Variable Cylinder Management

Abstract: A control device for a variable displacement engine, coupled with an automatic transmission, for an automobile, wherein the control device controls cylinders depending on the driving condition. The control device changes working cylinders without changing the number of working cylinders during the shift operation of the automatic transmission by detecting that the automatic transmission is going to shift. When the control device changes working cylinders without changing the number of working cylinders, the control device controls cylinders so that cylinders which are non-working before the changing work after the changing, and controls cylinders so that a non-working cylinder is not followed by another non-working cylinder in the firing order of the case of all cylinders are working. When intake air is introduced into non-working cylinders and catalytic converters are required, the catalytic converters are so arranged that gases exhausted from non-working cylinders are introduced into catalytic converters which are different from catalytic converters into which gases exhausted from working cylinders are introduced through all conditions with some of cylinders working, and the quantity of intake air introduced into each working cylinder when some of cylinders work is greater than the quantity of intake air introduced into each cylinder when all cylinders work. The control device also controls the throttle valve such that the smaller the number of working cylinders, the greater the throttle valve opening relative to the depression of the accelerator pedal.

Abstract: High vehicle fuel efficiency is achieved by reducing fuel consumption during driving both in the city and on the highway. During driving in the city, the system accumulates the energy derived from vehicle motion during braking, and uses it to assist in vehicle propulsion at a later time. The energy can be stored either in a compressed-air reservoir or in an electric battery. During cruising on the highway, the engine operates in a two-stage gas-expansion cycle. The engine has primary and secondary cylinders. Only primary cylinders operate in internal-combustion mode. After expansion in primary cylinders, combustion gas is subjected to a second stage of expansion in secondary cylinders. This substantially improves the engine efficiency. Whenever heavy engine load is needed, all cylinders operate in internal-combustion mode.

Abstract: The Accord Hybrid has been developed to offer the driving performance of a V6 midsize sedan while achieving Civic class fuel economy. The engine is based on a V6 3.0L SOHC VTEC engine, with VCM (variable cylinder management) system. The transmission is a thin 5-speed automatic transmission, modified to integrate with a hybrid system for idle stop, regeneration driving and so on. The IMA (Integrated Motor Assist) system is based on the model employed in the Civic Hybrid. During development the size of the thin DC brushless motor was increased and an IPM (Interior Permanent Magnet) rotor employed, resulting in an improvement of approximately 26% in maximum torque. Controls were developed to effectively utilize the deceleration energy regenerated by the IMA system that assist in providing expansion to the 3-cylinder operation zone, and increase the frequency of the 3-cylinder operation. Establishing these fuel economy-improving technologies has resulted in the vehicle achieving the world's best fuel economy for a V6 midsize sedan, with a value of 29 mpg in the city and 37mpg on the highway.