Engine control system for construction machine
First Claim
1. An engine control system for a construction machine comprising a diesel engine, at least one variable displacement hydraulic pump rotatively driven by said engine for driving a plurality of actuators, flow rate instruction means for instructing a delivery rate of said hydraulic pump, and an electronic fuel injection device for controlling an injected fuel amount in said engine, said electronic fuel injection device including a fuel injection rate control actuator for controlling a fuel injection rate of said engine, wherein said engine control system comprises:
- first detecting means for detecting a status variable of said hydraulic pump,load calculating means for calculating a load of said hydraulic pump based on a value detected by said first detecting means, andinjection rate calculation control means for operating said fuel injection rate control actuator so that the fuel injection rate depending on the load of said hydraulic pump is resulted.
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Accused Products
Abstract
The pump controller determines pump load torques (Tr1, Tr2) from tilting signals (θ1, θ2) of hydraulic pumps and delivery pressure signals ( PD1, PD2) of the hydraulic pumps based on Tr1 =K·θ1 ·PD1 and Tr2 =K·θ2 ·PD2 (K: constant), and adds these pump load torques to provide a resulting value as an engine load torque signal (T). Using the signal (T) and an engine revolution speed signal, an engine controller determines a fuel injecting rate to control a pre-stroke actuator. Simultaneously, the engine controller calculates target injection timing not to change fuel injection start timing, thereby controlling a timer actuator. This makes it possible to control the fuel injection rate with good response and high accuracy following load fluctuation, achieve improved combustion, and hold a fuel injection period within an optimum angle range. As a result, optimum combustion is achieved and such a deterioration of exhaust gas as the generation of NOx and black smoke can be avoided.
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Citations
5 Claims
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1. An engine control system for a construction machine comprising a diesel engine, at least one variable displacement hydraulic pump rotatively driven by said engine for driving a plurality of actuators, flow rate instruction means for instructing a delivery rate of said hydraulic pump, and an electronic fuel injection device for controlling an injected fuel amount in said engine, said electronic fuel injection device including a fuel injection rate control actuator for controlling a fuel injection rate of said engine, wherein said engine control system comprises:
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first detecting means for detecting a status variable of said hydraulic pump, load calculating means for calculating a load of said hydraulic pump based on a value detected by said first detecting means, and injection rate calculation control means for operating said fuel injection rate control actuator so that the fuel injection rate depending on the load of said hydraulic pump is resulted. - View Dependent Claims (2, 3, 4)
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5. An engine control system for a construction machine comprising a diesel engine and an electronic fuel injection device for controlling an injected fuel amount in said engine, wherein said engine control system comprises:
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means for detecting a load of said engine, means for detecting a revolution speed of said engine, and fuel injection control means for making control, based on the load of said engine and the revolution speed of said engine, such that a fuel injection rate reduces as the load of said engine increases or as the revolution speed of said engine lowers, and fuel injection start timing is not essentially changed regardless of the fuel injection rate.
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Specification