Isuzu Motors Limited

Naoki Shimazaki

Terukazu Nishimura

Naoya Ishikawa

A diesel engine having: a reentrant type cavitydepressed in the top of a piston; fuel injection meansthat injects fuel towards the cavity; exhaust gas recirculation meansthat recirculates a part of the exhaust gas into a combustion chamber; and a control devicethat controls the fuel injection timing by the fuel injection meansand the EGR ratio or EGR quantity by the exhaust gas recirculation means, wherein in a predetermined operating region, the control deviceimplements premixed combustion by controlling the fuel injection timing by the fuel injection meansso that fuel injection is completed before the compression top dead center of the pistonand so that all the injected fuel enters the cavity, as well as controlling the EGR ratio or the EGR quantity by the exhaust gas recirculation meansso that the fuel injected by the fuel injection meansis ignited near the compression top dead center of the pistonafter injection of fuel is completed. In this way, favorable premixed combustion can be implemented, and favorable combustion can be ensured even when the combustion is switched to diffuse combustion.

Diesel engine

A diesel engine comprising a fuel injection device (), an EGR device (), and a control device () for controlling the fuel injection device () and EGR device () so as to realize a premixed combustion in which a mixture is ignited after the end of fuel injection, the diesel engine further comprising detection unit () for detecting the ignition timing of the mixture, wherein when the actual ignition timing detected by the detection unit () shifts from the preset optimum ignition timing, the control device () corrects the timing of fuel injection conducted by the fuel injection device () and matches the actual ignition timing with the optimum ignition timing.

A diesel engine includes a fuel injection device (), an external EGR device (), an internal EGR device (), and a control device () for controlling the fuel injection device (), external EGR device (), and internal EGR device (), wherein the control device () implements in a prescribed operation region a premixed combustion in which the fuel is injected before the vicinity of the top dead center and the EGR of a comparatively large quantity is implemented, and implements outside the prescribed operation region a normal combustion in which the fuel is injected in the vicinity of the top dead center and the EGR of a small quantity is implemented. The control device () controls the EGR ratio by using both the external EGR device () and the internal EGR device () when the premixed combustion is implemented and controls the EGR ratio by using only the external EGR device () when the normal combustion is implemented.

A combustion control device for an engine, comprises a fuel injection valve for injecting a fuel into a combustion chamber, ignition timing adjustment unit for adjusting an ignition timing of a mixture inside the combustion chamber, and control unit for controlling the fuel injection valve and the ignition timing adjustment unit. The control unit controls the fuel injection valve so as to execute at least a first injection which is conducted within the interval from an intake stroke to a compression stroke and a second injection conducted in the vicinity of a compression top dead center after the execution of the first injection, and controls the ignition timing adjustment unit so that the mixture formed by a fuel injected by the first injection and second injection and an intake air or the like is ignited after completion of the injection of the second injection.

Combustion control device and method for engine

A fuel injection control device in which fuel injected into the combustion chamber is ignited after a pre-mixing period has elapsed following the completion of the injection of the fuel, includes target pre-mixing period determining unit for determining the target pre-mixing period on the basis of the engine operating conditions, actual pre-mixing period detection unit for detecting the actual pre-mixing period, and pre-mixing period adjustment means for adjusting the pre-mixing period of the fuel so that the actual pre-mixing period approaches the target pre-mixing period. With this device, the pre-mixing period of the fuel can be appropriately controlled, and the exhaust gas can be reliably improved.

Fuel injection control device

Cleaning of exhaust gas and reduction of fuel costs are aimed at while realizing homogenious charge (or pre-mixing) compression ignition combustion and performing fuel injection in a suitable manner in all regions of engine operation. In a direct injection diesel engine there are provided an conventional injection mode in which fuel is injected with a timing (I) in the vicinity of the compression top dead center of piston () and a homogenious charge compression injection mode in which fuel is injected with a timing (II to V) which is earlier than that in the conventional injection mode, and such that fuel ignition does not occur at least until injection has been completed, fuel injection being performed by the conventional injection mode during full load operation of the engine and fuel injection being performed by the homogenious charge compression injection mode during part (low/medium) load operation of the engine. Ordinary diffusion combustion is realized when operating the engine under full load yet while receiving the benefit of amelioration of exhaust gas etc due to homogenious charge compression ignition combustion; thus, suitable fuel injection can be implemented over the entire operating range.

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Fujisawa, Japan

Naoki Shimazaki