DE10301298A1 - Engine fuel injection device for an alternative fuel to petrol operates with a diesel/petrol engine and liquid petroleum gas injection. - Google Patents

Abstract

A basic engine system has a diesel/petrol engine (1), a petrol electric control unit (ECU) (2), a liquid petroleum gas (LPG) ECU (3) and an LPG fuel injection system device. An LPG tank (4) stores LPG. An LPG pump (5) in the tank pumps LPG out of it. An acceleration unit operates a throttle valve (11) on an intake pipe (9). Sensors (31-35) record multiple engine operating parameters.

Description

The present invention relates to a Injection control unit of an engine for an alternative to petrol Fuel for supplying fuels such as alternative to petrol liquefied petroleum gas (LPG) or liquefied natural gas or Natural gas (LNG) by injecting one into each cylinder Engine. More specifically, the present invention relates to a Injection control unit of an alternative fuel to petrol of an engine with a structure with a basic system that a Gasoline injection control unit as well as an additional one Injection control unit for one gasoline fuel and one additional fuel system device for injecting too Gasoline alternative fuel, wherein a Gasoline injection signal from the gasoline injection control unit of the Base system is generated by the injection control unit of the to petrol alternative fuel is corrected to Output of an alternative fuel injection signal to petrol, and the fuel system device for injecting the fuel Alternative fuel gasoline injects the gasoline alternative fuel.

Various technologies have been proposed that refer to an engine that, for example, LPG as too Petrol uses alternative fuel. In a publication ("AUTOMOBILE TECHNOLOGIES", Vol. 55, No. 5, 2001 is one Announcement entitled "Trend of Research and Development of LPG Fuel Engine System ". This announcement introduces Fuel system, called "an LPi system" by Vialle Corporation as a result of research and development of an electronic liquid fuel Fifth generation injection control system produces and on sale is.

The LPi system is designed as a dual fuel system that switches the injected fuel from petrol to LPG and vice versa. As shown in FIG. 21, this LPi system includes a basic automotive gasoline engine control unit (a gasoline ECU), a gasoline fuel system device with a gasoline injector, an LPG control computer (an LPE), an LPG fuel system device with an LPG injector, and an LPG / Gasoline switch on. The LPG / gasoline switch is switched to switch the LPi system from a gasoline injection mode to an LPG injection mode and vice versa. In the gasoline injection mode, the gasoline ECU injects gasoline into the engine using a gasoline injector and other components. In the LPG injection mode, on the other hand, LPG is injected into the engine using the LPE and an LPG injector and other components. In the LPG injection mode, the LPE interlocks with the gasoline ECU to control the injection volume of LPG to be supplied by the LPG injector. That is, the gasoline ECU determines a gasoline injection volume (or a gasoline injection duration) based on measured quantities and outputs an injection signal that represents the gasoline injection volume to the LPE. The measured variables include an air flow, an intake air temperature, an engine cooling water temperature and an engine load. The LPE converts (or corrects) the gasoline injection period to an LPG injection volume (or an LPG injection period) and injects LPG to the LPG injector according to the LPG injection volume (or the LPG injection period).

The LPG system of the LPi system uses the Cylinder group injection technology for injecting LPG into two cylinders same time even if the gasoline system that is based serves for the LPi system, an individual Cylinder injection technology. As an alternative, the LPE starts without itself relying on a crank angle signal, an LPG injection through the LPG injector in sync with one Injection end time of a gasoline injection period, which is determined by the gasoline ECU is determined, which serves as the basis of the LPi system.

Fig. 22 (a) and (b) show relationships between fuel injection timings which are determined by the petrol ECU, and LPG injection timings which are determined by the LPE, for the cylinder group injection control to inject LPG in the two cylinders at the same time in the LPi system. These timing diagrams represent such a relationship for a four cylinder engine in which the gasoline injection system that serves as the basis of the LPi system implements the individual cylinder injection technique. Gasoline is injected into individual cylinders in the following order: an injection into cylinder # 1, which is used as a first cylinder, an injection into cylinder # 3, which is used as a third cylinder, an injection into cylinder # 4, which as a fourth cylinder is used and an injection into cylinder # 2 which is used as a second cylinder. Regarding LPG injection, the fuel is injected into groups of cylinders in the following order: an injection into a group consisting of the first cylinder # 1 and the third cylinder # 3 followed by an injection into a group which consists of the fourth cylinder # 4 and the second cylinder # 2.

Rectangles A and B shown in Fig. 22 (a) represent gasoline injection signals for cylinders # 1 and # 4, respectively. On the other hand, rectangles A 'and B' shown in Fig. 22 (b) represent LPG -Injection signals for the group consisting of the first cylinder # 1 and the third cylinder # 3, or the group consisting of the fourth cylinder # 4 and the second cylinder ## 2. The differences in length between the rectangles represent a difference in length between injection periods corresponding to the injection signals represented by the rectangles. As shown in Fig. 22 (a), a gasoline injection signal for gasoline injection is output for a predetermined period of time at the start of an intake process. An operation for outputting an LPG injection signal is started for each cylinder group in synchronism with a timing for completion of an operation for outputting a gasoline injection signal, as shown in Fig. 22 (b).

Fig. 23 (a) and (b) show relationships between fuel injection timings which are determined by the petrol ECU, and LPG injection timings which are determined by the LPE for the LPG injection control of the LPi system based on an individual cylinder injection control a multi-cylinder engine is applied. These timing diagrams represent such relationships for a four-cylinder engine. Fuel is injected into the cylinders in the following order: an injection into the first cylinder # 1, an injection into the third cylinder # 3, then an injection into the fourth cylinder # 4, and finally an injection into the second cylinder # 4. Rectangles A, B, C and D shown in Fig. 23 (a) represent the gasoline injection signals for cylinders # 1, # 3, # 4 and # 2, respectively. On the other hand, rectangles A ', B', C 'and D' shown in Fig. 23 (b) are LPG injection signals for cylinders # 1, # 3, # 4 and # 2, respectively. The difference in length between the rectangles represents a difference in length between Injection times according to the injection signals, which are represented by the rectangles. As shown in Fig. 23 (a), a gasoline injection signal for gasoline injection is output for a predetermined period of time at the start of an intake process. An LPG injection signal outputting operation is started for each of the cylinders # 1, # 3, # 4, and # 2 in synchronism with a timing to end a gasoline injection signal outputting operation, as shown in Fig. 23 (b).

However, when the LPG injection control is applied to the cylinder group injection control or the individual cylinder injection control for a multi-cylinder engine as described above, in the cylinder group injection control, an action to output an LPG injection signal for each of the cylinders # 1 to # 4 is synchronized with a timing at An activity for outputting a gasoline injection signal for each of the cylinders # 1 and # 4 in the basic system is started, as shown in Figs. 22 (a) and 22 (b). Thus, for cylinders # 2 and # 3, LPG is injected at a point in time that leads to the injection of gasoline before a point in time. For cylinders # 1 and # 4, LPG is injected at a time that is later than when gasoline was injected. On the other hand, in the individual cylinder injection control, an operation for outputting an LPG injection signal for each of the cylinders # 1 to # 4 is started in synchronization with a timing for completion of an operation for outputting a gasoline injection signal in the basic system, as in Figs. 23 (a) and 23 (b) is shown. Thus, for cylinders # 1 to # 4, LPG is injected with each injection at a time behind a gasoline injection timing.

In general, it is said that it is normally desirable to set a fuel injection timing at which injection of fuel has ended before the start of the intake process. In the case of the LPG injection control performed as a cylinder group injection control, however, a gasoline injection signal is output at the start of an intake process for each of the cylinders # 1 and # 4, as shown in Fig. 22 (a). Thus, cylinders # 1 and # 4, which are used as the first and fourth cylinders, respectively, are injected with LPG corresponding to these signal outputs at such times that the injection periods are extended to the middle or a rear part of the intake processes, as in FIG As shown Fig. 22 (b). As a result, LPG that is injected at a time near the end of the suction process is hardly absorbed into cylinders # 1 or # 4 into which the LPG is injected. The fact that LPG is hardly absorbed into the cylinders leads to a fear of a decrease in engine performance. Also in the case of the LPG injection control executed as an individual cylinder injection control, gasoline is injected into each of the cylinders # 1 and # 4 at the beginning of the intake process, as shown in Fig. 23 (a). Thus, LPG is injected into the cylinders # 1 to # 4 into which gasoline is injected at such timings that the injection periods are extended to the middle or the rear of the intake processes, as shown in Fig. 23 (b). As a result, LPG that is injected at a time near the end of the suction process is hardly absorbed into one of the cylinders # 1 to # 4 into which the LPG is injected. The fact that LPG is hardly absorbed into the cylinders leads to the risk of a decrease in engine power.

In particular, if the engine carries a heavy load, the fuel injection volume of the basic system, which of the Gasoline ECU is calculated relative to what is consequently the result of the LPE corrected LPG injection signal extended. Thus a time near the end of LPG injection at one Compression process in some cases extended what in a Device results that the injected LPG is not complete to the inside of cylinders # 1 through # 4. In In this case, the fact that the injected LPG does not completely delivered to the inside of the cylinder, too the fear that engine performance will decrease significantly.

The problems described above can also apply to an engine occur, the liquefied gas fuel as a substitute for Used gasoline that is not LPG. An example of the liquefied gas fuel unlike LPG is LNG.

It is thus an object of the present invention, the above solve problems described and an injection control unit for an alternative fuel for an engine to petrol to provide that suppresses a decrease in performance of the engine, by an injection shift of the alternative to gasoline Fuel in each cylinder is avoided.

To achieve the above object sees according to claim 1 The present invention is an engine injection control device for an alternative fuel to petrol, with: one Engine having a plurality of cylinders and sequentially executes a series of processes involving one suction process, one Compression process, an expansion process and one Ejection process repeats one process after another for each of the Cylinder, the process series for any of the Cylinder opposite the process line for any other of the Cylinder is shifted; a plurality of Injectors, each for injecting gasoline alternative fuel into one of the cylinders by injection is used; an operational control device which each for detecting an operating state of the engine is used; a gasoline injection control unit for calculation an injection volume of gasoline to each of the cylinders is to be delivered in a predetermined injection sequence, based on that of the Operating state detection device detected operating state and output one Gasoline injection signal that the calculated Represents fuel injection volume at the beginning of everyone's intake process the cylinder; and an injection control unit for the Petrol alternative fuel to correct the Gasoline injection signals to be output to the cylinders for Adaptation of the petrol injection signals to injections from that to Gasoline alternative fuel and producing Injection signals for the alternative fuel to petrol, the sequentially output to the cylinder injector in which for a current injection from that to Gasoline alternative fuel in a special one of the cylinders the injection control unit for the alternative to petrol Fuel that from the gasoline injection control unit issued fuel injection signal for a cylinder at a Injection corrected for the current injection of the to petrol alternative fuel by at least one Injection precedes an order of injections to adapt the gasoline injection signal to the current one Injection of fuel alternative to gasoline, and a Injection volume of the alternative fuel to petrol calculated and an injection signal of the alternative to gasoline Fuel based on the calculated Injection volume of the alternative fuel to gasoline to the Injector of the special one of the cylinders outputs starting from a start of an activity of issuing a current one Gasoline injection signals from the gasoline injection control unit on the special of the cylinders.

According to the structure of the injection control unit for petrol alternative fuel of the present invention for the Motor detected in the motor for sequentially executing one Process series with a suction process, a compression process, a process after an expansion process and an ejection process the other repeated for each cylinder, the Process series for one cylinder from the process series for another Cylinder is shifted that Operating state detection device an operating state of the engine. Then calculate the Gasoline injection control unit to a gasoline injection volume each of the cylinders in a predetermined injection order gasoline injection volume to be supplied on the Basis of an operating state by the Operating state detection device is detected and inputs Gasoline injection signal from that the calculated gasoline injection volume represents, at the beginning of everyone's suction process Cylinder. The injection control unit of the alternative to petrol Fuel corrects a gasoline injection signal that is on every cylinder is spent to adjust the Gasoline injection signals to the injection of the alternative to gasoline Fuel gives sequential injection signals to gasoline alternative fuel to the injector one of the Cylinder so that the alternative fuel to petrol on the injector is injected.

Corrected specifically for a current injection of the to gasoline alternative fuel in a special one Cylinder the injection control unit for the petrol alternative fuel a gasoline injection signal that from the Gasoline injection control unit is issued for a cylinder on an injection that is around the current injection at least one injection in an order of Injections precedes to adjust the Gasoline injection signals to the injection of the alternative to gasoline Fuel, and calculates an injection volume of petrol alternative fuel. Then the injection control unit gives the to petrol alternative fuel an injection signal of the Alternative fuel based on the gasoline calculated injection volume of the alternative to petrol Fuel to the injector of the special cylinder off, starting at a start of issuing activity of a current gasoline injection signal from the Gasoline injection control unit on the specific of the cylinders. Consequently becomes the start of an activity to inject the gasoline alternative fuel to the special of the cylinders with the start of the activity of issuing a current one Gasoline injection signals on the special of the cylinders synchronized. As a result for all cylinders the petrol alternative fuel is injected before the intake process.

According to claim 3, the gasoline injection control unit inputs Gasoline injection signal from that the calculated Represents fuel injection volume at the beginning of the intake process for everyone the cylinder selected from the cylinders; the Injection control unit of alternative fuel to petrol corrects that from the gasoline injection control unit output fuel injection signal for each of the selected cylinders for adapting the gasoline injection signal to an injection of the alternative fuel to gasoline, sequential Output of injection signals of the alternative to petrol Fuel to the injectors of each cylinder group from at least two cylinders representing the selected cylinder contains; and for a current injection of gasoline alternative fuel for a specific cylinder group corrects the injection control unit to petrol alternative fuel a gasoline injection signal that from the Fuel injection control unit is issued for one of the Cylinder on an injection that the current injection alternative fuel to petrol by at least one Injection in an order of injections goes ahead to adapt the gasoline injection signal to the current injection of alternative fuel to gasoline, and calculates an injection volume of the alternative to gasoline Fuel and gives the injection signal to gasoline alternative fuel based on the calculated Injection volume of the alternative fuel to petrol the injectors of the cylinders belonging to the special Cylinder group belong, starting at a start of the activity outputting a current gasoline injection signal from the gasoline injection control unit to the special Cylinder group.

According to the structure of the injection control unit for petrol alternative fuel for the engine according to the Present invention is provided, detected in the engine for sequential execution of a series of processes with a Suction process, a compression process, an expansion process and one ejection process one process after another repeated for each cylinder, the process series for one of the cylinders shifted from the process line for another one of the cylinders is, the operating state detection device Operating state of the engine. Then calculate the Gasoline injection control unit has a gasoline injection volume of gasoline that suits everyone Cylinder in a predetermined injection order deliver, based on an operating condition of the operating state detection device is detected, and there a gasoline injection signal that the calculated Represents fuel injection volume at the beginning of the intake process of each cylinder selected from the cylinders. In addition, the injection control unit corrects the to gasoline alternative fuel that of the Gasoline injection control unit output fuel injection signal for each of the Cylinder to adapt the gasoline injection signal to the Injection of fuel alternative to gasoline, whereby sequential injection signals of the alternative fuel to petrol to the injectors of each cylinder group from Cylinder, which has at least two cylinders, issued become. In this way, the alternative to gasoline Fuel injected into the cylinders.

Additionally corrected for a current injection of the to gasoline alternative fuel in a special Cylinder group the injection control of the alternative to gasoline Fuel one from the gasoline injection control unit issued fuel injection signal for one of the cylinders at one Injection that is the current injection of gasoline alternative fuel by at least one injection in precedes an order of injections to adjust of the gasoline injection signal to the current injection of the alternative fuel to petrol and calculates one Injection volume of the alternative fuel to petrol and gives an injection signal of the alternative fuel to petrol based on the calculated injection volume of the Alternative fuel gasoline to the injectors the cylinders belonging to the special cylinder group off, starting at the start of a spending activity of a current gasoline injection signal from the Gasoline injection control unit to the special cylinder group. So is the start of an injection of the alternative to gasoline Fuel into a plurality of cylinders that lead to a special one Cylinder group belong to the start of an activity of the Outputting a gasoline injection signal to any of the Cylinder synchronized. As a result, the injections of the to gasoline alternative fuel in all cylinders in front of theirs Intake processes started.

Further features and advantages of the invention result itself from the description of exemplary embodiments on the basis of the Characters. From the figures show:

Fig. 1 is a diagram showing schematically the structure of an engine system of the first embodiment;

Fig. 2 is a block diagram showing an electrical structure related to an LPG injection control;

Fig. 3 (a) u. (b) timing charts showing relationships between gasoline injection signals and LPG injection signals for each cylinder;

Fig. 4 is a flowchart illustrating a processing LPG injection for a first cylinder;

Fig. 5 is a flowchart showing LPG injection processing for the first cylinder;

Fig. 6 is a flowchart illustrating an LPG injection processing for a third cylinder;

Fig. 7 is a flowchart illustrating an LPG injection processing for the third cylinder;

Fig. 8 is a flowchart illustrating an LPG injection processing for a fourth cylinder;

Fig. 9 is a flowchart illustrating a processing LPG injection for the fourth cylinder;

Fig. 10 is a flowchart illustrating an LPG injection processing for a second cylinder;

Fig. 11 is a flowchart illustrating an LPG injection processing for the second cylinder;

Fig. 12 is an image showing an area for storing data in a memory;

FIG. 13 is a block diagram showing an electrical structure, which refers to the LPG injection control in a second embodiment;

Fig. 14 (a) and. 14 (b) timing charts showing relationships between gasoline injection signals and LPG injection signals for each cylinder;

Fig. 15 is a flowchart illustrating a processing LPG injection for a first cylinder;

Fig. 16 is a flowchart illustrating a processing LPG injection for the first cylinder;

17 is a flowchart illustrating an LPG injection processing for a fourth cylinder.

Fig. 18 is a flowchart illustrating a processing LPG injection for the fourth cylinder;

Fig. 19 is an image showing an area for storage in a memory;

Fig. 20 (a) and. (b) timing diagrams showing relationships between gasoline injection signals and LPG injection signals for each cylinder in another embodiment;

Fig. 21 is a schematic structural view showing a conventional engine system;

Fig. 22 (a) u. (b) timing diagrams showing relationships between gasoline injection signals and LPG injection signals for each cylinder of a group of an injection system; and

Fig. 23 (a) u. (b) timing diagrams, the relationships between gasoline injection signals and.

LPG injection signals for everyone Cylinder of an individual Show injection system.

The following description explains a first one in detail Embodiment, which is an injection control unit of a gasoline alternative fuel of an engine realized, on reference is made to the accompanying drawings.

This embodiment realizes an LPG engine system that uses liquefied petroleum gas (LPG) as an alternative fuel to gasoline. Fig. 1 is a diagram schematically showing the structure of the LPG engine system according to the embodiment. The engine system is composed of a base system with a gasoline engine 1 and a gasoline ECU 2 and an LPG-ECU 3 and an LPG injection fuel system device, both of which are implanted in the base system. The gasoline ECU 2 is an electronic gasoline control unit that serves as a unit for controlling the injection of gasoline. The LPG-ECU 3 is an electronic fuel alternative control unit that serves as a unit for controlling the injection of the alternative fuel. The engine system is a one-fuel system having a structure in which the LPG-ECU 3 corrects a gasoline injection signal generated by the gasoline ECU 2 to adapt the gasoline injection signal to an injection of LPG to output an LPG injection signal so that the LPG injection fuel system that injects LPG.

The engine system mounted on a vehicle has an LPG tank 4 for storing LPG. An LPG pump 5 , which is embedded in the LPG tank 4 , pumps the LPG out of the tank 4 .

In this embodiment, the engine 1 is a four-cylinder engine having a cylinder # 1 serving as the first cylinder, a cylinder # 2 serving as the second cylinder, a cylinder # 3 serving as the third cylinder, and a cylinder # 4, which serves as the fourth cylinder.

The engine 1 sequentially executes a series of processes including an intake process, a compression process, an expansion process, and an exhaust process. One process after another is repeatedly carried out for each of the cylinders # 1 to # 4, the process series for one of the cylinders # 1 to # 4 being shifted from the process series for another of the cylinders # 1 to # 4. Each of the cylinders # 1 to # 4 has an LPG injector 6 for injecting LPG into each cylinder. The LPG output from the LPG pump 5 is supplied to each of the LPG injectors 6 through an LPG pipe 7 and a delivery pipe 8 . The LPG injectors 6 operate to inject the supplied LPG into the cylinders # 1 to # 4 through an intake pipe 9 . Air is also supplied to the intake pipe 9 from the atmosphere. The air supplied to the intake pipe 9 from the atmosphere and the LPG injected into the intake pipe 9 by the LPG injectors 6 form an ignitable mixed gas to be supplied to the combustion chambers 10 of the cylinders # 1 to # 4.

A throttle valve 11 is provided on the intake pipe 9 and is operated by a predetermined acceleration unit, not shown in the figure. The throttle valve 11 is opened and closed to adjust an input flow, which is the air flow supplied from the intake pipe 9 to the combustion chamber 10 .

Each of the combustion chambers 10 of the cylinders # 1 to # 4 has a spark plug 12 for generating an ignition in accordance with an ignition signal received from an ignition coil 13 . The ignition coil 12 and the ignition coil 13 form an ignition unit for igniting the combustible mixed gas supplied to the combustion chamber 10 . In each of the cylinders # 1 to # 4, the combustible mixed gas is supplied to the combustion chamber 10 in an intake process. The combustible mixed gas is compressed in a compression process. In an expansion process, the spark plug 12 generates sparks to explode and burn the combustible mixed gas, causing the gas to expand. In an exhaust process after combustion, the burned gas is exhausted into the atmosphere from the combustion chamber 10 through an exhaust pipe / exhaust 14 . Accompanying the combustion of the combustible mixed gas in the combustion chambers 10 of the cylinders # 1 to # 4, a piston 15 moves up and down, whereby a crankshaft 16 is rotated. In this way, the engine 1 receives drive power to run the vehicle.

At the outlet of the LPG pump 5 and at a position of the LPG line 7 , cutoff valves 17 and 18 are respectively provided for forcibly cutting off the flow of the LPG. At the end of a return line 19 for returning the LPG from the delivery pipe 8 to the LPG tank 4 , a pressure regulator 20 is provided for maintaining the pressure of the LPG in the delivery pipe 8 at a fixed level.

A plurality of sensors 31 , 32 , 33 , 34 and 35 are provided on the engine 1 and elsewhere and serve as operating condition detection means for detecting a plurality of operating parameters related to the operating condition of the engine 1 . The sensors 31 , 32 , 33 , 34 and 35 are connected to the gasoline ECU 2 , respectively. Specifically, the throttle sensor 31 , which is provided close to the throttle valve 11 , detects a throttle opening degree TA of the throttle valve 11 and outputs an electrical signal representing a detection value of the throttle opening degree TA. The intake pressure sensor 32 , which is provided on the intake pipe 9 downstream of the throttle valve 11 , detects an intake air pressure PM of the intake air in the intake pipe 9 and generates an electrical signal representing a detection value of the intake air pressure PM. The water temperature sensor 33 provided on the engine 1 detects a water temperature THW of the cooling water and generates an electrical signal that is a detection value of the cooling water temperature THW. The speed sensor 34 provided on the engine 1 detects a speed NE of the crankshaft 18 and generates an electrical signal representing a detection value of the engine speed NE. The oxygen sensor 35 provided on the exhaust pipe 14 detects an oxygen concentration Ox in the exhaust gas, which is discharged to the exhaust pipe 14 , that is, it detects an output voltage and generates an electrical signal representing a detection value of the oxygen concentration Ox.

In this embodiment, the gasoline ECU 2 receives a plurality of signals generated by the sensors 31 to 35 . The gasoline ECU 2 then performs various types of controls such as the control of the fuel injection and the control of the injection timings on the basis of the received signals, supplying the fuel injection signals Q1, Q2, Q3 and Q4 to the corresponding cylinders # 1 to # 4 to the LPG-ECU 3 outputs and outputs ignition signals for the corresponding cylinders # 1 to # 4 to the ignition coil 13 . The gasoline injection signals each correspond to a drive signal for driving an injector in the basic system.

The control of the gasoline injection is a control of the amount of gasoline to be injected by the injector provided on each of the cylinders # 1 to # 4 and the control of the injection timing of the gasoline executed in the basic system based on the operating state of the Motors 1 performed. Thus, in this embodiment, the gasoline ECU 2 calculates a gasoline injection volume in accordance with an operating state of the engine 1 and outputs a gasoline injection signal representing the gasoline injection volume to the LPG ECU 3 . The control of the ignition timings is an adjustment of the ignition timings by the spark plugs 12 , which are provided on the cylinders # 1 to # 4, for controlling the ignition coils 13 according to the operating state of the engine 1 .

In order for the basic system to function as an LPG engine system of the one-fuel type, the LPG tank 4 , the LPG pump 5 , the LPG line 7 , the delivery pipe 8 , the LPG injectors 6 , the return line 9 as well as the cut-off valves 17 and 18 is used as the LPG injection fuel system, which is intended as a replacement for a gasoline injection fuel system. Compared to gasoline, LPG shows large changes in property with changes in temperature and changes in pressure. Thus, to find the exact volume of injection of LPG from each of the LPG injectors 6, it is necessary to correct the LPG injection volume by taking into account the temperature and pressure of the LPG. An LPG tank temperature sensor 36 and an LPG tank pressure sensor 36 are provided on the LFG tank 4 as means for detecting the temperature or the pressure of the LPG. An LPG pipe temperature sensor 38 and an LPG pipe pressure sensor 39 are provided on the delivery pipe 8 . The sensors 36 to 39 are each connected to the LPG-ECU 3 . In addition, the LPG pump 5 , the two cut-off valves 17 and 18 and the LPG injectors 6 of the cylinders # 1 to # 4 are also connected to the LPG-ECU 3 . The throttle sensor 31 is similarly connected to the LPG-ECU 3 .

In this embodiment, the LPG-ECU 3 receives a plurality of signals generated by the throttle sensor 31 and the sensors 36 to 39 . The LPG-ECU 3 performs the control for correcting a gasoline injection signal to adapt to an injection of the LPG on the basis of these signals and performs the timing control for replacing a gasoline injection timing with an LPG injection timing, it outputs an LPG injection signal to the LPG- Injector 6 of each of cylinders # 1 to # 4.

The gasoline ECU 2 and the LPG ECU 3 each have a CPU (central processing unit), ROM (read only memory), RAM (random access memory), backup RAM, external input circuit and external output circuit. In each of the gasoline ECU 2 and the LPG ECU 3 , the CPU, the ROM, the RAM, the backup RAM, the external input circuit and the external output circuit are connected to each other through a bus to form a logic processing circuit. The ROMs are previously used to store predetermined control programs for various types of control. The RAMs are used for temporarily storing results of the processing performed by the CPU in accordance with the RAM. The backup RAMs are used to store data in advance. The CPUs each perform the aforementioned various types of controls based on the predetermined control programs in accordance with the detection signals provided by the sensors 31 to 39 through the external input circuit.

Fig. 2 is a block diagram showing an electrical structure related to the LPG injection control of this engine system. The sensors 31 to 35 are connected to the gasoline ECU 2 . On the other hand, the throttle sensor 31 and the sensors 36 to 39 are connected to the LPG-ECU 3 . The gasoline ECU 2 has output ports 41 a, 41 b, 41 c and 41 d for outputting gasoline injection signals to the corresponding cylinder # 1, which is used as a first cylinder, the cylinder # 3, which is used as a third cylinder cylinder # 4, which is used as a fourth cylinder, and cylinder # 2, which is used as a second cylinder. The output terminals 41 a, 41 b, 41 c and 41 d are correspondingly connected to input terminals 42 a, 42 b, 42 c and 42 d, which are provided in the LPG-ECU 3 . The LPG-ECU 3 has output ports 43 a, 43 b, 43 c and 43 d for outputting the LPG injection signals for the corresponding cylinders # 1, # 3, # 4 and # 2. The output ports 43 a, 43 b, 43 c and 43 d are connected to the LPG injectors 6 of the corresponding cylinders # 1, # 3, # 4 and # 2.

Thus, a gasoline injection signal output from the gasoline ECU 2 to the cylinder # 1, that is, a signal A shown in FIG. 2 is corrected by the LPG ECU 3 to adjust the gasoline injection signal to the current injection of LPG. The corrected gasoline injection signal is output from the LPG-ECU 3 to the LPG injector 6 of the cylinder # 4 as an LPG injection signal, that is, a signal A 'shown in FIG. 2. A gasoline injection signal output from the gasoline ECU 2 to the cylinder # 3, that is, the signal B shown in FIG. 2, is corrected by the LPG-ECU 3 to adapt to the gasoline injection signal to a current injection of LPG. The corrected gasoline injection signal is output from the LPG-ECU 3 to the LPG injector 6 of the cylinder # 2 as an LPG injection signal, that is, a signal B 'shown in FIG. 2.

In the same way, a gasoline injection signal output from the gasoline ECU 2 to the cylinder # 4, that is, the signal C shown in FIG. 2, is corrected by the LPG-ECU 3 to adapt to the gasoline injection signal to a current injection of LPG. The corrected gasoline injection signal is output from the LPG-ECU 3 to the LPG injector 6 of the cylinder # 1 as an LPG injection signal, that is, a signal C 'shown in FIG. 2. Similarly, the gasoline injection signal output from the gasoline ECU 2 to the cylinder # 2, that is, a signal D shown in FIG. 2 is corrected by the LPG-ECU 3 to adapt to the gasoline injection signal to a current injection of LPG. The corrected injection signal is output from the LPG-ECU 3 to the LPG injector 6 of the cylinder # 3, that is, a signal D 'shown in FIG. 2.

Fig. 3 (a) and 3 (b) are timing charts showing the relationships between fuel injection signals which are output from the petrol ECU 2 for the cylinders # 1 to # 4, and LPG injection signals applied to the LPG ECU 3 the LPG injectors 6 of cylinders # 1 through # 4 are output. In these timing diagrams, LPG is injected into cylinders # 1 through # 4 in the following order:

Cylinder # 1, Cylinder # 3, Cylinder # 4 and Cylinder # 2. Rectangles A, B, C and D shown in Fig. 3 (a) denote gasoline injection signals for cylinders # 1, # 3, # 4 and # 2, respectively. On the other hand, rectangles C ', D', A 'and D' shown in Fig. 3 (b) denote LPG injection signals for cylinders # 1, # 3, # 4 and # 2, respectively. The differences in the length between the rectangles represents a difference in the length between the injection periods which correspond to the injection signals represented by the rectangles.

In the following description, reference numerals A, B, C and D denote gasoline injection signals output from the gasoline ECU 2 for cylinders # 1, # 3, # 4 and # 2, respectively, and also denote the gasoline injection durations (or the pulse widths of the Pulse signals or the ON durations of the pulses of the signals) corresponding to the gasoline injection volume for cylinders # 1, # 3, # 4 and # 2. Reference numerals C ', D', A 'and B' denote LPG injection signals output from the LPG-ECU 3 for the LPG injectors 6 of the cylinders # 1, # 3, # 4 and # 2, respectively, and also denote the LPG -Injection times corresponding to the LPG injection volume for cylinders # 1, # 3, # 4 and # 2.

In this embodiment, for a predetermined order of current injections starting with cylinder # 1, followed by cylinder # 3, followed by cylinder # 4, and ending with cylinder # 2, the LPG-ECU 3 corrects the gasoline injection signals that are output from the gasoline ECU 2 in an order of corresponding injections starting with cylinder # 4, followed by cylinder # 2, followed by cylinder # 1 and ending with cylinder # 3, which is an injection order that the predetermined injection order by two injections to match the fuel injection signals to the current injections of LPG and calculates the LPG injection durations of LPG to be injected in the predetermined injection order. Then, the LPG-ECU 3 sequentially outputs LPG injection signals based on the calculated LPG injection periods to the LPG injectors 6 of the cylinders # 1, # 3, # 4 and # 2 in that order at the start of the activities for outputting the current gasoline injection signals in the predetermined. Order of current injections of cylinders # 1, # 3, # 4 and # 2.

Specifically, to inject LPG sequentially into the cylinders # 1, # 3, # 4 and # 2, the LPG-ECU 3 corrects the gasoline injection signals output for the cylinders # 4, # 2, # 1 and # 3, respectively Timings that precede the corresponding current injection timings by two injections, or in the case of a four-cylinder engine 1 with timings that precede the corresponding current injection timings by a crank angle CA of 360 ° C., and calculates the LPG injection durations using the equation (1 ) as follows:

(LPG injection period) = (gasoline injection period) × (various correction coefficients) (1).

To be more specific, the LPG-ECU 3 calculates an LPG injection period C 'for the cylinder # 1 in Fig. 2 by multiplying the pulse width (or the ON duration) of a gasoline injection signal C which is for the cylinder # 4 at a time that was issued at the current time by two injections in an order of injections with the "different correction coefficients". The LPG-ECU 3 calculates an LPG injection duration D 'for the cylinder # 3 by multiplying the pulse width (or the ON duration) of a gasoline injection signal D which is for the cylinder # 2 by a timing which is two injections in at the current timing an order of injections precedes is output by the "different correction coefficients".

In the same way, the LPG-ECU 3 calculates an LPG injection period A 'for the cylinder # 4 by multiplying the pulse width (or ON duration) of a gasoline injection signal A that is for the cylinder # 1 by a time which is the current time two injections in a sequence of injections preceding, was issued with the "different correction coefficients". Similarly, the LPG-ECU 3 calculates an LPG injection duration D 'for the cylinder # 2 by multiplying the pulse width (or ON duration) of a gasoline injection signal B that for the cylinder # 3 by a timing that is two injections in at the current timing an order of the injections has been output with the "different correction coefficients".

The "various correction coefficients" are determined according to the temperature and pressure of the LPG, which are actually detected by the various sensors 36 to 39 . The correction coefficients are used to match gasoline injections to LPG injections.

Then, the LPG-ECU 3 sequentially outputs LPG injection signals based on the calculated one of the LPG injection periods C ', D', A 'and B' to the LPG injectors 6 of the cylinders # 1, # 3, # 4 and 4, respectively . # 2 at the start of the activities for outputting the current gasoline injection signals A, B, C and D for cylinders # 1, # 3, # 4 and # 2, respectively.

For example, the LPG ECU 3 for the LPG injection for the cylinder # 1 (C 'in FIG. 3 (b)) corrects the gasoline injection signal C (in FIG. 3 (a)) that for the cylinder # 4 with a Timing that has preceded the current time by two injections in an order of injections has been made to match the gasoline injection signal to the current injection of LPG into cylinder # 1 and calculates an LPG injection period C '. Then, the LPG-ECU 3 starts outputting an LPG injection signal based on the calculated LPG injection period C 'to the LPG injector 6 of the cylinder # 1 at the start of an operation to output a current gasoline injection signal A for the cylinder # 1 Start injection of LPG into cylinder # 1. LPG is injected into the other cylinders # 3, # 4 and # 2 in the same way.

Referring to the flowcharts shown in FIGS . 4 through 12, the following description explains the processes performed by the LPG ECU 3 for injecting LPG. FIG. 4 is a flowchart showing process processing executed in synchronization with an output start time (an ON time) of the gasoline injection signal A output from the gasoline ECU 2 for the cylinder # 1.

The flowchart starts with a step 100 at which the LPG-ECU 3 reads an ON time of the fuel injection signal A for the cylinder # 2 and stores the ON time in a memory. The ON time is the time of a time a1 shown in FIG. 3.

Then, in a step 110, the LPG-ECU 3 reads from the memory a gasoline injection period (or an ON period) C of a gasoline injection signal output for the cylinder # 4 at a point in time that is the current time by an angle CA of 360 ° precedes.

Subsequently, in a step 120, the LPG-ECU 3 calculates an LPG duration C 'according to equation (2) as follows:

C '= C × (different correction coefficients) (2).

Then, in step 130, the LPG-ECU 3 starts applying electric power to the LPG injector 6 of the cylinder 42 .

Finally, in step 140, the LPG-ECU 3 ends the application of the electric power to the LPG injector 6 of the cylinder # 1 after the expiration of the LPG duration C 'since the start of the application of the electric power to the LPG injectors ( 6 ) of cylinder # 1 in step 130 .

Fig. 5 is a flowchart illustrating the processing is in synchronism with an output end time (an OFF time) of the fuel injection signal A, which is output from the petrol ECU 2 for the cylinder # 1.

The flowchart starts with a step 150 in which the LPG-ECU 3 reads an OFF time of the fuel injection signal A for the cylinder # 1. The OFF time is the time of a time a2 shown in FIG. 3.

Then, in a step 160, the LPG-ECU 3 calculates an injection period (or an ON period) A of the gasoline injection signal output from the gasoline ECU 2 for the cylinder # 1 according to the equation (3) shown below and stores it Calculation value in the memory.

A = (# 1 OFF time) - (# 1 ON time) (3).

As described above, the LPG-ECU 3 performs the processing for injecting LPG into the cylinder # 1.

FIG. 6 is a flowchart showing processing that is performed in synchronism with an output start time (an ON time) of the gasoline injection signal B output from the gasoline ECU 2 for the cylinder # 3.

The flowchart begins with a step 200 in which the LPG ECU 3 reads an ON time of the fuel injection signal B for the cylinder # 3 and stores the ON time into a memory. The ON time is the time of a time b1 shown in FIG. 3.

Then, in a step 210, the LPG-ECU 3 reads out from the memory a gasoline injection period (or an ON period) D of the gasoline injection signal output for the cylinder # 2 at a timing that is the current time by an angle CA of Leads 360 °.

Subsequently, in a step 220, the LPG-ECU 3 calculates an LPG injection duration D 'according to the equation (4) as follows:

D '= D × (various correction coefficients) (4).

Then, in a step 230, the LPG-ECU 3 starts to apply electric power to the LPG injector 6 of the cylinder # 3.

Finally, in a step 240, the LPG-ECU 3 ends the application of the electric current to the LPG injector 6 of the cylinder # 3 after the expiration of the LPG injection period D 'since the start of the application of the electric current to the LPG injector 6 of the Cylinder # 3 in step 230 .

Which is output from the petrol ECU 2 for the cylinder # 3 is Fig. 7 shows a flow chart illustrating a processing in synchronism with an output end time (an OFF time) carried out of the petrol injection signal B.

The flowchart begins with a step 250 in which the LPG ECU 3 reads an OFF time of the fuel injection signal B for the cylinder # 3. The OFF time is the time of a time B2 shown in FIG. 3.

Then, in a step 260, the LPG-ECU 3 calculates an injection period (or an ON period) B of the gasoline injection signal for the cylinder # 3 according to the equation (5) shown below and stores the injection period in the memory:

B = (# 3 OFF time) - (# 3 ON time) (5).

As described above, the LPG-ECU 3 executes the processing for injecting LPG into the cylinder # 3.

Fig. 8 shows a flowchart illustrating the processing performed in synchronization with an output start time (an ON time) of the fuel injection signal C outputted from the petrol ECU 2 for the cylinder # 4. The processing is performed in steps 300 through 340 , which are the same as the processing represented by the flowcharts shown in FIGS . 4 and 6. Fig. 9 shows a flowchart illustrating the processing that is performed in synchronism with an output end time (an OFF time) of the fuel injection signal C outputted from the petrol ECU 2 for the cylinder # 4. The processing is performed in steps 350 and 360 and corresponds to the flowcharts in FIGS. 5 and 7 shown. Fig. 10 shows a flowchart illustrating the processing in synchronism (ON time a) of the fuel injection signal D is carried out with an output start time, which is output from the petrol ECU 2 for the cylinder # 2. The processing is performed in steps 400 to 440 corresponding to the processing represented by the flowcharts shown in Figs. 4, 6 and 8. Fig. 11 is a flowchart illustrating the processing which is executed in synchronism with an output end time (an OFF time) of the fuel injection signal D outputted from the petrol ECU 2 for the cylinder # 2. The processing is performed in steps 450 and 460 corresponding to the processing represented by the flowcharts shown in Figs. 5, 7 and 9.

Therefore, no description will be given of the processing shown by the flowcharts in Figs. 8 to 11.

FIG. 12 is an image showing an area for storing data in a memory (RAM) of the LPG-ECU 3 . The data stored in the memory area includes the ON times (or output start times) of the gasoline injection signals that are output for the cylinders # 1, # 3, # 4 and # 2. The data also includes the ON durations (or gasoline injection durations) A through D for cylinders # 1, # 3, # 4 and # 2, respectively.

According to the LPG injection control device of this embodiment, the various sensors 31 to 35 detect an operating state of the engine 1 , as described above, in the engine 1 having a plurality of cylinders # 1 to # 4 and sequentially executing a series of processes that perform an intake process , a compression process, an expansion process and an exhaust process, the processes being carried out one by one for each of the cylinders # 1 to # 4 and the process series for any of the cylinders # 1 to # 4 versus the process series for any other of the cylinders # 1 to # 4 is shifted. Then, according to the detected operating condition, the gasoline ECU 2 calculates gasoline injection periods A to D, which represent gasoline volumes to be injected into the cylinders # 1 to # 4. The gasoline ECU 2 then outputs gasoline injection signals representing the calculated gasoline injection periods A to D at the start of the intake processes of the cylinders # 1 to # 4. The LPG-ECU 3 corrects the gasoline injection signals to match the injections of LPG to the LPG injectors 6 of the cylinders # 1 to # 4, and sequentially outputs the LPG injection signals in the order of injecting LPG into the LPG injectors 6 ,

Thus, for a particular order of current injections starting with cylinder # 1, followed by cylinder # 3, followed by cylinder # 4, and with cylinder # 2, LPG-ECU 3 corrects the gasoline injection signals C, D, A and B that are output from the gasoline ECU 2 in an order of corresponding injections starting with the cylinder # 4, followed by the cylinder # 2, followed by the cylinder # 1, and ending with the cylinder # 3, which is one Injection order, which precedes the particular current injection order by two injections in an order of injections, to match the gasoline injection signals to the current injections of LPG into the cylinders in the particular order, and calculates the LPG injection periods C ', D', A 'and B' of LPG to be injected in the specific current injection order. Then, the LPG-ECU 3 sequentially outputs LPG injection signals based on the calculated LPG injection periods C ', D', A 'and B' to the LPG injectors 6 of the cylinders # 1, # 3, # 4 and # 2 in this order from the beginning of the activities of outputting the current gasoline injection signals (or with ON times) in the specific order of the current injections; cylinders # 1, # 3, # 4 and # 2. Since the start of the sequential outputting operations of the LPG injection signals in the specific order of the cylinders # 1, # 3, # 4: and # 2 begins with the corresponding activities for the sequential outputting of the gasoline injection signals in the specific order of the cylinders # 1, # 3, # 4 and # 2 is synchronized, the injections of LPG into cylinders # 1, # 3, # 4 and # 2 are started before the intake processes of cylinders # 1, # 3, # 4 and # 2, respectively. As a result, it is possible to prevent LPG from being injected into all the cylinders at late times and to prevent the engine 1 from decreasing in performance.

In this embodiment, a gasoline injection signal is corrected in accordance with an LPG temperature and pressure that are actually sensed by the various sensors 36 through 39 to match the gasoline injection signals to a current injection of LPG so that more accurate LPG injection signals are generated. Thus, the accuracy of the LPG injection control can be improved.

The following description explains a second one in detail Embodiment which is an injection control unit for one Gasoline alternative fuel to an engine according to the present invention explained with reference to the accompanying drawings. It should be noted that the second Embodiment has structural elements identical to theirs corresponding counterparts in the first embodiment are used, they are given the same reference numerals referred to, and the explanation of these identical elements not repeated. The following explanation is in view on the different characteristics from those of the first Given embodiment.

This embodiment differs from the first embodiment in which LPG is individually injected into the cylinders in that, in the case of this embodiment, LPG is injected into the four cylinders of the engine 1 for each cylinder group. FIG. 13 is a block diagram showing an electrical structure related to the LPG injection control performed by this engine system. The gasoline ECU 2 has output terminals 41 a to 41 d. The output ports 41 a and 41 c for the cylinder # 1 and the cylinder 44 are respectively connected to the input ports 42 a and 42 c of the LPG-ECU 3 . The output ports 43 a to 43 d of the LPG-ECU 3 are connected to the LPG injectors 6 of the cylinders # 1, # 3, # 4 and # 2. Signal lines of the output terminals 43 a and 43 b, which are connected to the LPG injectors 6 of the cylinders # 1 and # 3, are accordingly connected to one another internally in the LPG-ECU 3 . Signal lines of the output ports 43 c and 43 d, which are connected to the LPG injectors 6 of the cylinders # 4 and # 2, are also internally connected to each other in the LPG-ECU 3 . In this embodiment, LPG is simultaneously injected into cylinders # 1 and # 3, which form a first cylinder group, from their respective LPG injectors 6 . In the same way, LPG is simultaneously injected into cylinders # 4 and # 2, which form a second cylinder group, from their respective LPG injectors 6 .

Fig. 14 (a) and 14 (b) are timing charts of relationships between fuel injection signals which are output from the petrol ECU 2, and LPG injection signals which are output from the LPG ECU 3, for each cylinder group. As shown in the timing diagrams, LPG is first injected into the first cylinder group consisting of cylinders # 1 and # 3, and then into the second cylinder group consisting of cylinders # 4 and # 2. Rectangles A and B shown in Fig. 14 (a) represent gasoline injection signals for cylinder # 1 and cylinder # 4. On the other hand, rectangles D 'and A' shown in Fig. 14 (b) represent LPG injection signals for the first and second cylinder groups, respectively. The length difference between the rectangles represents a length difference between the injection periods corresponding to the injection signals, represented by the rectangles.

In this embodiment, for a current injection of LPG into a particular one of the cylinder groups, the LPG-ECU 3 corrects a previous gasoline injection signal output from the gasoline ECU 2 for a cylinder at an injection twice before the current injection of LPG in the particular cylinder group was made to match the gasoline injection signal to the current injection of LPG, and it calculates an LPG injection duration corresponding to an LPG injection volume. Then, the LPG-ECU 3 starts outputting an LPG injection signal based on the calculated LPG injection period to the two LPG injectors 6 of the cylinders related to the specific cylinder group at the start of an operation other than the gasoline engine. ECU 2 is executed to output a current gasoline injection signal for a previous one of the cylinders related to the specific cylinder group.

To be more specific, for a current injection of LPG into a particular one of the cylinder groups, the LPG-ECU 3 corrects a previous gasoline injection signal for a cylinder at one injection, which corresponds to the current injection of LPG into the particular cylinder group by two injections in an order of ordinary precedes individual cylinder injections and calculates an LPG injection duration corresponding to an LPG injection volume according to equation (1). In the case of a four-cylinder engine 1 , the two individual cylinder injections correspond to a crank (shaft) angle CA of 360 ° in the order of the usual individual cylinder injections.

More specifically, a duration B 'of injecting LPG into the first cylinder group consisting of cylinders # 1 and # 3 as shown in Fig. 13 is calculated by multiplying the pulse width (or the ON duration) B of a gasoline injection signal output for cylinder # 4 with an injection made twice before LPG was injected into cylinder # 2 with the "different correction coefficients".

A duration A 'of LPG injection into the second Cylinder group consisting of cylinders # 4 and # 2 is calculated by multiplying the pulse width (or the ON duration) A of a gasoline injection signal, which for cylinder # 1 at a Injection was issued twice before Injection of LPG into the # 4 cylinder was made with the "different correction coefficients".

Then, the LPG-ECU 3 starts the simultaneous output of LPG injection signals based on the calculated LPG injection period B 'to the LPG injectors 6 of the cylinders # 1 and # 3 of the first cylinder group in synchronism with the start of an operation for outputting one current gasoline injection signal A for cylinder # 1. The LPG-ECU 3 later starts to simultaneously output LPG injection signals based on the calculated LPG injection period A 'to the LPG injectors 6 of the cylinders # 4 and # 2 of the second cylinder group in synchronism with the start of an operation of outputting a current one Gasoline injection signal B for cylinder # 4.

For example, for an injection B 'of LPG into the first cylinder group, as shown in Fig. 14 (b), the LPG-ECU 3 corrects a previous gasoline injection signal B which, as shown in Fig. 14 (a), by the gasoline ECU 2 for cylinder # 4 has been issued to an injection that precedes injection B 'of the LPG into cylinder # 1 by two injections in the order of injections to match the gasoline injection signal to the LPG injection B', and calculates it an LPG injection period B 'representing an LPG injection volume. Then, the LPG-ECU 3 simultaneously starts outputting LPG injection signals based on the calculated LPG injection period B 'to the two LPG injectors 6 of the cylinders # 1 and # 2 of the first cylinder group at the start of an operation which is performed by the Gasoline ECU 2 is executed to output a current gasoline injection signal A. In this way, the injection of LPG into the first cylinder group is started. LPG is injected into the second cylinder group in the same manner as the first cylinder group described above.

Referring to the flowcharts shown in Figs. 15 to 19, the following description explains operations performed by the LPG-ECU 3 for injection. LPG is running. FIG. 15 is a flowchart showing processing executed in synchronism with an output start time (an ON time) of the gasoline injection signal A output from the gasoline ECU 2 for the # 1 cylinder.

The flowchart starts with a step 500 in which the LPG-ECU 3 reads an ON time of the fuel injection signal A for the cylinder # 1 and stores the ON time in a memory. The ON time is the time of a time a1 shown in FIG. 14.

Then, in a step 510 , the LPG-ECU 3 reads out from the memory a gasoline injection period (or an ON period) B of a gasoline injection signal B output for the cylinder # 4 at a timing that is 360 ° CA of the present time precedes.

Subsequently, in a step 520, the LPG-ECU 3 calculates an LPG duration B 'according to equation (6) as follows:

B '= B × (different correction coefficients) (6).

Then, in a step 530, the LPG-ECU 3 starts applying an electric current to the LPG injectors 6 of the cylinders # 1 and # 3 of the first cylinder group.

Finally, in a step 540, the LPG-ECU 3 ends the application of the electric current to the LPG injectors 6 of the cylinders # 1 and # 3 of the first cylinder group after the LPG duration D 'has elapsed since the start of the application of the electric current the LPG injectors 6 of cylinders # 1 and # 3 in step 530 .

Fig. 16 is a flowchart illustrating a processing which is executed in synchronism with an output end time (an OFF time) of the fuel injection signal A, which is output from the petrol ECU 2 for the cylinder # 1. The flowchart starts with a step 550 in which the LPG-ECU 3 reads an OFF time of the fuel injection signal A for the cylinder # 1. The OFF time is the time of a time a2 shown in FIG. 14.

Then, in a step 560, the LPG-ECU 3 calculates an injection period (or an ON period) A of the gasoline injection signal for the cylinder # 1 according to the equation (7) shown below and stores the injection period in the memory:

A = (# 1 OFF time) - (# 1 ON time) (7).

As described above, the LPG-ECU 3 performs the processing for injecting LPG into the first cylinder group.

FIG. 17 is a flowchart showing processing executed in synchronization with an output start time (an ON time) of the gasoline injection signal B output from the gasoline ECU 2 for the # 4 cylinder. The processing is performed in steps 600 to 640 and corresponds to the processing represented by the flowchart shown in FIG. 15. Fig. 18 is a flowchart illustrating a processing which is executed in synchronism with an output end time (an OFF time) of the fuel injection signal B outputted from the petrol ECU 2 for the cylinder # 4. The processing is performed in steps 650 and 660 and corresponds to the processing represented by the flow chart shown in FIG. 16. No description will be given of the processing represented by the flowcharts shown in Figs. 17 and 18.

Fig. Is a diagram of the LPG ECU shows an area for storing data in a memory (RAM) 3 19. The data stored in the memory area includes ON times (or output start times) of the gasoline injection signals that are output for cylinders # 1 and # 4, respectively. The data includes ON periods (or gasoline injection durations) A and B for cylinders # 1 and # 4, respectively.

In the LPG injection control device of the second embodiment described above, for a current injection of LPG into one of the cylinder groups, the LPG-ECU 3 corrects a previous injection signal output from the gasoline ECU 2 for a cylinder at an injection, that precedes the current injection of LPG into the particular cylinder group by two injections in a sequence of ordinary individual cylinder injections, and calculates an LPG injection period B ', A'. Then, the LPG-ECU 3 starts the simultaneous output of LPG injection signals based on the calculated LPG injection periods B ', A' to the LPG injectors 6 of two cylinders of the particular cylinder group in synchronism with the start of an operation by the gasoline -ECU 2 is executed to output the current gasoline injection signal (A, B) for the particular cylinder group. As a result, the start of an activity becomes simultaneous. Injecting LPG into the two cylinders of the special cylinder group synchronized with the start of an activity to output a gasoline injection signal for those cylinders. That is, the injection of LPG into any of the cylinders is started before the cylinder's suction process. As a result, LPG injection delay for all cylinders can be avoided, and in addition, it is possible to prevent the engine 1 from decreasing in performance. Other effects of the second embodiment are basically the same as those of the first embodiment.

(1) As shown in FIGS. 3 (a) and 3 (b), in the first embodiment, for a current injection into one of the cylinders # 1 to # 4, the LPG-ECU 3 corrects a gasoline injection signal output from the gasoline engine. ECU 2 was output at the second previous injection, for the current injection in an order of cylinders # 1 to # 4 to match the current injection of LPG, and calculates the injection period LPG.

As shown in FIGS. 20 (a) and 20 (b), the LPG-ECU 3 for the current injection of LPG into a specific cylinder (cylinder # 1) can also correct a gasoline injection signal A output from the gasoline ECU 2 has been output to cylinder # 1 at an injection preceding the current injection by four injections to match the gasoline injection signal to the current injection of LPG and calculates an injection duration A 'of the LPG. In this case too, the start of LPG injection is synchronized with the start of the intake process. As a result, an LPG injection delay for all cylinders can be avoided, and in addition, it is possible to prevent the engine 1 from decreasing in performance.

(2) The above embodiments realize one Injection control system for the alternative fuel to petrol for the Four cylinder engine. The injection control system for the petrol however alternative fuel can be for one Two-cylinder engine or a six-cylinder engine can be used.

(3) The above embodiments each realize one Injection control unit for the alternative to petrol Fuel that is exclusive to the engine system of the single fuel type is applied for LPG. The injection control unit for the too However, gasoline alternative fuel can also be based on that Engine system of the dual fuel type can be applied, the Can switch fuel from gasoline to LPG or vice versa.

(4) In the above embodiments, this is Injection control system for the alternative fuel to petrol present invention on an LPG injection control unit for Injecting LPG as the alternative fuel to petrol directed. However, it can also be applied to an injection control system the fuel alternative to petrol is directed at injected into LNG as the alternative fuel to petrol becomes.

(5) In the above embodiments, the gasoline alternative fuel injection control device of the present invention is implemented as the so-called DJ system, which includes a basic system constructed by the engine 1 and the gasoline ECU 2 for injecting fuel based on an intake air pressure PM in the intake pipe 9 , which is detected by the intake pressure sensor 32 . Alternatively, the injection control device for the fuel alternative to gasoline can also be implemented as the so-called LJ system with a basic system which is constructed from a gasoline engine and a gasoline ECU for injecting fuel on the basis of a special volume of intake air in the intake pipe, which is detected by an air flow meter.

According to the structure of the injection control unit for petrol alternative fuel of an engine according to the present Invention corrected for a current injection of an alternative fuel to gasoline into a specific one Cylinder the injection control unit of the alternative to gasoline Fuel a gasoline injection signal from the Gasoline injection control unit for a cylinder on an injection is given up to the current injection order at least one most recent injection in an order of Injections precedes to adjust the Gasoline injection signals to the current injection of gasoline alternative fuel and calculates an injection volume of the Alternative fuel gasoline. Then there is Injection control unit of the alternative fuel to petrol Injection signal of the alternative fuel to petrol on the Basis of the injection volume of the alternative to gasoline Fuel to the injector of the special Cylinders, being at a start of an activity of issue of a current gasoline injection signal from the Gasoline injection control unit for the special cylinder is started.

Thus, the injection of gasoline can be alternative Fuel in the special cylinder with the start of the activity outputting a current gasoline injection signal from the petrol injection control unit for the special cylinder be synchronized so that the injection of gasoline alternative fuel in the special cylinder in front of you Intake process of the special cylinder can be started. As a result, there is an effect that a delay of one Injection of fuel alternative to petrol for everyone Cylinder can be avoided, and in addition it is possible to prevent the performance of the engine from decreasing.

According to the structure of the injection control unit for one Gasoline alternative fuel to an engine according to the corrected the present invention according to the other aspect for a current injection of alternative to gasoline Into a special cylinder group Injection control unit for the alternative fuel to petrol Gasoline injection signal from the gasoline injection control unit for one of cylinders to an injection that the current one Injection of fuel alternative to petrol into the special cylinder group by at least one most recent Injection precedes an order of injections to adapt the gasoline injection signal to the current one Injection of alternative fuel to petrol and calculates an injection volume of the alternative to petrol Fuel. Then the injection control unit gives it to gasoline alternative fuel simultaneously injection signals of the Alternative fuel based on the gasoline calculated injection volume of the alternative to petrol Fuel to the injectors of the cylinders of the special Cylinder group, starting at the start of an activity for outputting a current gasoline injection signal from the gasoline injection control unit for one of the cylinders that refer to the specific cylinder group. Thus the Start of an injection from the alternative to gasoline Fuel in a plurality of cylinders that relate to the refer to a specific cylinder group when starting an activity an output of a gasoline injection signal for one of the Cylinders that refer to the specific cylinder group, see above synchronized that the injections of the gasoline alternative fuel in all cylinders before their intake processes is started. As a result, an effect is shown that a Delay of an injection of the alternative to gasoline Fuel for all cylinders can be avoided, and in addition, it is possible to prevent the engine performance decreases.

Claims (10)

1.Injection control unit of an engine for an alternative fuel to petrol, with:
an engine ( 1 ) having a plurality of cylinders (# 1- # 4) and sequentially executing a series of processes that repeats an intake process, a compression process, an expansion process, and an exhaust process one by one for each of the cylinders (# 1- # 4), the process series for any of the cylinders (# 1- # 4) being shifted from the process series for any other of the cylinders (# 1- # 4);
a plurality of injectors, each of which is used to inject the gasoline alternative fuel into one of the cylinders (# 1- # 4) by injection;
an operating state detection device ( 31-35 ) which is used in each case for detecting an operating state of the engine ( 1 );
a gasoline injection control unit ( 2 ) for calculating an injection volume of gasoline to be supplied to each of the cylinders (# 1- # 4) in a predetermined injection order based on the operating condition detected by the operating condition detection means ( 31-35 ) and outputting a gasoline injection signal that the calculated gasoline injection volume represents at the beginning of the intake process of each of the cylinders (# 1- # 4); and
an alternative fuel control unit ( 3 ) for gasoline to correct the fuel injection signals to be output to the cylinders (# 1- # 4), to adapt the fuel injection signals to injections of the fuel alternative to gasoline and to generate injection signals for the fuel Petrol alternative fuel to be successively output to the injectors ( 6 ) of the cylinders (# 1- # 4), wherein for a current injection of the alternative fuel to petrol into a particular one of the cylinders (# 1- # 4) the injection control unit ( 3 ) for the gasoline alternative fuel, corrects the gasoline injection signal output from the gasoline injection control unit ( 2 ) for one of the cylinders (# 1- # 4) during an injection that corresponds to the current injection of the gasoline alternative fuel by at least one injection in an order of Injections precedes to adjust the gasoline injection signal the current injection of alternative fuel to gasoline, and
calculates an injection volume of the alternative fuel to gasoline and outputs an injection signal of the alternative fuel to gasoline based on the calculated injection volume of the alternative fuel to petrol to the injector ( 6 ) of the particular one of the cylinders (# 1- # 4) starting from one Start an activity to output a current gasoline injection signal from the gasoline injection control unit ( 2 ) to the special cylinder (# 1- # 4). 2. The injection control unit according to claim 1, wherein for a current injection of the alternative fuel to gasoline into the special one of the cylinders (# 1- # 4), the alternative fuel injection control unit ( 3 ) corrects a gasoline injection signal which is generated by the gasoline injection control unit ( 2 ) is issued for one of the cylinders (# 1- # 4) at an injection that precedes the current gasoline alternative fuel by two injections in an order of injections to match the gasoline injection signal to the current gasoline alternative injection Fuel, and which calculates an injection volume of the alternative fuel to gasoline. 3. Injection control device according to claim 1 or 2,
wherein the gasoline injection control unit ( 2 ) outputs a gasoline injection signal that the calculated gasoline injection volume at the beginning of the intake process represents each of the cylinders (# 1 and # 4) selected from the cylinders (# 1 to # 4);
the alternative fuel injection control unit ( 3 ) corrects the gasoline injection signal output from the gasoline injection control unit ( 2 ) for each of the selected cylinders (# 1 and # 4) to adapt the gasoline injection signal to an injection of the alternative gasoline fuel, sequentially outputs fuel alternative fuel signals to the injectors ( 6 ) of each cylinder group of at least two cylinders (# 1 through # 4) containing the selected cylinders (# 1 and # 4); and
the alternative fuel injection control unit ( 3 ) corrects a gasoline injection signal output from the gasoline injection control unit ( 2 ) for one of the cylinders (# 1 and # 4) for current injection of the alternative gasoline fuel into a specific cylinder group an injection preceding the current gasoline alternative fuel injection by at least one injection in an order of injections to match the gasoline injection signal to the current gasoline alternative fuel injection, and calculating an injection volume of the gasoline alternative fuel and an injection signal of the Based on the injection volume of the alternative fuel to gasoline, alternative fuel gasoline outputs to the injectors ( 6 ) of the cylinders (# 1 to # 4) related to the specific cylinder group, starting from a start of an activity for outputting a current gasoline injection signal from the gasoline injection control unit. ( 2 ) to the special cylinder group. 4. The injection control device according to claim 3, wherein for a current fuel alternative fuel injection for the particular cylinder group, the fuel alternative fuel injection control unit ( 3 ) corrects a gasoline injection signal output from the gasoline injection control unit ( 2 ) for one of the cylinders (# 1 and # 4) is output at an injection preceding the current gasoline alternative fuel injection by two injections in an order of injections to match the gasoline injection signal to the current gasoline alternative fuel injection, and an injection volume of the gasoline alternative fuel Fuel calculated. 5. Injection control device according to one of claims 1 to 4, in which the operating state detection device ( 31-35 ) comprises:
a throttle sensor ( 31 ) for detecting an opening degree (TA) of a throttle valve ( 31 ) which is provided on an intake pipe ( 9 ) of the engine ( 1 );
an intake pressure sensor ( 32 ) for detecting an intake air pressure (PM) in the intake pipe ( 9 ),
a water temperature sensor ( 33 ) for detecting a cooling water temperature (THW) of the engine ( 1 );
a speed sensor ( 34 ) for detecting a speed (NE) of the engine ( 1 ); and
an oxygen sensor ( 35 ) for detecting an oxygen concentration (Ox) contained in the gas discharged from the engine ( 1 ). 6. Injection control device according to one of claims 1 to 5,
wherein the injection controller further comprises temperature sensing means ( 36 and 38 ) for sensing a temperature of the gasoline alternative fuel and pressure sensing means ( 37 and 39 ) for sensing a pressure of the gasoline alternative fuel; and
the fuel alternative fuel injection control unit ( 3 ) corrects the gasoline injection signal based on the temperature sensed by the temperature sensing means ( 36 and 39 ) and the pressure sensed by the pressure sensing means ( 37 and 39 ) to adapt the petrol injection signal to the injection of the petrol alternative fuel. 7. An injection control device according to any one of claims 1 to 6, wherein the engine ( 1 ) is an engine of a single fuel type for injecting only the fuel alternative to gasoline. 8. An injection control device according to any one of claims 1 to 6, wherein the engine ( 1 ) is a two-fuel type engine for injecting gasoline and the alternative fuel to gasoline by switching gasoline to the alternative gasoline fuel and vice versa. 9. Injection control device according to one of claims 1 to 8, where the alternative fuel to petrol is LPG. 10. Injection control device according to one of claims 1 to 8, where the alternative fuel to gasoline is LNG.