Split cycle engine
A split cycle internal combustion engine comprising a compression cylinder accommodating a compression piston; a combustion cylinder accommodating a combustion piston; a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder; a controller arranged to determine a peak temperature of combustion in the combustion cylinder based on a received indication of a peak temperature of combustion in the combustion cylinder; and a coolant system arranged to regulate a temperature of the working fluid supplied to the combustion cylinder; wherein, in response to determining that the peak temperature of combustion exceeds a selected threshold, the controller is configured to control the coolant system to regulate the temperature of the working fluid supplied to the combustion cylinder so that a peak temperature of combustion in the combustion cylinder is less than the selected threshold.
1 . A split cycle internal combustion engine comprising:
a compression cylinder accommodating a compression piston;
a combustion cylinder accommodating a combustion piston;
a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder;
a reactivity adjuster operable to adjust the reactivity of a fuel to be used during a combustion process; and
a controller arranged to receive an indication of at least one of: (i) a pressure of the working fluid, (ii) a temperature of the working fluid, (iii) NOx generation from combustion, and (iv) an extent of engine knocking in the combustion cylinder;
wherein the controller is configured to operate the reactivity adjuster to adjust the reactivity of the fuel based on the received indication.
2 . The split cycle internal combustion engine of claim 1 , wherein the controller is configured to determine an ignition parameter associated with the fuel based on the received indication.
3 . The split cycle internal combustion engine of claim 2 , wherein adjusting the reactivity of the fuel comprises: in response to determining that the ignition parameter is below an ignition threshold, operating the reactivity adjuster to increase the reactivity of the fuel.
4 . The split cycle internal combustion engine of claim 2 , wherein adjusting the reactivity of the fuel comprises: in response to determining that the ignition parameter is greater than an over-reactivity threshold, operating the reactivity adjuster to decrease the reactivity of the fuel.
5 . The split cycle internal combustion engine of claim 2 , wherein the ignition parameter comprises an indication of the ability of the fuel to ignite in the combustion cylinder.
6 . The split cycle internal combustion engine of claim 2 , wherein the ignition parameter is determined based on the fuel to be used for combustion.
7 . The split cycle internal combustion engine of claim 2 , wherein the ignition parameter comprises an indication of at least one of: (i) whether or not the fuel will ignite in the combustion cylinder, and (ii) a proportion of the fuel expected to ignite in the combustion cylinder.
8 . The split cycle internal combustion engine of claim 2 , wherein the reactivity adjuster is operable to increase the ability of the fuel to ignite.
9 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster is operable to adjust at least one chemical or physical property of the fuel and/or the working fluid supplied to the combustion cylinder to increase the ability of the fuel to ignite.
10 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster is operable to direct electromagnetic radiation towards the fuel to provide a source of ignition for the fuel.
11 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster is operable to inject an oxidising agent into the combustion cylinder to increase the ability of the fuel to ignite.
12 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster is operable to provide a stratified ignition process configured to increase the ability of the fuel to ignite.
13 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster provides a source of at least one of: free radicals and ozone to increase the ability of the fuel to ignite.
14 . The split cycle internal combustion engine of claim 1 , wherein the engine is a recuperated split cycle internal combustion engine having a recuperator arranged to heat compressed working fluid as the compressed working fluid flows from the compression cylinder to the combustion cylinder through the crossover passage.
15 . The split cycle internal combustion engine of claim 14 , wherein the recuperator is arranged to recover heat from fluid exhausted from the combustion cylinder and to use the recovered heat to heat the compressed working fluid as the compressed working fluid flows from the compression cylinder to the combustion cylinder through the crossover passage.
16 . The split cycle internal combustion engine of claim 1 , wherein the engine comprises a fuel reservoir and the reactivity adjuster is operable to adjust the reactivity of fuel in the fuel reservoir.
17 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster is operable to adjust the reactivity of fuel in the combustion cylinder.
18 . The split cycle internal combustion engine of claim 1 , wherein the reactivity adjuster comprises a system for selective energy transfer.
19 . A method of controlling a split cycle internal combustion engine comprising:
a compression cylinder accommodating a compression piston;
a combustion cylinder accommodating a combustion piston;
a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder; and
a reactivity adjuster operable to adjust the reactivity of a fuel to be used during the combustion process;
wherein the method comprises:
receiving an indication of at least one of: (i) a pressure of the working fluid, (ii) a temperature of the working fluid, (iii) NOx generation from combustion, and (iv) an extent of engine knocking in the combustion cylinder; and
operating the reactivity adjuster to increase the reactivity of the fuel based on the received indication.
20 . A non-transitory computer-readable storage medium storing instructions executable by one or more processors for performing the method of claim 19 .