Controller and control method for an internal combustion engine using an engine-mounted accelerometer
First Claim
1. A control system for an internal combustion engine having a cylinder block with multiple cylinders, a piston in each cylinder and defining therewith an air/fuel combustion chamber, a crankshaft rotatably driven by the pistons, an air/fuel intake valve and a combustion gas exhaust valve for each combustion chamber;
- a rotary camshaft connected to each valve whereby the valves are activated between open and closed states, the camshaft being connected to the crankshaft with a defined speed ratio;
an accelerometer vibration sensor secured to the cylinder block whereby engine block vibrations created by combustion are sensed, the energy of the vibrations creating a vibration signal related functionally to combustion energy;
a crankshaft position sensor for the crankshaft, the crankshaft position sensor supplying a crankshaft position signal;
a camshaft position sensor for the camshaft whereby a given camshaft position corresponds to a defined intake and exhaust valve state for each cylinder;
an electronic engine controller comprising a microprocessor in electrical communication with said sensors, said microprocessor having an integrator for integrating the vibration signal and a processing unit for computing the combustion energy level and identifying the combustion chamber corresponding to the vibration signal;
said microprocessor having memory portions containing a known relationship between accelerometer vibration sensor signals and combustion energy when combustion is stable;
said processor unit of the microprocessor calculating the combustion energy as a function of sensor data from the sensors and comparing it with memory data to detect combustion instability.
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Accused Products
Abstract
A control system and method for obtaining combustion stability in an internal combustion engine including an accelerometer mounted on the engine for detecting engine block vibrations and an engine controller for processing an accelerometer output signal indicating engine block vibration intensity to measure cylinder combustion energy, the energy measurement being correlated to other combustion parameters including indicated mean effective pressure (IMEP), the controller developing a control signal that may be used in a closed loop fashion to adjust engine variables including exhaust gas recirculation, air/fuel ratio, and spark advance, thereby adjusting the engine operating characteristics to achieve optimum combustion energy.
63 Citations
8 Claims
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1. A control system for an internal combustion engine having a cylinder block with multiple cylinders, a piston in each cylinder and defining therewith an air/fuel combustion chamber, a crankshaft rotatably driven by the pistons, an air/fuel intake valve and a combustion gas exhaust valve for each combustion chamber;
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a rotary camshaft connected to each valve whereby the valves are activated between open and closed states, the camshaft being connected to the crankshaft with a defined speed ratio;
an accelerometer vibration sensor secured to the cylinder block whereby engine block vibrations created by combustion are sensed, the energy of the vibrations creating a vibration signal related functionally to combustion energy;
a crankshaft position sensor for the crankshaft, the crankshaft position sensor supplying a crankshaft position signal;
a camshaft position sensor for the camshaft whereby a given camshaft position corresponds to a defined intake and exhaust valve state for each cylinder;
an electronic engine controller comprising a microprocessor in electrical communication with said sensors, said microprocessor having an integrator for integrating the vibration signal and a processing unit for computing the combustion energy level and identifying the combustion chamber corresponding to the vibration signal;
said microprocessor having memory portions containing a known relationship between accelerometer vibration sensor signals and combustion energy when combustion is stable;
said processor unit of the microprocessor calculating the combustion energy as a function of sensor data from the sensors and comparing it with memory data to detect combustion instability. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling combustion stability in the combustion chambers of a multiple cylinder combustion engine, the engine including a cylinder block, a crankshaft and a camshaft comprising the steps of:
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measuring engine vibration energy caused by combustion;
identifying the cylinder at which combustion occurs based on instantaneous crankshaft and camshaft positions;
measuring vibration energy at the cylinder block using an accelerometer;
storing a known relationship between accelerometer readings and combustion chamber energy during a time interval when combustion is stable;
computing cylinder combustion energy in the engine cylinders as a function of cylinder pressure; and
comparing measured vibration energy with the known relationship between accelerometer readings and combustion chamber energy to detect combustion instability. - View Dependent Claims (8)
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Specification