JP7752014B2 - Engine control unit - Google Patents

Description

The present invention relates to an engine control device that sets the fuel injection amount at engine startup.

For example, in engines installed in vehicles such as automobiles, when the engine is not yet warmed up, particularly in low-temperature environments, increased friction torque can cause poor starting performance. To address this issue, it is known that the engine coolant temperature is detected, and if the detected value is low, the amount of fuel injected at startup is increased.

As a technology for setting such a fuel injection amount at startup, for example, Patent Document 1 describes a technique in which, when a failure is detected in a water temperature sensor that detects the engine's cooling water temperature, the input signal from the water temperature sensor at engine startup is switched to a predetermined startup set value, and the fuel injection amount is increased.
Patent Document 2 describes that when the water temperature sensor fails during engine start-up, the input/output of the water temperature sensor is switched to a start-up set value, and the start-up set value is gradually increased and corrected based on the subsequent fuel injection amount and engine speed.
Furthermore, as a technology relating to estimating engine friction at start-up, for example, Patent Document 3 describes a hybrid-drive electric vehicle in which an electric motor cranks an internal combustion engine via a clutch, in which the clutch is engaged while the electric motor is rotating, and the friction torque of the internal combustion engine is estimated based on the power consumption of the electric motor in a half-clutch state before the clutch is engaged.

Japanese Patent Application Publication No. 1-41642 Japanese Patent Application Publication No. 8-326590 JP 2009-280049 A

In the above-mentioned Patent Documents 1 and 2, when the water temperature sensor fails, the output value of the water temperature sensor is replaced with a predetermined value that has been set in advance, thereby ensuring startability.
With this technology, the amount of fuel injected at startup is set uniformly regardless of the engine's warm-up state or the outside temperature, which raises concerns that sufficient starting performance may not be ensured in low-temperature conditions where starting is difficult.
In view of the above-mentioned problems, an object of the present invention is to provide an engine control device that ensures starting performance without relying on the detected value of a water temperature sensor.

In order to solve the above-mentioned problems, the engine control device of the present invention is an engine control device that controls an engine having a starter motor that rotates an output shaft at start-up, a power source that supplies power to the starter motor, and a fuel injection device that injects fuel into at least one of a combustion chamber and an intake port, and is equipped with a voltage detection unit that detects the voltage of the power source, a rotation speed detection unit that detects the rotation speed of the output shaft, and a fuel injection amount setting unit that sets a startup fuel injection amount in the fuel injection device based on the rotation speed detected at a timing when the cumulative rotation speed of the output shaft is two cycles or less after the starter motor begins to rotate the output shaft, and based on the voltage, and is characterized in that the fuel injection amount setting unit sets the startup fuel injection amount so that the startup fuel injection amount increases as the rotation speed decreases, and so that the startup fuel injection amount increases as the voltage increases .
This makes it possible to grasp the engine friction, which varies in accordance with changes in temperature, from the angular acceleration of the output shaft after the starter motor starts to rotate the output shaft.
Furthermore, since the driving force of the starter motor varies depending on the output voltage of the power source (typically a battery), friction can be determined more accurately by detecting the voltage of the power source.
By setting the fuel injection amount at startup (increasing correction) in accordance with the engine friction thus determined, engine startability can be ensured without relying on the value detected by the water temperature sensor.

In the present invention, the fuel injection amount setting section may be configured to increase the startup fuel injection amount in accordance with a decrease in the angular acceleration when the voltage is constant.
According to this, when the friction of the engine increases, for example, at low temperatures, the amount of fuel injected at startup is increased, thereby ensuring the startability of the engine.

In the present invention, the fuel injection amount setting unit can be configured to set the startup fuel injection amount based on the angular acceleration detected at a timing when the cumulative rotation number of the output shaft is two cycles or less after the starter motor begins to rotate the output shaft.
In the present invention, engine friction is determined using the angular acceleration of the output shaft, so it is possible to appropriately set the amount of fuel injection at startup even for a short period of time such that the cumulative number of rotations of the output shaft is less than two cycles (four rotations in the case of a four-stroke engine), thereby enabling the engine to start earlier and improving the marketability of the vehicle.

In the present invention, the engine may be provided with a water temperature sensor that detects the temperature of cooling water, and a water temperature sensor abnormality detection unit that detects an abnormality in the water temperature sensor, and the fuel injection amount setting unit may be configured to set the startup fuel injection amount based on the cooling water temperature detected by the water temperature sensor when the water temperature sensor is normal, and to set the startup fuel injection amount based on the angular acceleration and the voltage when the water temperature sensor is abnormal.
According to this, when the water temperature sensor is normal, the amount of fuel injected at startup is set according to the cooling water temperature detected by the water temperature sensor, thereby advancing the timing of initial combustion at engine startup and enabling the engine to be started quickly.
On the other hand, even if an abnormality occurs in the water temperature sensor, the start-up fuel injection amount can be set based on the angular velocity of the output shaft and the voltage of the power supply, thereby ensuring the startability of the engine and avoiding situations where it cannot be started.

As described above, the present invention makes it possible to provide an engine control device that ensures starting performance without relying on the detection value of the water temperature sensor.

1 is a diagram schematically illustrating the configuration of an engine having an embodiment of an engine control device to which the present invention is applied. 2 is a block diagram showing a configuration related to setting of a fuel injection amount at startup in the engine control device according to the embodiment; FIG. 3 is a flowchart showing an outline of fuel injection increase control at engine start in the engine control device of the embodiment. 1 is a diagram showing an example of changes in battery voltage and engine speed during engine start-up in a water temperature sensor failure state in an engine having an engine control device according to an embodiment;

An embodiment of an engine control device to which the present invention is applied will be described below.
The engine control device of the embodiment comprehensively controls an engine and its accessories that are installed as a power source for driving an automobile such as a passenger car, for example.
In the embodiment, the engine is, for example, a horizontally opposed four-cylinder direct injection gasoline engine, but the cylinder layout, the number of cylinders, etc. are not particularly limited.

FIG. 1 is a diagram showing a schematic configuration of an engine having a catalyst temperature estimation device according to an embodiment.
The engine 1 is configured with a crankshaft 10, a cylinder block 20 (20R, 20L), a cylinder head 30 (30R, 30L), an intake system 40, an exhaust system 50, an EGR device 60, an engine control unit (ECU) 100, etc.

The crankshaft 10 is a rotating shaft that serves as the output shaft of the engine 1 .
One end of the crankshaft 10 is connected to a power transmission mechanism such as a transmission (not shown).
A crank pin is formed on the crankshaft 10 and is disposed eccentrically from the rotation axis of the crankshaft 10. A piston (not shown) is connected to the crank pin via a connecting rod (not shown).
A crank angle sensor 11 is provided at the end of the crankshaft 10 to detect the angular position of the crankshaft.
The output of the crank angle sensor 11 is transmitted to the engine control unit 100 .
The engine control unit 100 calculates the engine speed (crankshaft rotation speed) based on the output of the crank angle sensor 11 .
When starting the engine 1, the engine speed at a predetermined timing (for example, two cycles after) after the start of driving (cranking) of the crankshaft 10 by the starter motor 111 described later can be used as an indicator of the average angular acceleration of the crankshaft 10 in two cycles after the start of cranking.
The crank angle sensor 11 functions as an angular acceleration detector of the present invention.

The cylinder block 20 is divided into two parts, a right cylinder block 20R and a left cylinder block 20L, so that the crankshaft 10 is sandwiched between them in the left and right direction when the crankshaft 10 is mounted longitudinally on the vehicle body.
A crankcase portion is provided in the center of the cylinder block 20 .
The crankcase portion is a space portion that accommodates the crankshaft 10 .
The crankcase portion is provided with a main bearing that rotatably supports the journal portion of the crankshaft 10 .
The right cylinder block 20R and the left cylinder block 20L are arranged on either side of the crankcase section, and each block has, for example, two cylinders (in the case of four cylinders) into which pistons (not shown) are inserted and which reciprocate inside.

The cylinder block 20 is provided with a water temperature sensor 21 .
The water temperature sensor 21 is a temperature sensor that detects the temperature of the cooling water that cools the engine 1.
The output of the water temperature sensor 21 is transmitted to the engine control unit 100 .

The cylinder heads 30 (right cylinder head 30R, left cylinder head 30L) are provided at the ends (left and right ends) of the cylinder block 20 opposite the crankshaft 10, respectively.
The cylinder head 30 is configured to include a combustion chamber 31, an ignition plug 32, an intake port 33, an exhaust port 34, an intake valve 35, an exhaust valve 36, an intake camshaft 37, an exhaust camshaft 38, an injector 39, etc.
The combustion chamber 31 is formed by recessing a portion of the cylinder head 30 facing the piston crown surface, for example, in a pent roof shape.
The spark plug 32 generates a spark in response to an ignition signal from the engine control unit 100 to ignite the air-fuel mixture.
The spark plug 32 is provided in the center of the combustion chamber 31 when viewed in the axial direction of the cylinder.

The intake port 33 is a flow path that introduces combustion air (fresh air) into the combustion chamber 31 .
The exhaust port 34 is a flow path for discharging burned gas (exhaust gas) from the combustion chamber 31 .
The intake valve 35 and the exhaust valve 36 open and close the intake port 33 and the exhaust port 34 at predetermined valve timing.
For example, two intake valves 35 and two exhaust valves 36 are provided for each cylinder.
The intake valve 35 and the exhaust valve 36 are opened and closed by an intake camshaft 37 and an exhaust camshaft 38 which rotate in synchronization with each other at half the rotation speed of the crankshaft 10 .
The cam sprocket portions of the intake camshaft 37 and the exhaust camshaft 38 are provided with variable valve timing mechanisms (not shown) that advance or retard the phase of each camshaft to change the opening and closing timing of each valve.
The injector 39 is a fuel injection unit that injects fuel into the combustion chamber 31 to form an air-fuel mixture in response to a valve-opening signal issued by the engine control unit 100 .
The injector 39 is provided so that a nozzle portion for injecting fuel is exposed inside the cylinder from an area on the intake port 33 side of the inner surface of the combustion chamber 31 .

The intake system 40 is an intake device that introduces air into the intake port 33 .
The intake system 40 includes an intake duct 41, a chamber 42, an air cleaner 43, an air flow meter 44, a throttle valve 45, an intake manifold 46, an intake pressure sensor 47, and the like.

The intake duct 41 is a flow path that introduces outside air into the intake port 33 .
The chamber 42 is a space provided in communication with the vicinity of the inlet of the intake duct 41 .
The air cleaner 43 filters the air to remove dust and other particles.
The air cleaner 43 is provided downstream of the point where the intake duct 41 communicates with the chamber 42 .
The air flow meter 44 measures the flow rate of air passing through the intake duct 41 (the amount of intake air of the engine 1).
The air flow meter 44 is provided near the outlet of the air cleaner 43 .
The output of the air flow meter 44 is transmitted to the engine control unit 100 .

The throttle valve 45 is a butterfly valve that adjusts the flow rate of air to control the output of the engine 1 .
The throttle valve 45 is provided in the intake duct 41 near the connection with the intake manifold 46 .
The throttle valve 45 is driven to open and close by an electric throttle actuator (not shown) in accordance with a target throttle opening degree set by the engine control unit 100 in accordance with the driver's required torque and the like.
The throttle valve 45 is also provided with a throttle sensor that detects the opening of the throttle valve 45, and the output of the throttle sensor is transmitted to the engine control unit 100.
The intake manifold 46 is a branch pipe that distributes air to the intake ports 33 of each cylinder.
The intake manifold 46 is provided downstream of the throttle valve 45 .
The intake pressure sensor 47 detects the pressure of the air in the intake manifold 46 (intake pressure).
The output of the intake pressure sensor 47 is transmitted to the engine control unit 100 .

The exhaust system 50 is an exhaust device that discharges exhaust gases (exhaust gases) discharged from the exhaust ports 34 to the outside.
The exhaust system 50 includes an exhaust manifold 51, an exhaust pipe 52, a catalytic converter 53, a _NOx trap catalyst 54, an air-fuel ratio sensor 55, and the like.

The exhaust manifold 51 is a collecting pipe that collects the exhaust gases emitted from the exhaust ports 34 of the cylinders.
The exhaust pipe 52 is a pipe (exhaust flow path) that discharges the exhaust gas from the exhaust manifold 51 to the outside.
The catalytic converter 53 is provided in the middle of the exhaust pipe 52 and includes a three-way catalyst that purifies HC, _NOx , CO, and the like in the exhaust gas.
A three-way catalyst is a catalyst in which a precious metal such as platinum, rhodium, or palladium is supported on a carrier such as alumina, and performs purification functions when the air-fuel ratio of the engine 1 is in the range close to stoichiometric (theoretical air-fuel ratio).
The catalytic converter 53 is provided in a region of the exhaust pipe 52 adjacent to the outlet of the exhaust manifold 51 .

The _NOx trap catalyst 54 is a NOx storage reduction catalyst that temporarily traps (stores) _NOx in the exhaust gas during lean operation when there is an excess of air (λ>1) relative to the active range of the three-way catalyst, and reduces it (to _N2 ) during rich operation.
The _NOx trap catalyst 54 is provided in the exhaust pipe 52 in a region downstream of the catalytic converter 53 .

The air-fuel ratio sensor (A/F sensor) 55 is provided in the exhaust pipe 52 near the inlet of the catalytic converter 53, and detects the λ value (excess air ratio) which correlates with the amount of oxygen in the exhaust gas passing through that location by generating a voltage corresponding to the amount of oxygen in the exhaust gas.
When the actual intake air volume of the engine is L and the theoretically required minimum air volume is _L0 ,
It is expressed as λ=L/ _L0 .
The λ value can be used as an index showing the amount of oxygen remaining in the exhaust gas.
As the air-fuel ratio sensor 55, for example, a wideband sensor that combines a limited current type lean sensor and a zirconia sensor can be used.

The EGR device 60 performs exhaust gas recirculation (EGR) by extracting a portion of the exhaust gas from the exhaust manifold 51 as EGR gas and introducing it into the intake manifold 46 .
The EGR device 60 includes an EGR passage 61, an EGR cooler 62, an EGR valve 63, and the like.
The EGR passage 61 is a pipe that introduces exhaust gas (EGR gas) from the exhaust manifold 51 to the intake manifold 46 .
The EGR cooler 62 cools the EGR gas flowing through the EGR passage 61 by heat exchange with the cooling water of the engine 1 .
The EGR cooler 62 is provided midway along the EGR passage 61 .
The EGR valve 63 is a regulating valve that adjusts the flow rate of EGR gas passing through the EGR passage 61 .
The EGR valve 63 is provided in the EGR passage 61 downstream of the EGR cooler 62 .
The EGR valve 63 has a valve body that is driven to open and close by an electric actuator such as a solenoid, and its opening is controlled by the engine control unit 100 using an opening map set based on a predetermined target EGR rate (EGR gas flow rate/intake air flow rate).

The engine control unit (ECU) 100 is an engine control device that controls the engine 1 and its accessories in an integrated manner.
The engine control unit 100 is configured to include an information processing means such as a CPU, storage means such as a RAM and a ROM, an input/output interface, and a bus connecting these.
The engine control unit 100 is also provided with an accelerator pedal sensor 101 that detects the amount of depression of an accelerator pedal (not shown) by the driver.

The engine control unit 100 has a function of setting a driver-requested torque based on the output of the accelerator pedal sensor 101 and the like.
The engine control unit 100 controls the throttle valve opening, boost pressure, fuel injection amount, fuel injection timing, ignition timing, valve timing, etc. so that the torque actually generated by the engine 1 approaches the set driver requested torque.
During steady-state operation after the engine 1 has been started and has completed warming up, the engine control unit 100 performs air-fuel ratio feedback control to control the fuel injection amount so that the air-fuel ratio is within a predetermined target air-fuel ratio range (for example, within the activation range of the three-way catalyst (stoichiometry) or a predetermined lean air-fuel ratio range).
Furthermore, when the engine 1 is cold started, the engine control unit 100 performs a starting fuel injection amount setting (increase correction) as described below in order to ensure startability.

FIG. 2 is a block diagram showing a configuration related to setting of a fuel injection amount at startup in the engine control device according to the embodiment.
The engine control device 100 has a function of controlling a starting device 110 that starts the engine 1 .
The starting device 110 includes a starter motor 111, a starter relay 112, and the like.
The starter motor 111 is an electric motor that rotates (cranks) the crankshaft 10 using electric power supplied from a battery 120 .
The starter motor 111 can be configured, for example, to drive the outer edge of a flywheel attached to the end of the crankshaft 10 via a reduction gear, but is not limited to this. For example, an integrated starter generator (ISG) connected to the crankshaft 10 via a belt and pulley and having the function of generating electricity when the engine 1 is operating may also be used.
The starter relay 112 is a relay that switches between a power-on state in which power is supplied from the battery 120 to the starter motor 111 and a power-off state in which power is cut off in response to a command from the engine control device 100 .

The battery 120 is a secondary battery having a rated voltage of, for example, 12V or 48V, which supplies power to the electrical components of the vehicle.
A voltage sensor 121 that detects the output voltage of the battery 120 is provided in a circuit that supplies power from the battery 120 to the starter relay 112 .
The detected value of the voltage sensor 121 is transmitted to the engine control unit 100 .

Hereinafter, the fuel injection increase control at the time of starting a cold (unwarmed) engine in the engine control device of the embodiment will be described.
FIG. 3 is a flowchart showing an outline of fuel injection increase control at engine start in the engine control device of the embodiment.
Each step will be explained in order below.

<Step S01: Water Temperature Sensor Failure Determination>
The engine control unit 100 uses known on-board diagnostic techniques to determine whether there is an abnormality in the water temperature sensor 21 or its wiring (such as a sensor failure or a broken wire).
For example, if the output voltage of the water temperature sensor 21 is not within a predetermined normal range, it is determined that an abnormality (failure) has occurred in the water temperature sensor 21.
If an abnormality (failure) has occurred in the water temperature sensor 21, the process proceeds to step S03, and otherwise the process proceeds to step S02.

<Step S02: Setting fuel injection amount at startup based on water temperature sensor output>
The engine control unit 100 sets the startup fuel injection amount, which is the fuel injection amount to be applied after cranking has started and before air-fuel ratio feedback control is started, based on the output of the water temperature sensor 21.
When the pressure of the fuel supplied to the injector 39 at the time of starting is constant, the fuel injection amount can be controlled by the pulse width of the fuel injection signal (which correlates with the valve opening time). The fuel injection amount at the time of starting can be set as the pulse width of the fuel injection signal.
Specifically, as the cooling water temperature detected by the water temperature sensor 21 becomes lower, the amount of fuel injected at startup is increased (the pulse width is widened and the injection time is extended) to accommodate increased friction due to, for example, increased viscosity of the lubricating oil.
Then, proceed to step S05.

<Step S03: Obtaining rotation speed and voltage two cycles after cranking starts>
Based on the output of the crank angle sensor 11, the engine control unit 100 obtains the timing at which the crankshaft 10 rotates four times (two cycles elapse in each cylinder) after the starter motor 101 starts cranking the crankshaft 10.
Then, the rotation speed of the crankshaft 10 (so-called engine speed) after two cycles have elapsed is detected.
The rotational speed of the crankshaft 10 after two cycles has elapsed is used as a parameter indicating the average angular acceleration of the crankshaft 10 during two cycles after the start of cranking.
Furthermore, the engine control unit 100 detects the output voltage of the battery 120 immediately after cranking starts, using the voltage sensor 121 .

FIG. 4 is a diagram showing an example of changes in the battery voltage and engine speed during engine start-up in a state where the water temperature sensor of an engine having the engine control device of the embodiment has failed.
In FIG. 4, the horizontal axis represents time, and the vertical axis represents the output voltage of the battery 120 and the engine speed (the rotational speed of the crankshaft 10).
The battery voltage 120 drops when cranking starts and then gradually recovers.
Furthermore, the engine speed increases when cranking starts, but is lower than the target idle speed (for example, about 500 to 600 rpm).
After that, when fuel injection begins and ignition (explosion) occurs, the engine speed increases rapidly and once exceeds (overshoots) the target idle speed, after which it converges to the idle speed by feedback control of the intake air amount, etc.
In this embodiment, the rotation speed and voltage are acquired two cycles after the start of cranking, which is immediately before the start of fuel injection.
After acquiring the rotation speed and voltage, the process proceeds to step S04.

<Step S04: Setting fuel injection amount at startup from rotation speed-voltage map>
The engine control unit 100 sets the fuel injection amount at startup using a rotation speed-voltage map that is prepared in advance and stored in a memory unit.
The rotation speed-voltage map is a three-dimensional map from which the rotation speed (rotation speed) of the crankshaft 10 and the output voltage of the battery 120 are input and the fuel injection amount at startup is read out.
For example, when the output voltage of the battery 120 is constant, the lower the temperature of the engine 1, the more friction there is and the lower the rotation speed becomes.
For this reason, the fuel injection amount at startup is set to increase in accordance with a decrease in rotation speed so as to obtain torque that resists the increasing friction.
On the other hand, if the temperature of the engine 1 is constant, that is, the friction is constant, the higher the output voltage of the battery 120, the greater the torque of the starter motor and the higher the rotation speed.
For this reason, the fuel injection amount at startup for a certain engine speed is set to tend to increase as the output voltage of the battery 120 increases (the fact that a higher voltage is required to achieve the same engine speed means that friction is greater).
After setting the fuel injection amount at startup, the process proceeds to step S05.

<Step S05: Start of fuel injection>
The engine control unit 100 uses the startup fuel injection amount set in step S02 or step S04 to issue an injection command (injection pulse signal) to the injector 39 to start fuel injection.
Then, the series of processes ends.
Once the engine 1 is determined to have completely exploded (for example, when the engine speed is equal to or greater than a predetermined threshold) and the sensors and catalysts reach their activation temperatures, the control of the fuel injection amount shifts to normal air-fuel ratio feedback control.

According to the present embodiment described above, the following effects can be obtained.
(1) The engine speed, which indicates the average angular acceleration of the crankshaft 10 for two cycles after the starter motor 111 starts rotating the output shaft, allows the friction of the engine 1, which fluctuates in accordance with changes in temperature, to be determined.
Furthermore, since the driving force of the starter motor 111 varies depending on the output voltage of the battery 120, by detecting the output voltage of the battery 120, it is possible to grasp the friction more accurately.
By setting (increasing) the fuel injection amount at startup according to the friction of the engine 1 thus determined, the startability of the engine 1 can be ensured without depending on the detection value of the water temperature sensor.
(2) When the output voltage of the battery 120 is the same, the amount of fuel injected at startup is increased in accordance with a decrease in the engine speed, so that when friction in the engine 1 increases, for example, at low temperatures, the amount of fuel injected at startup can be increased to ensure the startability of the engine 1.
(3) By setting the startup fuel injection amount based on the engine speed (indicating the average angular acceleration of two cycles after startup) detected at the timing when the cumulative number of rotations of the crankshaft is two cycles after the starter motor 111 starts rotating the crankshaft 10, it is possible to appropriately set the startup fuel injection amount even in a short period of time, thereby speeding up engine startup and improving the marketability of the vehicle.
(4) When the water temperature sensor 21 is normal, the amount of fuel injected at startup is set according to the cooling water temperature detected by the water temperature sensor 21, thereby advancing the timing of initial combustion at engine startup and completing the startup of the engine 1 earlier.
On the other hand, even if an abnormality occurs in the water temperature sensor 21, the startability of the engine 1 can be ensured and a situation in which it cannot be started can be avoided by setting the amount of fuel injection at startup based on the angular velocity of the crankshaft 10 and the voltage of the battery 120.

(Modification)
The present invention is not limited to the above-described embodiment, and various modifications and variations are possible, and these are also within the technical scope of the present invention.
(1) The configurations of the engine control device, the engine, the vehicle in which the engine is mounted, etc. are not limited to those in the above-described embodiment, and may be modified as appropriate.
For example, the engine cylinder layout, the number of cylinders, whether or not supercharging is performed, the fuel injection method, the configuration of other auxiliary equipment, etc. can be changed as appropriate.
(2) In the embodiment, the rotational speed (rotational velocity) of the crankshaft during two cycles after the start of rotational driving is used as an index indicating the angular acceleration of the crankshaft, but this is not limiting and the angular acceleration of the output shaft (or an index indicating the angular acceleration) may be obtained by other methods. For example, the rotational angular position of the output shaft may be acquired at a predetermined sampling period, and the angular acceleration may be obtained by differentiating the angular position twice with respect to time.
Furthermore, the timing for obtaining the angular acceleration for setting the fuel injection amount at startup is not limited to two cycles after the start of driving, and can be changed as appropriate.

1 Engine 10 Crankshaft 11 Crank angle sensor 20 Cylinder block 20R Right cylinder block 20L Left cylinder block 21 Water temperature sensor 30 Cylinder head 30R Right cylinder head 30L Left cylinder head 31 Combustion chamber 32 Spark plug 33 Intake port 34 Exhaust port 35 Intake valve 36 Exhaust valve 37 Intake camshaft 38 Exhaust camshaft 39 Injector 40 Intake system 41 Intake duct 42 Chamber 43 Air cleaner 44 Air flow meter 45 Throttle valve 46 Intake manifold 47 Intake pressure sensor 50 Exhaust system 51 Exhaust manifold 52 Exhaust pipe 53 Catalytic converter 54 NOx trap catalyst 55 Air-fuel ratio sensor 60 EGR device 61 EGR flow path 62 EGR cooler 63 EGR valve 100 Engine control unit (ECU)
110 Starting device 111 Starter motor 112 Starter relay 120 Battery 121 Voltage sensor

Claims (2)

a starter motor that rotates and drives the output shaft at start-up;
a power supply that supplies power to the starter motor;
An engine control device for controlling an engine having a fuel injection device that injects fuel into at least one of a combustion chamber and an intake port,
a voltage detection unit that detects the voltage of the power supply;
a rotation speed detection unit that detects the rotation speed of the output shaft;
a fuel injection amount setting unit that sets a startup fuel injection amount of the fuel injection device based on the rotation speed detected at a timing when the cumulative rotation number of the output shaft is two cycles or less after the starter motor starts to rotate the output shaft, and the voltage ,
the fuel injection amount setting unit sets the startup fuel injection amount so that the startup fuel injection amount increases in accordance with a decrease in the rotation speed and so that the startup fuel injection amount increases as the voltage increases . a water temperature sensor for detecting a cooling water temperature of the engine;
a water temperature sensor abnormality detection unit that detects an abnormality in the water temperature sensor,
2. The engine control device according to claim 1, wherein the fuel injection amount setting unit sets the startup fuel injection amount based on the cooling water temperature detected by the water temperature sensor when the water temperature sensor is normal, and sets the startup fuel injection amount based on the rotation speed and the voltage when the water temperature sensor is abnormal .