodiment shown in fig. 4 corresponds to the transceiver 53 in this embodiment, and the transceiver 53 forms a communication interface.

Alternatively, the processor 51, the memory 52 and the transceiver 53 are connected by a system bus, which may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The system bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus. The communication interface is used for realizing communication between the database access device and other vehicles (such as a client, a read-write library and a read-only library). The memory may comprise Random Access Memory (RAM) and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

The vehicle provided by the embodiment of the application can be used for executing the scheme in the embodiment, the implementation principle and the technical effect are similar, and the detailed description is omitted.

The embodiment of the application also provides a chip for running the instructions, and the chip is used for executing the scheme in the embodiment.

The embodiment of the present application further provides a computer-readable storage medium, in which computer instructions are stored, and when the computer instructions are run on a computer, the computer is caused to execute the scheme of the foregoing embodiment.

Embodiments of the present application also provide a computer program product, which includes a computer program stored in a computer-readable storage medium, where the computer program can be read by at least one processor from the computer-readable storage medium, and the at least one processor can implement the solutions in the above embodiments when executing the computer program.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of transient compensation for gas injection, comprising:

2. The method of claim 1, wherein said determining a transient correction to fuel flow based on said pedal acceleration, said engine speed, and said air intake flow comprises:

3. The method according to claim 1 or 2, characterized in that the method further comprises:

4. The method of claim 3, wherein the modifying the gas demand according to the transient modification value to obtain a modified gas demand comprises:

5. The method according to claim 1 or 2, characterized in that the method further comprises:

6. A gas injection transient compensation device, comprising: the device comprises an acquisition module, a determination module and a processing module;

7. The apparatus of claim 6, wherein the determining module is specifically configured to:

8. A vehicle comprising a processor, a memory and a computer program stored on and executable on the memory, the processor implementing the gas injection transient compensation method of any of claims 1-5 when executing the program.

9. A computer-readable storage medium having computer-executable instructions stored thereon, which when executed by a processor, are configured to implement the gas injection transient compensation method of any of claims 1-5.

10. A computer program product comprising a computer program, characterized in that the computer program is adapted to be executed by a processor for implementing a gas injection transient compensation method according to any of claims 1-5.