Methods and systems are provided for a multi-fuel engine. In one example, a method includes adjusting a substitution ratio based on an intake manifold temperature. The method further including adjusting the intake manifold temperature to increase the substitution ratio.

An engine device (21) including: an intake manifold (67) configured to supply air into a cylinder (77), an exhaust manifold (44) configured to output exhaust gas from the cylinder; a gas injector (98) which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve (79) configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to another between a gas mode and a diesel mode, a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, and then is controlled by a speed-governing control based on the engine rotation number. The switching threshold value is set based on the engine rotation number or the engine load.

An engine (21) including a main fuel injection valve (79), a pilot fuel injection valve (82), a liquid fuel supply rail pipe (42), and a pilot fuel supply rail pipe (47). The main fuel injection valve (79) supplies liquid fuel from the liquid fuel supply rail pipe (42) to a combustion chamber (110) during combustion in a diffusion combustion system. The pilot fuel injection valve (82) supplies pilot fuel from the pilot fuel supply rail pipe (47) to the combustion chamber (110) in order to ignite gaseous fuel during combustion in a premixed combustion system. The liquid fuel supply rail pipe (42) is disposed at one side of an imaginary vertical plane (P1) including an axis of a crank shaft. The pilot fuel supply rail pipe (47) is disposed at the side of the imaginary vertical plane (P1) at which the liquid fuel supply rail pipe (42) is disposed.

In previous control systems for engines that fuelled with a conventional fuel and an alternative fuel, a conventional fuel controller controlled fuelling for both fuels. This required extensive modifications to both the conventional fuel controller and an alternative fuel controller. A control system for an engine comprises a first control unit programmed to generate a first pulse width to actuate a first fuel injector to introduce a first fuel; a second control unit programmed to generate a second pulse width to actuate a second fuel injector to introduce a second fuel; and a communication line between the first and second control units. The first control unit determines a total fuel energy amount to be introduced by the first and second fuel injectors. The second control unit determines a first fraction of the total fuel energy amount to be from the first fuel and a second fraction of the total fuel energy amount to be from the second fuel.

A dual-chamber electrolysis vessel safely stores HHO gas for use by an internal combustion engine.

Safety of vehicles employing an electrolysis generator is improved by a rollover abatement system.

HHO gas is introduced to a diesel particulate filter to improve combustion of a fuel to aid in regeneration.

A dual-chamber onboard electrolysis system is configured to produce HHO gas for heavy duty trucking applications.

An HHO gas stream for use in an internal combustion engine is heated by heat exchange from with an exhaust gas stream from the internal combustion engine.

Timing of HHO gas injection into a 4-stroke engine is optimized based on engine operating parameters to improve fuel economy.