JPH01280661A - Atmospheric pressure detecting device for control of engine - Google Patents

Abstract

PURPOSE:To perform simple and accurate detection of an atmospheric pressure, by a method wherein when a throttle opening and the number of revolutions of an engine are within an atmospheric pressure detection zone for a given time in succession, a set value is added to the pressure in a suction passage to compute the atmospheric pressure value. CONSTITUTION:The opening of a throttle valve 5 to limit an amount of intake air to an engine 1 is detected by a sensor 5A. A pressure in a suction passage 2 on the downstream side of a throttle valve 5 is detected by a sensor 6. Further, the number of revolutions of an engine 1 is detected by a sensor, not shown. Detecting signals from sensors 5A and 6 are inputted to a control device 13. In this case, the control device 13 detects that an input signal pair therefrom is within an atmospheric pressure detection zone, set based on a throttle opening, at which the pressure loss of the suction passage 2 is reduced to a value lower than a given value, and the number of revolutions of an engine, for up to a given time in succession. According to an in-zone detecting resulting, a set value is added to a pressure signal to compute an atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an atmospheric pressure detection device for engine control that can detect atmospheric pressure without using an atmospheric pressure sensor.

[Conventional technology]

Conventionally, engine operating characteristic quantities have been electronically controlled based on parameters such as engine speed, intake manifold pressure, throttle opening, and atmospheric pressure. The intake manifold pressure in the intake passage downstream from the throttle valve, which is linked to the accelerator pedal and limits the amount of air taken into the engine, is detected as an absolute pressure by a pressure sensor.

Furthermore, atmospheric pressure has been detected by an atmospheric pressure sensor provided separately from the pressure sensor described above.

[Problem to be solved by the invention]

Since the conventional atmospheric pressure detection device for engine control is configured as described above, there have been problems such as the device itself being expensive because the atmospheric pressure sensor is provided separately from the pressure sensor.

This invention was made in order to solve the above-mentioned problems, and specifically aims to provide an atmospheric pressure detection device for engine control that can accurately detect atmospheric pressure with an inexpensive configuration without using an atmospheric pressure sensor. do.

[Means to solve the problem]

The atmospheric pressure detection device for engine control according to the present invention includes a throttle opening sensor, a pressure sensor that detects the intake manifold pressure as an absolute pressure, a rotation speed detection means, and a throttle opening sensor that detects the throttle opening degree and the engine rotation speed. an in-zone timer means for detecting that B remains within a predetermined atmospheric pressure detection zone for a predetermined period of time or longer; and an arithmetic means for calculating an atmospheric pressure value by adding a set value to a pressure signal when the in-zone timer means detects the in-zone timer means. It has been established.

[For production]

The atmospheric pressure detection device for engine control according to the present invention uses an in-zone timer means to detect that the throttle opening and the engine rotational speed are within the atmospheric pressure detection zone where the pressure loss is small and the detection error is small for a predetermined continuous time or more. When the detection also detects that the intake manifold pressure has shifted from the transient state to the stable state, the calculating means calculates the atmospheric pressure value from the pressure signal of the pressure sensor and the set value.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows one embodiment of the present invention, and in the figure, 1 is a well-known engine mounted on a vehicle, 21 is an intake manifold of the engine 1, and 2A is an intake manifold 2.
3 is an air cleaner installed at the entrance of the intake pipe body 2A, and 4 is an injector that injects fuel into the intake pipe body 2A. . 5 is the intake pipe body 2
The throttle valve 5A is provided in A and controls the opening of the intake passage to limit the intake air amount to the engine 1. 5A is interlocked with the throttle valve 5 and has an analog voltage corresponding to the opening of the throttle valve 5. For example, a potentiometer-type throttle opening sensor 6 is installed in the intake pipe body 2A on the downstream side from the throttle valve 5, and detects the intake manifold pressure P as an absolute pressure, and outputs a magnitude corresponding to the detected pressure. This is a pressure sensor that outputs a pressure signal. Also, 7 is engine 1
8 is an exhaust manifold of engine 1; 9 is an air-fuel ratio sensor; 10 is a three-way catalytic converter; 11 is a supply of high voltage to the spark plug (not shown) of engine 1; An ignition coil 12 is an igniter for energizing the ignition coil 11.

Step 13: Input various parameters obtained by detecting each state of the engine 1, perform various judgments and calculations based on these parameters, and calculate atmospheric pressure values representing atmospheric pressure, fuel injection amount, etc. This is a control device that performs control accordingly.

Next, the internal configuration of the control device 13 and the like will be described in detail with reference to FIGS. 2 and 3. In Figure 2, 1
00 is a microcomputer, which includes a CPU 200, a counter 201, and an engine 1 that execute the flow shown in FIG.
an A/D converter 203 that converts an analog signal into a digital signal, an input port 2o4 that inputs and transmits a digital signal, a nonvolatile RAM 205 that functions as a work memory, etc. 3
The flow shown in the figure is stored in a program, and the lower limit value θA (N,) of the atmospheric pressure detection zone, which will be described later, is set to the engine rotational speed (N
ROM 206 which stores throttle opening value in correspondence with E) and other calculation data such as setting values for correcting pressure loss described later and comparison judgment data, and the calculated fuel injection amount. Output boat 207 for outputting etc.
, a common bus 208 that commonly connects each of the above components.

Reference numeral 101 is connected to the connection between the primary coil terminal of the ignition coil 11 and the collector of the switching transistor of the igniter 12, and is used for inputting an ignition signal to the microcomputer 100 to detect, for example, the engine speed. Interface circuit, 102, throttle opening sensor 5A.

A second manual interface circuit 103 is for sequentially introducing analog output signals from the pressure sensor 6, cooling water temperature sensor 7, and air-fuel ratio sensor 9 into the A/D converter 203; This is a one-person interface circuit. Reference numeral 104 denotes an output interface circuit which converts the fuel injection amount outputted from the output coupler 1-207 into a time-width pulse and outputs it to the injector 4. ] 05 connects the e of the battery 15 whose e side is grounded via the key switch 14.
A second power supply circuit 106 is connected to the e side of the battery 15 and constantly supplies power to the RAM 205.

In FIG. 4, the horizontal axis shows the engine rotational speed NE, the vertical axis shows the throttle opening θ, and the range of the atmospheric pressure detection zone is shown by diagonal lines -C. Lower limit value θA (NE
) is shown as the value of the throttle opening θ corresponding to the engine speed NE, and increases as the engine speed N increases, and the throttle opening value corresponding to the engine speed NE is mapped in advance in the ROM 206. Stored. In this atmospheric pressure detection zone, when the throttle opening is fully open, for example, 80°, the lower limit value of the atmospheric pressure detection zone θA (NE)
The pressure loss in the intake passage on the downstream side from the throttle valve 5 is ΔPA shown in FIG.
This is a zone with low pressure loss, which is less than (mmtlg).

In FIG. 5, the horizontal axis shows the engine speed N5, and the vertical axis shows the pressure loss ΔP8 in the intake system. When the pressure loss ΔP8 is 0, the intake manifold pressure P is equal to atmospheric pressure. The throttle opening θ is the lower limit value θA of the atmospheric pressure detection zone (
When it is at N, ), it is a straight line, and the pressure loss △P is as shown in
8-△ is constant. This ΔP is multiplied by 8×1 to a set value for correcting the pressure loss in the intake passage downstream from the throttle valve 5, and is stored in the ROM 206 in advance. When the throttle opening degree θ is fully open, the pressure loss ΔP8 increases from a value close to 0 as the engine speed NE increases and approaches the pressure loss ΔPA, as shown by a curve L2. When the throttle opening corresponds to the engine speed within the atmospheric pressure detection zone, the pressure loss is within the zone between the straight line L1 and the curve L2.

Next, the operations executed by the CPU 200 in the microcomputer 100 will be explained.

First, when the key switch 14 is turned on, the battery 15
A voltage is applied to the first power supply circuit 105. The first power supply circuit 105 applies a constant voltage to the microcomputer 100, and the control device 13 starts operating. Upon this start of operation, an interrupt is generated at regular intervals, and the flow of the interrupt routine shown in FIG. 3 is repeatedly executed.

First, in step 300, the rotation speed N6 of the engine 1 is calculated based on the measurement data of the timer 202 that measures the rotation period of the engine, and is stored in the RAM 205.

The timer 202 measures the time from the previous ignition to the current ignition by inputting the ignition signal generated when the igniter 12 changes from on to off from the igniter 12 via the first human interface circuit 101. Measured as engine rotation period. This measured value is stored in the RAM 205 in a separate routine. Next, in step 301, a pressure signal representing the intake manifold P is read from the pressure sensor 6 via the second human power interface circuit 102 and the A/D conversion N2O3, and similarly, a pressure signal representing the intake manifold P is read from the throttle opening sensor 5A. A throttle opening signal representing θ is read and stored in the RAM 205.

Next, in step 302, the volumetric efficiency CE V of the engine 1 determined by the intake manifold pressure P and the engine speed NE is calculated. Next, in step 303, the basic pulse width TPuo of the basic fuel injection amount is set to TPuo.
-K (coefficient) xpxc, calculated using the equation of V. Next, in step 304, whether or not the air-fuel ratio sensor 9 is in an active state, that is, whether the output signal of the air-fuel ratio sensor 9 changes within a predetermined time (or whether the cooling water temperature detected by the cooling water temperature sensor 7 WT level), etc., it is determined whether the air-fuel ratio feedback condition is satisfied.

When the feedback condition is satisfied in step 304, the process proceeds to step 305, and the feedback correction term C of the fuel injection time is performed by comparison-integral control according to the output of the air-fuel ratio sensor 9.
Perform FB calculation. On the other hand, if it is determined in step 304 that the feedback condition is not satisfied, step 3
Proceeding to step 06, the correction term CF8 is set to 1.

Step 30 follows the process of step 305 or 306.
7, and in this step, the throttle opening θ of the throttle opening signal read from the RAM 205 corresponds to the engine rotation speed N6 of the rotation speed signal read from the RAM 205, and the lower limit value of the atmospheric pressure detection zone is read as a signal from the ROM 206. It is determined whether the pressure is greater than or equal to θA(N,), that is, whether it is within the atmospheric pressure detection zone.

If it is determined in step 307 that θ<θ (N) and outside the atmospheric pressure detection zone, the process proceeds to step 308;
The evening/ima TM by the counter 201 is reset to 0. On the other hand, if it is determined in step 307 that θ≧θA(NE) and the throttle opening θ when the engine speed is N is within the atmospheric pressure detection zone, the process proceeds to step 309, and the counter 201 is counted for a certain period of time. The timer TM is counted up and the process then proceeds to the next step 310.

In step 310, the timer TM, which is the count value of the counter 201, is read, and it is determined whether TM is greater than or equal to the predetermined value TMo read from the ROM 206, that is, the continuous time when the throttle opening θ and the engine speed NE are within the atmospheric pressure detection zone. It is determined whether a predetermined period of time has elapsed. The timer value TM is a predetermined value TM.

If it is above, it is assumed that the intake manifold pressure P in the atmospheric pressure detection zone has become stable, and the process proceeds from step 310 to step 311. In this step, the intake manifold pressure P and the pressure loss Δ at the lower limit of the atmospheric pressure detection zone are An atmospheric pressure value representing the determined atmospheric pressure is calculated and stored in the RAM 205. This calculation formula is P, -P+Δ×7, and the pressure signal representing P is read from the RAM 205, and the set value representing ΔPAX T is read from the ROM 206.

After the processing in step 308, in step 310 the TM
After determining that TMo is true or after the processing in step 311, the process proceeds to step 312. Step 3
12, the basic pulse width TPuo is multiplied by the correction term CF to obtain the fuel injection pulse width Tp.

Calculate and proceed to the next step.

Note that the pressure loss Δ may be changed depending on the engine speed, and the lower limit value θA(N,
, ) may be a function using the engine speed as a variable, and in this case, θA(N,) can be calculated by the function.

〔Effect of the invention〕

As described above, according to the present invention, it is detected that the continuous time when the intake manifold pressure and engine speed are within the atmospheric pressure detection zone has exceeded a predetermined time, and this detection stabilizes the intake manifold pressure. Since the configuration is configured to detect atmospheric pressure by adding a set value to the pressure signal from the pressure sensor, it is possible to improve atmospheric pressure detection accuracy by not detecting atmospheric pressure during transient conditions of intake manifold pressure. This has the advantage that an inexpensive structure can be obtained since there is no need to use a separate atmospheric pressure sensor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the entire device according to an embodiment of the present invention;
FIG. 2 is a block diagram showing the configuration of the control device etc. in FIG. 1, FIG. 3 is a flow diagram showing the operation flow of the CPU in the control device, FIG. 4 is an explanatory diagram showing the atmospheric pressure detection zone, FIG. 5 is an explanatory diagram showing the relationship between engine speed and intake system pressure loss using throttle opening as a parameter. In the diagram, 1 engine, 2 intake manifold, 2
A... Intake pipe body, 5 - Throttle valve, 5A Throttle opening sensor, 6... Pressure sensor, 11... Ignition coil, 12... Igniter, 13... Control device, 14
Key switch, 15 Battery, 100 ・Microcomputer, 101, 102 1st. 2nd Kaintafu Chair Circuit, 105#106-・1st. Second power supply circuit.

Claims (1)

[Claims] a throttle opening sensor that detects the opening of a throttle valve that limits the amount of intake air to the engine; a pressure sensor that detects the intake manifold pressure in the intake passage downstream from the throttle valve as an absolute pressure; and a rotational speed of the engine. A throttle opening signal from the throttle opening sensor and an engine rotational speed signal from the rotation speed detecting means are input, and the throttle opening is adjusted so that the pressure loss in the intake passage becomes equal to or less than a predetermined value. an in-zone timer means for detecting that the continuous time when the input signal pair is present within an atmospheric pressure detection zone defined by the temperature and the engine rotational speed has reached a predetermined time or more; An atmospheric pressure detection device for engine control, comprising a calculation means for calculating an atmospheric pressure value by receiving a detection signal and adding a set value to the pressure signal from the pressure sensor.