KR100532611B1 - Gasoline Alternative Fuel Injection Control Apparatus of Engine - Google Patents

Abstract

As an invention to prevent injection delay of gasoline alternative fuel and to optimize the air-fuel ratio, the LPG injection control apparatus of the present invention is characterized in that each cylinder is provided from an injector 6 provided in each cylinder and an operating state detected by various sensors 31 to 35. Gasoline electronic control device (gasoline ECU) 2 which outputs gasoline injection signal at the beginning of the intake stroke of gasoline, and LPG ECU 3 which outputs gasoline injection signal to LPG injection signal to each injector 6 as LPG injection signal. . The LPG ECU3 outputs the LPG injection signal to the corresponding injector 6 during the first injection amount expected from the start of outputting the current gasoline injection signals Q1 to Q4 from the gasoline ECU2 at the time of the current LPG injection of a cylinder, From the end of the output of the current gasoline injection signals Q1 to Q4, the LPG injection signal is output to each injector 6 during the second injection amount portion which is the difference between the LPG injection amount corresponding to the current gasoline injection amount and the first injection amount.

Description

Gasoline Alternative Fuel Injection Control Apparatus of Engine}

The present invention relates to a gasoline alternative fuel injection control apparatus that injects and supplies gasoline alternative fuel such as liquefied petroleum gas (LPG) and liquefied natural gas (LNG) for each cylinder of the engine. More specifically, in the base system including the gasoline injection control unit, the gasoline alternative fuel injection control unit and the fuel system device for gasoline alternative fuel injection are added, and the gasoline injection signal output from the gasoline injection control unit of the base system is converted to gasoline. The present invention relates to a gasoline alternative fuel injection control apparatus for an engine configured to correct and output a gasoline alternative fuel injection signal from an alternative fuel injection control unit, and to perform gasoline alternative fuel injection by a fuel meter device for gasoline alternative fuel injection.

Background Art Conventionally, various techniques have been proposed for engines using LPG as a fuel for gasoline alternative fuels. For example, the following non-patent document 1 has been published in relation to the 'research and development trend of LPG fuel engine system', and among them, Vialle Corporation as a research and development of the fifth generation (electronically controlled liquid injection method), A fuel supply system produced and sold as an LPi system 'is introduced.

The LPi system consists of the Bi-Fuel system, which exchanges gasoline and LPG. As shown in Fig. 4, the system includes an engine control unit (gasoline ECU) for a base vehicle gasoline, a gasoline fuel gauge device including a gasoline injector, a control computer for LPG (LPE), and an LPG. A fuel gauge device for LPG including an injector and an LPG / gasoline replacement switch. By replacing this switch, the motor which injects gasoline into an engine using a gasoline ECU, a gasoline injector, etc., and the motor which injects LPG into an engine using an LPE and LPG injector etc. are replaced. In the LPG injection motor, the LPE cooperates with the gasoline ECU to control the LPG injection amount by the LPG injector.

That is, the underlying gasoline ECU determines the gasoline injection amount (gasoline injection time) based on measured values such as air amount, intake air temperature, engine coolant temperature and engine load, and outputs the injection signal to the LPE. The LPE executes LPG injection by converting (correcting) the gasoline injection time into LPG injection amount (LPG injection time) and outputting the result to the LPG injector.

In the LPi system, even when the underlying gasoline system employs an independent injection, a group injection that simultaneously injects into two cylinders is adopted for the LPG system. In addition, in the LPE, the crank angle signal is not supplied, and the injection by the LPG injector is started at the same time as the injection end timing of the gasoline injection time determined by the base gasoline ECU.

Here, when the LPG injection control of the LPi system is applied to the independent injection of the multi-cylinder engine, the relationship between the gasoline injection timing by the gasoline ECU and the LPG injection timing by the LPE is shown in Figs. 5 (a) and (b). Can be as shown in In this graph, a four-cylinder engine is shown, and fuel injection is performed in the order of cylinder # 1, cylinder # 3, cylinder # 4, and cylinder # 2. In Fig. 5 (a), the rectangles labeled 'A', 'B', 'C' and 'D' represent gasoline injection signals corresponding to cylinders # 1, # 3, # 4 and # 2, In Fig. 5 (b), the rectangles labeled A ', B', C ', and D' represent LPG injection signals corresponding to cylinders # 1, # 3, # 4, and # 2, and the difference in length is The difference in injection time is shown. As shown in Fig. 5A, a gasoline injection signal for a predetermined time is output at the beginning of the intake stroke. At the same time as the end timing of the gasoline injection signal, as shown in Fig. 5B, the LPG injection signal starts to be output for each cylinder # 1, # 3, # 4, # 2.

[Non-Patent Document 1]

'Car Technology' Vol. 55, No. 5, 2001, p. 30-37

When the LPG injection control is applied to the multi-cylinder independent injection control as described above, in each cylinder # 1 to # 4, since the LPG injection is started at the end timing of the underlying gasoline injection, the individual LPG injection is performed by the gasoline. This is delayed rather than injection.

Here, generally, it is known that the injection ends preferably until the start of the intake stroke with respect to the fuel injection timing. However, in the LPG injection control, as shown in Fig. 5 (a), since gasoline injection is performed at the beginning of the intake stroke for each cylinder # 1 to # 4, the respective cylinders # 1 to # 4 corresponding to this are In Fig. 5, the LPG injection timing is spread over the middle and second stages of the intake stroke, as shown in Fig. 5B. For this reason, LPG injected near the end of LPG injection is hard to be sucked into the corresponding cylinders # 1 to # 4, and an appropriate air-fuel ratio cannot be obtained, resulting in a decrease in engine power, There is a risk of deteriorating exhaust emissions.

In particular, when the engine is under high load, the amount of basic gasoline injection calculated by the gasoline ECU becomes relatively large, and accordingly, the LPG injection signal corrected in the LPE is also long. For this reason, the vicinity of the LPG injection end time enters into a compression stroke, and LPG cannot fully enter each corresponding cylinder # 1-# 4, and the said problem becomes more serious.

The above problems can also occur in engines using gasoline alternative fuels such as LNG other than LPG in place of gasoline.

This invention is made | formed in view of the said situation, The objective is to provide the gasoline alternative fuel injection control apparatus of the engine which prevented the fuel delay of the gasoline alternative fuel in all cylinders, and aimed at optimizing the air-fuel ratio of an engine.

In order to achieve the above object, the invention as set forth in claim 1 includes an engine comprising a plurality of cylinders, the engine being operated to repeat sequentially a series of intake strokes, compression strokes, expansion strokes, and exhaust strokes for each cylinder; A plurality of injectors for injecting and supplying a gasoline alternative fuel for each cylinder, an operation state detecting means for detecting an operating state of the engine, and a gasoline to be supplied to a corresponding cylinder in a predetermined injection order based on the detected operating state A gasoline injection control unit for calculating the injection amount and outputting the injection amount as a gasoline injection signal at the beginning of the intake stroke of each cylinder, and correcting the gasoline injection signal output for each cylinder to be suitable as a gasoline alternative fuel to inject gasoline alternative fuel. Gasoline alternative fuel injection control unit for sequential output to injectors for each cylinder as signals As a gasoline alternative fuel injection control device for an engine including a gasoline alternative fuel injection control unit, at the time of the current gasoline alternative fuel injection of a cylinder, the gasoline alternative fuel injection control unit is expected from the start of output of this gasoline injection signal from the gasoline injection control unit. Outputting the gasoline replacement fuel injection signal for the first injection time corresponding to the first injection amount, and then, from the end of output of the current gasoline injection signal from the gasoline injection control unit, the gasoline replacement fuel injection amount corresponding to the current gasoline injection amount and The difference from the anticipated first injection amount is intended to output the gasoline replacement fuel injection signal during the second injection time corresponding to the post injection amount as the post injection amount.

According to the configuration of the present invention, the operation state is detected by the operation state detection means in the engine that operates to sequentially repeat the series of intake strokes, compression strokes, expansion strokes and exhaust strokes for each cylinder. And based on the detected operation state, the gasoline injection control unit calculates the amount of gasoline injection which should be supplied to the cylinder corresponding to a predetermined injection sequence, and the injection amount is the gasoline injection at the beginning of the intake stroke of each cylinder. It is output as a signal. In the gasoline alternative fuel injection control unit, the gasoline injection signal output for each cylinder is corrected to be suitable for the gasoline alternative fuel and sequentially output to the injector for each cylinder as the gasoline alternative fuel injection signal, and the injection of the gasoline alternative fuel by each injector is performed. Is performed.

Here, in the gasoline alternative fuel injection control unit, at the time of the current gasoline alternative fuel injection of a cylinder, the first equivalent to the first injection amount expected from the start of output of the current gasoline injection signal from the gasoline injection control unit is first described. During one injection time, the gasoline alternative fuel injection signal is output to the corresponding injector. Thereafter, from the time when the output of the current gasoline injection signal from the gasoline injection control unit ends, the difference between the gasoline replacement fuel injection amount corresponding to the current gasoline injection amount and the expected first injection amount corresponds to the second injection amount. The gasoline replacement fuel injection signal is output to the corresponding injector during the second injection time. Therefore, at the time of injection of the gasoline alternative fuel in one cylinder, the injection of the current gasoline replacement fuel injection amount is divided into the expected first injection amount and the second injection amount, and is performed until the intake stroke of the cylinder is completed.

In order to achieve the above object, in the invention described in claim 2, in the invention according to claim 1, the expected first injection amount is a predetermined amount of gasoline injection amount calculated corresponding to the injection sequence performed before the current injection in the gasoline injection control unit. It is intended to correspond to ratio.

According to the structure of the said invention, in addition to the effect | action of the invention of Claim 1, since the estimated 1st injection amount is determined by the gasoline injection amount computed corresponding to the injection sequence performed before this time injection in a gasoline injection control unit, At that time, an estimated first injection amount in accordance with the operating state of the engine is obtained at that time.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment which actualized the gasoline alternative fuel injection control apparatus of the engine of this invention is described in detail with reference to drawings.

In FIG. 1, the LPG engine system which is this embodiment is shown in schematic block diagram. This engine system is for LPG as a gasoline alternative fuel injection control unit of the present invention with respect to a basic system including an engine 1 for gasoline and an electronic control unit (gasoline ECU) 2 for gasoline as the gasoline injection control unit of the present invention. The electronic control device (LPG ECU) 3 and the LPG injection fuel system device are provided. The engine system is a mono-fuel type configured to correct the gasoline injection signal output from the gasoline ECU2 to LPG by the LPG ECU3, output it as an LPG injection signal, and perform LPG injection from the LPG injection fuel system. to be.

This engine system mounted on a vehicle has an LPG tank 4 for storing LPG as a gasoline alternative fuel. The LPG pump 5 embedded in the LPG tank 4 discharges the LPG stored in the tank 4. In this embodiment, the gasoline engine 1 is a four-cylinder engine of a reciprocating type, and has a series of intake strokes for each of the first cylinder # 1, the second cylinder # 2, the third cylinder # 3, and the fourth cylinder # 4, It works by repeating sequentially the compression stroke, expansion stroke and exhaust stroke. In each cylinder # 1-# 4, the LPG injector 6 for injection-injecting LPG is provided. The LPG discharged from the LPG pump 5 is supplied to each LPG injector 6 through the LPG line 7 and the conveying pipe 8. The LPG supplied is injected into the liquid phase by the operation of each LPG injector 6 to the intake ports of the cylinders # 1 to # 4 leading to the intake passage 9. Air is supplied to the intake passage 9 from the outside. The air supplied to the intake passage 9 and the LPG injected from each LPG injector 6 are sucked into the fuel chamber 10 of the cylinders # 1 to # 4 as combustible mixed air.

The intake passage 9 is provided with a control valve 11 operated by a predetermined accelerator (not shown). By opening and closing this control valve 11, the amount of air (intake amount) sucked into each combustion chamber 10 from the intake passage 9 is adjusted.

The spark plugs 12 provided in the fuel chambers 10 of the cylinders # 1 to # 4, respectively, receive an ignition signal output from the ignition coil 13 and perform ignition operation. Each spark plug 12 and ignition coil 13 constitute an ignition device for igniting with combustible mixed air sucked into the fuel chamber 10. In each of cylinders # 1 to # 4, the combustible mixed air sucked into the combustion chamber 10 in the intake stroke is compressed in the compression stroke and explodes and combusts and expands when the spark plug 12 fires in the expansion stroke. The exhaust gas after combustion is discharged from the fuel chamber 10 to the outside through the exhaust passage 14 in the subsequent exhaust stroke. In the fuel chamber 10 of each of cylinders # 1 to # 4, the piston 15 moves up and the crankshaft 16 rotates in response to the combustion of the combustible mixed air, so that the driving force for driving the vehicle is obtained by the engine 1. .

In the middle of the outlet of the LPG pump 5 and the LPG line 7, shutoff valves 17 and 18 for forcibly shutting off the LPG flow are provided. In the conveying pipe 8, a pressure adjusting device 20 for maintaining the LPG pressure constant is provided.

The various sensors 31, 32, 33, 34, 35 provided in the engine 1 and the like correspond to the driving state detecting means of the present invention for detecting various operating parameters relating to the operating state of the engine 1, and are connected to the gasoline ECU2, respectively. do. That is, the adjustment sensor 31 provided in the vicinity of the regulation valve 11 detects the opening degree (adjustment degree) TA of the regulation valve 11, and outputs the electric signal according to the detected value. The intake pressure sensor 32 provided in the intake passage 9 detects the intake pressure PM in the intake passage 9 downstream from the regulating valve 11 and outputs an electric signal corresponding to the detected value. The water temperature sensor 33 provided in the engine 1 detects the temperature (cooling water temperature) THW of the cooling water flowing inside the engine 1, and outputs an electric signal corresponding to the detected value. The rotational speed sensor 34 provided in the engine 1 detects the rotational speed (engine rotational speed) NE of the crankshaft 16 and outputs an electric signal corresponding to the detected value. The oxygen sensor 35 provided in the exhaust passage 14 detects the oxygen concentration (output voltage) Ox in the exhaust gas discharged into the exhaust passage 14, and outputs an electric signal corresponding to the detected value.

In this embodiment, the gasoline ECU2 inputs various signals output from the various sensors 31 to 35 described above. The gasoline ECU2 executes gasoline injection control, ignition time control, etc. based on these input signals, and the gasoline injection signals Q1, Q2, Q3, corresponding to the cylinders # 1 to # 4, for the LPG ECU3. At the same time as outputting Q4, the ignition signal corresponding to the cylinders # 1 to # 4 is output to the ignition coil 13. The gasoline injection signals Q1, Q2, Q3, and Q4 originally correspond to a drive signal for driving a gasoline injector in the basic system.

Here, the gasoline injection control is to control the amount of gasoline injection by the gasoline injectors provided in the cylinders # 1 to # 4 and the injection timing thereof in the original basic system based on the operating state of the engine 1. Therefore, in the gasoline ECU2, the gasoline injection amount corresponding to the operation state of the engine 1 is calculated, and the injection amount is output to the LPG ECU3 as the gasoline injection signals Q1, Q2, Q3, Q4. The ignition timing control is to control the ignition timing by the spark plugs 12 of the cylinders # 1 to # 4 by controlling the ignition coil 13 in accordance with the operating state of the engine 1.

Here, LPG tank 4, LPG pump 5, LPG line 7, pressure regulator 8, each LPG injector 6, recovery line 19 and shut-off valves 17 and 18, in order to make the base system a mono-fuel type LPG engine system It is a fuel system device for LPG injection provided in place of the fuel system device for gasoline injection. Since LPG has a larger change in properties with respect to temperature and pressure than gasoline, it is necessary to correct the LPG injection amount according to the LPG temperature state and the pressure state in order to accurately calculate the LPG injection amount from each LPG injector 6. Thus, in order to detect the LPG temperature state and the pressure state, the LPG tank 4 is provided with a tank LPG temperature sensor 36 and a tank LPG pressure sensor 37, and the conveying pipe 8 is equipped with a pipe LPG temperature sensor 38 and a pipe LPG Pressure sensor 39 is provided. These sensors 36 to 39 are connected to the ECU 3 for LPG, respectively. In addition, LPG pump 5, two shutoff valves 17 and 18, and LPG injectors 6 of cylinders # 1 to # 4 are respectively connected to the LPG ECU3. In addition, an adjustment sensor 31 is also connected to the LPG ECU3.

In this embodiment, the LPG ECU3 inputs various signals output from various sensors 31 and 36 to 39. The LPG ECU3 executes correction control for correcting the gasoline injection signals Q1, Q2, Q3, and Q4 so as to be suitable for LPG based on these input signals, and time control for replacing the gasoline injection time with the LPG injection time. The LPG injectors 6 for each cylinder # 1 to # 4 are sequentially output as LPG injection signals.

The ECU2 for gasoline and the ECU3 for LPG each include a central processing unit (CPU), a read only memory, a random-access memory, a backup ram, an external input circuit, an external output circuit, and the like. Each ECU2, 3 comprises a logic arithmetic circuit formed by connecting a CPU, a ROM, a RAM, a backup RAM, an external input circuit, an external output circuit and the like by a bus, respectively. Each ROM stores predetermined control programs relating to various controls in advance. Each RAM temporarily stores the calculation result of each CPU. Each CPU executes the above-described various control and the like according to a predetermined control program based on the detection signals from the various sensors 31 to 39 input through the input circuit.

Fig. 2 is a block diagram showing the electrical configuration of LPG injection control of this engine system. The various sensors 31 to 35 are connected to the gasoline ECU2, respectively. The various sensors 31 and 36 to 39 are connected to the LPG ECU3, respectively. The ECU2 for gasoline has output terminals 41a, 41b for gasoline injection signals Q2, Q1, Q3, and Q4 corresponding to cylinders # 2, cylinder # 1, cylinder # 3, and cylinder # 4 respectively. , 41c, 41d. These output terminals 41a-41d are connected in parallel with each input terminal 42a, 42b, 42c, 42d provided in the LPG ECU3. In addition, ECU3 for LPG has output terminals 43a, 43b, 43c, 43d for LPG injection signals corresponding to cylinder # 2, cylinder # 1, cylinder # 3, and cylinder # 4 respectively. . These output terminals 43a to 43d correspond to signals from each of the input terminals 42a to 42d provided in the ECU 3 for LPG, and each of cylinder # 2, cylinder # 1, cylinder # 3, and cylinder # 4. It is connected to each LPG injector 6 provided. As a result, the gasoline injection signal Q2 corresponding to the second cylinder # 2 output from the gasoline ECU2 is corrected to be suitable for the LPG in the LPG ECU3, and the LPG injection is performed with the LPG injector 6 corresponding to the second cylinder # 2. It is output as a signal. Similarly, the gasoline injection signal Q1 corresponding to cylinder # 1 output from the gasoline ECU2 is corrected to be suitable for LPG in the LPG ECU3, and the LPG injector 6 corresponding to cylinder # 1 is used as the LPG injection signal. Is output. In addition, the gasoline injection signal Q3 corresponding to cylinder # 3 output from the gasoline ECU2 is corrected to be suitable for LPG in the LPG ECU3, and the LPG injector 6 corresponding to cylinder # 3 is used as the LPG injection signal. Is output. Also, the gasoline injection signal Q4 corresponding to cylinder # 4 output from the gasoline ECU2 is corrected to be suitable for LPG in the LPG ECU3 and the LPG injection signal to the LPG injector 6 corresponding to cylinder # 4. Is output as.

Hereinafter, the contents of the LPG injection control processing executed by the LPG ECU3 will be described with reference to FIGS. 3A and 3B. 3 (a) and 3 (b) are time charts showing the relationship between the gasoline injection signal output from the gasoline ECU2 and the LPG injection signal output from the LPG ECU3 corresponding to the cylinders # 1 to # 4. In this chart, LPG injection is performed in the order of cylinder # 1, cylinder # 3, cylinder # 4, and cylinder # 2. In Fig. 3 (a), the rectangles labeled 'A', 'B', 'C' and 'D' indicate gasoline injection amounts (gasoline injection times) corresponding to cylinders # 1, # 3, # 4, and # 2. The gasoline injection signal corresponding to FIG. 3 (b) shows rectangles labeled 'A1, A2', 'B1, B2', 'C1, C2', and 'D1, D2', respectively. An LPG injection signal corresponding to the LPG injection amount (LPG injection time) corresponding to 3, # 4, # 2 is shown, and the difference in length indicates the difference in injection time, respectively.

In the following, LPG injection is described as an example at the timing according to cylinder # 4 shown as an ellipse in Fig. 3B.

First, at time a1, the LPG ECU3 stores the injection start time # 1 ON in the RAM in the gasoline injection signal Q1 from the gasoline ECU2. Next, at time a2, the LPG ECU3 stores the injection end time # 1 OFF in the RAM in the gasoline injection signal Q1. And between time a2 and time c1, LPG ECU3 calculates with the following values.

① gasoline injection time TAU _g360

TAU _g360 = (# 1 OFF)-(# 1 ON)

Here, gasoline injection time TAU _g360 means the gasoline injection time before 360 _degreeCA from cylinder # 4. That is, the time equivalent to the length of the rectangle to which "A" was initially attached in FIG. 3 (a) is calculated.

② LPG 1st injection time T _lpg1

T1 = TAU _g360 * (n / 100)

T _lpg1 = T1 + TVL

Here, 'n' means a percentage of the required value T _lpg1 of the LPG injection time, and a value of about '50 to 60 'is applied. 'TVL' means an invalid energization time (defined as an integer) of LPG injection time.

③ Correction coefficient K _LPG peculiar to LPG fuel

The correction coefficient K _lpg is used to correct the gasoline injection amount to be suitable for LPG. The correction coefficient K _lpg is used to correct the gasoline and LPG by the difference in the fuel properties of the gasoline and the LPG. It is calculated | required from a calculation formula or the like.

Next, at time c1, the LPG ECU3 stores the injection start time # 4 ON in the RAM in the gasoline injection signal Q4 from the gasoline ECU2. In other words, in Fig. 3 (a), the time span of the beginning of the rectangle to which 'C' is first added is stored. At the timing, the LPG ECU3 turns on the LPG injector 6 of cylinder # 4 and _turns off the injector 6 when the LPG first injection time T _lpg1 calculated above has elapsed. As a result, in Fig. 3B, LPG injection is performed during the rectangular portion to which 'C1' is first attached. As a result, the LPG ECU3 is the LPG first corresponding to the first injection amount expected from the start of the output of the current gasoline injection signal Q4 from the gasoline ECU2 at the time of the current LPG injection in the fourth cylinder # 4. The LPG injection signal is output to the corresponding LPG injector 6 during the injection time T _lpg1 , and the injector 6 is energized.

Next, at time c2, the LPG ECU3 stores the injection end time # 4 OFF in the RAM in the gasoline injection signal Q4. That is, the time over the end of the rectangle to which 'C' is first attached is stored in Fig. 3A. At this timing, the LPG ECU3 turns on the LPG injector 6 of cylinder # 4. At the timing of this time c2, the LPG ECU3 calculates the following values.

④ TAU _g gasoline injection time

TAU _g = (# 4 OFF)-(# 4 ON)

⑤ Effective gasoline injection time T _gas

T _gas = TAU _g -TV _G

Here, "TV _G " means an invalid energization time (defined as an integer) of gasoline injection time.

⑥ Required value of LPG injection time for LPG injector 6 in cylinder # 4 TAU _lpg

TAU _lpg = T _gas * K _lpg

⑦ Effective energization time T2 during LPG 2nd injection time for LPG injector 6 of cylinder # 4

T2 = TAU _lpg -T1

At this time, _since the portion of the LPG first injection time T _lpg1 has already been injected at the request value TAU _lpg , the remaining portion is required as the effective energization time T2.

⑧ LPG 2nd Injection Time for LPG Injector 6 in Cylinder 4 # 4 T _lpg2

T _lpg2 = T2 + TV _L

Then, the LPG ECU3 turns off the LPG injector 6 of cylinder # 4 that is turned on at time c2 when the LPG second injection time T _lpg2 has elapsed. As a result, in Fig. 3B, LPG injection is performed during the rectangular portion to which 'C2' is first attached. As a result, the LPG ECU3 uses the LPG second injection amount as the LPG second injection amount based on the difference between the LPG injection amount corresponding to the current gasoline injection amount and the expected first injection amount from the end of output of the current gasoline injection signal Q4 from the gasoline ECU2. The LPG injection signal is output to the corresponding injector 6 during the LPG second injection time T _lpg2 corresponding to the injection amount to energize the injector 6. The same applies to the LPG injection of the other cylinders # 2, # 1, and # 3.

According to the LPG injection control apparatus of the engine of this embodiment described above, it operates so that each cylinder # 1, # 3, # 4, # 2 may repeat a series of intake strokes, a compression stroke, an expansion stroke, and an exhaust stroke, and change it sequentially. In the engine 1 for gasoline, the operation state is detected from various sensors 31 to 35. And based on the detected operation state, in gasoline ECU2, the gasoline injection amount which should be supplied to cylinder # 1, # 3, # 4, # 2 corresponding to a predetermined | prescribed injection sequence is computed, and the gasoline injection amount, It is output as gasoline injection signals Q1, Q3, Q4, Q2 at the beginning of the intake stroke of each cylinder # 1, # 3, # 4, # 2. In the LPG ECU3, the gasoline injection signals Q1, Q3, Q4, and Q2 output for each cylinder # 1, # 3, # 4, and # 2 are corrected to be suitable for LPG, and each cylinder # 1, # 3 is used as an LPG injection signal. LPG injector 6 is sequentially output to # 4, # 2, and LPG injection is performed by each LPG injector 6.

At this time, in the LPG ECU3, at the time of the current LPG injection of any of cylinders # 1, # 3, # 4, and # 2, the output of the current gasoline injection signals Q1, Q3, Q4, Q2 is first started from the gasoline ECU2. From the time, the LPG injection signal is output to the corresponding LPG injector 6 during the portion of the LPG first injection time T _lpg1 corresponding to the expected first injection amount. Thereafter, the difference between the LPG injection amount corresponding to the current gasoline injection amount and the expected first injection amount is defined as the second injection amount from the end of the output of the current gasoline injection signals Q1, Q3, Q4 and Q2 from the gasoline ECU2. The LPG injection signal is output to the corresponding LPG injector 6 during the portion of the LPG second injection time T _lpg2 corresponding to the two injection amounts. Therefore, in the present LPG injection of any of cylinders # 1, # 3, # 4, # 2, the injection of the current LPG injection amount portion is divided into the expected first injection amount and the second injection amount, and the cylinders # 1, # The intake stroke of 3, # 4, and # 2 is performed until completion. As a result, LPG injection delay can be prevented in all cylinders # 1, # 3, # 4, and # 2, the air-fuel ratio can be optimized in engine 1, and the output of engine 1 is reduced due to an inadequate air-fuel ratio. It becomes possible to suppress deterioration of exhaust emission.

In this embodiment, the estimated first injection amount is determined according to the gasoline injection amount (gasoline injection time TAU _g360 ) calculated in response to the injection order before 360 ° C. in the LPG ECU3. Therefore, the estimated first injection amount according to the operating state of the engine 1 before 360 ° C. approaching the present injection sequence is obtained, and the LPG first injection time T _lpg1 suitable for the operating state at that time is divided into two parts. Used as LPG injection in the preceding part. For this reason, oversupply does not arise in the estimated 1st injection amount, and the LPG injection amount for one time can be divided into the estimated 1st injection amount and the 2nd injection amount in a balanced manner. This prevents concentration unevenness from occurring in the combustible mixed air supplied to the fuel chamber 10, and ensures good fuel characteristics of the combustible mixed air.

In this embodiment, the gasoline injection signals Q1 to Q4 are corrected according to the LPG temperature state and the pressure state actually detected by the various sensors 36 to 39 in order to make the gasoline injection amounts according to the gasoline injection signals Q1 to Q4 suitable for LPG. For this reason, a more accurate LPG injection signal can be obtained and the degree of LPG injection control can be improved.

In addition, this invention is not limited to the said embodiment, It can implement as follows within the range which does not deviate from the meaning of invention.

(1) In the above embodiment, the engine gasoline alternative fuel injection control apparatus of the present invention is embodied in a four-cylinder engine, but can be embodied in a two-cylinder and six-cylinder engine in addition to the four-cylinder.

(2) In the above embodiment, the engine gasoline alternative fuel injection control apparatus of the present invention is applied to an LPG-only mono-fuel type engine system, but it is also applicable to a bi-fuel type engine system replacing gasoline and LPG. good.

(3) In the above embodiment, the LPG injection control apparatus using LPG as the gasoline alternative fuel is specified, but can be embodied in the LNG injection control apparatus using LNG as the gasoline alternative fuel.

(4) In the said embodiment, the 1st injection amount anticipated in this time LPG injection was computed based on the gasoline injection amount computed corresponding to the injection sequence before 360 degreeCA, ie, the last time. On the other hand, the estimated 1st injection amount can be calculated based on the gasoline injection amount computed corresponding to the last injection order, or it can be based on the gasoline injection quantity about the same cylinder before one cycle. Moreover, the 1st injection amount anticipated can also be made into arbitrary predetermined values.

According to the configuration of the invention as set forth in claim 1, the gasoline injection control unit is adapted to the expected first injection amount from the start of output of the current gasoline injection signal from the gasoline injection control unit at the time of the current gasoline replacement fuel injection in any cylinder. Output a gasoline replacement fuel injection signal for a corresponding first injection time. Thereafter, from the time when the output of the current gasoline injection signal from the gasoline injection control unit ends, the difference between the gasoline replacement fuel injection amount corresponding to the current gasoline injection amount and the expected first injection amount corresponds to the second injection amount. Output a gasoline replacement fuel injection signal for a second injection time. Therefore, at the time of the current gasoline alternative fuel injection of a cylinder, the partial injection of the current gasoline alternative fuel injection amount is divided into the expected first injection amount and the second injection amount, and is performed until the intake stroke of the cylinder is completed. For this reason, the injection delay of the gasoline alternative fuel can be prevented in the whole cylinder, and the air-fuel ratio of an engine can be attained.

According to the invention described in claim 2, in the invention described in claim 1, the expected first injection amount corresponds to a predetermined ratio in the gasoline injection amount calculated corresponding to the injection procedure performed before the current injection in the gasoline injection control unit. Therefore, the estimated first injection amount according to the operating state of the engine is obtained each time. For this reason, in addition to the effect of the invention described in claim 1, there is no oversufficiency in the expected first injection amount, and the gasoline replacement fuel injection amount can be divided into the first injection amount and the second injection amount in a balanced manner. There is an effect of preventing the concentration unevenness from occurring in the combustible mixed air supplied to the engine, and ensuring good fuel characteristics of the combustible mixed air.

1 is a schematic configuration diagram showing an engine system according to an embodiment of the present invention.

2 is a block diagram showing the electrical configuration of the LPG injection control.

3 (a) and 3 (b) are time charts showing the relationship between the gasoline injection signal and the LPG injection signal corresponding to each cylinder.

4 is a schematic configuration diagram showing a conventional engine system.

5 (a) and 5 (b) are time charts showing the relationship between the gasoline injection signal and the LPG injection signal corresponding to each cylinder according to the conventional example.

* Description of the sign *

One … Engine for gasoline 2. ECU (Gasoline Injection Control Unit) for Gasoline

3…. ECU (Gasoline Alternative Fuel Injection Control Unit) for LPG

6. LPG injector 31. Adjustable sensor

32. Intake pressure sensor 33. Water temperature sensor

34. Rotational speed sensor 35. Oxygen sensor (31 to 35 correspond to the operation state detecting means)

#One … Cylinder # 1. 2 cylinders

# 3… Cylinder # 3… Cylinder 4

Q1…. Gasoline injection signal Q2. Gasoline injection signal in cylinder 2

Q3…. Gasoline injection signal Q4…. Gasoline injection signal in cylinder 4

Claims (11)

An engine comprising a plurality of cylinders, each of which operates to sequentially repeat a series of intake strokes, compression strokes, expansion strokes and exhaust strokes, A plurality of injectors for injecting and supplying a gasoline alternative fuel for each cylinder; Driving state detecting means for detecting a driving state of the engine; A gasoline injection control unit for calculating the gasoline injection amount to be supplied to the cylinder corresponding to the predetermined injection sequence based on the detected operation state and outputting the injection amount as a gasoline injection signal at the beginning of the intake stroke of each cylinder. and, A gasoline alternative fuel injection of an engine including a gasoline alternative fuel injection control unit for correcting the gasoline injection signal output for each cylinder to be suitable for gasoline alternative fuel and sequentially outputting the gasoline alternative fuel injection signal to an injector for each cylinder. As a control device, The said gasoline alternative fuel injection control unit is the 1st equivalent to the estimated total injection quantity from the start of output of this gasoline injection signal from the said gasoline injection control unit at the time of the current gasoline alternative fuel injection of a cylinder. Outputting the gasoline alternative fuel injection signal during the injection time, and then, from the end of the output of the current gasoline injection signal from the gasoline injection control unit, the gasoline alternative fuel injection amount corresponding to the current gasoline injection amount and the expected first injection amount Outputting the gasoline alternative fuel injection signal for a second injection time corresponding to the second injection amount as a second injection amount. The method of claim 1, The estimated first injection amount corresponds to a predetermined ratio of the gasoline injection amount calculated corresponding to the injection sequence performed before the current injection in the gasoline injection control unit. The method of claim 1, The gasoline alternative fuel injection control unit is configured to obtain the estimated first injection amount by correcting the gasoline injection amount calculated in response to the last injection order in the gasoline injection control unit by a correction coefficient peculiar to the gasoline alternative fuel. Gasoline alternative fuel injection control device. The method of claim 1, The gasoline alternative fuel injection control unit is configured to obtain the estimated first injection amount by correcting the gasoline injection amount calculated corresponding to the last injection order in the gasoline injection control unit by a correction factor peculiar to the gasoline alternative fuel. Gasoline alternative fuel injection control device. The method of claim 1, The gasoline alternative fuel injection control unit is configured to obtain the estimated first injection amount by correcting the gasoline injection amount calculated corresponding to the same cylinder before one cycle in the gasoline injection control unit by a correction factor peculiar to the gasoline alternative fuel. A gasoline alternative fuel injection control device for an engine. The method of claim 3, Temperature state detection means (36, 38) for detecting a temperature state of the gasoline alternative fuel; Pressure state detection means (37, 39) for detecting the pressure state of the gasoline alternative fuel, The gasoline alternative fuel injection control unit calculates a correction coefficient peculiar to the gasoline alternative fuel by a predetermined calculation method based on the detected temperature state and the pressure state. . The method of claim 1, The driving state detection means, An adjustment sensor for detecting an opening degree of a control valve provided in an intake passage of the engine; An intake pressure sensor for detecting an intake pressure in the intake passage; A water temperature sensor for detecting a coolant temperature of the engine; A rotational speed sensor for detecting a rotational speed of the engine; And an oxygen sensor for detecting the oxygen concentration in the exhaust gas discharged from the engine. The method of claim 1, The engine is a gasoline alternative fuel injection control apparatus of the engine, characterized in that the injection of the gasoline alternative fuel only mono-fuel type. The method of claim 1, The engine is a gasoline alternative fuel injection control apparatus for an engine, characterized in that the injection of the gasoline and the gasoline alternative fuel is replaced by a bi-fuel type. The method of claim 1, The gasoline alternative fuel is an LPG gasoline alternative fuel injection control device, characterized in that the LPG. The method of claim 1, The gasoline alternative fuel is a gasoline alternative fuel injection control device of the engine, characterized in that the LNG.