Measuring and testing – Vehicle chassis – Steering
Reexamination Certificate
2002-02-08
2003-07-29
Cuneo, Kamand (Department: 2855)
Measuring and testing
Vehicle chassis
Steering
C073S117020
Reexamination Certificate
active
06598469
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an operating state detecting method for internal combustion engines for determining whether an internal combustion engine is being accelerated and/or whether it is being decelerated, and an operating state detecting apparatus for implementing this detecting method.
BACKGROUND OF THE INVENTION
In controlling an internal combustion engine, it is often necessary to determine whether the engine is being accelerated or decelerated. For instance, where an electronic fuel injection (EFI) device is used for feeding fuel to an internal combustion engine, it is determined whether the engine is being accelerated or decelerated, and the finding is taken into consideration in determining the quantity of fuel to be injected.
The EFI device is comprised of an electromagnetic fuel injection valve (injector) for injecting fuel into an air intake pipe or a cylinder of the engine, a fuel pump for feeding fuel to the injector, a pressure regulator for keeping the pressure of fuel fed to the injector substantially constant, and an electronic control unit (ECU) for controlling the injector so that it may inject a predetermined quantity of fuel when the internal combustion engine is at a predetermined position of rotational angle.
The ECU, provided with injection quantity operating means for arithmetically operating the fuel injection quantity on the basis of various control conditions such as the atmospheric pressure and the engine temperature and a drive circuit for supplying a drive signal to the injector so that the injector injects the arithmetically operated quantity of fuel, controls the injector so that a mixture in a predetermined air/fuel ratio is supplied into each cylinder of the engine according to various control conditions.
In order to determine the quantity of fuel to be injected by the injector, a fuel injection device of this kind needs knowledge of the quantity of air having flowed into each cylinder of the engine. One of known ways to determine the quantity of air having flowed into each cylinder is to estimate it from the (negative) pressure in the air intake pipe and the volume efficiency of the engine.
In an internal combustion engine wherein the fuel injection quantity is determined on the basis of the estimated quantity of air having flowed into each cylinder from the pressure in the air intake pipe and the volume efficiency of the engine, when the engine is being accelerated or decelerated, the air/fuel ratio of the mixture may be made leaner or richer by a delay in response. Thus, when a driver abruptly opens a throttle valve to accelerate the engine, since a delay is occurred by the time that the estimated quantity of air flowing into each cylinder is corrected by means of detecting a pressure variation in the air intake pipe ensuring from the variation in the opening degree of the throttle valve, the quantity of fuel injection arithmetically operated by the ECU tends to be smaller than the quantity of injection actually required by the engine and accordingly the air/fuel mixture becomes too lean. Meanwhile, when the driver abruptly closes the throttle valve to decelerate the engine, a similar delay in response makes the quantity of air/fuel mixture arithmetically operated by the ECU tends to be greater than the quantity of air/fuel mixture actually required by the engine and accordingly the air/fuel mixture becomes too rich. For this reason, if the quantity of fuel injection is controlled with no allowance for the delay in response at the time of accelerating or decelerating the engine, the exhaust gas composition may deteriorate, and so may deteriorate the operating performance of the engine, at the time of accelerating or decelerating the engine.
In order to solve the problem noted above, an electronic fuel injection device may be provided with means for detecting an accelerating state and a decelerating state of an engine and, when either of these states is detected, prevent the exhaust gas composition or the operating performance of the engine from deteriorating at the time of acceleration or deceleration by correcting the quantity of fuel injection arithmetically operated on the basis of the estimated quantity of air flowing into each cylinder and thereby keeping the air/fuel ratio within an appropriate range.
Control taking into account the states of acceleration or deceleration of an engine may be carried out not only when the quantity of fuel injection into the engine is to be controlled but also when, for instance, the ignition timing of the engine is to be controlled to improve the accelerating performance or the exhaust composition of the engine.
A fuel injection device according to the prior art comprises a throttle position sensor to detect the opening degree of the throttle valve. The fuel injection device determines that the engine is being accelerated when the variation of the opening degree of the throttle valve by a predetermined quantity in the accelerating direction in a predetermined length of time is detected and determines that the engine is being decelerated when the variation of the opening degree of the throttle valve by a predetermined quantity in the decelerating direction in a predetermined length of time is detected.
Since the internal combustion engine according to the prior art detects the accelerating state or the deteriorating state of the engine from any variation in the opening degree of the throttle as described above, it requires a throttle position sensor and inevitably a corresponding increase in cost.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an operating state detecting method and apparatus for internal combustion engines whereby it can be determined, without a throttle position sensor, whether an internal combustion engine is being accelerated and/or whether it is being decelerated from any variation in pressure within an air intake pipe.
The present invention provides an operating state detecting method for internal combustion engines for determining whether an internal combustion engine is being accelerated or decelerated. According to the present invention, a plurality of rotational angle positions of a crankshaft of an internal combustion engine are predetermined in advance to be sampling positions for sampling pressures within the air intake pipe of the internal combustion engine, and each pressure within the air intake pipe of the internal combustion engine sampled at each sampling position is stored. Every time each pressure within the air intake pipe is sampled at each sampling position, a newly sampled pressure within the air intake pipe is compared with a previous pressure within the air intake pipe sampled at the same sampling position one combustion cycle before, and whether the internal combustion engine is in an accelerating state and/or whether it is in a decelerating state is determined from the result of comparison.
In one aspect of the invention, the newly sampled pressure within the air intake pipe is compared with the previous pressure within the air intake pipe obtained by sampling at the same sampling position one combustion cycle before, and it is determined that the internal combustion engine is being accelerated when the newly sampled pressure within the air intake pipe is higher by at least a predetermined level than the previously sampled pressure within the air intake pipe and that the internal combustion engine is being decelerated when the newly sampled pressure within the air intake pipe is lower by at least a predetermined level than the previously sampled pressure within the air intake pipe.
As described above, if it is so disposed that the internal combustion engine be determined whether in an accelerating state and/or whether in a decelerating state by specifying in advance a plurality of rotational angle positions of the crankshaft of the internal combustion engine to be sampling positions for sampling the pressure within the air intake pipe of the internal combustion engine and, every time the p
Kishibata Kazuyoshi
Shimoyama Akira
Cuneo Kamand
Harrison Monica D.
Kokusan Denki Co. Ltd.
Pearne & Gordon LLP
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