Alternating Cylinder Deactivation for Fuel Efficiency
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Solution Overview
Problem
Three- and five-cylinder internal combustion engines face challenges in reducing part-load consumption due to uneven ignition intervals and efficiency losses associated with cylinder deactivation methods that involve trapping exhaust gas or fresh air in deactivated cylinders, leading to increased fuel consumption.
Innovation Solution
The method involves deactivating and reactivating the intake valves of deactivated cylinders at the beginning of their intake stroke, operating them in a largely empty state with a vacuum, and using electrohydraulic valve trains for precise control, allowing for internal exhaust gas recirculation and adjustable residual gas management to minimize wall heat and blow-by losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If exhaust gas or fresh air is trapped in deactivated cylinders, then cylinder deactivation is achieved, but wall heat and blow-by losses increase leading to higher fuel consumption
Solution Approach 1:
The patent extracts the harmful trapped gases (exhaust gas or fresh air) from the deactivated cylinders by introducing a blow-by valve that actively removes these gases. This prevents the compression and expansion cycles that cause wall heat and blow-by losses, directly resolving the contradiction by eliminating the source of energy losses while maintaining cylinder deactivation functionality.
Solution Approach 2:
The patent changes the pressure parameter inside deactivated cylinders by connecting them to the intake manifold through the blow-by valve. This maintains near-atmospheric pressure in deactivated cylinders rather than subjecting trapped gases to compression and expansion cycles, thereby minimizing wall heat losses and blow-by losses while enabling efficient cylinder deactivation.
2Productivity
If cylinder deactivation is implemented in three- or five-cylinder engines, then fuel efficiency improves, but uneven ignition intervals cause rough running
Solution Approach 1:
The patent implements alternating deactivation of cylinders in a periodic pattern, switching between different combinations of active and deactivated cylinders. For example, in a three-cylinder engine, it alternates between deactivating cylinder 1 then cylinder 2, maintaining regular ignition intervals. This periodic reconfiguration ensures smooth engine operation while preserving fuel efficiency benefits.
3Device complexity
If gas exchange valves remain closed during deactivation, then valve actuation is deactivated, but cylinder pressure control becomes challenging
Solution Approach 1:
The patent introduces a blow-by valve as an intermediary component that connects deactivated cylinders to the intake manifold. This intermediate valve provides pressure control and gas removal functionality without requiring complex multi-valve mechanisms, simplifying the overall valve actuation system while maintaining ease of cylinder pressure control during deactivation.
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 approach significantly reduces fuel consumption by minimizing efficiency-reducing losses, achieving a greater fuel savings potential compared to traditional methods, while maintaining engine smoothness and extending component lifespan.
Implementation Method 1
operating them in a largely empty state with a vacuum
Implementation Method 2
the deactivated cylinder is filled with fresh air or exhaust gas and this filling is first compressed and then expanded
Implementation Method 3
wall heat and blow-by losses, which are otherwise associated with the compression and expansion of exhaust gas or fresh air
Data Source
Figure 1~4
Figure 5~6
AI summary
The invention relates to a method for the alternating cylinder shutdown of a three-cylinder or five-cylinder internal combustion engine during partial load operation, in which the opening of the gas exchange valves of the shut-down cylinders is deactivated. The valve deactivation of the shut-down cylinders is intended to begin and end with the deactivation and the subsequent reactivation of the inlet valves of said cylinders, in each case at the start of the regular intake cycle of said cylinders.