Four-Cylinder Engine Unequal Explosion Interval Torque Control
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Solution Overview
Problem
A four-cylinder engine with unequal explosion intervals (270°, 180°, 90°, and 180° crank angles) causes discomfort to vehicle occupants due to non-uniform driving energy delivery, leading to irregular torque changes and misunderstood torque magnitudes at low engine speeds.
Innovation Solution
The engine incorporates a discomfort eliminator that adjusts the indicated mean effective pressure of cylinders with a 90° explosion interval to be lower than those with other intervals, using ignition timing retardation and intake air volume control to ensure uniform driving energy delivery, mimicking the experience of a three-cylinder engine with equal intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a two-plane-type crankshaft with unequal explosion intervals (270°, 180°, 90°, 180°) is used, then the inertial torque is removed and the accelerator operation matches the vehicle body behavior, but the driving energy per unit time becomes non-uniform causing occupant discomfort at low engine speeds
Solution Approach 1:
The patent applies parameter changes by adjusting the ignition timing of specific cylinders (second and fourth cylinders) to retard the explosion timing. This changes the temporal parameters of energy delivery, smoothing out the torque fluctuations that cause discomfort while preserving the beneficial unequal explosion interval configuration.
Solution Approach 2:
The patent introduces dynamic control mechanisms including variable ignition timing adjustment and intake air volume control that can adaptively modify the explosion characteristics. These dynamic parameters allow the system to optimize performance across different operating conditions, particularly at low engine speeds where discomfort is most noticeable.
2Productivity
If explosions occur in two cylinders with a 90° explosion interval in succession, then torque rises twice within a short time, but the driving energy becomes non-uniform and creates the sensation of irregular torque change
Solution Approach 1:
The patent changes the timing parameters of explosions in the second and fourth cylinders by retarding ignition timing. This parameter adjustment spreads out the energy delivery more evenly across the rotation cycle, transforming the non-uniform driving energy pattern into a more uniform one while maintaining high torque generation capability.
Solution Approach 2:
The patent applies preliminary action by controlling the intake air volume to the second and fourth cylinders before the explosion occurs. By managing the air-fuel mixture preparation in advance, the system can control the magnitude and timing of torque generation to achieve uniform energy delivery while maintaining productivity.
3Stability of the object's composition
If the indicated mean effective pressure of cylinders with 90° explosion interval is reduced, then uniform driving energy delivery is achieved, but the torque magnitude in those cylinders decreases
Solution Approach 1:
The patent applies preliminary action by controlling the intake air volume to the second and fourth cylinders before the explosion occurs. By managing the air-fuel mixture preparation in advance, the system can control the magnitude and timing of torque generation to achieve uniform energy delivery while maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly reduces the sensation of discomfort by ensuring uniform torque fluctuations and energy delivery, even at low engine speeds, while maintaining fuel efficiency and avoiding increased costs.
Implementation Method 1
spark plugs attached to the cylinder head for the respective cylinder holes, an ignition device including the spark plugs
Implementation Method 2
explosion intervals of four cylinders defined by the four cylinder holes are 270°, 180°, 90°, and 180° as crank angles
Data Source
AI summary
An engine includes a cylinder body, a cylinder head, and an ignition device including spark plugs. The engine also includes an intake device connected to intake ports, an exhaust device connected to exhaust ports, pistons, and a crankshaft connected to the pistons by connecting rods. Explosion intervals of the cylinders are 270°, 180°, 90°, and 180° as crank angles. The engine further includes a discomfort eliminator which, when the engine speed is lower than a predetermined value, makes the indicated mean effective pressure of at least one of two cylinders having an explosion interval of 90° lower than the indicated mean effective pressures of the other cylinders having an explosion interval of not 90°. The engine causes unequal-interval explosions but produces little change in the driving energy per unit time during an operating state in which an occupant is liable to feel torque fluctuations.