Refine Your Search

Search Results

Viewing 1 to 4 of 4
Journal Article

Effects of Hydrotreated Vegetable Oil (HVO) as Renewable Diesel Fuel on Combustion and Exhaust Emissions in Diesel Engine

The effects of Hydrotreated vegetable oil (HVO) on combustion and emission characteristics in a diesel engine were investigated by using spray analyzer, engine dynamometer and vehicle tests. Spray analysis showed that spray characteristics was virtually the same for HVO and diesel. From the results of the engine dynamometer and the vehicle tests, it was found that the high cetane number and the zero aromatics of HVO could reduce in HC and PM emissions. Moreover, as a result of optimized engine calcification, HVO is capable of improving partial fuel consumption and full-load torque. These results indicate that HVO has beneficial fuel characteristics for diesel engine.
Technical Paper

Spark Plug Fouling: Behavior and Countermeasure

The higher compression ratio engines, two-stroke engines and flexible fuel vehicles currently under development tend to face the problems of spark plug fouling owing to the necessity of using cold type spark plugs. This paper analyzes the sparking of fouled spark plugs and investigates the characteristics required of an ignition system in order to avoid fouling problems. The results clearly establish that to maintain a strong spark even when the plug is fouled, a high voltage should be instantaneously applied to the spark plug. A series-gap on the high-tension side was confirmed to be an effective means of achieving this and a new plug cap provided with a series-gap has resolved fouling problems such as failure to start. Lately, fuel economy and long-term energy conservation have become critically important. For automobiles, higher compression ratio engines, two-stroke engines and flexible fuel vehicles (FFVs) are being developed.
Technical Paper

Development of Anti-Plug Fouling Ignition System

The new generation engines currently being developed tend to require cold type spark plugs, which are prone to fouling. This paper describes the development of a new Coil on Plug ignition system that resolves this problem by using the high energy and the fast secondary voltage rise time of a capacitive ignition while maintaining inductive ignition characteristics for good ignitability. To evaluate the effectiveness of the system, spark plug insulation resistance was monitored and cold tests were conducted. The results demonstrated that the new ignition system is remarkably effective: insulation resistance remains high and startability and driveability are unaffected under conditions normally leading to excessive misfires and failure to start with a conventional inductive system. To satisfy environmental concerns, automobile manufactures are increasingly turning to high compression ratio engines in view of their improved performance.
Technical Paper

Detection of Higher Frequency Vibration to improve Knock Controllability

For a Knock Control System (KCS) with a vibration sensor mounted on the engine block, means of improving the ratio of knock signal to engine vibration noise are discussed. From analyses of cylinder pressure and engine block vibration spectrums, it is shown that noise is lower in the second knock resonance frequency. The development of a resonance type knock sensor detecting this higher frequency is described. A new KCS utilizing this sensor is evaluated and found to improve knock controllability, especially in engines with a high compression ratio or supercharging.