JPH02259249A - Fuel injection amount control device for alcohol engine - Google Patents

Abstract

PURPOSE:To improve startability by searching a map for startable alcohol concentration from temperatures of intake air and main fuel and setting a driving rate of an auxiliary injector for injecting liquefiel gas as auxiliary fuel in accordance with a compared result with the actual alcohol concentration, when an engine is started. CONSTITUTION:When an engine is decided to be in cranking by a cranking decision means 58, startable alcohol concentration A0 is referred to a map by a reference means 48 while searching the map for a start-time fuel injection amount Ti' by a reference means 47 with temperatures of intake air and main fuel serving as a parameter. The searched startable alcohol concentration A0 is compared with alcohol concentration A1 of the main fuel calculated by an arithmetic means 49 in a decision means 50, and when a relation of A1>A0 is obtained, a setting means 54 sets a driving rate of an auxiliary injector 11 for injecting liquefied gas stored in a cartridge tank of the start-time fuel injection amount Ti, as auxiliary fuel in relation to a main injector 10 for injecting the main fuel.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection ffi for an alcohol engine that aims to improve startability by supplying a set amount of auxiliary fuel consisting of liquefied gas at the time of starting to lower the alcohol concentration. ii.Relating to a control device.

[Prior art and problems to be solved by the invention] Generally,
Alcohol fuel used in alcohol engines has characteristics such as being difficult to vaporize at low temperatures, having a large latent heat of vaporization, and having a high flash point compared to gasoline fuel. The main fuel is a mixed fuel.

However, 1 ml of alcohol in this main fuel! (Content) changes depending on the user's circumstances when refueling, so it is difficult to maintain a constant concentration at all times, and if the alcohol concentration changes, the output characteristics will fluctuate significantly depending on temperature conditions. In particular, when the alcohol concentration is high, there is a problem that low temperature startability deteriorates.

For example, in the alcohol engine starting device disclosed in Japanese Patent Application Laid-Open No. 58-158359, if the engine temperature is below a predetermined value during engine cranking, the opening/closing valve of the gasoline fuel supply system is opened and the gasoline is used as auxiliary fuel. of gasoline fuel is supplied to the intake passage to improve starting performance.

However, as mentioned above, the alcohol concentration that allows starting changes depending on the engine temperature conditions, so uniformly supplying gasoline as auxiliary fuel when the temperature is below the set temperature will waste gasoline fuel, which is economically undesirable. .

In addition, under the set conditions, alcohol fuel stored in the float chamber and gasoline fuel are supplied simultaneously, resulting in an excessively rich air-fuel ratio, which not only causes difficulty in starting, but also worsens exhaust emissions and fuel efficiency. There is.

Moreover, the gasoline fuel as the auxiliary fuel is supplied to the engine appropriately with the main purpose of improving low-temperature startability and shortening warm-up time, and is hardly used during steady driving. Therefore, the auxiliary fuel tank that stores gasoline fuel as auxiliary fuel is space-saving and
Light weight is preferable, and it is sufficient if the minimum required tank amount is 1 yen.

However, conventionally, in many engines of this type, an auxiliary fuel tank is permanently installed in the engine, and the tank capacity is almost the same as that of the main fuel tank. On the other hand, an auxiliary fuel tank is not required for alcohol engines used in areas other than low-lying wetlands, but whether or not to use one is up to the user, and all alcohol engines must be equipped with an auxiliary fuel tank at the time of shipment. No.

As a result, the auxiliary fuel tank occupies a large space with respect to the engine, which not only increases the overall size of the engine but also increases its weight.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it not only improves the durability of auxiliary fuel, improves exhaust emissions and fuel efficiency, and provides good starting performance. The present invention aims to provide a fuel injection opening control device for an alcohol engine that can save space and reduce weight.

[Means for Solving the Problems] A fuel injection opening control device for an alcohol engine according to the present invention includes: an alcohol concentration calculation means for calculating the alcohol concentration of the main fuel; an engine cranking determination means for determining a cranking state; When the engine cranking determination means determines that cranking is in progress, starting fuel injection m search is performed to search a map of the starting fuel injection amount using at least one of the output signal of the intake temperature sensor and the output signal of the main fuel temperature sensor as a parameter. and when the engine cranking determining means determines that the engine is cranking, a start-up method for searching a map for an alcohol concentration that allows start-up using at least one of the output signal of the intake air temperature sensor and the output signal of the main fuel temperature sensor as a parameter. an alcohol concentration search means; an alcohol concentration determination means for comparing the alcohol concentration of the main fuel calculated by the alcohol concentration calculation means with the startable alcohol concentration retrieved by the startable alcohol concentration search means; If it is determined that the alcohol S degree of the main fuel is equal to or higher than the starting alcohol concentration, the liquefied gas stored in the J-trudge tank is injected as auxiliary fuel out of the starting fuel injection amount searched by the starting fuel injection amount search means. and auxiliary injector drive rate setting means for setting the drive rate of the auxiliary injector to the main injector that injects the main fuel.

[Function 1] In such a configuration, first, the alcohol temperature of the main fuel is calculated, the cranking state is determined, and then, when it is determined that cranking is in progress, the output signal of the intake temperature sensor and the main fuel hot water are Using at least one of the output signal of the temperature sensor as a parameter, a map search is performed for the starting fuel injection a and the alcohol concentration that allows starting.

Then, the alcohol concentration is compared with the startable alcohol III, and if it is determined that the alcohol concentration is equal to or higher than the startable alcohol concentration, the liquefied gas stored in the cartridge tank is injected as auxiliary fuel from the start-up fuel injection M. Set the drive rate of the auxiliary injector to the main injector that injects the main fuel.

[Embodiments of the invention] Hereinafter, the present invention will be described in detail based on the drawings.

The drawings show one embodiment of the present invention, FIG. 1 is a functional block diagram of a fuel injection amount control device, FIG. 2 is a general schematic diagram of an engine control system, and FIG. 3 is a flowchart showing a procedure for controlling the fuel injection amount. , Figure 4 is a conceptual diagram of the starting fuel injection amount map,
Figure 5 is a conceptual diagram of the alcohol concentration map that allows starting.
The figure is a correlation diagram between temperature conditions and starting alcohol temperature, Figure 7 is a correlation diagram between alcohol concentration and alcohol content correction coefficient, and Figure 8 is a conceptual diagram of a combustible alcohol concentration map.
FIG. 9 is a conceptual diagram of the auxiliary injector drive rate map.

(Configuration) Reference numeral 1 in the figure is the engine body, and the figure shows a horizontally opposed engine. An intake manifold 3 is communicated with the intake boat 2a formed in the cylinder head 2 of the engine body 1, and a throttle chamber 5 is communicated with the upstream side of the intake manifold 3 via an air chamber 4. An air cleaner 7 is attached to the side via a suction pipe 6.

Further, an intake air amount sensor (a hot wire air flow meter in the figure) 8 is interposed immediately downstream of the air cleaner 7 in the intake pipe 6, and a throttle valve 5a provided in the throttle chamber 5 is connected to a throttle valve 5a provided in the throttle chamber 5. Turns on when position sensor 9a and throttle valve are fully closed.
An idle switch 9b is connected to the idle switch 9b.

Further, a main injector 10 is disposed immediately upstream of each intake boat 2a of each cylinder of the intake manifold 3, and an auxiliary injector 11 is further disposed upstream of the throttle valve 5a of the throttle chamber 5. ing.

Further, the main injector 10 is communicated with the main fuel tank 13 via the main fuel passage 12, and the main fuel pump 14, alcohol sensor 15, and main fuel temperature sensor 16 are connected to the main fuel passage 12 from the main fuel tank 13 side. is interposed. Further, an auxiliary fuel passage 18 is communicated with the auxiliary injector 11, and a cartridge connecting portion 1-8a is provided at the inlet of the auxiliary fuel passage 18. moreover,
The above-mentioned cart lip connection portion 18a of this auxiliary fuel passage 18
A vaporizer 19a is installed on the side, and an auxiliary fuel pressure sensor 19b is installed on the auxiliary injector 11 side.

Further, a nozzle 17a of a cartridge tank 17 for storing liquefied gas as auxiliary fuel is attached to the cartridge connecting portion 18a.

The main fuel tank 13 stores main fuel which is a mixture of alcohol fuel having a predetermined alcohol concentration A1 (%) and Ganlin fuel.

Further, an intake temperature sensor +j'20 is provided on the downstream side of the intake air amount sensor 8 of the intake pipe 6.

Further, a crank rotor 21 having protrusions or slits at predetermined crank angles on the outer periphery of the crankshaft 1b of the engine main body 1 is fixedly installed. A crank angle sensor 22 consisting of an electromagnetic pickup or the like is provided oppositely.

Furthermore, a cooling water temperature sensor 2 is installed in a cooling water passage (not shown) forming a riser formed in the intake manifold 3.
3 is coming.

Additionally, an exhaust boat 2 formed on the cylinder head 2
The 02 sensor 25 faces the exhaust gas @24 that communicates with the exhaust gas @24. In addition, the code|symbol 26 is a catalytic converter.

(Circuit configuration of fuel injection amount control device) On the other hand, reference numeral 31 is a fuel injection amount control device, and the CPU of this fuel injection amount control device 31 <Central processing calculation bag Eff) 3
2. The ROM 33, RAM 34, eYo'cF, and I10 interface 35 are connected to each other via a pass line 36, and each sensor 22.8 constituting the operating state parameter detection means 37 is connected to the input port of this I10 interface 35. , 9a.

23.25.15.20, 16.19b1 and the idle switch 9b are connected, and the output port of this 110 interface 35 is connected to the drive circuit 38.
The main injector 101 is connected to the auxiliary injector 11.

The ROM 33 stores control programs and fixed data. The fixed data includes a starting fuel injection amount map MpTi', a startable alcohol concentration map MPALI, and a combustible alcohol concentration map MP^[, which will be described later.
2, and an auxiliary injector drive rate map MPKI.

Further, the RAM 34 stores the output signals of the respective sensors after data processing and the data processed by the CPU 32t'.

Sarani, in the CPU 32, the ROM 331. : According to the stored control program, the pulse width for driving the main injector 10 and the auxiliary injector 11 is calculated based on various data stored in the RAM 34.

(Functional configuration of fuel injection amount control device) As shown in FIG. 1, the fuel injection amount control device 31 has the following features:
Engine rotation speed calculation means 41, intake air 11 calculation means 4
2. Basic fuel injection amount setting means 43, various increase correction coefficient setting means 44, air-fuel ratio feedback correction coefficient setting means 45, fuel injection surface setting means 46, starting fuel injection amount search means 47, startable alcohol concentration search means 48, alcohol concentration calculation means 49, alcohol concentration determination means 50
, alcohol content correction coefficient setting means 51, corrected fuel injection amount setting means 52, combustible alcohol concentration searching means 53,
It is composed of an auxiliary injector drive rate setting means 54, a main injector/auxiliary injector drive amount setting means 55, a main injector driving means 56, an auxiliary fuel pressure correction coefficient setting means 59, an auxiliary injector driving means 57, and an engine cranking determining means 58. ing.

In the engine rotation speed calculation means 41, the crank angle sensor 2
The engine rotation speed N is calculated from the output signal of step 2, and the intake air amount calculation means 42 outputs intake air f+IQ from the output signal of intake air 11 calculation step 8.

The basic fuel injection amount setting means 43 calculates the basic fuel injection amount Tp based on the engine rotation speed N calculated by the engine rotation speed calculation means 41 and the intake air mQ calculated by the intake air amount calculation means 42 (Tp- KXQ/NK
···constant). Alternatively, the basic fuel injection ff1Tp is set by map search using the engine speed N and intake air AtQ as parameters.

The various increase correction coefficient setting means 44 outputs the output signal of the idle switch 9b and the throttle position sensor 9a.
reads the throttle opening (θ) signal and the engine temperature (TE) signal of the coolant temperature sensor 23, and calculates various incremental m correction coefficients C0EF related to post-idle increase correction, acceleration/deceleration correction, full-open increase correction, coolant temperature correction, etc. Set.

In the air-fuel ratio feedback correction coefficient setting means 45, o2
Read the output voltage A/F of the sensor, compare the output voltage A/F of this 02 sensor with a preset slice level, and adjust the air-fuel ratio feedback correction coefficient α using proportional-integral control.
Set. Note that when the 02 sensor is inactive, the air-fuel ratio feedback correction coefficient α is fixed at α-1, 0, and the air-fuel ratio feedback control is stopped.

The fuel injection amount setting means 46 corrects the air-fuel ratio of the basic fuel injection ff1Tl) set by the basic fuel injection m setting means 43 using the various increase correction coefficients C0FF set by the various increase correction coefficient setting means 44. , the fuel injection &tTi' is set by feedback correction using the air-fuel ratio feedback correction coefficient α set by the air-fuel ratio feedback correction coefficient setting means 45 (Tbi=Tp xαxc
OEF).

In the starting fuel injection amount search means 47, the intake air temperature sensor 20
The intake air temperature (TA) signal of the main fuel temperature sensor 16 and the main fuel temperature (TF) signal of the main fuel temperature sensor 16 are read, and the starting fuel injection amount ff1T is searched from the starting fuel injection amount map MPTi' using these two signals as parameters. .

As shown in FIG. 4, the starting fuel injection amount map MP
Ti' is a grid-like three-dimensional map with intake air temperature TA and main fuel temperature TF as parameters, and the starting fuel injection ff1Ti determined in advance from experiments etc. is shown in the area surrounded by each grid.
' is stored.

The startable alcohol 111rx search means 48 reads the intake air temperature TA signal of the intake air temperature sensor 20 and the main fuel temperature TF multiplied signal of the main fuel temperature sensor 16, and uses the intake air temperature TA and main fuel temperature TF as parameters to determine the startable alcohol concentration. Alcohol concentration A that can be started from Mappu MPAL1
Search for O.

As shown in FIG. 5, the startable alcohol concentration map MPAL1 is a grid-like three-dimensional map with intake air temperature T^ and main fuel temperature [TF as parameters. The startable alcohol concentration AO determined from AO is stored.

Incidentally, the combustible alcohol concentration varies depending on temperature conditions such as intake air temperature, fuel temperature, and engine temperature.

That is, as shown in Figure 6, according to experiments, combustion becomes difficult when the temperature condition is below 130°C, and the maximum combustible alcohol concentration under temperature conditions higher than that is:
It changes almost linearly to 80% at -30°C and 85% at -20°C, and combustion is possible at 10°C even if the alcohol concentration is 100%.

In each area of the startable alcohol concentration map MPAL1, combustible alcohol concentrations are stored in advance in accordance with the intake air temperature TA and fuel temperature TF determined through experiments.

In the alcohol concentration calculation means 49, the alcohol sensor 1
5 is read, and the alcohol concentration A1 of the main fuel supplied to the main injector 10 is calculated.

The alcohol concentration determination means 50 compares the alcohol concentration A1 calculated by the alcohol concentration calculation means 49 with the startable alcohol concentration AO searched by the startable alcohol concentration search means 48, and if A1≦AO, the alcohol concentration is determined. (A1) A signal is output, and if AI > AO, a startable alcohol concentration (AO) signal is output.

The alcohol content correction coefficient setting means 51 sets an alcohol content correction coefficient KAL corresponding to the output signal (AI multiplied signal or AO multiplied signal) accompanying the determination result of the alcohol concentration determination means 50.

As is well known, the calorific value of liquefied gas (for example, propane gas) is approximately equal to that of gasoline fuel, and the calorific value of alcohol fuel is approximately 1/1 that of gasoline fuel or liquefied gas.
2, in order to obtain the same calorific value as gasoline fuel or liquefied gas, twice as much alcohol fuel as gasoline fuel or liquefied gas is required.

Therefore, as shown in Figure 7, alcohol concentration rxo
% (gasoline concentration 100%), the alcohol content correction coefficient is KAL-1, 0, and when the alcohol concentration ioo% (gasoline concentration 0%), the alcohol content correction coefficient is KAL
-2.0, and this alcohol content correction coefficient KAL continuously changes between 1.0 and 2.0 depending on the alcohol concentration.

The corrected fuel injection amount setting means 52 uses the fuel injection amount setting means 46 or the starting fuel injection amount searching means 4.
The alcohol content correction coefficient KA set by the alcohol content correction coefficient setting means 51 is set by the fuel injection ITi′ set in step 7.
Calculate the fuel injection amount Ti by correcting it with L (Ti-Ti'
xKAL).

The combustible alcohol concentration search means 53 takes in the output signal of the cooling water temperature sensor 23 as an engine temperature (TE) signal, and searches for the combustible alcohol concentration AO from the combustible alcohol concentration map MPAL2 using the engine temperature TE as a parameter.

As shown in FIG. 8, the combustible alcohol concentration map MPAL2 is a two-dimensional map using the engine temperature TE as a parameter, and each region has temperature conditions ( Stores the maximum combustible alcohol concentration that is set according to the engine temperature.

By the way, the combustible alcohol concentration at the time of starting (startable alcohol concentration) is more direct if the intake air temperature and main fuel temperature are set as parameters than by the engine temperature. Since the amount of fuel that adheres to the inner wall and vaporizes due to the rise increases, it is possible to appropriately control the fuel injection amount by setting the combustible alcohol m degree using the engine temperature (cooling water temperature) as a parameter.

The auxiliary injector drive rate setting means 54 selects the startable alcohol concentration AO1 searched by the startable alcohol concentration search means 48, the alcohol concentration A1 calculated by the alcohol concentration calculation means 49, and the alcohol concentration A1 determined by the alcohol concentration determination means 50. The drive rate of the auxiliary injector 11 is set based on alcohol concentration 1 or AO.

That is, when the alcohol concentration determining means 50h outputs a startable alcohol concentration (AO) signal, the alcohol concentration A1 is higher than the startable alcohol concentration AO (AI > AO).
1 must be modified to an alcohol concentration AO that can be started.

This means attempts to correct a predetermined proportion of the correction fuel injection rJJffiTi set by the correction fuel injection rAffl setting means 52 with the liquefied gas injected from the auxiliary injector 11. Specifically, the auxiliary injector 11 The driving rate Kl of is determined from the following formula.

When the alcohol concentration of the main fuel is AI (%), the ratio of the gasoline volume to the alcohol volume of this main fuel is: Gasoline volume! ? i: alcohol volume - 100 - AI: AI, and when the startable alcohol concentration is AO (%), the ratio of gasoline volume to alcohol volume is: gasoline volume: alcohol volume period 100 - AO: AO . Therefore, the main fuel with alcohol concentration A1 is
The total gasoline proportion X (%) for achieving the startable alcohol concentration AO (%) is 100-AO,: AO-X: A1.

Therefore, the additional ratio of auxiliary fuel (liquefied gas) to the main fuel to make the main fuel with alcohol concentration Al (%) to the startable alcohol concentration AO (%) xr <
%) is XI -X-(100-AI) -(2)
By substituting equation (1) into equation (2), the drive rate of the auxiliary injector becomes 100 AO (3).

In addition, in the embodiment shown in the figure, when calculating the drive rate K of the auxiliary injector 11 using the above formula (3), it takes a long calculation processing time.
The drive rate KI of the auxiliary injector 11 is calculated from 1 and the startable alcohol concentration AO (however, A1 > A
O) As shown in FIG. 9, an auxiliary injector drive rate map MPKr with alcohol concentration A1 and startable alcohol concentration AO as parameters is stored in the ROM 33, and the alcohol concentration A1 and startable alcohol concentration ff1AO at that time are stored in the ROM 33. With and as a parameter, map M
The auxiliary injector drive rate KI is determined by looking up the PKI.

In the auxiliary fuel pressure correction coefficient setting means 59, the auxiliary fuel passage 18
The auxiliary fuel pressure correction coefficient Kl) is set based on the line pressure P detected by the auxiliary fuel pressure sensor 19b installed in the auxiliary fuel pressure sensor 19b.
l) =:F(P)).

Main injector/auxiliary injector drive amount setting means 55
Now, based on the auxiliary injector driving rate KI set by the auxiliary injector driving rate setting means 54, the corrected fuel injection amount Ti set by the corrected fuel injection amount setting means 52 is set as the main fuel injection 1Ti1 minute and the basic auxiliary fuel injection amount Ti2. Separate into minutes.

That is, when the drive rate Kl of the auxiliary injector 11 is set by the auxiliary injector drive rate setting means 54, the basic auxiliary fuel injection! ) JfllTi2 is calculated by Ti2-TiXKI, and the basic auxiliary fuel injection ff1 is
Auxiliary fuel injection 54 is performed by correcting Ti2 with the auxiliary fuel pressure correction coefficient Kp set by the auxiliary fuel pressure correction coefficient setting means 59.
Calculate Ti2'"(Ti2" - Ti2xKp)
, an auxiliary injector drive pulse corresponding to this auxiliary fuel injection faTi2'' is outputted from the auxiliary injector driving means 57 to the auxiliary injector 11 at a predetermined timing, and from this auxiliary injector 11 the above-mentioned auxiliary fuel injection ff1T is output.
auxiliary fuel corresponding to i2'' is injected.

On the other hand, the main fuel injection ITiI is calculated by T il −T i −T 12 −Ti −(TixKI), and the main injector driving pulse corresponding to this main fuel injection JilTiI is sent from the main injector driving means 56 to the main injector 10. the main fuel injection amount 7i1 from this main injector 10 at a predetermined timing.
The main fuel (mixed fuel of alcohol fuel and gasoline fuel) corresponding to the fuel is injected.

On the other hand, when the auxiliary injector drive rate setting means 54 does not set the auxiliary injector drive rate Kl, that is, when A1≦AO, the main injector/auxiliary injector drive amount setting means 55 sets the corrected fuel injection!
A drive pulse signal corresponding to the fuel injection ff1Ti calculated by the IJ amount calculation means 52 is applied from the main injector driving means 56 to the main injector 10, and at the same time, the driving of the auxiliary injector 11 is stopped, and only the main injector 10 is started for 11 minutes. Inject the corresponding main fuel.

Further, the engine cranking determination means 58 reads the engine rotation speed N calculated by the engine rotation speed calculation means 41 and sets a preset reference value NO (for example, 500
r, 11. When N<N07), it is determined that the engine is cranking, and when N≧NO, it is determined that the engine is in a complete explosion.

When the engine cranking state is determined, the intake air ffi calculation means 42, the basic fuel injection amount setting means 43, the various increase correction coefficient setting means 44, the air-fuel ratio feedback correction coefficient setting means 45, and the fuel injection! ! 1
A calculation stop signal is output to the setting means 46, and a calculation command signal is output to the start fuel injection amount search means 47 and the startable alcohol concentration search means 48. When the engine cranking determining means 58 determines that the engine has completely exploded, it outputs a computation command signal to each of the means 42 to 46 and outputs a computation stop signal to each of the other means 47 and 48.

(i Control Procedure) Next, the control procedure of the fuel injection amount control device having the above configuration will be explained according to the flowchart of FIG. 3.

First, in step 5101, the output signal of the alcohol sensor 15 is read and the alcohol concentration A1 in the main fuel is determined.
In step 5102, the engine speed N is calculated based on the output signal of the crank angle sensor 22.

Then, in step 5103, the engine rotation speed N calculated in step 3102 and the preset reference value No.
(for example, 500 r, l), 1 ), and N
If the answer is NO, it is determined that the cranking condition is present and the process proceeds to step 8.
The process proceeds to step 104, and if N≧No, it is determined that the engine has completely exploded, and the process proceeds to step 5107.

When it is determined that the cranking state is in progress and the process proceeds to step 5104, the intake air temperature TA and main fuel temperature TF are read, and in step 5105, the fuel injection ITi' is calculated using the above-mentioned hot dust TA and TF as the starting fuel injection amount map MPT. Search from code. In addition, in step 8106, the above-mentioned hot dust TA
, alcohol concentration A that can be started using TF as a parameter
Search for O from the startable alcohol concentration map MPAL1.

On the other hand, when it is determined in step 5103 that the engine has completely exploded and the process proceeds to step 5107, the output signal of the intake air amount sensor 8 is read and the intake air 1Q is calculated, and step 8108
Then, basic fuel injection ff1T+1 is calculated from the engine speed N calculated in step 5102 and the intake air IQ (Tp-KxQ/N).

Then, in step 5109, the engine 111TE signal from the cooling water temperature sensor 23, the throttle opening θ signal from the throttle position sensor 9a, and the idle switch 9
The operation signal b is read, and in step 5110, the combustible alcohol concentration AO is searched from the combustible alcohol concentration map M P Al1 using the engine temperature TE as a parameter, and in step 5111, the engine temperature TE, throttle opening θ, Various increase correction coefficients C0FF are set from the output of the idle switch, and step 511
2, the air-fuel ratio feedback correction coefficient α is set based on the output signal from the 02 sensor 25.

Next, in step 5113, each of the above steps 5108
．． Fuel injection f based on the value set in 5111.5112
Set f1T (T i' -Tp XC0EFX
α).

Then, in step 5114, the above step 5101
Alcohol concentration A1 calculated in step 8106 above
Alternatively, compare the combustible alcohol concentration AO searched in step 5110, and if A1≦AO1, that is, the alcohol concentration of the main fuel is below the upper limit of the concentration sufficient for combustion, proceed to step 5115, and if AI > A
O, that is, if the alcohol concentration of the main fuel is greater than or equal to the upper limit of the concentration sufficient for combustion, the process proceeds to step 8118.

In step 5115, the alcohol 1 calculated in step 5101 above! *Set alcohol content correction coefficient KAL based on AI. Then, in step 8116, the fuel injection ITi' set in step 3105 or step 5113 is corrected by the alcohol content correction coefficient KAL set in step 5115 to inject a corrected fuel injection f.
f1Ti is set, this corrected fuel injection amount Ti is set as the main injector drive molecule i1, and in step 5111, the main injector 10 is driven with a drive pulse corresponding to the main injector drive molecule i1, and the program ends.

On the other hand, when proceeding from step 5114 to step 8118, first, the alcohol concentration A1 calculated in step 5101 and step 8106 or step 3 are
Auxiliary injector drive rate map MPKI using the combustible alcohol concentration AO searched in 110 as a parameter
is searched, and the driving ratio Kl of the auxiliary injector 11 with respect to the main injector 10 is set.

Further, in step 5119, an alcohol content correction coefficient KAL is set based on the combustible alcohol concentration AO.

Then, in step 5120, the fuel injection 1!1tTi set in step 5105 or step 5113 is performed.
' is corrected using the alcohol content correction coefficient KAL set in step 5119 to set a corrected fuel injection amount Ti.

Next, in step 5121, the corrected fuel injection ITi set in step 5120 and the step 811
The drive numerator il of the main injector 10 and the auxiliary injector 11 is based on the drive ratio KI of the auxiliary injector 11 with respect to the main injector 10 set in step 8.

Calculate Ti2 (Ti2-TixKI, Tl1
-Ti-Ti2).

Then, in step 5122, the auxiliary fuel pressure sensor 19
An auxiliary fuel pressure correction coefficient Kp is calculated based on the output signal of b.

Thereafter, in step 5123, the auxiliary injector basic drive numerator i2 calculated in step 5121 is corrected by the auxiliary fuel pressure correction coefficient Kp set in step 5122 to calculate the auxiliary injector drive numerator i2''.

Then, in step 5124, fuel is injected from the auxiliary injector 11 and the main injector 10 based on the auxiliary injector driving molecule i2'' calculated in the above step 5123 and the main injector driving molecule i1 calculated in the above step 5121.

As a result, the alcohol concentration A1 of the main fuel injected from the main injector 10 is changed to the alcohol concentration AO that can be burned by the gaseous fuel injected from the auxiliary injector 11.
Since the amount of fuel injected from the main injector 10 is set to be less than the amount of gas fuel injected from the auxiliary injector 11, good starting performance, output performance, and acceleration performance can be achieved. Furthermore, it is possible to significantly improve exhaust emissions and fuel efficiency.

In addition, due to the low-temperature start caused by such gas fuel (auxiliary fuel) replenishment, the engine temperature rises during warm-up, and the comparison between the alcohol concentration A1 of the main fuel and the combustible alcohol concentration AO becomes A.
When the relationship 1≦AO is established, the engine is in an operating state in which only the main fuel is supplied.

Roughly speaking, when cranking the engine, the engine speed N
Since the intake air amount Q is not stable, the fuel injection amount is not calculated using the engine speed N and the intake air fiQ, but the starting fuel injection ffiTM is calculated by a map search using the intake air temperature TA and main fuel flow TF as parameters. Since the setting is made, fuel injection amount control is performed appropriately.
This further improves startability.

Of course, if the alcohol engine is only used in areas other than low-lying wetlands, i.e. areas where alcohol fuel alone can be sufficient to start the engine, there is no need to supply auxiliary fuel and it is sufficient to remove the cartridge tank 17. By removing this cartridge tank, space can be saved and the product can be made lighter. Further, when the engine can be started sufficiently with only alcohol fuel (AI≦AO), the auxiliary injector driving rate setting means 54 does not set the auxiliary injector driving rate Kl, and the auxiliary injector 11 is not driven.

Note that the present invention is not limited to the above-mentioned embodiments; for example, the starting fuel injection amount and the starting alcohol concentration may be searched on a map using one of the intake air temperature and the main fuel temperature as a parameter; 11 may be arranged for each cylinder.

[Effects of the Invention] As described above, according to the present invention, the alcohol concentration calculation means for calculating the alcohol concentration of the main fuel, the engine cranking determination means for determining the cranking state, and the engine cranking determination means are provided. a starting fuel injection amount search means for searching a starting fuel injection m on a map using at least one of the output signal of the intake air temperature sensor and the output signal of the main fuel temperature sensor as a parameter when it is determined that the engine is cranking; If the cranking determination means determines that cranking is in progress, a startable alcohol concentration search means searches a map for a startable alcohol concentration using at least one of the output signal of the intake air temperature sensor and the output signal of the main fuel temperature sensor as a parameter. , alcohol concentration determination means for comparing the alcohol concentration of the main fuel calculated by the alcohol concentration calculation means and the startable alcohol concentration searched by the startable alcohol concentration search means;
When the alcohol concentration determining means determines that the alcohol concentration of the main fuel is equal to or higher than m degrees of alcohol for starting, the liquefied gas stored in the cartridge tank out of the starting fuel injection amount searched by the starting fuel injection amount searching means The auxiliary injector drive rate setting means is provided to set the drive rate of the auxiliary injector that injects auxiliary fuel to the main injector that injects the main fuel, so that regardless of the alcohol concentration of the main fuel, the appropriate one is always set at startup. The alcohol concentration can be set, and as a result, not only good starting performance can be obtained, but also exhaust emissions and fuel efficiency can be improved, gasoline fuel can be consumed economically, and the engine condition can be adjusted. Alcohol m
Since follow-up control is performed so that the alcohol concentration reaches the combustible alcohol concentration, excellent effects such as optimal fuel injection amount control can always be achieved regardless of whether the engine is cranking or warming up.

Furthermore, since the cartridge tank is used as the auxiliary fuel tank, it is easy to remove, and if there is no need to supply auxiliary fuel from the time of startup, you can save space and reduce weight by removing it. I can do it.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 shows a fuel injection rJJ
Fig. 2 is a general schematic diagram of the engine control system, Fig. 3 is a flowchart showing the procedure for controlling the fuel injection amount, Fig. 4 is a conceptual diagram of the starting fuel injection ship map, and Fig. 5 is a functional block diagram of the m control device. The figure is a conceptual diagram of the alcohol concentration map that allows for starting.
Figure 6 is a correlation diagram between temperature conditions and starting alcohol concentration, Figure 7 is a correlation diagram between alcohol concentration and alcohol content correction coefficient, Figure 8 is a conceptual diagram of a combustible alcohol concentration map, and Figure 9 is an auxiliary diagram. FIG. 3 is a conceptual diagram of an injector drive rate map. DESCRIPTION OF SYMBOLS 10... Main injector, 11... Auxiliary injector, 16... Main fuel temperature sensor, 17... Cartridge tank, 20... Intake temperature sensor, 47... Starting fuel injection amount search means , 48... Startable alcohol concentration search means, 49... Alcohol concentration calculation means, 5
0...Alcohol concentration determining means, 54...Auxiliary injector drive rate setting means, 58...Engine cranking determining means, AO...Startable alcohol concentration, A
1...Alcohol concentration (of the main fuel), K ■ Drive rate of the auxiliary injector, TM... (at startup) Fuel injection R0 Figure 4. Figure Figure 8 IN AX Engine Temperature Tε Figure 9 Procedure Neho (self-motivated) Director General of the Patent Office Furu 1) Moon Tsuyoshi July 7, 1989 Sako 1, Incident Display 1999 Patent Application No. 81803 2. Name of the invention Fuel injection amount control device for alcohol engine 3. Relationship with the case of the person making the correction

Claims (1)

[Scope of Claims] An alcohol concentration calculation means for calculating the alcohol concentration of the main fuel; an engine cranking determination means for determining the cranking state; a starting fuel injection amount search means for searching a map for the starting fuel injection amount using at least one of the output signal of the sensor and the output signal of the main fuel temperature sensor as a parameter; and the engine cranking determining means determines that cranking is in progress. a startable alcohol concentration search means for searching a map for a startable alcohol concentration using at least one of the output signal of the intake air temperature sensor and the output signal of the main fuel temperature sensor as a parameter; and the main fuel calculated by the alcohol concentration calculation means. alcohol concentration determination means for comparing the alcohol concentration of the main fuel with the startable alcohol concentration searched by the startable alcohol concentration search means, and when the alcohol concentration of the main fuel is determined to be equal to or higher than the startable alcohol concentration , an auxiliary unit for setting the drive rate of the auxiliary injector that injects the liquefied gas stored in the cartridge tank as auxiliary fuel, with respect to the main injector that injects the main fuel, out of the starting fuel injection amount searched by the starting fuel injection amount search means; 1. A fuel injection amount control device for an alcohol engine, comprising: injector drive rate setting means.