概要
Engine Simulatorの作法を調べてみた。
githubでエンジンジェネレータ見つけた。
練習問題やってみた。
練習問題
９０度V型４気筒エンジンを作れ。
写真
サンプルコード
def generate_v4():
cylinders0 = []
cylinders1 = []
cylinders = []
for i in range(2):
cylinders0.append(i * 2)
cylinders1.append(i * 2 + 1)
cylinders += [i * 2, i * 2 + 1]
b0 = Bank(cylinders0, -45)
b1 = Bank(cylinders1, 45)
engine = Engine([b0, b1], cylinders)
engine.engine_name = "V4"
engine.starter_torque = 400
engine.crank_mass = 200
engine.generate()
engine.write_to_console()
if __name__ == "__main__":
generate_v4()
実行結果
import "engine_sim.mr"
units units()
constants constants()
impulse_response_library ir_lib()
private node wires {
output wire0: ignition_wire();
output wire1: ignition_wire();
output wire2: ignition_wire();
output wire3: ignition_wire();
}
private node generated_head {
input intake_camshaft;
input exhaust_camshaft;
input chamber_volume: 300 * units.cc;
input intake_runner_volume: 149.6 * units.cc;
input intake_runner_cross_section_area: 1.75 * units.inch * 1.75 * units.inch;
input exhaust_runner_volume: 50.0 * units.cc;
input exhaust_runner_cross_section_area: 1.75 * units.inch * 1.75 * units.inch;
input flow_attenuation: 1.0;
input lift_scale: 1.0;
input flip_display: false;
alias output __out: head;
function intake_flow(50 * units.thou)
intake_flow
.add_flow_sample(0 * lift_scale, 0 * flow_attenuation)
.add_flow_sample(50 * lift_scale, 58 * flow_attenuation)
.add_flow_sample(100 * lift_scale, 103 * flow_attenuation)
.add_flow_sample(150 * lift_scale, 156 * flow_attenuation)
.add_flow_sample(200 * lift_scale, 214 * flow_attenuation)
.add_flow_sample(250 * lift_scale, 249 * flow_attenuation)
.add_flow_sample(300 * lift_scale, 268 * flow_attenuation)
.add_flow_sample(350 * lift_scale, 280 * flow_attenuation)
.add_flow_sample(400 * lift_scale, 280 * flow_attenuation)
.add_flow_sample(450 * lift_scale, 281 * flow_attenuation)
function exhaust_flow(50 * units.thou)
exhaust_flow
.add_flow_sample(0 * lift_scale, 0 * flow_attenuation)
.add_flow_sample(50 * lift_scale, 37 * flow_attenuation)
.add_flow_sample(100 * lift_scale, 72 * flow_attenuation)
.add_flow_sample(150 * lift_scale, 113 * flow_attenuation)
.add_flow_sample(200 * lift_scale, 160 * flow_attenuation)
.add_flow_sample(250 * lift_scale, 196 * flow_attenuation)
.add_flow_sample(300 * lift_scale, 222 * flow_attenuation)
.add_flow_sample(350 * lift_scale, 235 * flow_attenuation)
.add_flow_sample(400 * lift_scale, 245 * flow_attenuation)
.add_flow_sample(450 * lift_scale, 246 * flow_attenuation)
generic_cylinder_head head(
chamber_volume: chamber_volume,
intake_runner_volume: intake_runner_volume,
intake_runner_cross_section_area: intake_runner_cross_section_area,
exhaust_runner_volume: exhaust_runner_volume,
exhaust_runner_cross_section_area: exhaust_runner_cross_section_area,
intake_port_flow: intake_flow,
exhaust_port_flow: exhaust_flow,
valvetrain: standard_valvetrain(
intake_camshaft: intake_camshaft,
exhaust_camshaft: exhaust_camshaft
),
flip_display: flip_display
)
}
private node generated_camshaft {
input lobe_profile;
input intake_lobe_profile: lobe_profile;
input exhaust_lobe_profile: lobe_profile;
input lobe_separation: 114 * units.deg;
input intake_lobe_center: lobe_separation;
input exhaust_lobe_center: lobe_separation;
input advance: 0 * units.deg;
input base_radius: 0.5 * units.inch;
output intake_cam_0: _intake_cam_0;
output exhaust_cam_0: _exhaust_cam_0;
output intake_cam_1: _intake_cam_1;
output exhaust_cam_1: _exhaust_cam_1;
camshaft_parameters params (
advance: advance,
base_radius: base_radius
)
camshaft _intake_cam_0(params, lobe_profile: intake_lobe_profile)
camshaft _exhaust_cam_0(params, lobe_profile: exhaust_lobe_profile)
camshaft _intake_cam_1(params, lobe_profile: intake_lobe_profile)
camshaft _exhaust_cam_1(params, lobe_profile: exhaust_lobe_profile)
label rot360(360 * units.deg)
_exhaust_cam_0
.add_lobe(rot360 - exhaust_lobe_center + 0.0 * units.deg)
.add_lobe(rot360 - exhaust_lobe_center + 360.0 * units.deg)
_intake_cam_0
.add_lobe(rot360 + exhaust_lobe_center + 0.0 * units.deg)
.add_lobe(rot360 + exhaust_lobe_center + 360.0 * units.deg)
_exhaust_cam_1
.add_lobe(rot360 - exhaust_lobe_center + 180.0 * units.deg)
.add_lobe(rot360 - exhaust_lobe_center + 540.0 * units.deg)
_intake_cam_1
.add_lobe(rot360 + exhaust_lobe_center + 180.0 * units.deg)
.add_lobe(rot360 + exhaust_lobe_center + 540.0 * units.deg)
}
public node generated_engine {
alias output __out: engine;
engine engine(
name: "V4",
starter_torque: 400 * units.lb_ft,
starter_speed: 500 * units.rpm,
redline: 8000 * units.rpm,
throttle_gamma: 2.0,
fuel: fuel(
molecular_mass: 100 * units.g,
energy_density: 48.1 * units.kJ / units.g,
density: 0.755 * units.kg / units.L,
molecular_afr: 12.5,
max_burning_efficiency: 0.8,
burning_efficiency_randomness: 0.5,
low_efficiency_attenuation: 0.6,
max_turbulence_effect: 2,
max_dilution_effect: 10
),
hf_gain: 0.01,
noise: 1.0,
jitter: 0.1,
simulation_frequency: 10000
)
wires wires()
label stroke(86 * units.mm)
label bore(86 * units.mm)
label rod_length(120 * units.mm)
label rod_mass(50 * units.g)
label compression_height(25.4 * units.mm)
label crank_mass(200 * units.kg)
label flywheel_mass(10 * units.kg)
label flywheel_radius(100 * units.mm)
label crank_moment(
disk_moment_of_inertia(mass: crank_mass, radius: stroke)
)
label flywheel_moment(
disk_moment_of_inertia(mass: flywheel_mass, radius: flywheel_radius)
)
label other_moment( // Moment from cams, pulleys, etc [estimated]
disk_moment_of_inertia(mass: 1 * units.kg, radius: 1.0 * units.cm)
)
crankshaft c0(
throw: stroke / 2,
flywheel_mass: flywheel_mass,
mass: crank_mass,
friction_torque: 1.0 * units.lb_ft,
moment_of_inertia:
crank_moment + flywheel_moment + other_moment,
position_x: 0.0,
position_y: 0.0,
tdc: 45 * units.deg
)
rod_journal rj0(angle: 0 * units.deg)
rod_journal rj1(angle: 270.0 * units.deg)
rod_journal rj2(angle: 360.0 * units.deg)
rod_journal rj3(angle: 630.0 * units.deg)
c0
.add_rod_journal(rj0)
.add_rod_journal(rj1)
.add_rod_journal(rj2)
.add_rod_journal(rj3)
piston_parameters piston_params(
mass: (50) * units.g, // 414 - piston mass, 152 - pin weight
compression_height: compression_height,
wrist_pin_position: 0.0,
displacement: 0.0
)
connecting_rod_parameters cr_params(
mass: rod_mass,
moment_of_inertia: rod_moment_of_inertia(
mass: rod_mass,
length: rod_length
),
center_of_mass: 0.0,
length: rod_length
)
intake intake(
plenum_volume: 1.325 * units.L,
plenum_cross_section_area: 20.0 * units.cm2,
intake_flow_rate: k_carb(3000),
runner_flow_rate: k_carb(400),
runner_length: 16 * units.inch,
idle_flow_rate: k_carb(0),
idle_throttle_plate_position: 0.999,
velocity_decay: 0.5
)
exhaust_system_parameters es_params(
outlet_flow_rate: k_carb(2000.0),
primary_tube_length: 20.0 * units.inch,
primary_flow_rate: k_carb(200.0),
velocity_decay: 0.5
)
exhaust_system exhaust0(
es_params,
audio_volume: 1.0 * 0.004,
length: 20 * units.inch,
impulse_response: ir_lib.minimal_muffling_01
)
exhaust_system exhaust1(
es_params,
audio_volume: 1.0 * 0.004,
length: 20 * units.inch,
impulse_response: ir_lib.minimal_muffling_01
)
cylinder_bank_parameters bank_params(
bore: bore,
deck_height: stroke / 2 + rod_length + compression_height
)
label spacing(0.0)
cylinder_bank b0(bank_params, angle: -45 * units.deg)
cylinder_bank b1(bank_params, angle: 45 * units.deg)
b0
.add_cylinder(
piston: piston(piston_params, blowby: k_28inH2O(0.0)),
connecting_rod: connecting_rod(cr_params),
rod_journal: rj0,
intake: intake,
exhaust_system: exhaust0,
ignition_wire: wires.wire0,
sound_attenuation: 0.6587159145903814,
primary_length: 0 * spacing * 0.5 * units.cm
)
.add_cylinder(
piston: piston(piston_params, blowby: k_28inH2O(0.0)),
connecting_rod: connecting_rod(cr_params),
rod_journal: rj2,
intake: intake,
exhaust_system: exhaust0,
ignition_wire: wires.wire2,
sound_attenuation: 0.9289523204327862,
primary_length: 1 * spacing * 0.5 * units.cm
)
.set_cylinder_head(
generated_head(
intake_camshaft: camshaft.intake_cam_0,
exhaust_camshaft: camshaft.exhaust_cam_0,
flip_display: false,
flow_attenuation: 1.0)
)
b1
.add_cylinder(
piston: piston(piston_params, blowby: k_28inH2O(0.0)),
connecting_rod: connecting_rod(cr_params),
rod_journal: rj1,
intake: intake,
exhaust_system: exhaust1,
ignition_wire: wires.wire1,
sound_attenuation: 0.9559828716777936,
primary_length: 0 * spacing * 0.5 * units.cm
)
.add_cylinder(
piston: piston(piston_params, blowby: k_28inH2O(0.0)),
connecting_rod: connecting_rod(cr_params),
rod_journal: rj3,
intake: intake,
exhaust_system: exhaust1,
ignition_wire: wires.wire3,
sound_attenuation: 0.6603449645782972,
primary_length: 1 * spacing * 0.5 * units.cm
)
.set_cylinder_head(
generated_head(
intake_camshaft: camshaft.intake_cam_1,
exhaust_camshaft: camshaft.exhaust_cam_1,
flip_display: false,
flow_attenuation: 1.0)
)
engine
.add_cylinder_bank(b0)
.add_cylinder_bank(b1)
engine.add_crankshaft(c0)
harmonic_cam_lobe intake_lobe(
duration_at_50_thou: 234 * units.deg,
gamma: 1.1,
lift: 551 * units.thou,
steps: 512
)
harmonic_cam_lobe exhaust_lobe(
duration_at_50_thou: 235 * units.deg,
gamma: 1.1,
lift: 551 * units.thou,
steps: 512
)
generated_camshaft camshaft(
lobe_profile: "N/A",
intake_lobe_profile: intake_lobe,
exhaust_lobe_profile: exhaust_lobe,
intake_lobe_center: 90 * units.deg,
exhaust_lobe_center: 112 * units.deg
)
function timing_curve(1000 * units.rpm)
timing_curve
.add_sample(0 * units.rpm, 18 * units.deg)
.add_sample(1000 * units.rpm, 40 * units.deg)
.add_sample(2000 * units.rpm, 40 * units.deg)
.add_sample(3000 * units.rpm, 40 * units.deg)
.add_sample(4000 * units.rpm, 40 * units.deg)
.add_sample(5000 * units.rpm, 40 * units.deg)
.add_sample(6000 * units.rpm, 40 * units.deg)
.add_sample(7000 * units.rpm, 40 * units.deg)
.add_sample(8000 * units.rpm, 40 * units.deg)
.add_sample(9000 * units.rpm, 40 * units.deg)
ignition_module ignition_module(
timing_curve: timing_curve,
rev_limit: 9000 * units.rpm,
limiter_duration: 0.1)
ignition_module
.connect_wire(wires.wire0, 0.0 * units.deg)
.connect_wire(wires.wire1, 180.0 * units.deg)
.connect_wire(wires.wire2, 360.0 * units.deg)
.connect_wire(wires.wire3, 540.0 * units.deg)
engine.add_ignition_module(ignition_module)
}
private node generated_vehicle {
alias output __out:
vehicle(
mass: 798 * units.kg,
drag_coefficient: 0.9,
cross_sectional_area: (72 * units.inch) * (36 * units.inch),
diff_ratio: 4.1,
tire_radius: 9 * units.inch,
rolling_resistance: 200 * units.N
);
}
private node generated_transmission {
alias output __out:
transmission(
max_clutch_torque: 1000 * units.lb_ft
)
.add_gear(2.8)
.add_gear(2.29)
.add_gear(1.93)
.add_gear(1.583)
.add_gear(1.375)
.add_gear(1.19);
}
public node main {
run(
engine: generated_engine(),
vehicle: generated_vehicle(),
transmission: generated_transmission()
)
}
main()
成果物
以上。